Semiconductor Module Bump with Plastic Region for Thermal Stress
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Solution Overview
Problem
The miniaturization of semiconductor modules is hindered by heat stress caused by thermal expansion differences between silicon and metal components, leading to potential disconnection at electrode-bump interfaces, especially as pitch and size are reduced.
Innovation Solution
A semiconductor module design featuring a bump with a plastic region at its tip, which is integrally formed with the first electrode and penetrates an insulating layer to connect with a second electrode, reducing thermal stress and enhancing adhesion through plastic deformation and increased contact area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the pitch of external connection electrodes is narrowed to achieve miniaturization, then the size of semiconductor module is reduced, but heat stress causes disconnection at electrode-bump interfaces
Solution Approach 1:
The bump and plastic region are merged into a single integral structure, eliminating the interface between them. This prevents disconnection at the interface while maintaining miniaturization benefits, as the integral structure behaves as one unified component under thermal stress
Solution Approach 2:
The invention uses a composite structure combining a bump (high strength, conductive) with a plastic region (ductile, deformable). The bump provides mechanical strength and electrical conductivity, while the plastic region absorbs thermal expansion stress through deformation, creating a composite structure that withstands heat stress better than either material alone
2Reliability
If an adhesion layer is added to improve connection reliability, then connection strength increases, but manufacturing complexity and cost increase
Solution Approach 1:
The plastic region serves a dual function: it acts as both a structural component and a stress-absorbing element. The material itself provides the adhesion and stress relief functions that would otherwise require separate adhesion layers, eliminating additional manufacturing steps and materials
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
This design improves connection reliability by eliminating the interface between the bump and plastic region, matching thermal expansion coefficients, and increasing adhesion, thereby enhancing the module's resistance to heat stress and reducing manufacturing costs.
Implementation Method 1
the bump has a plastic region on a tip part thereof and the plastic region is plastic deformed and connected with the second electrode
Implementation Method 2
thermal expansion coefficients differs vastly between silicon constituting a semiconductor device and the metal sheet such as copper in the case of a semiconductor module. For this reason, heat stress due to a difference in thermal expansion coefficients between materials occurs at a connection portion
Data Source
AI summary
Connection reliability in electrode portions of a semiconductor module is improved. A semiconductor wafer is prepared where a plurality of semiconductor substrates each having an electrode and a protective film at the surface is formed in a matrix shape. Next, at the surface of the semiconductor wafer (semiconductor substrate) a insulation layer is held between the semiconductor substrate and a copper sheet (metal sheet) formed integrally with a bump containing a plastic region on a tip part. With the insulating held between them, the semiconductor substrate, the insulating layer and the copper sheet are press-formed by a press machine into a single block. The bump penetrates the insulating layer, and the plastic region on the tip part is plastic deformed at a contact surface with an electrode, so that the bump and the electrode are electrically connected together.