Wafer Protective Sheet Segmentation for Residue-Free Grinding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for disposing protective sheets on wafers with protruding electrodes result in adhesive layer residue on the electrodes after peeling, leading to quality degradation and potential disconnection issues during grinding processes.
Innovation Solution
A protective sheet disposing method involving a first protective sheet with a non-adhesive portion for the device region and an adhesive portion for the peripheral region, combined with a second adhesive-free sheet and liquid resin, ensures the electrodes are embedded and the adhesive layer is avoided on the electrodes, preventing damage and residue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective sheet with adhesive layer is affixed to the top surface of the wafer to protect protruding electrodes during grinding, then the wafer is prevented from being damaged, but adhesive layer remains on the protruding electrodes after peeling off the protective sheet
Solution Approach 1:
The protective sheet is divided into two distinct functional regions: a non-adhesive portion that contacts the device region with protruding electrodes, and an adhesive portion that contacts the peripheral surplus region. This segmentation allows the protective sheet to protect electrodes during grinding while preventing adhesive residue on the electrodes, as the non-adhesive portion can be cleanly peeled off without leaving residue.
Solution Approach 2:
Different regions of the protective sheet are given different adhesive properties: the non-adhesive portion has no adhesive layer to prevent residue on electrodes, while the adhesive portion has an adhesive layer to secure the sheet to the wafer periphery. This local differentiation of material properties resolves the contradiction between protection and residue-free peeling.
2Ease of operation
If the protective sheet is peeled off after grinding to access the protruding electrodes, then the electrodes become accessible for connection, but adhesive layer residue degrades quality and induces disconnection
Solution Approach 1:
By segmenting the protective sheet into non-adhesive and adhesive portions, the non-adhesive portion can be cleanly removed from the electrode region after grinding, providing electrode accessibility without adhesive residue that would compromise connection reliability.
Solution Approach 2:
The adhesive layer is extracted or removed from the region that contacts the protruding electrodes (the non-adhesive portion), ensuring that when the protective sheet is peeled off, no adhesive residue remains on the electrodes, thus maintaining connection reliability while still providing protection during grinding.
3Area of stationary object
If a single protective sheet covers both the device region and peripheral surplus region, then the entire wafer surface is protected, but adhesive layer cannot be avoided on the protruding electrodes
Solution Approach 1:
The protective sheet is segmented into a non-adhesive portion covering the device region and an adhesive portion covering the peripheral surplus region. This allows the entire wafer surface to be protected while ensuring the electrode region has no adhesive layer, maintaining manufacturing precision.
Solution Approach 2:
The protective sheet exhibits local quality differentiation where the non-adhesive portion has zero adhesive coverage for the device region, while the adhesive portion provides secure bonding on the peripheral surplus region. This local property variation enables full surface protection with adhesive-free electrode 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
This method effectively prevents wafer damage from protruding electrodes during grinding and eliminates adhesive layer residue, thereby maintaining device quality and preventing disconnections.
Implementation Method 1
dropping a liquid resin onto a region of the second protective sheet, the region corresponding to a center of the wafer; spreading the liquid resin over an entire surface corresponding to the wafer by the second protective sheet and the first protective sheet by pressing the wafer against the liquid resin
Data Source
AI summary
A protective sheet disposing method of disposing a protective sheet on a top surface of a wafer in which a device region having a plurality of devices formed thereon and a peripheral surplus region surrounding the device region are formed, the protective sheet disposing method including: a first protective sheet preparing step of preparing a first protective sheet having a non-adhesive portion corresponding to the device region and an adhesive portion having an adhesive layer laid on a periphery of the non-adhesive portion; a protective sheet affixing step of affixing the first protective sheet to the peripheral surplus region; a liquid resin dropping step of dropping a liquid resin onto a region of a second protective sheet; an integrating step of integrating the first protective sheet and the second protective sheet with each other; and a cutting step of cutting the first protective sheet and the second protective sheet.