Wafer Polishing Head Pressure Cavities for Accurate Loading Detection
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Solution Overview
Problem
The existing wafer polishing devices using single-cavity medium cavity and flexible single-cavity film with negative conduction mechanism face delays, misjudgment risks, and high risks of wafer fragments due to high pressure and inefficient loading state judgment.
Innovation Solution
A wafer polishing device with a second pressure medium cavity, a porous disc, and a conduction valve unit that employs a forward conduction mechanism, utilizing a conduction valve seat, conduction valve, and elastic part to facilitate accurate and timely judgment of wafer loading, reducing pressure on the wafer and eliminating the need for multiple gas pathways.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If negative conduction mechanism is used with single-cavity medium cavity, then device complexity is reduced, but measurement precision and response time deteriorate
Solution Approach 1:
The single-cavity medium cavity is segmented into multiple cavities (first medium cavity, second medium cavity, third medium cavity) with independent conduction paths. Each cavity has its own conduction valve that can be independently controlled, allowing precise detection of wafer loading states in different regions without requiring a single complex sensing mechanism.
Solution Approach 2:
Conduction valves are introduced as intermediary components between the medium cavities and the detection system. These valves act as controlled mediators that regulate the transmission of pressure signals from the cavities to the detection mechanism, enabling precise control over when and how loading states are detected, thereby improving measurement precision and response time.
2Device complexity
If negative conduction mechanism is used, then device complexity is reduced, but productivity deteriorates due to delayed loading state judgment
Solution Approach 1:
The conduction valves are designed to enable preliminary detection of wafer loading states before the complete loading process finishes. By having multiple cavities with independent conduction paths, the system can detect loading status in advance through selective conduction, allowing the polishing head to prepare for subsequent operations without waiting for full loading completion, thereby improving productivity.
Solution Approach 2:
The conduction valves are designed to enable preliminary detection of wafer loading states before the complete loading process finishes. By having multiple cavities with independent conduction paths, the system can detect loading status in advance through selective conduction, allowing the polishing head to prepare for subsequent operations without waiting for full loading completion, thereby improving productivity.
3Measurement precision
If high negative pressure is applied to achieve conduction, then measurement precision improves, but harmful factors increase due to wafer fragment risk
Solution Approach 1:
Instead of applying high negative pressure uniformly across the entire wafer surface, the system applies pressure selectively through specific conduction valves and cavities. The conduction valves control the distribution and magnitude of negative pressure in each cavity, applying just enough pressure to achieve reliable conduction and loading state detection without exceeding the threshold that would cause wafer fragmentation.
Solution Approach 2:
Different regions of the wafer are subjected to different pressure conditions through the multiple cavities. Each cavity can independently apply or release negative pressure based on local loading conditions, allowing precise control that achieves accurate detection while minimizing the risk of wafer damage by avoiding excessive uniform pressure.
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 solution enables faster, more accurate, and safer judgment of wafer loading states, reducing the risk of wafer fragments and lowering costs by eliminating the need for multiple gas pathway systems.
Implementation Method 1
by pressurizing the medium cavity inside the polishing head, the flexible film connecting with the medium cavity expands, contacts with the wafer and gradually eliminates the air and liquid between the flexible film and the wafer; after the wafer and the flexible film tightly contact, release negative pressure into the medium cavity; under upward and negative atmospheric force, the wafer adsorbed onto the flexible film can be ideally loaded onto the polishing head
Implementation Method 2
release negative pressure into the medium cavity; under upward and negative atmospheric force, the wafer adsorbed onto the flexible film can be ideally loaded onto the polishing head
Data Source
AI summary
The present invention discloses a wafer polishing device, which comprises a second pressure medium cavity for detecting pressure changes; a porous disc with a plurality of through holes, and its lower surface is covered with a flexible single cavity film; a conduction valve unit for conduction or isolation between the second pressure medium cavity and the third pressure medium cavity, which at least includes a conduction valve seat, a conduction valve and an elastic part. The lower end of the conduction valve seat extends into the through hole, and protrudes from the lower end face of the conduction valve seat; The conduction valve seat, the porous disc and the covered flexible single cavity membrane combined to form the third pressure medium cavity; a first pressure medium cavity.