Semiconductor Fuse Trimming for Temperature Sensing Accuracy
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Solution Overview
Problem
Conventional semiconductor integrated circuits face challenges in accurately sensing temperature due to variations in the VF characteristics of temperature sensing diodes formed on polysilicon layers, which affect the heating protection function of power devices like IGBTs.
Innovation Solution
A semiconductor device is designed with a semiconductor substrate, a convex-shaped insulating film, a diffusion layer, a conductive layer forming a fuse element, and a second insulating film, where fuse elements are trimmed by laser cutting to adjust resistance values and improve temperature sensing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a high power laser beam is used for laser-cutting a fuse in a short time period, then productivity is improved, but the heat may cause an adverse effect on the semiconductor substrate located below the fuse
Solution Approach 1:
A laser-resistant film is introduced as an intermediary layer between the fuse and the semiconductor substrate. This film absorbs the laser beam during the laser-cutting process, preventing the heat from reaching and damaging the substrate. The film acts as a mediator that enables high-power laser cutting while protecting the underlying substrate from thermal damage.
Solution Approach 2:
The laser-resistant film converts the potentially harmful laser heat into a beneficial protective function. By strategically placing the film between the laser source and the substrate, the harmful thermal energy is absorbed by the film rather than the substrate, transforming what would be a damaging effect into a protective mechanism that enables faster cutting.
2Ease of manufacture
If a temperature sensing diode is formed of a polysilicon layer on an oxide film, then the device can be manufactured, but the VF characteristics greatly vary, resulting in poor temperature sensing accuracy
Solution Approach 1:
The invention changes the material parameter of the temperature sensing diode from polysilicon to single-crystal silicon. This parameter change fundamentally improves the VF characteristics and temperature sensing accuracy while maintaining compatibility with the existing oxide film structure, thus preserving ease of manufacture.
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 solution effectively corrects variations in temperature sensing diode characteristics, enhancing the accuracy of temperature sensing and protecting IGBTs from overheating by precisely trimming fuse elements in the semiconductor device.
Implementation Method 1
a laser trimming fuse is configured such that a desired fuse element can be separated using a laser beam
Implementation Method 2
a first diffusion layer formed on the semiconductor substrate and provided to surround the first insulating film
Data Source
AI summary
A semiconductor device includes: a semiconductor substrate having a main surface; a first insulating film formed in a convex shape and provided on the main surface of the semiconductor substrate; a first diffusion layer formed on the semiconductor substrate and provided to surround the first insulating film formed in a convex shape, the first diffusion layer being different in conductivity type from the semiconductor substrate; a first conductive layer formed so as to extend across the first insulating film formed in a convex shape, the first conductive layer forming a fuse element; and a second insulating film provided on the first conductive layer.