High Breakdown Voltage Passive Element Thermal Warping
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Solution Overview
Problem
The manufacturing process of high breakdown voltage passive elements is hindered by warping of semiconductor wafers due to differences in thermal expansion rates between the substrate and insulating films, leading to processing failures, cracking, and misalignment issues.
Innovation Solution
A high breakdown voltage passive element is designed with an insulating unit comprising a first insulating film with a lower thermal expansion rate and a second insulating film with a higher thermal expansion rate, strategically stacked to offset warping, using materials like plasma TEOS and polyimide films, and formed at temperatures that preserve the properties of already deposited films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single insulating film is formed on the substrate, then the insulation performance is achieved, but warping of the substrate occurs due to thermal expansion mismatch
Solution Approach 1:
The insulating film is segmented into multiple layers with different thermal expansion coefficients. The first insulating film (lower thermal expansion) and second insulating film (higher thermal expansion) are stacked to create a composite structure that balances thermal stresses and prevents substrate warping while maintaining insulation performance.
Solution Approach 2:
A composite insulating structure is formed by stacking materials with different thermal expansion properties. The first insulating film (e.g., plasma TEOS with lower thermal expansion) and second insulating film (e.g., polyimide with higher thermal expansion) create a composite that compensates for thermal mismatch with the substrate, eliminating warping.
2Reliability
If high breakdown voltage is achieved through thick insulating films, then insulation performance improves, but substrate warping increases
Solution Approach 1:
The thick insulating film required for high breakdown voltage is divided into multiple segments (first and second insulating films) with different thermal expansion coefficients. This segmentation allows the total thickness to be maintained for electrical insulation while the differential thermal expansion between layers compensates for substrate warping.
Solution Approach 2:
The thermal expansion parameters of the insulating structure are changed by selecting materials with different coefficients. The first insulating film has lower thermal expansion than the substrate, while the second has higher thermal expansion, creating a balanced composite that achieves both high voltage insulation and warping prevention.
3Stability of the object's composition
If multiple insulating films with different thermal expansion rates are stacked, then substrate warping is reduced, but manufacturing process complexity increases
Solution Approach 1:
The manufacturing process controls the thickness parameters of each insulating film layer to achieve the desired thermal expansion balance. By carefully selecting thickness ratios between the first and second insulating films, the patent reduces substrate warping while maintaining a manageable manufacturing process using standard deposition techniques.
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 configuration effectively reduces warping of the substrate to less than 100 μm, preventing processing failures, cracking, and misalignment, while ensuring high breakdown voltage and efficient insulation.
Implementation Method 1
the insulating unit has a first insulating film whose thermal expansion rate is lower than the thermal expansion rate of the substrate, and a second insulating film, formed on the first insulating film, whose thermal expansion rate is higher than the thermal expansion rate of the substrate
Data Source
AI summary
Warping of a semiconductor wafer occurring due to a difference in the thermal expansion rates of an insulating film and the semiconductor wafer is restricted. Therefore, processing failures and conveying failures in the manufacturing process, as well as cracking of the semiconductor wafer, are restricted. Provided is a high breakdown voltage passive element including a substrate, a lower metal layer and upper metal layer stacked on the substrate, and an insulating unit formed between the lower metal layer and upper metal layer, wherein the insulating unit has a first insulating film whose thermal expansion rate is lower than the thermal expansion rate of the substrate, and a second insulating film, formed on the first insulating film, whose thermal expansion rate is higher than the thermal expansion rate of the substrate.