IGBT Backside Laser Pre-Treatment After Thinning Defects
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The conventional manufacturing process for insulated gate bipolar transistors (IGBTs) introduces defects such as micro-cracks and crystal dislocations during the thinning process, which affect the electrical characteristics and consistency of the devices.
Innovation Solution
A laser pre-treatment process is introduced after the thinning process to remove these defects, using a green laser at temperatures between 1000° C to 1500° C for 60-150 seconds, which effectively addresses the substrate defects without impacting the front side elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a grinding process is used to reduce substrate thickness, then the substrate thickness is reduced, but micro-cracks and crystal dislocations are introduced on the back side of the substrate
Solution Approach 1:
A laser pre-treatment process is performed after the grinding process to proactively remove micro-cracks and crystal dislocations before subsequent ion doping and annealing steps. This preliminary defect removal action prevents defects from propagating and affecting the electrical characteristics of the final device.
Solution Approach 2:
The laser pre-treatment process converts the harmful defects (micro-cracks and dislocations) created by grinding into an opportunity for improvement. By selectively removing these defects through laser heating and controlled elimination, the substrate quality is enhanced beyond its original state, leading to better device performance.
2Manufacturing precision
If a laser pre-treatment process is added after thinning, then defect removal is improved, but manufacturing complexity increases
Solution Approach 1:
The mechanical grinding process is supplemented with a laser-based pre-treatment process that uses optical energy instead of mechanical contact to remove defects. This substitution avoids the need for additional mechanical processing steps and enables precise, contactless defect elimination.
Solution Approach 2:
The laser pre-treatment process utilizes controlled temperature parameters (heating to specific temperature ranges) and timing parameters to selectively remove defects while preserving the substrate structure. By optimizing these parameters, the process achieves high defect removal efficiency without requiring complex multi-step procedures.
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 method enhances the stability and consistency of electrical characteristics and product quality by removing micro-cracks and crystal dislocations, reducing substrate breakage and improving reproducibility.
Implementation Method 1
performing a laser pre-treatment process on the back side of the substrate
Implementation Method 2
The laser pre-treatment process is performed at a temperature ranged from about 1000° C. to about 1500° C.
Implementation Method 3
performing at least one ion doping process on the back side of the substrate for forming at least one ion doping layer
Implementation Method 4
performing an annealing process on the back side of the substrate
Data Source
AI summary
A method for manufacturing an insulated gate bipolar transistor includes (a) providing a substrate comprising a front side and a back side; (b) forming at least one front side element and at least one front side metal layer on the front side of the substrate; (c) performing a thinning process on the back side of the substrate; (d) performing a laser pre-treatment process on the back side of the substrate; (e) performing at least one ion doping process on the back side of the substrate for forming at least one ion doping layer; (f) performing an annealing process on the back side of the substrate; and (g) forming a collector metal layer on the back side of the substrate.