Silicon Substrate Through Hole Burr Prevention
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Solution Overview
Problem
The existing methods for forming through holes in silicon substrates for liquid discharge heads, such as ink jet heads, often result in the formation of burrs (crown) during the dry etching process, which can obstruct liquid flow and contaminate the discharge, increasing manufacturing complexity and costs.
Innovation Solution
A substrate processing method that forms a through hole by creating a communication portion wider than the opening of the first hole between the first and second holes during dry etching, preventing the formation of burrs by scraping off the edge portion of the first hole's side wall continuous with the second hole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dry etching is performed to form through holes in silicon substrate, then through holes can be formed perpendicular to substrate surface, but burrs (crown) are formed at the opening edge portions of holes
Solution Approach 1:
The patent applies preliminary action by forming a protective film on the side walls of holes before performing the etching operation that would create burrs. This protective film is deposited in advance to prevent the formation of unwanted material at the hole openings during the subsequent etching process
Solution Approach 2:
The patent converts the harmful effect of etching that creates burrs into a beneficial process by using the same etching conditions to selectively remove the protective film from specific areas. The protective film serves dual purposes: preventing burr formation during etching, and being selectively removed to create the desired hole pattern
2Reliability
If additional steps are performed to remove burrs after etching, then liquid flow obstruction is prevented, but manufacturing complexity and costs increase
Solution Approach 1:
The patent extracts the burr prevention function from a separate post-etching removal step and integrates it into the etching process itself by using protective films. This eliminates the need for additional dedicated steps to remove burrs, as the protective film prevents their formation in the first place
Solution Approach 2:
The patent merges multiple functions into the etching process: the protective film simultaneously protects side walls during etching, prevents burr formation, and serves as a mask for defining the final hole pattern. This consolidation eliminates separate steps for burr removal and hole patterning
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 ensures unobstructed liquid flow and prevents burrs from detaching as foreign objects, simplifying the manufacturing process and reducing costs by eliminating the need for additional steps to address burrs.
Implementation Method 1
a reaction gas is introduced into a processing chamber and transformed into plasma, and one of the surfaces of the substrate, which is to be processed, is etched by using the reaction gas, which has been transformed into plasma
Data Source
AI summary
A substrate processing method includes forming a first hole in a first surface of a silicon substrate to have a depth that it does not extend through the substrate and forming a second hole in a second surface to make the second hole to communicate with the first hole, so that a through hole formed of the first and second holes is formed in the substrate. The process of forming the second hole includes forming a communication portion wider than an opening of the first hole between the first and second holes after the second hole has been made to communicate with the first hole by dry etching.