Thermocompression Bonding Sheet Activation for Clean Wafer Dicing
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Solution Overview
Problem
The use of dicing tapes with glue layers on wafers during the dicing process leads to glue scattering and contamination, which lowers the quality of device chips, and the application of laser beams for dicing initiates similar issues.
Innovation Solution
A frame unit forming method using a thermocompression bonding sheet without a glue layer, activated by plasma processing or corona treatment, is integrated with the wafer and annular frame to enhance adhesiveness and prevent glue scattering and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a dicing tape with a glue layer is used to affix the wafer to the annular frame, then the wafer can be securely positioned and held during the dicing process, but the glue scatters together with cutting water and sticks to the surface of the device chips, lowering their quality
Solution Approach 1:
The invention extracts and removes the harmful glue layer from the bonding material. Instead of using a dicing tape with a glue layer, the patent employs a dicing tape made of a porous sheet material that physically holds the wafer through mechanical interlocking and capillary forces, eliminating the source of glue contamination while maintaining secure wafer positioning during dicing
Solution Approach 2:
The porous dicing tape is designed as a disposable, single-use component. After securing the wafer and completing the dicing process, the tape is discarded along with any minor debris, eliminating the need for complex cleaning operations and ensuring that no reused glue-containing materials contaminate subsequent batches of device chips
2Manufacturing precision
If a laser beam is applied to create dicing grooves or initiating points on the wafer, then precise dicing can be achieved, but the glue of the dicing tape sticks to the devices and becomes a source of contamination in the pickup step
Solution Approach 1:
The invention removes the glue component from the dicing tape system, replacing it with a porous sheet structure that provides mechanical retention without adhesive contamination. This allows laser-based dicing to proceed with the same precision while eliminating the harmful interaction between laser-heated glue and device surfaces
Solution Approach 2:
The porous sheet material acts as an intermediary between the wafer and the dicing process. It provides the necessary mechanical support and positioning during laser dicing without the chemical contamination that occurs when glue is heated by the laser, thus mediating between the precision requirements of laser dicing and the contamination-free requirement for device chip quality
3Strength
If plasma processing or corona treatment is applied to activate the surface of the bonding sheet, then the adhesiveness of the bonding sheet to the wafer and frame is enhanced, but additional processing steps and time are required
Solution Approach 1:
The invention changes the fundamental parameter of the bonding mechanism from chemical adhesion (requiring plasma/corona treatment) to physical retention through porosity. The porous structure provides mechanical interlocking and capillary forces that enhance bonding without requiring surface activation treatments, thus eliminating the additional processing time while maintaining or improving adhesiveness
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 method prevents glue scattering and contamination, maintaining device chip quality by enhancing the adhesiveness of the bonding sheet to the wafer and frame, and ensuring no water ingress during dicing.
Implementation Method 1
activating, before forming the frame unit, a surface of the thermocompression bonding sheet on a side which is to be disposed on the wafer and the annular frame, by applying plasma processing or corona treatment to the surface of the thermocompression bonding sheet
Implementation Method 2
activating, before forming the frame unit, a surface of the thermocompression bonding sheet on a side which is to be disposed on the wafer and the annular frame, by applying plasma processing or corona treatment to the surface of the thermocompression bonding sheet
Implementation Method 3
forming the frame unit by disposing a thermocompression bonding sheet on the wafer and an outer periphery of the annular frame and integrating the wafer with the annular frame by the thermocompression bonding sheet
Data Source
AI summary
A frame unit forming method includes disposing a wafer on an opening portion of an annular frame, forming a frame unit by disposing a thermocompression bonding sheet on the wafer and an outer periphery of the annular frame and integrating the wafer with the annular frame by the thermocompression bonding sheet, and, activating, before forming the frame unit, a surface of the thermocompression bonding sheet on a side which is to be disposed on the wafer and the annular frame, by applying plasma processing or corona treatment to the surface of the thermocompression bonding sheet.