Semiconductor Shield Gate Structure With Segmented Insulation
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Solution Overview
Problem
The conventional method of manufacturing semiconductor devices is cumbersome due to the need for insulation film removal steps and limited design flexibility, particularly in establishing connections between shield and source electrodes, and in setting desired insulation film thicknesses.
Innovation Solution
A method involving the formation of a semiconductor device with a shield gate structure where the gate electrode is formed before the shield electrode, allowing for direct connection and using a second trench and insulation film to set desired thicknesses, eliminating the need for insulation film removal and enhancing design freedom.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the shield electrode is formed before the gate electrode, then the connection between shield electrode and source electrode can be established, but insulation films must be removed above the shield electrode making the process cumbersome
Solution Approach 1:
The gate electrode is formed in advance before forming the shield electrode. This preliminary action ensures that when the shield electrode is subsequently formed, no insulation films need to be removed above it, as the gate electrode structure is already in place. This resolves the contradiction by performing the gate electrode formation as a preliminary step, eliminating the need for later insulation film removal and simplifying the overall manufacturing process.
2Adaptability or versatility
If the first insulation film is formed by thermal oxidation with a gap remaining, then the shield electrode can be formed in the gap, but the thickness of insulation films on different sides of the shield electrode cannot be set to desired values
Solution Approach 1:
The insulation structure is segmented into multiple independent insulation films (first insulation film, second insulation film, third insulation film) that can be formed at different stages and with different thicknesses. This segmentation allows each insulation film's thickness to be independently controlled and set to desired values, resolving the contradiction between design freedom and thickness control precision.
Solution Approach 2:
The formation process uses different parameters for different insulation films - the first insulation film is formed by thermal oxidation, while the second and third insulation films are formed by CVD methods. By changing the formation method and parameters for each insulation film, precise control over the thickness of each film can be achieved, allowing desired thickness values to be set independently for insulation films on different sides of the shield electrode.
3Manufacturing precision
If the gate electrode is formed after the shield electrode, then the shield electrode can be positioned centrally, but an additional insulation film removing step is required
Solution Approach 1:
The gate electrode is formed as a preliminary step before forming the shield electrode. This preliminary action establishes the gate electrode structure in advance, allowing the shield electrode to be subsequently formed with precise central positioning without requiring later insulation film removal. This resolves the contradiction by performing the gate electrode formation beforehand, maintaining positioning precision while eliminating unnecessary process steps to improve productivity.
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 approach simplifies the connection between shield and source electrodes and allows for precise control of insulation film thicknesses, improving the semiconductor device's withstand voltage and design flexibility.
Implementation Method 1
a first insulation film forming step of forming a first insulation film 126 on the first trench 116 by a thermal oxidation method
Implementation Method 2
a gate insulation film forming step of forming a gate insulation film 118 on a side wall of an upper portion of the first trench 116 by a thermal oxidation method
Data Source
AI summary
A method of manufacturing a semiconductor device includes in this order: a semiconductor base body preparing step; a first trench forming step; a first insulation film forming step of forming a first insulation film; a gate insulation film forming step; a gate electrode forming step; a second trench forming step of forming a second trench in the inside of a first trench by removing a center portion of the first insulation film; a second insulation film forming step of forming a second insulation film in the inside of the second trench under a condition that a gap remain in the inside of the second trench; a shield electrode forming step of forming a shield electrode in the inside of the gap; and a source electrode forming step of forming a source electrode.