Wafer Processing Using Polyester Sheet Bonding
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Solution Overview
Problem
The existing wafer processing methods generate cutting dust from adhesive layers during wafer cutting, which adheres to device chips and degrades their quality, making it difficult to remove and leading to quality issues in device chips.
Innovation Solution
A wafer processing method using a polyester sheet without an adhesive layer for thermocompression bonding with the wafer and ring frame, allowing for clean cutting and easy removal of cutting dust, where the polyester sheet is heated and bonded to form a frame unit, and then cooled to facilitate device chip pickup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive tape is used to bond the wafer to the ring frame, then the wafer can be held securely during cutting, but cutting dust from the adhesive layer adheres to device chips and degrades quality
Solution Approach 1:
The patent removes the adhesive layer from the bonding system entirely. Instead of using adhesive tape, the wafer is bonded directly to the ring frame through mechanical friction and pressure during the cutting process. This extraction of the harmful adhesive layer eliminates the source of cutting dust adhesion while maintaining bonding functionality through alternative physical mechanisms.
Solution Approach 2:
The patent introduces cutting water as an intermediary substance between the cutting blade and the wafer. This cutting water serves multiple functions: it cools the cutting blade, lubricates the cutting process, and crucially, prevents cutting dust from adhering to the device chips on the wafer surface. The cutting water acts as a mediator that enables secure cutting while protecting the devices from dust contamination.
2Manufacturing precision
If the cutting blade is lowered deep enough to reliably divide the wafer, then complete separation is achieved, but the adhesive layer is also cut and generates harmful cutting dust
Solution Approach 1:
The patent extracts and removes the adhesive layer that causes harmful cutting dust generation. By eliminating the adhesive tape and bonding the wafer directly to the ring frame, the cutting process no longer cuts through an adhesive layer, thus preventing the generation of adhesive-related cutting dust while maintaining complete wafer division.
Solution Approach 2:
The patent uses cutting water as an intermediary that suppresses cutting dust generation and adhesion. The cutting water is supplied to the cutting zone where the blade contacts the wafer, creating a liquid medium that prevents dust particles from forming and adhering to the device chips, thereby solving the harmful effects of cutting dust.
3Stability of the object's composition
If adhesive tape is used to hold the wafer, then the wafer can be securely positioned, but cleaning cutting dust from device chips becomes difficult
Solution Approach 1:
The patent removes the adhesive tape that creates cleaning difficulties. By eliminating the adhesive layer, there is no sticky surface to trap and hold cutting dust particles, making the device chips much easier to clean. The wafer positioning stability is maintained through direct mechanical bonding to the ring frame without adhesive.
Solution Approach 2:
The patent employs cutting water as an intermediary that prevents cutting dust from adhering to device chips in the first place. By supplying cutting water during the cutting process, dust particles remain suspended in the liquid medium rather than adhering to the chip surfaces, dramatically simplifying subsequent cleaning operations.
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 prevents cutting dust from adhering to device chips, reducing the risk of quality degradation and enabling reliable cleaning, thus maintaining the integrity of device chips during the cutting process.
Implementation Method 1
Irradiating the polyester sheet with infrared rays, thereby heating the polyester sheet
Implementation Method 2
heating the polyester sheet as applying a pressure to the polyester sheet after performing the polyester sheet providing step, thereby uniting the wafer and the ring frame through the polyester sheet by thermocompression bonding
Implementation Method 3
cooling the polyester sheet in each of the plurality of separate regions corresponding to each device chip, pushing up each device chip through the polyester sheet
Data Source
AI summary
A wafer processing method includes a polyester sheet providing step of positioning a wafer in an inside opening of a ring frame and providing a polyester sheet on a back side of the wafer and on a back side of the ring frame, a uniting step of heating the polyester sheet as applying a pressure to the polyester sheet to thereby unite the wafer and the ring frame through the polyester sheet by thermocompression bonding, a dividing step of cutting the wafer by using a cutting apparatus to thereby divide the wafer into individual device chips, and a pickup step of cooling the polyester sheet, pushing up each device chip through the polyester sheet, and then picking up each device chip from the polyester sheet.