Plasma Etching Cover Member Shields Substrate Edge
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Solution Overview
Problem
During semiconductor device manufacturing, plasma etching leads to the formation of 'black silicon' at the substrate surface due to exposure of the bevel region, and the outer edge portion of substrates is prone to dust generation or separation when resist is removed, especially in stacked substrates, causing surface roughening and potential cracking.
Innovation Solution
A plasma etching apparatus with a cover member that supports the substrate and prevents plasma from reaching the outer edge portion, using a control unit to generate plasma for etching and ashing processes, ensuring the outer edge is protected throughout the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the resist is removed from the outer edge portion of the substrate before etching, then dust generation is prevented, but black silicon forms on the exposed substrate surface
Solution Approach 1:
The patent applies preliminary action by removing the resist from the outer edge portion before the etching process begins. This preliminary removal prevents the resist from coming off during transfer and causing dust generation later. The exposed substrate surface is then protected during etching to prevent black silicon formation.
Solution Approach 2:
The patent introduces a cover member as an intermediary element that covers the outer edge portion of the substrate during the etching process. This cover member acts as a mediator between the plasma and the exposed substrate surface, preventing direct contact between plasma and the substrate edge, thereby preventing black silicon formation while allowing the resist to be removed beforehand.
2Manufacturing precision
If the resist is kept on the outer edge portion to protect from plasma, then black silicon is prevented, but dust is generated when resist comes off during transfer
Solution Approach 1:
The patent performs the resist removal action in advance, before substrate transfer, so that no resist remains on the outer edge portion during transfer operations. This eliminates the source of potential dust generation while the cover member provides protection during etching.
Solution Approach 2:
The cover member serves as an intermediary that provides plasma protection during etching without requiring the resist to remain on the substrate edge. It replaces the resist's protective function while allowing the substrate edge to be clear of resist material.
3Productivity
If plasma is allowed to reach the outer edge portion, then complete etching is achieved, but substrate separation and cracking occur in stacked substrates
Solution Approach 1:
The patent segments the substrate processing area by introducing a cover member that specifically targets and protects only the outer edge portion. This allows the bulk of the substrate to undergo complete etching while the vulnerable edge region is shielded, preventing substrate separation and cracking.
Solution Approach 2:
The patent applies local quality by providing differential treatment to different regions of the substrate. The outer edge portion receives protective coverage while the central and inner regions undergo full plasma etching, allowing complete etching where needed while protecting vulnerable areas.
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
Prevents surface roughening of the substrate and reduces dust generation by effectively shielding the outer edge portion from plasma exposure, maintaining substrate integrity during etching and ashing processes.
Implementation Method 1
a plasma etching apparatus that performs plasma etching on a substrate
Implementation Method 2
a high frequency power supply that supplies high frequency power, and a control unit that generates plasma by controlling the supply of the high frequency power
Data Source
AI summary
A plasma etching apparatus performs plasma etching on a substrate having a resist pattern formed thereon and an outer edge portion where the substrate surface is exposed. The plasma etching apparatus includes a support part that supports the substrate, a cover member that covers the outer edge portion of the substrate and prevents plasma from coming around the outer edge portion, and a control unit that generates plasma by controlling high frequency power application and supply of a processing gas for etching, and uses the generated plasma to etch the substrate that is supported by the support part and has the outer edge portion covered by the cover member. After etching the substrate, the control unit generates plasma by controlling high frequency power application and supply of a processing gas for ashing, and uses the generated plasma to perform ashing on the resist pattern on the etched substrate.