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With every smartphone brand applying the 18:9 and wider aspect ratio screens to its newer models, the rate of adoption is expected to quicken in the second half of 2018. Smartphones using 18:9 and wider aspect screens are forecast to increase to 66 percent of total smartphone shipments in the third quarter of 2018, soaring up from 10 percent in the same period last year, according to business information provider IHS Markit (Nasdaq: INFO).

After Samsung Electronics and Apple released their phones last year with new wider aspect ratios of 18.5:9 and 19.5:9, respectively, most smartphone brands have similarly followed suit by applying wider aspect screens to their 2018 lineup to keep up with product differentiation.

Improvements in display technologies have hastened the expansion of the wider screen adoption in smartphones. Initially, flexible active-matrix organic light-emitting diode (AMOLED) technology was required to realize a full-screen display, and thus, 18:9 or wider screens were expected predominantly to be used in premium and high-end smartphones in 2018. However, with rapidly improving designs in liquid crystal display (LCD) cell structure, thin-film transistor (TFT) array and light-emitting diode (LED) backlight, TFT LCD can now be used in full-screen smartphones.

“With the improvement in TFT LCD technology, smartphone makers are now aggressively applying 18:9 aspect ratio of TFT LCD to their 2018 models even for mid-end and entry-level smartphones, instead of using high-priced flexible AMOLED panels,” said Hiroshi Hayase, senior director at IHS Markit.

“It would be correct to assume that smartphone displays are undergoing a quick generation change to TFT LCD-based full screens later this year,” Hayase said. “The new generation of smartphones will be expected to stimulate replacement demand in the 2019 smartphone market.”

Despite concerns about TV demand and falling profit margins, major South Korean and Chinese TV makers are expected to stock up on display panels in the third quarter to prepare for the seasonal year-end shopping spree by consumers. Already carrying inventories from prior stocking, these TV makers will have factored in the risk of a correction in panel demand in the fourth quarter, according to IHS Markit (Nasdaq: INFO), a world leader in critical information, analytics and solutions.

According to the latest TV Display & OEM Intelligence Service by IHS Markit, South Korean TV brands’ panel purchasing volume is forecast to increase to 20.4 million units in the third quarter of 2018, up 18 percent from the previous quarter or up 3 percent from a year ago. This is indicative of a recovery in panel purchasing from a decline of 3 percent in the second quarter on a quarter-to-quarter basis and down 1 percent year-over-year.

China’s top five TV brands, which bought more panels than expected in the first quarter, again increased their panel purchasing in the second quarter to meet their sales target by 0.4 percent quarter-on-quarter or 18 percent year-on-year to 19.8 million units. In the third quarter, these Chinese brands are likely to keep their purchasing volumes at a similar growth level of 1 percent quarter-on-quarter or 17 percent year-on-year.

“Although the panel demand outlook from South Korean and Chinese TV makers for the third quarter looks positive, the TV brands are still anxious about uncertainty in market demand in the second half of the year while carrying high inventories,” said Deborah Yang, director of display supply chain at IHS Markit. “The TV demand in Europe has particularly been weaker than expected, and the depreciation of local currencies in the emerging markets against the US Dollar has led to a higher price tag in local currencies.”

Another concern is the eroding profit margins caused by fast-falling average selling prices of TV sets. “As TV makers, particularly the Chinese brands, keep high inventories on hand, they end up cutting TV prices to manage their inventories, leading to lower margins – even for larger and premium TVs,” Yang said. “If their inventory clearance strategies and upcoming seasonal demand fall short of the expectations, these TV brands will eventually have to cut panel purchasing later in the year to lower the inventory burden.”

The Semiconductor Industry Association (SIA), representing U.S. leadership in semiconductor manufacturing, design, and research, today announced worldwide sales of semiconductors reached $38.7 billion for the month of May 2018, an increase of 21.0 percent compared to the May 2017 total of $32.0 billion. Global sales in May were 3 percent higher than the April 2018 total of $37.6 billion. All monthly sales numbers are compiled by the World Semiconductor Trade Statistics (WSTS) organization and represent a three-month moving average.

“The global semiconductor market has posted consistent growth of greater than 20 percent for 14 consecutive months, and May 2018 marked the industry’s highest-ever monthly sales,” said John Neuffer, president and CEO, Semiconductor Industry Association. “The Americas led the way once again, with sales increasing by more than 30 percent compared to last year, and sales were up across all major semiconductor product categories on both a year-to-year and month-to-month basis.”

Year-to-year sales increased solidly across all regions: the Americas (31.6 percent), China (28.5 percent), Europe (18.7 percent), Japan (14.7 percent), and Asia Pacific/All Other (8.7 percent). Month-to-month sales increased more modestly across all regions: China (6.3 percent), Japan (2.6 percent), Asia Pacific/All Other (1.2 percent), the Americas (1.1 percent), and Europe (1.0 percent).

Despite better-than-expected first-quarter demand for thin-film transistor liquid-crystal display (TFT-LCD) TV sets and TV panels, market players would be well advised to adopt a more conservative outlook in demand growth for the coming quarters, according to IHS Markit (Nasdaq: INFO), a world leader in critical information, analytics and solutions.

Earlier market expectations assumed that demand would slow in the first quarter prompted by the observation that TV set makers would put a hold on panel purchases based on hopes that panel prices would drop further. Such a view was largely attributed by the development of Chinese panel makers planning aggressive investments over the next two to three years.

As it turned out, panel makers managed to sell more panels than originally forecasted in the first quarter because panel prices declined much faster than expected. According to IHS Markit, TV panel unit shipments increased by 13.3 percent in the first quarter compared to a year ago, while TV set shipments rose 7.9 percent during the same period.

“LCD TV panel shipments are expected to grow faster than the LCD TV set shipments, expanding the accumulated gap between the two even further,” said Ricky Park, director of display research at IHS Markit.

According to the latest Display long term demand forecast tracker by IHS Markit, the accumulated gap between LCD TV panel and set shipments in the second and third quarters of 2018 is expected to be higher than past 10 years, reaching 8.3 percent and 8.4 percent, respectively, from 7.9 percent in the first quarter. Furthermore, the gap is expected to remain high until 2019.

“The main reason for the higher gap is the aggressive investment in 10.5 generation fabs. TFT LCD capacity, in terms of area, will soar in the next four years,” Park said. “As capacity is expected to increase more than demand, panel suppliers will likely push to sell panels at lower prices while set makers are to hesitate buying panels expecting the price to drop even further.”

However, when the accumulated gap in panel-set shipments is high, an inventory correction should always follow. “TV makers should narrow the gap for healthy inventory control and reducing panel orders is a step in that direction,” Park said. “If TV set makers’ panel purchasing drops, it will likely cause a cash flow issue to panel suppliers, and they would need to reduce the utilization rate to control the supply.”

The global demand for automotive display systems is expected to continue a strong growth path in 2018, according to recent analysis from business information provider IHS Markit (Nasdaq: INFO).

According to the latest Automotive Display Systems Forecasts , OEM production of the three primary automotive display systems — instrument cluster, center stack and head-up display systems — is expected to reach 118.5 million units globally by the end of 2018, representing a 9 percent growth in volume over 2017. While the volume is growing significantly, the value of the market is growing even faster. In 2018, IHS Markit estimates just these three display systems to bring in $13.5 billion in tier-one supplier revenue, representing a 17 percent growth over 2017.

“In the quest for differentiation, automakers are using displays to transform vehicle interiors into a futuristic digital user experience with more pixels in front of consumers than ever before,” said Brian Rhodes, automotive user experience analyst at IHS Markit. “While high resolution, large displays previously were reserved for luxury applications only, declining average selling prices and increasing consumer demand and production volumes are enabling mass-market car brands to standardize displays that were optional only a few years ago.”

Demand for more displays in automotive applications is strong, but a major enabler to this growth comes from the supply chain. Large global display panel manufacturers in Asia have recently invested heavily in automotive display panel production in order to continue sales growth as display markets in other areas have slowed, such as smartphones and tablet PCs.

According to the latest Automotive Display Market Tracker by IHS Markit, global shipments of automotive display panels are set to increase by 11 percent reaching 164 million units in 2018, following an equally strong 9 percent growth in 2017, which had reached 148 million units.

These two IHS Markit forecasts are fundamentally linked, but also differ in that the shipment forecasts include additional volumes, applications and factors that the current OEM production-side forecasts do not.

“As vehicles adopt more technology, more new display use-cases become viable and new display applications are born,” said Hiroshi Hayase, senior director of small and medium displays at IHS Markit. “In addition to the strong growth in the primary display market, we also expect strong growth in display mirrors, rear seat entertainment and even in aftermarket systems as buyers clamor for more digital interfaces.”

As an example, global display shipments for rearview mirror applications are forecast to soar 52 percent in 2018 to 1.6 million units, beyond the 1.0-million-unit mark set just last year. While automakers are keenly aware of the growing demand in this sector, the aftermarket mirror manufacturers are responding quicker to the trend and represent a majority of today’s global production.

The IHS Markit Automotive Display Systems Forecasts provide customers with demand-side monthly updates to automotive instrument cluster, center stack display and head-up display system forecasts, tracked globally to the segment, OEM, brand, model, platform, and program. Coverage of tier-one suppliers and key technical characteristics like display system size, type, touch, orientation and more enabling a precise view of the volumes, technology and revenue market shares in the industry are also included. Meanwhile, the Automotive Display Market Tracker by IHS Markit contains supply-side quarterly updates of automotive display shipments and revenues by application, size, resolution and technology. It also provides supply chain information between tier-two display suppliers and the rest of the supply chain.

Global sales of smartphones to end users returned to growth in the first quarter of 2018 with a 1.3 percent increase over the same period in 2017, according to Gartner, Inc. Compared to the first quarter of 2017 sales of total mobile phones stalled and reached 455 million units in the first quarter of 2018.

Nearly 384 million smartphones were sold in the first quarter of 2018, representing 84 percent of total mobile phones sold (see Table 1). “Demand for premium and high-end smartphones continued to suffer due to marginal incremental benefits during upgrade,” said Anshul Gupta, research director at Gartner. “Demand for entry-level smartphones (sub-$100) and low midtier smartphones (sub-$150) improved due to better-quality models.”

Continued weakness in Greater China’s mobile phone market also limited growth potential for the top global brands, including Chinese brands such as OPPO and Vivo, with over 70 percent of their sales coming from Greater China.

Table 1

Worldwide Smartphone Sales to End Users by Vendor in 1Q18 (Thousands of Units)

Vendor

1Q18

Units

1Q18 Market Share (%)

1Q17

Units

1Q17 Market Share (%)

Samsung

78,564.8

20.5

78,776.2

20.8

Apple

54,058.9

14.1

51,992.5

13.7

Huawei

40,426.7

10.5

34,181.2

9.0

Xiaomi

28,498.2

7.4

12,707.3

3.4

OPPO

28,173.1

7.3

30,922.3

8.2

Others

153,782.1

40.1

169,921.1

44.9

Total

383,503.9

100.0

378,500.6

100.0

Source: Gartner (May 2018)

Samsung Growth Slows, Apple Share Increases

Samsung’s midtier smartphones faced continued competition from Chinese brands, which led to unit sales contraction year on year. This is despite the earlier launch of its flagship Galaxy S9/S9+ compared to the S8/S8+ in 2017, and despite the Note 8 having a positive impact on Samsung sales in the first quarter of 2018. Samsung’s smartphone growth rate will remain under pressure through 2018, with Chinese brand’s growing dominance and expansion into Europe and Latin America markets. Samsung is challenged to   raise the average selling price (ASP) of its smartphones, while facing increasing competition from Chinese brands that are taking more market share.

The delayed sales boost for Apple from last quarter materialized. Apple’s smartphone unit sales returned to growth in the first quarter of 2018, with an increase of 4 percent year on year.

“Even though demand for Apple’s iPhone X exceeded that of iPhone 8 and iPhone 8 Plus, the vendor struggled to drive significant smartphone replacements, which led to slower-than-expected growth in the first quarter of 2018,” said Mr. Gupta. “With its exclusive focus on premium smartphones, Apple needs to significantly raise the overall experience of its next-generation iPhones to trigger replacements and lead to solid growth in the near future.”

Huawei and Xiaomi Remained the Big Winners

Huawei’s refreshed smartphone portfolio helped strengthen its No. 3 global smartphone vendor position.

“Achieving 18.3 percent growth in the first quarter of 2018 helped Huawei close the gap with Apple,” said Mr. Gupta. “However, its future growth increasingly depends on the vendor ramping up share in Emerging Asia/Pacific and resolving issues in the U.S. market, through the development of a stronger consumer brand. Huawei’s attempt to grow its premium smartphone portfolio with its recent launches of the P20, P20 Pro and Honor 10 helps raise its competitiveness and growth potential.”

Xiaomi was the clear winner of the first quarter, achieving a growth of 124 percent year on year. Xiaomi’s refreshed portfolio of smartphones and aggressive pricing strategy helped it hold the No. 4 spot in the first quarter of 2018. “This strategy led Xiaomi to achieve 330 percent growth in the Emerging Asia/Pacific region,” said Mr. Gupta.

In the smartphone operating system (OS) market, Google’s Android and Apple’s iOS achieved growth in units in the first quarter of 2018, but Android saw its share slightly contract (see Table 2).

Table 2

Worldwide Smartphone Sales to End Users by Operating System in 1Q18 (Thousands of Units)

Operating System

1Q18

Units

1Q18 Market Share (%)

1Q17

Units

1Q17 Market Share (%)

Android

329,313.9

85.9

325,900.9

86.1

iOS

54,058.9

14.1

51,992.5

13.7

Other OS

131.1

0.0

607.3

0.2

Total

383,503.9

100.0

378,500.6

100.0

Source: Gartner (May 2018)

Notch design of smartphone displays is estimated to raise manufacturing cost of display panels by more than 20 percent, according to IHS Markit.

According to the OLED Display Cost Model by IHS Markit, manufacturing cost of the 5.9-inch organic light-emitting diode (OLED) panel with notch design, as in the Apple iPhone X, is estimated to be $29. It is found to be 25 percent higher than manufacturing cost of full-display OLED panel without the notch design used in the 5.8-inch display for the Samsung Galaxy S9. Similar cost gap is also found in the thin-film transistor liquid crystal display (TFT-LCD). Manufacturing cost of a 6-inch notch TFT-LCD panel is estimated to be $19, 20 percent higher than similar-sized non-notch, full-display LCD panel.

“Notch cutting should accompany yield loss, resulting in increases in manufacturing cost. In case of TFT-LCD, a notch design may push up the manufacturing cost even to the level of rigid, full-screen OLED’s,” said Jimmy Kim, Ph.D. and senior principal analyst for display materials at IHS Markit. “For OLED panels, cost increase caused by notch design seems to be even higher.”

Quarterly shipments of the iPhone X, Apple’s first smartphone model using OLED panels, have reportedly been smaller than previous iPhone models’ so far, mainly due to higher selling price, caused by expensive OLED panels. “Apple seems to be in the middle of manufacturing optimization,” Kim said.

“Eventually, manufacturing cost for notch OLED will fall more rapidly than that for notch TFT-LCD. The plastic substrate for OLED is not as brittle as glass used in TFT-LCD, so it should be easier to cut the notch, theoretically.”

The OLED Display Cost Model by IHS Markit includes manufacturing cost analysis and forecasts of OLED display panels in mass production for smartwatch, smartphone, tablet PC and TV.

Organic light-emitting diodes (OLEDs) truly have matured enough to allow for first commercial products in form of small and large displays. In order to compete in further markets and even open new possibilities (automotive lighting, head-mounted-displays, micro displays, etc.), OLEDs need to see further improvements in device lifetime while operating at their best possible efficiency. Currently, intrinsic performance progress is solely driven by material development.

This is a graphic about improving OLEDS on the nanoscale. Credit: Joan Rafols Ribé (UAB) and Paul Anton Will (TU Dresden)To

Now researchers from the Universitat Autònoma de Barcelona and Technische Universität Dresden demonstrate the possibility of using ultrastable film formation to improve the performance of state-of-the-art OLEDs. In their joint paper published in Science Advances with the title ‘High-performance organic light-emitting diodes comprising ultrastable glass layers’, the researchers show in a detailed study significant increases of efficiency and operational stability (> 15% for both parameters and all cases, significantly higher for individual samples) are achieved for four different phosphorescent emitters. To achieve these results, the emission layers of the respective OLEDs were grown as ultrastable glasses – a growth condition that allows for thermodynamically most stable amorphous solids.

This finding is significant, because it is an optimization which does neither involve a change of materials used nor changes to the device architecture. Both are the typical levers for improvements in the field of OLEDs. This concept can universally be explored in every given specific OLED stack, which will be equally appreciated by leading industry. This in particular includes thermally activated delayed fluorescence (TADF) OLEDs, which see a tremendous research and development interest at the moment. Furthermore, the improvements that, as shown by the researchers, can be tracked back to differences on the exciton dynamics on the nanoscale suggest that also other fundamental properties of organic semiconductors (e.g. transport, charge separation, energy transfer) can be equally affected.

Memory devices employ a wide range of packaging technology from wire-bond leadframe and BGA to TSV.

BY SANTOSH KUMAR, Yole Développement, Lyon-Villeurbanne, France

The memory market is going through a strong growth phase. The total memory market grew by >50% YoY to more than US$125 billion in 2017 from US$79.4 billion in 2016. [1] RAM and NAND dominate the market, representing almost 95 % of standalone memory sales. There is a supply/demand mismatch in the market which is impacting on the ASP of memory devices, and as a result the large memory IDMs are reaping record profits. The memory industry has consolidated with the top five players – Samsung, SKHynix, Micron, Toshiba and Western Digital – accounting for 90% of the market.

The demand for memory is coming from all sectors but the mobile and computing (mainly servers) market is showing particularly strong growth. On average, the DRAM memory capacity per smartphone will rise more than threefold to reach around 6GB by 2022. DRAM cost per smartphone represents >10% of the bill of materials of the phone and is expected to increase further. The NAND capacity per smartphone will increase more than fivefold to reach >150GB by 2022. For servers, the DRAM capacity per unit will increase to a whopping 0.5TB by 2022, and the NAND capacity per SSD for the enterprise market will be in excess of 5TB by 2022. The growth in these markets is led by applications like deep learning, big-data, networking, AR/ VR, and autonomous driving. The automotive market, which traditionally used low density (low-MB) memory, will see the adoption of DRAM memory led by the emerging trend of autonomous driving and in-vehicle infotainment. The NOR flash memory market also saw a resurgence and is expected to grow at an impressive 16% CAGR to reach ~US$4.4 billion by 2022, due to its application in new areas such as AMOLED displays, touch display driver ICs and industrial IoTs.

On the supply side, the consolidation of players, the difficulty in migrating to advanced nodes due to technical challenges, and the need for higher investment to migrate from 2D to 3D NAND, has led to shortfall in both DRAM & NAND flash supply. DRAM players want to retain high ASPs (& high profitability) to justify the huge capex investment for advanced node migration and as such are not inclined to increase capacity. Entry of Chinese memory players will ease the supply side constraint, but it’ll not happen before 2020.

Memory device packaging

There are many variations of memory device packaging. This implies a wide range of packaging technology from the low pin count SOP package to the high pin-count TSV, all depending upon the specific product requirements such as density, performance, cost, etc. We have broadly identified five packaging platforms for memory devices: viz lead frame, wire-bond BGA, flip-chip BGA, WLCSP and TSV, even though in each platform there are many varia- tions and different nomenclature in industry.

The total memory package market is expected to grow at 4.6% CAGR2016-2022 to reach ~US$26 billion by 2022. [1] Wire-bond BGA accounted for more than 80% of the packaging market in dollar terms in 2016. Flip-chips, however, started making inroads in the DRAM memory packaging market and is expected to grow at ~20% CAGR in the next five years to account for more than 10% of the memorypackagingmarket.Currentlytheflip-chipmarket is only around 6% of the total memory packaging market. Flip-chip growth is led by its increased adoption in the DRAM PC/server segment fueled by a high bandwidth requirement.

Currently Samsung has already converted >90% of its DRAM packaging line. SK Hynix have started the conversion and other players will also adopt it in future. At Yole Développement (Yole), we believe that all DDR5 memory for PC/servers will move to flip-chip.

TSV is employed in high bandwidth memory devices requiring high bandwidth with low latency memory chips for high performance computing in various applications. In 2016 the TSV market was <1% of the total memory market. However, it is expected to grow by >30% CAGR to reach ~8% of memory packaging in dollar terms. WLSCP packaging is used in NOR flash and niche memory devices (EEPROMs/EPROM/ROM). It is expected to grow at >10% CAGR, but in terms of value will remain <1% of the market by 2022.

In mobile applications, memory packaging will mainly remain on the wire-bond BGA platform but will start to move into the multi-chip package (ePoP) for high end smartphones.

The main requirement of NAND flash devices is high storage density at low cost. NANDs are stacked using wire bonding to provide high density in a single package. The NAND packaging market is expected to reach ~ US$ 10 billion by 2022. NAND flash packaging will remain on the wire bond BGA platform and will not migrate to flip-chip. Toshiba, however, will start using TSV packaging in NAND devices to increase the data transfer rate for high end applications. Following Toshiba, we believe Samsung and SKHynix will also bring TSV packaged NAND devices into the market.

OSATs account for <20% of the memory packaging business

The total memory packaging market is estimated to have been ~US$20 billion in 2016. There are many OSATs involved in the memory packaging business, and >80% of the packaging (by value) is still done internally by OSATs. The majority of these are small OSATs and have only low-end packaging capability. Global memory IDMs have much experience in packaging, accumulated over years, and have their own internal large capacity. Therefore, there is limited opportunity for OSATs to make inroads into the packaging activity of IDMs. Many Chinese players, however, are entering the memory market with more than US$50 billion investment committed. [1] These new entrants do not have experience in memory assembly / packaging, unlike global IDMs, and they will outsource major packaging activities to OSATs. The flip-chip business for memory packaging will increase to 13% of the total market to reach US$3.5 billion in 2022. This is an opportunity for low-end memory OSATs to invest in flip-chip bumping and assembly capacity. Otherwise they will lose business to the big OSATs with advanced packaging capability.

Conclusion

The memory industry is going through a golden phase with strong demand coming from all sectors, particularly from the mobile and computing (mainly servers) markets.

Memory devices employ a wide range of packaging technology from wire-bond leadframe and BGA to TSV. Wire-bond BGA still accounts for the bulk of the memory packaging market. However, flip-chip technology will start making inroads in DRAM memory packaging and will grow at 20% CAGR (by revenue) over the next five years, accounting for ~13% of the total memory packaging market by 2022. The memory packaging market is mainly controlled by IDMs. OSATs have limited opportunity to impact IDM packaging activity. Many Chinese players, however, are entering the memory business and, unlike global IDMs, these new players lack experience in memory assembly/packaging and they outsource most of their packaging activity to OSATs.

SANTOSH KUMAR is a Senior Technology and Market Research Analyst at Yole Développement in France.

References

1. Memory Packaging Market and Technology Report 2017, Yole Développement

Technology trends in backplane technology are driving higher gas demand in display manufacturing. Specific gas requirements of process blocks are discussed, and various supply modes are reviewed.

BY EDDIE LEE, Linde Electronics, Hsinchu, Taiwan

Since its initial communalization in the 1990s, active matrix thin-film-transistor (TFT) displays have become an essential and indispensable part of modern living. They are much more than just televisions and smartphones; they are the primary communication and information portals for our day-to- day life: watches (wearables), appliances, advertising, signage, automobiles and more.

There are many similarities in the display TFT manufacturing and semiconductor device manufacturing such as the process steps (deposition, etch, cleaning, and doping), the type of gases used in these steps, and the fact that both display and semiconductor manufacturing both heavily use gases.

However, there are technology drivers and manufacturing challenges that differentiate the two. For semiconductor device manufacturing, there are technology limitations in making the device increasingly smaller. For display manufacturing, the challenge is primarily maintaining the uniformity of glass as consumers drive the demand for larger and thinner displays.

While semiconductor wafer size has maxed because of the challenges of making smaller features uniformly across the surface of the wafer, the size of the display mother glass has grown from 0.1m x 0.1m with 1.1mm thickness to 3m x 3m with 0.5mm thickness over the past 20 years due to consumer demands for larger, lighter, and more cost-effective devices.

As the display mother glass area gets bigger and bigger,so does the equipment used in the display manufacturing process and the volume of gases required. In addition, the consumer’s desire for a better viewing experience such as more vivid color, higher resolution, and lower power consumption has also driven display manufacturers to develop and commercialize active matrix organic light emitting displays (AMOLED).

Technology

Layers of display device

In general, there are two types of displays in the market today: active matrix liquid crystal display (AMLCD) and AMOLED. In its simplicity, the fundamental components required to make up the display are the same for AMLCD and AMOLED. There are four layers of a display device (FIGURE 1): a light source, switches that are the thin-film-transistor and where the gases are mainly used, a shutter to control the color selection, and the RGB (red, green, blue) color filter.

About backplane/TFT

The thin-film-transistors used for display are 2D transitional transistors, which are similar to bulk CMOS before FinFET. For the active matrix display, there is one transistor for each pixel to drive the individual RGB within the pixel. As the resolution of the display grows, the transistor size also reduces, but not to the sub-micron scale of semiconductor devices. For the 325 PPI density, the transistor size is approximately 0.0001 mm2 and for the 4K TV with 80 PPI density, the transistor size is approximately 0.001 mm2.

Technology trends TFT-LCD (thin-film-transistor liquid-crystal display) is the baseline technology. MO / White OLED (organic light emitting diode) is used for larger screens. LTPS / AMOLED is used for small / medium screens. The challenges for OLED are the effect of < 1 micron particles on yield, much higher cost compared to a-Si due to increased mask steps, and moisture impact to yield for the OLED step.

Mobility limitation (FIGURE 2) is one of the key reasons for the shift to MO and LTPS to enable better viewing experience from higher resolution, etc.

The challenge to MO is the oxidation after IGZO metalization / moisture prevention after OLED step, which decreases yield. A large volume of N2O (nitrous oxide) is required for manufacturing, which means a shift in the traditional supply mode might need to be considered.

Although AMLCD displays are still dominant in the market today, AMOLED displays are growing quickly. Currently about 25% of smartphones are made with AMOLED displays and this is expected to grow to ~40% by 2021. OLED televisions are also growing rapidly, enjoying double digit growth rate year over year. Based on IHS data, the revenue for display panels with AMOLED technol- ogies is expected to have a CAGR of 18.9% in the next five years while the AMLCD display revenue will have a -2.8% CAGR for the same period with the total display panel revenue CAGR of 2.5%. With the rapid growth of AMOLED display panels, the panel makers have accel- erated their investment in the equipment to produce AMOLED panels.

Types of backplanes

There are three types of thin-film-transistor devices for display: amorphous silicon (a-Si), low temperature polysilicon (LTPS), and metal oxide (MO), also known as transparent amorphous oxide semiconductor (TAOS). AMLCD panels typically use a-Si for lower-resolution displays and TVs while high-resolution displays use LTPS transistors, but this use is mainly limited to small and medium displays due to its higher costs and scalability limitations. AMOLED panels use LTPS and MO transistors where MO devices are typically used for TV and large displays (FIGURE 3).

How gases are used

This shift in technology also requires a change in the gases used in production of AMOLED panels as compared with the AMLCD panels. As shown in FIGURE 4, display manufacturing today uses a wide variety of gases.

These gases can be categorized into two types: Electronic Specialty gases (ESGs) and Electronic Bulk gases (EBGs) (FIGURE 5). Electronic Specialty gases such as silane, nitrogen trifluoride, fluorine (on-site generation), sulfur hexafluoride, ammonia, and phosphine mixtures make up 52% of the gases used in the manufacture of the displays while the Electronic Bulk gases–nitrogen, hydrogen, helium, oxygen, carbon dioxide, and argon – make up the remaining 48% of the gases used in the display manufacturing.

Key usage drivers

The key ga susage driver in the manufacturing of displays is PECVD (plasma-enhanced chemical vapor deposition), which accounts for 75% of the ESG spending, while dry etch is driving helium usage. LTPS and MO transistor production is driving nitrous oxide usage. The ESG usage for MO transistor production differs from what is shown in FIGURE 4: nitrous oxide makes up 63% of gas spend, nitrogen trifluoride 26%, silane 7%, and sulfur hexafluoride and ammonia together around 4%. Laser gases are used not only for lithography, but also for excimer laser annealing application in LTPS.

Silane: SiH4 is one of the most critical molecules in display manufacturing. It is used in conjunction with ammonia (NH3) to create the silicon nitride layer for a-Si transistor, with nitrogen (N2) to form the pre excimer laser anneal a-Si for the LTPS transistor, or with nitrous oxide (N2O) to form the silicon oxide layer of MO transistor.

Nitrogen trifluoride: NF3 is the single largest electronic material from spend and volume standpoint for a-Si and LTPS display production while being surpassed by N2O for MO production. NF3 is used for cleaning the PECVD chambers. This gas requires scalability to get the cost advantage necessary for the highly competitive market.

Nitrous oxide: Used in both LTPS and MO display production, N2O has surpassed NF3 to become the largest electronic material from spend and volume standpoint for MO production. N2O is a regional and localized product due to its low cost, making long supply chains with high logistic costs unfeasible. Averaging approximately 2 kg per 5.5 m2 of mother glass area, it requires around 240 tons per month for a typical 120K per month capacity generation 8.5 MO display production. The largest N2O compressed gas trailer can only deliver six tons of N2O each time and thus it becomes both costly and risky
for MO production.

Nitrogen: For a typical large display fab, N2 demand can be as high as 50,000 Nm3/hour, so an on-site generator, such as the Linde SPECTRA-N® 50,000, is a cost-effective solution that has the added benefit of an 8% reduction in CO2 (carbon dioxide) footprint over conventional nitrogen plants.

Helium: H2 is used for cooling the glass during and after processing. Manufacturers are looking at ways to decrease the usage of helium because of cost and availability issues due it being a non-renewable gas.

Gas distribution at the fab

N2 On-site generators: Nitrogen is the largest consumed gas at the fab, and is required to be available before the first tools are brought to the fab. Like major semiconductor fabs, large display fabs require very large amounts of nitrogen, which can only be economically supplied by on-site plants.

Cryogenic liquid truck trailers: Oxygen, argon, and carbon dioxide are produced at off-site plants and trucked short distances as cryogenic liquids in specialty vacuum-insulated tankers.
Compressed gas truck trailers: Other large volume gases like hydrogen and helium are supplied over longer distances in truck or ISO-sized tanks as compressed gases.

Individual packages: Specialty gases are supplied in individual packages. For higher volume materials like silane and nitrogen trifluoride, these can be supplied in large ISO packages holding up to 10 tons. Materials with smaller requirements are packaged in standard gas cylinders.

Blended gases: Laser gases and dopants are supplied as blends of several different gases. Both the accuracy and precision of the blended products are important to maintain the display device fabrication operating within acceptable parameters.

In-fab distribution: Gas supply does not end with the delivery or production of the material of the fab. Rather, the materials are further regulated with additional filtration, purification, and on-line analysis before delivery to individual production tools.

Conclusion

The consumer demand for displays that offer increas- ingly vivid color, higher resolution, and lower power consumption will challenge display makers to step up the technologies they employ and to develop newer displays such as flexible and transparent displays. The transistors to support these new displays will either be LTPS and / or MO, which means the gases currently being used in these processes will continue to grow. Considering the current a-Si display production, the gas consumption per area of the glass will increase by 25% for LTPS and ~ 50% for MO productions.

To facilitate these increasing demands, display manufacturers must partner with gas suppliers to identify which can meet their technology needs, globally source electronic materials to provide customers with stable and cost- effective gas solutions, develop local sources of electronic materials, improve productivity, reduce carbon footprint, and increase energy efficiency through on-site gas plants. This is particularly true for the burgeoning China display manufacturing market, which will benefit from investing in on-site bulk gas plants and collaboration with global materials suppliers with local production facilities for high-purity gas and chemical manufacturing.