Double-Sided IGBT Manufacturing via Segmented Protection
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Solution Overview
Problem
Existing methods face challenges in manufacturing structurally double-sided Insulated Gate Bipolar Transistors (IGBTs) without interfering between the front and back structures and metal layers.
Innovation Solution
A method involving the formation of oxide layers, buffer layers, protection layers, and sequential processing to create and protect both the front and back IGBT structures and metal layers on an N-type substrate, allowing for independent formation and protection of each side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing IGBT manufacturing methods are used, then single-sided IGBT structures can be formed, but structurally double-sided IGBTs cannot be manufactured due to interference between front and back structures
Solution Approach 1:
The patent divides the manufacturing process into distinct segments: front structure formation, protection layer application, back structure formation, and selective removal. This segmentation allows independent processing of front and back structures without mutual interference, enabling double-sided IGBT manufacturing while maintaining ease of production
Solution Approach 2:
The patent applies protection layers to the back substrate before forming the front structure, and forms the buffer layer in advance. These preliminary actions prevent damage to the back structure during front processing and enable subsequent selective removal, resolving the contradiction between manufacturing versatility and ease
2Reliability
If protection layers are applied to both front and back, then both structures can be protected independently, but process complexity increases
Solution Approach 1:
The patent applies different protection strategies to different locations: a buffer layer with specific doping concentration is applied to the back surface, while the front surface receives standard protection. The protection layers are selectively removed based on location, providing localized protection that ensures reliability without uniformly increasing process complexity across the entire device
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
Enables the successful manufacturing of structurally double-sided IGBTs by protecting and processing each side independently, overcoming previous manufacturing difficulties.
Implementation Method 1
forming a buffer layer located in the surface of the back of the N-type substrate by implanting N-type impurities
Implementation Method 2
diffusing at high temperature
Data Source
AI summary
A method for manufacturing an IGBT includes: forming oxide layers on the surfaces of the front and the back of an N-type substrate; forming a buffer layer in the surface of the back of the N-type substrate; forming protection layers on the surfaces of the oxide layers; removing the protection layer and the oxide layer overlying the front of the N-type substrate while reserving the oxide layer and the protection layer on the back of the N-type substrate for protection of the back of the N-type substrate; forming a front IGBT structure and applying a protection film on the surface of the front IGBT structure for protection of the front IGBT structure; removing the protection layer and the oxide layer overlying the back of the N-type substrate; forming a back IGBT structure and a back metal layer; and removing the protection film overlying the surface of the front IGBT structure.