CMP Retaining Ring with Soft Bevel Scrubber and Spray Nozzles
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Solution Overview
Problem
Conventional chemical-mechanical-polishing (CMP) processes for semiconductor wafers often result in wafer scratches due to residue particles on the bevel regions, which are difficult to remove, leading to wafer failures and reduced yields.
Innovation Solution
A CMP polishing head with a retaining ring containing a soft material component and a rotationally flexible mechanism, along with integrated spray nozzles, is used to effectively scrub and rinse the bevel regions, preventing scratches by loosening and removing residue without cracking the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional CMP processes are used to polish wafer surfaces, then polishing function is achieved, but wafer scratches occur due to residue particles on bevel regions
Solution Approach 1:
The patent applies preliminary action by cleaning the bevel regions before the main polishing process. A cleaning head with spray nozzles removes residue particles from the bevel regions prior to polishing, preventing scratches during the subsequent polishing operation. This sequential approach eliminates harmful factors before they can cause damage.
Solution Approach 2:
The patent segments the polishing system into separate functional components: a cleaning head for removing residue particles from bevel regions, and a polishing head for polishing the wafer surface. This segmentation allows each component to perform its specific function optimally without interfering with the other, thereby improving overall wafer quality while preventing scratches.
2Reliability
If bevel regions are cleaned separately before polishing, then wafer scratches are reduced, but process time and equipment complexity increase
Solution Approach 1:
The patent merges the cleaning and polishing operations into a single integrated apparatus. The cleaning head with spray nozzles and the polishing head are combined in one device, allowing both cleaning and polishing to occur during the same process cycle. This integration eliminates the need for separate cleaning and polishing steps, reducing overall process time while maintaining wafer quality.
Solution Approach 2:
The integrated polishing head serves multiple functions: it includes both cleaning capabilities (via spray nozzles) and polishing capabilities (via polishing pads). This multi-functionality allows the single apparatus to perform both residue removal and surface polishing, eliminating the need for separate equipment and reducing process time while ensuring high wafer quality.
3Reliability
If separate cleaning equipment is used before polishing, then bevel defects are removed, but equipment complexity and cost increase
Solution Approach 1:
The patent combines separate cleaning equipment and polishing equipment into a single integrated apparatus. The cleaning head with spray nozzles and the polishing head are merged, allowing both functions to be performed by one device. This integration reduces equipment complexity and cost while maintaining the ability to effectively remove bevel defects and ensure high wafer quality.
Solution Approach 2:
The polishing head is designed with multi-functionality, incorporating both cleaning (spray nozzles) and polishing (polishing pads) capabilities. This universal design allows a single piece of equipment to perform multiple functions that previously required separate devices, thereby reducing overall equipment complexity and cost while ensuring effective bevel defect removal and high wafer 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 solution significantly reduces wafer scratches and improves yield by efficiently removing bevel defects during the polishing process, integrating cleaning into the polishing stage and reducing the need for separate cleaning equipment, thus saving time and cost.
Implementation Method 1
a component embedded in the retaining structure, wherein the component is softer than the wafer, and wherein the component is operable to make contact with a bevel region of the wafer
Implementation Method 2
spray nozzles that are rotatably coupled to the polishing head, wherein the spray nozzles are operable to dispense a cleaning solution to the bevel region of the wafer
Data Source
AI summary
The present disclosure provides an apparatus for fabricating a semiconductor device. The apparatus includes a polishing head that is operable to perform a polishing process to a wafer. The apparatus includes a retaining ring that is rotatably coupled to the polishing head. The retaining ring is operable to secure the wafer to be polished. The apparatus includes a soft material component located within the retaining ring. The soft material component is softer than silicon. The soft material component is operable to grind a bevel region of the wafer during the polishing process. The apparatus includes a spray nozzle that is rotatably coupled to the polishing head. The spray nozzle is operable to dispense a cleaning solution to the bevel region of the wafer during the polishing process.