Glue-Free Wafer Protective Sheet Bonding Without Wrinkling
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Solution Overview
Problem
Existing methods for attaching a glue-free sheet to a substrate, such as a semiconductor wafer, often result in wrinkling due to differential pressure and high temperatures, which can lead to adhesive residue issues.
Innovation Solution
A protective member attaching apparatus and method using a pressure reduction chamber with a heating unit and control system to soften and closely contact a thermoplastic resin sheet with the substrate, employing a temporary fixing section with a tack force and ventilation holes to prevent wrinkling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a sheet free of glue layer is compression-bonded to the substrate while softened by heat, then adhesive residue is eliminated, but the sheet becomes contracted and liable to be wrinkled
Solution Approach 1:
The patent applies parameter changes by controlling temperature and pressure conditions during the bonding process. The sheet is heated to soften it for bonding while maintaining controlled pressure differentials to prevent excessive contraction and wrinkling, thus eliminating adhesive residue while minimizing shape distortion
Solution Approach 2:
The patent replaces traditional mechanical compression bonding with a pressure differential system using vacuum chambers. By creating pressure differentials between chambers rather than applying direct mechanical compression, the sheet is bonded more uniformly with reduced risk of wrinkling while still achieving glue-free attachment
2Ease of manufacture
If a sheet is fixed only at an outer periphery in a pressure reduction chamber, then the sheet can be attached to the substrate, but the sheet swings in a sagging manner and becomes wrinkled
Solution Approach 1:
The patent divides the pressure reduction system into multiple chambers (first pressure reduction chamber and second pressure reduction chamber) with different pressure levels. This segmentation allows differential pressure control across different regions of the sheet, preventing sagging and wrinkling while enabling secure attachment at the outer periphery
Solution Approach 2:
The patent employs dynamic pressure control by varying pressure levels between chambers during the bonding process. The pressure differential is dynamically adjusted to maintain sheet tension and prevent wrinkling while allowing the sheet to be fixed at the outer periphery and bonded to the substrate
3Temperature
If the temperature inside the chamber is high to soften the sheet, then the sheet can be bonded to the substrate, but the sheet is contracted and liable to be wrinkled
Solution Approach 1:
The patent applies parameter changes by precisely controlling temperature and pressure parameters during bonding. The sheet is heated to softening temperature while pressure differentials are simultaneously controlled to counteract thermal contraction, preventing wrinkling while enabling effective bonding
Solution Approach 2:
The patent employs beforehand cushioning by pre-applying pressure differentials before and during heating. This compensates for the expected thermal contraction of the sheet, preventing wrinkling while allowing the temperature to rise sufficiently for bonding to occur
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
The solution effectively attaches a glue-free sheet to a substrate while minimizing wrinkling, ensuring secure adhesion without adhesive residue.
Implementation Method 1
a heating unit that heats the sheet to soften the sheet
Implementation Method 2
a control unit that controls the pressure reduction chamber and the heating unit to reduce pressures inside the upper housing and the lower housing, and thereafter softens and brings the sheet into close contact with the substrate mounted on the support table by a differential pressure generated by opening the upper housing to the atmospheric air
Implementation Method 3
the temporary fixing section is a support plate provided on a lower surface thereof with a resin layer for holding the sheet by a tack force
Data Source
AI summary
A protective member attaching apparatus includes a pressure reduction chamber having an upper housing and a lower housing, a support table that is provided inside the lower housing and on which a substrate is mounted, a sheet fixing section for fixing the sheet in such a manner as to partition the inside space of the pressure reduction chamber into a first space and a second space, a heating unit that heats the sheet to soften the sheet, and a control unit. The sheet fixing section has an outer periphery fixing section that fixes an outer periphery of the sheet, and a temporary fixing section that temporarily fixes a central portion of the sheet to the substrate mounted on a support table through a gap between the sheet and the substrate.