Semiconductor Wafer Back-Grinding Defect Reduction
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Solution Overview
Problem
Current semiconductor wafer processing methods, such as back-grinding using flip chip ball grid array (FCBGA) and through silicon vias (TSV), face defects like bubbling, warpage, and breakage due to improper taping pressure and speed, or adhesive application pressures not within acceptable ranges.
Innovation Solution
The implementation of pressure and position sensors integrated into chuck and support tables to monitor and control the application of lamination tape and adhesive pressure during the back-grinding process, using computer-implemented statistical process control to ensure parameters are within predetermined limits, thereby pausing and adjusting the process to prevent defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If taping pressure and speed are increased to improve lamination efficiency, then productivity increases, but bubbling of tape occurs causing impurities and wafer breakage
Solution Approach 1:
The system incorporates sensors that continuously monitor taping pressure and speed parameters, providing real-time feedback to the control system. This feedback mechanism enables dynamic adjustment of process parameters to maintain optimal conditions, preventing both bubbling defects and maintaining high productivity through precise control rather than relying on fixed high-pressure/high-speed settings
Solution Approach 2:
The invention implements dynamic modification of taping parameters (pressure and speed) based on real-time process conditions and sensor data. Rather than using constant high pressure and speed for productivity, the system adjusts these parameters within optimal ranges to prevent defects while maintaining efficient lamination, resolving the contradiction between productivity and reliability
2Reliability
If adhesive application pressure is increased to improve bonding strength, then reliability of carrier bonding increases, but wafer warpage and breakage occur during back-grinding
Solution Approach 1:
Sensors monitor adhesive application pressure in real-time, providing feedback to the control system to maintain pressure within optimal ranges. This prevents both insufficient bonding and excessive pressure that would cause wafer warpage and breakage, resolving the contradiction between bonding strength and wafer structural integrity
Solution Approach 2:
The system dynamically adjusts adhesive application pressure based on wafer properties and process conditions, modifying the pressure parameter to achieve adequate bonding without exceeding thresholds that would compromise wafer structural integrity during subsequent back-grinding operations
3Manufacturing precision
If taping pressure is reduced to prevent bubbling and impurities, then manufacturing precision improves, but lamination efficiency and productivity decrease
Solution Approach 1:
Real-time sensor feedback enables the system to maintain precisely controlled taping pressure that prevents bubbling and impurities while optimizing lamination speed and other parameters to sustain high productivity. The feedback loop allows dynamic compensation that maintains quality without requiring consistently low pressure settings
Solution Approach 2:
The system transitions from static, fixed pressure settings to dynamic pressure control that adapts to real-time conditions. This dynamic approach allows the taping process to maintain high precision through active control while sustaining high productivity through optimized parameter combinations that would be impossible with fixed low-pressure settings
Data Source
AI summary
A system for reducing processing defects during processing of a semiconductor wafer prior to back-grinding the wafer includes a table having one or more holes formed therein, wherein the table comprises at least one of a chuck table or a support table, wherein the holes are perpendicular to the surface upon which a pre-back-grinding (PBG) process occurs. The system further includes one or more sensors disposed in said holes for monitoring a parameter during the PBG process. The system further includes a computer-implemented process control tool coupled with the one or more sensors and configured to determine whether the PBG process will continue.