Semiconductor Back-Surface Metal Layer Segmentation for Dicing
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Solution Overview
Problem
Semiconductor devices with thick back-surface metal layers face challenges in chip separation from the wafer due to increased on-resistance, making the dicing process more difficult and potentially leading to poor manufacturing yields.
Innovation Solution
A semiconductor device design featuring a metal layer with a thin region for dicing and a thick region for current flow, where the metal layer includes a first layer with a thickness of 1 micrometer or less and a second layer with a thickness of several dozen micrometers, separated by a groove-shaped space, allowing for easier chip formation and improved manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick metal layer is provided on the back-surface of the semiconductor layer to reduce on-resistance, then the on-resistance is reduced, but cutting off the semiconductor device chip from the wafer becomes harder
Solution Approach 1:
The metal layer is divided into a first metal layer and a second metal layer with different thicknesses. The first metal layer has a thickness of 1 micrometer or less to facilitate chip separation, while the second metal layer has a thickness of several dozen micrometers to reduce on-resistance. This segmentation allows each layer to fulfill its specific function without compromising the other.
Solution Approach 2:
Different regions of the metal layer structure have different thicknesses optimized for different purposes. The first metal layer region is thin for easy dicing, while the second metal layer region is thick for low on-resistance. This local quality variation resolves the contradiction between manufacturability and electrical performance.
2Reliability
If a thick metal layer is provided on the back-surface to serve as current path, then the on-resistance is reduced, but the dicing process becomes more difficult and manufacturing yield decreases
Solution Approach 1:
The metal layer is segmented into two distinct layers with different thickness characteristics. The first metal layer (thin) enables easy dicing operations, while the second metal layer (thick) provides the low on-resistance current path. This segmentation resolves the conflict between electrical performance and manufacturing productivity.
Solution Approach 2:
The thickness parameter of the metal layer is changed across different regions and layers. By varying the thickness from 1 micrometer or less in the first layer to several dozen micrometers in the second layer, the patent optimizes both the electrical performance (low on-resistance) and the manufacturing processability (easy dicing with high yield).
Data Source
AI summary
A semiconductor device includes a semiconductor part, a metal layer, first and second electrodes, and first and second control electrodes. The first and second electrodes are provided on a front surface of the semiconductor part and arranged along the front surface of the semiconductor part. The first control electrode is provided between the semiconductor part and the first electrode. The second control electrode is provided between the semiconductor part and the second electrode. The metal layer covers a back-surface of the semiconductor part. The metal layer includes a first layer and a second layer. The first layer of the metal layer is electrically connected to the semiconductor part. The second layer of the metal layer is provided on the first layer inside a periphery of the first layer. The second layer has a layer thickness thicker than a layer thickness of the first layer.