MEMS Device Packaging Using Stud Bumps and Solder Bumps
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Solution Overview
Problem
The existing assembly and packaging methods for Micro Electro Mechanical Systems (MEMS) devices, particularly the use of wire bonding, result in increased device size and limitations in reducing the profile dimension due to the thickness of gold wires and polymer encapsulation, which can damage the MEMS device and hinder profile reduction.
Innovation Solution
The implementation of a MEMS device with a CMOS-MEMS die vertically stacked and electrically connected using stud bumps and solder bumps, eliminating wire bonding and incorporating an air gap to reduce stress and profile, while using a polymer that does not fill the gap between the MEMS die and the substrate, thereby reducing the device's overall height and enhancing protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonding is used to electrically connect the CMOS die with the substrate, then electrical connection is achieved, but the device profile increases and the MEMS device becomes more susceptible to damage
Solution Approach 1:
The patent removes the wire bonding process entirely from the assembly. Instead of using gold wires to connect the CMOS die to the substrate, the invention uses direct electrical connection through the stacked die architecture where the MEMS die is bonded directly to the CMOS die, eliminating the need for external wire bonds and thereby reducing the device profile.
Solution Approach 2:
The patent merges the electrical connection function with the mechanical bonding structure. The MEMS die and CMOS die are bonded together in a stacked configuration where the bonding interface itself provides both mechanical support and electrical connection, eliminating the need for separate wire bonding components and reducing overall device height.
2Reliability
If wire bonding is used to electrically connect the CMOS die with the substrate, then electrical connection is achieved, but the MEMS device becomes more susceptible to damage
Solution Approach 1:
The patent removes the wire bonding process entirely from the assembly. Instead of using gold wires to connect the CMOS die to the substrate, the invention uses direct electrical connection through the stacked die architecture where the MEMS die is bonded directly to the CMOS die, eliminating the need for external wire bonds and thereby reducing the device profile.
Solution Approach 2:
The patent merges the electrical connection function with the mechanical bonding structure. The MEMS die and CMOS die are bonded together in a stacked configuration where the bonding interface itself provides both mechanical support and electrical connection, eliminating the need for separate wire bonding components and reducing overall device height.
3Reliability
If polymer encapsulation is used to protect the gold wire, then wire protection is achieved, but the device profile increases
Solution Approach 1:
The patent removes the wire bonding process entirely from the assembly. Instead of using gold wires to connect the CMOS die to the substrate, the invention uses direct electrical connection through the stacked die architecture where the MEMS die is bonded directly to the CMOS die, eliminating the need for external wire bonds and thereby reducing the device profile.
Data Source
AI summary
A Micro Electro Mechanical systems (MEMS) device includes a solder bump on a substrate, a CMOS-MEMS die comprising a CMOS die and a MEMS die, and stud bumps on the CMOS die. The MEMS die is disposed between the CMOS die and the substrate. The stud bumps and the solder bumps are positioned to provide an electrical connection between the CMOS die and the substrate.