Semiconductor Substrate with Sintered Metal Bump for Pressure Reduction
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Solution Overview
Problem
In semiconductor devices, the miniaturization and performance improvement through three-dimensional integration are hindered by the variation in bump electrode heights, leading to potential malfunctions due to excessive pressure during mounting, which existing techniques struggle to address effectively.
Innovation Solution
A substrate design featuring a support layer with a column-shaped first bump filled with conductive metal and a second bump composed of fine particles of a second conductive metal, where the second bump covers the first bump's surface and side surface, providing flexibility and reducing the required bonding pressure by deforming under load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bump electrodes are pressed by applying pressure during mounting to counteract height variation, then connection reliability is improved, but distortion occurs inside the bump electrodes causing malfunction
Solution Approach 1:
The invention changes the physical state of the bump electrode material from solid metal to sintered metal powder, which can undergo densification under pressure without distorting the electrode structure. This phase/state change allows the material to compact and fill voids while maintaining structural integrity
Solution Approach 2:
The invention uses a composite structure combining sintered metal powder with organic binder materials. This composite allows the bump electrode to be formed at lower temperatures and pressures, reducing thermal and mechanical stress that would cause distortion while still achieving adequate mechanical strength and electrical conductivity
2Object-affected harmful factors
If planarization technique is used to flatten the surface of bump electrodes to reduce necessary pressure, then distortion is reduced, but manufacturing complexity increases
Solution Approach 1:
The invention extracts the planarization step from the manufacturing process by using sintered metal powder that naturally forms compact, uniform bump electrodes during the sintering process itself, eliminating the need for subsequent planarization operations
Solution Approach 2:
The sintering process performs the compaction and surface formation action in advance during bump electrode fabrication, so that when mounting occurs, the electrodes are already in their final compacted state without requiring additional planarization steps
3Stability of the object's composition
If excessive pressure is applied during mounting to compensate for bump height variation, then connection stability is improved, but malfunction occurs due to internal distortion
Solution Approach 1:
By changing the material state from solid to sintered powder, the invention enables the bump electrode to undergo controlled densification under mounting pressure, achieving stable contact without the harmful distortion that occurs in solid metal electrodes under the same conditions
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 substrate design reduces the pressure needed for bonding, enhances flexibility, and stabilizes the bump structure, thereby minimizing malfunctions and improving the reliability of three-dimensional semiconductor device integration.
Implementation Method 1
a second bump composed of fine particles formed of a second conductive metal... providing flexibility and reducing the required bonding pressure by deforming under load
Data Source
AI summary
A substrate includes a support layer, a column-shaped first bump, and a second bump. The support layer has a main surface. The first bump is filled with a first conductive metal and also has a first upper surface and a side surface. The second bump includes a plurality of fine particles formed of a second conductive metal and also has a third portion configured to cover the first upper surface and a fourth portion configured to cover a part of the side surface. The first bump is disposed on the main surface, or the first bump is connected to an electrode disposed on the main surface. The second bump has a convex second upper surface. A height of the fourth portion in a direction perpendicular to the first upper surface is smaller than that of the first bump.