Glass Substrate Through-Hole Formation via Excimer Laser
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Solution Overview
Problem
The challenge lies in forming micro through-holes in glass substrates for semiconductor devices without cracking, as existing methods are inefficient and prone to warpage, deformation, and complex processing steps, limiting their use in high-density mounting and wafer-level packaging applications.
Innovation Solution
A glass substrate with a specific thermal expansion coefficient and SiO2 content is produced using excimer laser light, with a mask and projection lens to form through-holes, optimizing the process for high precision and efficiency while minimizing cracking and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser light is emitted to form through-holes in glass substrate, then through-holes can be formed simultaneously, but glass brittleness causes cracks and formation difficulty
Solution Approach 1:
The patent changes the physical parameters of laser processing by using excimer laser with specific wavelength (193nm or 248nm) and controlling irradiation conditions (number of shots, irradiation amount per shot) to achieve clean through-hole formation in glass without causing cracks, resolving the contradiction between formation efficiency and substrate integrity
Solution Approach 2:
The patent applies periodic laser irradiation by controlling the number of shots (e.g., 1-10 shots) and irradiation intervals, allowing cumulative energy deposition that gradually forms through-holes without excessive heat accumulation that would cause cracking, thus maintaining both productivity and reliability
2Manufacturing precision
If wet etching or dry etching is used to form through-holes in glass, then through-holes can be formed, but process steps become complicated and processing time increases
Solution Approach 1:
The patent replaces complex chemical etching processes (wet etching/dry etching) with direct laser ablation using excimer laser, eliminating the need for multiple process steps including mask preparation, chemical exposure, and waste liquid disposal, thereby simplifying the overall manufacturing process while maintaining precision
Solution Approach 2:
The patent extracts the essential function of through-hole formation from the complex multi-step etching process and achieves it through a single laser irradiation step, removing unnecessary process complexity while preserving the core manufacturing capability
3Ease of manufacture
If resin insulating layer is used for through-holes, then through-holes can be easily formed, but positioning accuracy deteriorates due to warpage and deformation
Solution Approach 1:
The patent uses a composite structure combining glass substrate with specific thermal expansion coefficient (10×10^-7 to 50×10^-7/K) and resin layer, where the glass provides dimensional stability and positioning accuracy while the resin enables easy through-hole formation, resolving the contradiction between ease of manufacture and manufacturing precision
4Ease of manufacture
If silicon wafer is used for through-hole electrodes, then microfabrication is easier, but insulating treatment of inner wall is required and process becomes more complex
Solution Approach 1:
The patent uses glass substrate as a copy or alternative to silicon wafer for through-hole electrode applications, replicating the through-hole formation capability while eliminating the need for insulating treatment of inner walls, as glass inherently provides the required insulating properties, thus reducing process complexity
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 enables the simultaneous formation of micro through-holes in glass substrates, preventing exfoliation and deformation when laminated with silicon wafers, and achieving excellent device properties with low dielectric constant and loss.
Implementation Method 1
a process for producing the glass substrate by emitting excimer laser light to a plate glass thereby to form plural through-holes
Data Source
AI summary
It is an object of the present invention to provide a glass substrate having plural through-holes which is not likely to peel from a silicon wafer, even though laminated on and jointed to a the silicon wafer and then subjected to heat treatment. The above object is accomplished by a glass substrate having an average thermal expansion coefficient of from 10×10−7 to 50×10−7/K within a range of from 50° C. to 300° C., having plural through-holes with a taper angle of from 0.1 to 20° and having a thickness of from 0.01 to 5 mm.