By Dr. Phil Garrou, Contributing Editor
I have said many times that it will be impossible for a complicated technology like 3DIC to ever become commercial without standardization. SEMI has been working on this now for 3+ years. Let’s take a look at their recent update from their SEMICON Singapore presentation. So far, they have published the following standards:
SEMI 3D1-0912, Terminology for Through Silicon via Geometrical Metrology
– Clear and commonly accepted definitions are needed for efficient communication and to prevent misunderstanding between buyers and vendors of metrology equipment and manufacturing services.
– The purpose of this Document is to provide a consistent terminology for the understanding and discussion of metrology issues important to through silicon vias (TSV).
SEMI 3D2-1113, Specification for Glass Carrier Wafers for 3DS-IC
– This Specification describes dimensional, thermal, and wafer preparation characteristics for glass starting material that will be used as carrier wafers in a temporary bonded state;
– Methods of measurements suitable for determining the characteristics in the specifications indicated.
SEMI 3D3-0613, Guide for Multi-Wafer Transport and Storage Containers for 300 mm, Thin Silicon Wafers on Tape Frames
–Address the methods for shipping thin wafers on tape frames.
SEMI 3D4-0613, Guide for Metrology for Measuring Thickness, Total Thickness Variation (TTV), Bow, Warp/Sori, and Flatness of Bonded Wafer Stacks
– Control of bonded wafer stack (BWS) thickness, total thickness variation (TTV), bow, warp/sori, and
– This std provides a description of tools that can be used to determine these key parameters before, during, and after the process steps involved in wafer bonding.
SEMI 3D5-0314, Guide for Metrology Techniques to be used in Measurement of Geometrical Parameters of Through- Silicon Vias (TSVs) in 3DS-IC Structures
– This std assists in the selection and use of tools for performing measurements of geometrical parameters of an individual TSV (through-silicon via), or of an array of TSVs.
SEMI 3D6-0913, New Standard: Guide for CMP and Micro-bump Processes for Frontside Through Silicon Via (TSV) Integration
– This std provides a generic middle-end process flow to define acceptable TSV and CMP quality criteria as well as to develop methodology and measuring procedures for micro-bump.
SEMI 3D7-0913, New Standard: Guide for Alignment Mark for 3DS-IC Process
– Photo alignment mark configuration is the key to ensure consistent and precise alignment of layers, chips and wafers.
– This standard provides an alignment mark strategy for chip to chip, chip to wafer, and wafer to wafer stacking.
SEMI also has organized task forces in North America, Taiwan and Japan focused on various aspects of 3DIC manufacturing and testing. The North America task force is focused on:
Bonded Wafer Stacks – Create and/or modify specifica- tions that reflect bonded wafer stacks parameters and the wafer bonding process.
Inspection & Metrology – Develop standards for metrology and inspection methods to be used for measuring TSV properties, bonded wafer stacks, and dies used in the 3DIC manufacturing process.
Thin Wafer Handling – Develop standards for reliable handling and shipping of thin wafers, dies (e.g., Micro- pillar Grid array -MPGA) used in 3DIC high-volume manufacturing (HVM).