Wafer Tape Peeling via Expanding Sheet Tension
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Solution Overview
Problem
When peeling off surface protective tape from a workpiece with division starting points along intersecting planned dividing lines, the chips often come into contact and get damaged due to the lack of sufficient tension in the expanding sheet, especially as chip size decreases.
Innovation Solution
A method involving affixing the workpiece's undersurface to an expanding sheet, preliminary expanding the sheet, peeling the tape while the sheet is expanded, and further expanding it to create sufficient intervals between chips, with the peeling direction set differently from the dividing lines to prevent chip contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the workpiece is held via an expandable flexible sheet during tape peeling, then the workpiece can be processed with some flexibility, but the workpiece cannot be firmly fixed and chips may come into contact and be damaged
Solution Approach 1:
The expanding sheet is expanded in advance before the surface protective tape is peeled off. This preliminary expansion creates sufficient tension in the sheet to firmly hold the workpiece and prevent chip contact during the subsequent tape peeling operation, while still maintaining the flexibility of the expandable sheet holding method.
2Ease of operation
If the expanding sheet is not expanded sufficiently, then the workpiece can be held during processing, but chips come into contact with each other and are damaged when handled
Solution Approach 1:
The expanding sheet is expanded preliminarily before tape peeling to establish sufficient chip separation. This ensures that when the workpiece is handled after processing, the chips remain separated and undamaged, while still allowing the workpiece to be held securely during the operation.
3Ease of manufacture
If the surface protective tape is peeled off before expanding the sheet, then the tape can be removed, but the workpiece breaks into individual chips and they come into contact and are damaged
Solution Approach 1:
The expanding sheet is expanded in advance before the surface protective tape is peeled off. This preliminary expansion creates the necessary chip separation and tension in the sheet to prevent chip damage during tape removal, allowing the tape to be peeled off smoothly without causing workpiece breakage or chip contact.
Solution Approach 2:
The expanding sheet is expanded beforehand to create a counteracting force that prevents the harmful effect of chip contact during tape peeling. The tension in the pre-expanded sheet opposes the forces that would otherwise cause chips to come into contact and be damaged during the tape removal process.
Data Source
AI summary
In a processing method, a surface protective tape peeling step of peeling a surface protective tape off the top surface of a wafer is performed in a state in which an expanding sheet is expanded while a preliminary expanding step of expanding the expanding sheet is performed after an affixing step is performed. Therefore, the surface protective tape can be peeled off the top surface of the wafer while a tension is applied to the expanding sheet. It is thereby possible to prevent chips from coming into contact with each other and being damaged. When an expanding step is thereafter performed, the expanding sheet is expanded by an amount of expansion which amount is a value larger than an amount of expansion of the expanding sheet in the preliminary expanding step. Thus, sufficient intervals can be formed between the chips, and the chips can be transported smoothly.