Wafer Laser Processing Chamber With High-Pressure Bubble Suppression
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Solution Overview
Problem
Laser processing in wafer fabrication generates bubbles in the liquid medium, hindering the application of the laser beam and causing debris to adhere to the workpiece, leading to quality degradation and productivity issues.
Innovation Solution
A laser processing apparatus with a chamber that supplies liquid under high pressure to compress bubbles and prevent their interference with the laser beam, eliminating the need for pre-coating the workpiece with liquid resin and ensuring debris does not adhere to the workpiece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If liquid resin is applied to the front side of the wafer to prevent debris adherence, then device quality is improved, but productivity deteriorates due to additional coating and removal steps
Solution Approach 1:
The harmful liquid resin coating step is extracted and removed from the process. Instead of applying liquid resin to protect the wafer, the invention uses a liquid medium in a chamber to suppress bubbles and capture debris, eliminating the need for pre-coating and post-removal steps while maintaining device quality
Solution Approach 2:
A liquid medium is introduced as an intermediary substance in the chamber that serves dual functions: suppressing bubble formation through high pressure and capturing laser processing debris. This intermediary liquid replaces the need for liquid resin coating on the wafer surface
2Manufacturing precision
If wafer is immersed in water to prevent debris adherence, then device quality is improved, but laser processing is hindered by fine bubbles generated in the water
Solution Approach 1:
High pressure hydraulic control is applied to the liquid medium in the chamber. By maintaining high pressure (e.g., 1-10 atm) on the liquid, bubble formation is suppressed and existing bubbles are compressed, preventing laser beam hindrance while maintaining the liquid's debris-capturing function
Solution Approach 2:
The pressure parameter of the liquid medium is changed and elevated to high levels. This parameter change fundamentally alters the liquid's behavior regarding bubble formation, transitioning from bubble-prone conditions to bubble-suppressed conditions, thereby enabling stable laser processing
3Reliability
If liquid is used to suppress bubbles under high pressure, then laser beam transmission is improved, but device quality may deteriorate if debris adheres to the workpiece
Solution Approach 1:
The liquid medium acts as an intermediary that serves dual functions: suppressing bubbles through high pressure to ensure laser beam transmission, and capturing debris through the liquid's ability to trap particles. The chamber design allows the liquid to flow and collect debris away from the wafer surface
Solution Approach 2:
Debris is extracted from the potential contamination path by allowing it to be captured and removed with the liquid flow in the chamber, preventing adherence to the wafer while maintaining laser processing quality
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 apparatus effectively prevents bubble hindrance and debris adherence, maintaining the quality of the processed devices and improving productivity by maintaining high pressure in the chamber to compress bubbles and efficiently manage debris.
Implementation Method 1
liquid supplying means supplying the liquid into the enclosed space of the chamber to make a condition that the enclosed space is filled with the liquid under a predetermined pressure and that the liquid discharged from the outlet opening of the chamber is allowed to flow through the spacing, thereby compressing bubbles generated in the liquid by the application of the laser beam to the workpiece
Implementation Method 2
the top wall having a transparent plate located directly below the focusing means and allowing pass of the laser beam applied from the focusing means
Implementation Method 3
A laser beam having an absorption wavelength to a workpiece is applied to the workpiece in the condition where the focal point of the laser beam is set on the front side (upper surfaces of the workplace, thereby performing ablation
Data Source
AI summary
A laser processing apparatus includes a laser beam applying unit having a focusing unit applying a laser beam to a workpiece held on a chuck table, a feeding mechanism relatively moving the chuck table and the laser beam applying unit, and a chamber having a top wall connected to the focusing unit and a side wall connected to the top wall to define an enclosed space, the top wall having a transparent plate located directly below the focusing unit and allowing the pass of the laser beam applied from the focusing unit. The laser processing apparatus further includes a liquid supplying unit supplying a liquid into the enclosed space to make a condition that the enclosed space is filled with the liquid under a predetermined pressure.