Silicon Through-Hole Laser Processing via Etch Resist Defects
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Solution Overview
Problem
Conventional laser processing methods for forming through holes require a patterning step to inhibit etch resist film growth on modified regions, making the process complex and cumbersome, and may result in defects that affect the accuracy of the through hole formation.
Innovation Solution
The method inhibits etch resist film growth on modified regions by making it coarser or defect-prone, allowing etchant infiltration through defects for selective etching, eliminating the need for a patterning step and enabling accurate through hole formation without additional processing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a patterning step by exposure to light is added to form an opening in the etch resist film, then the through hole can be formed accurately, but the processing becomes complicated and cumbersome
Solution Approach 1:
The invention extracts and eliminates the patterning step from the conventional process by using laser processing to directly create the opening in the etch resist film over the modified region, thereby simplifying the overall processing while maintaining through hole formation accuracy
Solution Approach 2:
The invention replaces the optical patterning system (exposure to light) with a laser processing system that directly modifies the etch resist film, substituting a complex optical alignment and exposure process with a more direct laser-based approach
2Reliability
If the etch resist film is made dense and defect-free, then the etching is restrained, but the etchant cannot infiltrate into the modified region for selective etching
Solution Approach 1:
The invention applies local quality by creating a spatial variation in etch resist film density - the film is dense in most areas to provide protection, but has controlled defects or coarser structure specifically in the modified region to allow etchant infiltration, thus achieving both reliability and precision
3Manufacturing precision
If the etch resist film covers the whole area of the outer surface, then the through hole opening does not widen in excess, but an additional patterning step is required
Solution Approach 1:
The invention merges the functions of the etch resist film coverage and the opening formation into a single step - the laser processing simultaneously creates the modified region and the opening in the etch resist film, combining what were previously separate operations into one integrated process
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 allows for accurate and simplified formation of through holes, facilitating the processing by ensuring reliable etchant infiltration and preventing excessive widening of the through hole opening, while maintaining surface accuracy and securing insulation between through-hole electrodes.
Implementation Method 1
converging laser light at a sheet-like object to be processed so as to form a modified region within the object
Implementation Method 2
an etchant may infiltrate from the defects in the etch resist film into the modified region, thereby advancing the etching selectively along the modified region
Data Source
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AI summary
A laser processing method of converging laser light into an object to be processed made of silicon so as to form a modified region and etching the object along the modified region so as to form the object with a through hole comprises a laser light converging step of converging the laser light at the object so as to form the modified region along a part corresponding to the through hole in the object; an etch resist film producing step of producing an etch resist film resistant to etching on an outer surface of the object after the laser light converging step; and an etching step of etching the object so as to advance the etching selectively along the modified region and form the through hole after the etch resist film producing step; while the laser light converging step exposes the modified region to the outer surface of the object.