Wafer Surface Etching Using Pre-Ground Recessed Thickness Profiles
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Solution Overview
Problem
Existing methods for etching semiconductor wafers, such as those described in Patent Document 1, fail to adequately control the surface shape of the wafer, particularly under the discharge nozzle, leading to uneven etching amounts at the central and peripheral portions.
Innovation Solution
A substrate processing method that involves grinding the substrate to form a recessed center, measuring thickness distribution, calculating optimal etching conditions, and etching the substrate with a movable nozzle to optimize etching amount deviation, ensuring uniform etching across the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional spin etching is used to etch the wafer surface, then the etching process can be completed, but the etching amount becomes uneven between the central portion (under the nozzle) and peripheral portions, resulting in poor surface shape control
Solution Approach 1:
The patent applies preliminary action by performing a grinding process before etching to create a recessed center shape on the wafer surface. This pre-shaping of the surface allows the subsequent spin etching process to achieve uniform etching amounts across the entire surface, including the central portion under the nozzle, thereby resolving the uneven etching problem while maintaining good surface shape control
Solution Approach 2:
The patent changes the physical parameter of the wafer surface shape by creating a recessed center through grinding. This parameter change in the surface topography modifies how the etching liquid flows and distributes during spin etching, enabling uniform etching amounts across the surface and improving both surface shape control and etching uniformity
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 allows for precise control of the substrate's surface shape during etching, achieving uniformity and consistency in the etched surface profile.
Implementation Method 1
grinding a first surface of the substrate to form, on the first surface, a recess portion
Implementation Method 2
etching, under the optimal etching condition, the first surface of the substrate after being ground by supplying an etching liquid to the first surface
Data Source
AI summary
A substrate processing method of processing a substrate includes grinding a first surface of the substrate to form, on the first surface, a recess portion whose center is more depressed than an outer peripheral portion thereof; measuring a thickness of the substrate after being ground, to acquire a thickness distribution of the substrate; calculating, based on the thickness distribution, an optimal etching condition for optimizing an etching amount deviation distribution when etching the first surface; and etching, under the optimal etching condition, the first surface of the substrate after being ground by supplying an etching liquid to the first surface from an etching liquid supply.