MEMS-ASIC Stack Adapter Chip to Prevent Adhesive Bleeding
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Solution Overview
Problem
The challenge is to securely stack ASIC and MEMS chips of different sizes while preventing adhesive bleeding onto critical ASIC structures, which is exacerbated by the need for a large safety zone due to the geometry and design constraints of existing chip-on-chip designs.
Innovation Solution
An adapter chip, made from materials like silicon or glass, is placed between the ASIC and MEMS chips to provide a larger support surface and prevent adhesive bleeding, allowing for partial stacking and minimizing the package footprint without altering the bond pad arrangement on the ASIC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a MEMS chip is mounted directly on an ASIC chip using a soft adhesive with a thick adhesive layer, then the MEMS chip can be securely attached, but the adhesive bleeds out and contaminates the bonding region on the ASIC
Solution Approach 1:
An adapter chip is introduced as an intermediary component between the MEMS chip and the ASIC chip. The adapter chip provides a larger mounting surface for the MEMS chip while its edges act as barriers to prevent adhesive from flowing onto the ASIC's bonding region. This mediator structure enables secure bonding without adhesive contamination.
2Reliability
If the ASIC chip size is increased to accommodate the bonding region and safety zones, then adhesive bleeding is prevented, but the overall package footprint increases
Solution Approach 1:
The adapter chip extends the bonding interface in the z-direction (vertical stacking) rather than requiring horizontal expansion of the ASIC chip. By stacking the adapter chip on top of the ASIC, the solution achieves reliable bonding with proper safety zones while maintaining a compact footprint in the x-y plane.
3Ease of manufacture
If existing ASIC chips are reused for new components, then development time and cost are reduced, but the MEMS chip size and shape are severely limited by the ASIC design
Solution Approach 1:
The bonding interface is segmented into two independent levels: the ASIC chip maintains its original design with its existing bond pads, while the adapter chip provides a separate, flexible mounting platform for the MEMS chip. This segmentation allows the MEMS chip size and shape to be optimized independently without being constrained by the ASIC's bonding region geometry.
4Shape
If a complete redevelopment of the AVT concept and chip design is performed to optimize geometry, then geometric compatibility is achieved, but manufacturing complexity and time increase
Solution Approach 1:
The adapter chip serves multiple functions simultaneously: it provides a larger mounting surface for the MEMS chip, creates physical barriers to prevent adhesive bleeding, maintains electrical isolation, and enables geometric compatibility between differently sized chips. This multi-functional component achieves geometric optimization without requiring complex redesign of the entire system.
Data Source
AI summary
A micromechanical component having a printed circuit board with a main extension plane, having an ASIC chip and a MEMS chip, which are arranged parallel to the main extension plane, wherein the ASIC chip is arranged above the printed circuit board, and the MEMS chip is arranged above the ASIC chip, wherein the ASIC chip is electrically contacted to the printed circuit board in a bonding region by bonding wires. An adapter chip is arranged between the ASIC chip and the MEMS chip, which adapter chip at least partially covers the bonding region in a z-direction perpendicular to the main extension plane. A method for producing a micromechanical component is also described.