Semiconductor Wafer Structure With Dielectric Stress Relief
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Solution Overview
Problem
The manufacturing process of semiconductor devices often results in wafer warp, which reduces manufacturing efficiency and poses challenges in achieving both a thin semiconductor layer and a thick metal layer without increasing warp and on-resistance.
Innovation Solution
Incorporating a dielectric layer between the metal layers to apply stress in an opposite direction, thereby reducing total stress on the semiconductor region and suppressing warp, while allowing for a thin semiconductor layer and a thick metal layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick metal layer is formed to reduce on-resistance, then electrical conductivity is improved, but wafer warp increases
Solution Approach 1:
A dielectric layer is introduced as an intermediary between the semiconductor layer and the thick metal layer. This dielectric layer has a stress different from both the semiconductor and metal layers, acting as a stress buffer that absorbs the stress mismatch. This allows a thick metal layer to be formed for low on-resistance without the full stress impact causing excessive wafer warp, thus resolving the contradiction between electrical conductivity and wafer shape stability.
2Reliability
If a thin semiconductor layer is used to reduce on-resistance, then electrical performance is improved, but manufacturing precision deteriorates due to increased warp
Solution Approach 1:
The dielectric layer serves as a stress management intermediary that enables the use of thin semiconductor layers for better electrical performance. By absorbing stress differences, particularly when the dielectric layer has appropriate stress characteristics, it prevents the thin semiconductor layer from being overly susceptible to warp, thereby maintaining manufacturing precision while achieving improved electrical performance.
Solution Approach 2:
The stress parameter of the dielectric layer is specifically selected and controlled to be different from both the semiconductor layer and metal layer. By adjusting the stress parameter of the dielectric layer (through material selection, thickness control, or deposition conditions), the overall stress distribution in the stacked structure is optimized, enabling thin semiconductor layers to be manufactured with acceptable warp control.
3Strength
If metal layers are made thicker to compensate for warp, then structural strength is improved, but on-resistance increases
Solution Approach 1:
The dielectric layer acts as a stress-absorbing intermediary that decouples the relationship between metal layer thickness and wafer warp. This allows metal layers to be made thick enough for structural strength without the proportional increase in on-resistance that would normally occur, because the dielectric layer buffers the stress that would otherwise require even thicker metal for compensation.
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 dielectric layer acts as a stress relaxation layer, reducing warp and on-resistance, and enhancing the strength of the wafer or chip, making it easier to achieve both a thin semiconductor layer and a thick metal layer without increasing warp.
Implementation Method 1
Incorporating a dielectric layer between the metal layers to apply stress in an opposite direction, thereby reducing total stress on the semiconductor region and suppressing warp
Data Source
AI summary
A semiconductor device includes first and second metal layers, a dielectric layer, first, second, and third semiconductor regions, a first control electrode, and a first electrode. The dielectric layer is located on the first metal layer. The second metal layer is located on the dielectric layer, and electrically connected with the first metal layer. The first semiconductor region is located on the second metal layer and electrically connected with the second metal layer. The second semiconductor region is located on the first semiconductor region. The third semiconductor region is located on the second semiconductor region. The first control electrode faces the second semiconductor region via a first insulating film. The first electrode is located on the third semiconductor region and the first control electrode, electrically connected with the third semiconductor region, and insulated from the first control electrode by a first insulating portion.