CMP Retaining Ring with Insert-Blocked Alignment Slots
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The installation of incorrect retaining rings on carrier heads during chemical mechanical polishing (CMP) processes leads to quality control issues and substrate scrap, as visually identical rings require attentive installation.
Innovation Solution
A retaining ring design with a unique combination of alignment slots and inserts that only allow specific alignment pins from the carrier head to mate, ensuring only the correct retaining ring is installed, thereby preventing incorrect mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If retaining rings have identical top surfaces to facilitate attachment to the same carrier head, then ease of manufacture and assembly are improved, but the risk of incorrect installation increases because visual differentiation is lost
Solution Approach 1:
The patent applies local quality by making only specific localized changes to the retaining ring structure - adding inserts in certain alignment slots while leaving others open. This allows differentiation between retaining ring types without changing the overall design or top surface appearance, maintaining ease of attachment while enabling correct identification and installation.
Solution Approach 2:
The patent uses asymmetry by creating non-uniform patterns of inserts and open alignment slots. Each retaining ring type has a unique asymmetric configuration where specific slots contain inserts and others remain open, providing clear visual and physical differentiation while maintaining the same basic attachment interface.
2Device complexity
If retaining rings are visually identical except for product numbers stamped inside, then device complexity is reduced, but quality control difficulty increases because technicians must rely on attentiveness to install the correct ring
Solution Approach 1:
The patent applies preliminary action by pre-configuring the retaining rings with unique insert patterns during manufacturing. This preliminary differentiation is built into the ring structure itself, so that when technicians install rings, the correct identification and matching to carrier head types is already established, eliminating the need for careful visual inspection during installation.
Solution Approach 2:
The inserts act as intermediaries that provide the differentiation function. Rather than relying on technicians to visually identify and select the correct retaining ring, the inserts serve as physical mediators that enable the carrier head to receive only the correct ring type through complementary alignment slot configurations.
3Ease of operation
If alignment slots are all open to allow flexible installation, then ease of operation is improved, but the ability to prevent incorrect installation is lost
Solution Approach 1:
The patent applies segmentation by dividing the alignment slot configuration into distinct categories - some slots contain inserts while others remain open. This segmentation creates a coded pattern that provides installation guidance and prevention, while still maintaining operational ease through the straightforward align-and-install process.
Data Source
AI summary
A retaining ring used in the polishing of semiconductor substrates is described herein. A retaining ring includes a bottom surface configured to contact a polishing pad and a top surface configured to attach to a carrier head. The top surface includes a plurality of screw holes and a plurality of alignment slots. The top surface also includes a first insert disposed in a first alignment slot of the plurality of alignment slots, the first insert flush with or below the top surface, and where the first insert configured to prevent insertion of an alignment pin into the first alignment slot.