Semiconductor Via Reinforcement for Airtightness
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Solution Overview
Problem
Existing semiconductor devices face issues with maintaining air tightness due to adhesion deterioration and thermal expansion coefficient differences between conductive metals and substrates, leading to airtightness breakdown and reduced durability.
Innovation Solution
A semiconductor device design featuring a device substrate, a cap substrate, and bump portions that connect via portions to the cap substrate, enhancing bonding reliability and reinforcing the via portions to maintain air tightness and improve yield and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive metal is formed in via holes to connect semiconductor circuit to outside parts, then electrical connection is achieved, but adhesion deteriorates and airtightness breakdown occurs due to thermal expansion coefficient differences
Solution Approach 1:
The patent uses a composite structure consisting of a conductive metal layer and a reinforcing layer in the via portions. The conductive metal provides electrical connection while the reinforcing layer (made of material with thermal expansion coefficient matching the substrate) compensates for thermal stress, preventing adhesion deterioration and maintaining airtightness under thermal cycling conditions.
2Reliability
If cap substrate is bonded to device substrate to form hollow part, then electromagnetic shielding and packaging are achieved, but stress concentration causes cracking and airtightness breakdown
Solution Approach 1:
The reinforcing layers are formed in the via portions before bonding the cap substrate to the device substrate. This preliminary reinforcement prevents stress concentration and cracking that would otherwise occur during subsequent thermal cycling and operation, ensuring long-term airtightness reliability.
3Reliability
If via portions are formed to penetrate device substrate, then electrical connection is enabled, but close adhesion between conductive metal and substrate deteriorates
Solution Approach 1:
The via portions are constructed as composite structures with both conductive metal and reinforcing layer. The reinforcing layer provides strong adhesion to the substrate while the conductive metal layer provides electrical connection, resolving the contradiction between achieving electrical connectivity and maintaining strong adhesion.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively stabilizes air tightness and enhances the durability of semiconductor devices by reinforcing via portions with bump portions, reducing stress and deformation caused by thermal expansion differences.
Implementation Method 1
bump portions respectively provided at all positions of the via portions in the hollow part and connecting the via portions to the cap substrate
Implementation Method 2
cap substrate including a substrate having a front surface and a back surface, wherein the back surface is bonded to the whole perimeter of the sealing frame while covering the semiconductor circuit to form a hollow part provided between the device substrate and the cap substrate and housing the semiconductor circuit in an airtight state
Implementation Method 3
a plurality of via portions formed of a conductive material for connecting the semiconductor circuit to outside parts, and penetrating the device substrate
Data Source
AI summary
Airtightness of a hollow portion is maintained, and yield and durability are improved. A semiconductor device 1 includes a device substrate 2, a semiconductor circuit 3, a sealing frame 7, a cap substrate 8, via portions 10, electrodes 11, 12 and 13, and a bump portion 14 or the like. A hollow portion 9 in which the semiconductor circuit 3 is housed in an airtight state is provided between the device substrate 2 and the cap substrate 8. The bump portion 14 connects all the via portions 10 and the cap substrate 8. Thus, the via portions 10 can be reinforced using the bump portion 14A.