Blended Contact Fingers for Thin Substrate Crack Prevention

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Solution Overview

Problem

Thin substrates, such as semiconductor wafers, are prone to cracking and chipping during electroplating due to insufficient support and adherence issues with carrier substrates, leading to handling and processing challenges.

Innovation Solution

The design of blended contact fingers with varying lengths and profiles that provide both electrical connection to the substrate and lift to prevent sticking, while minimizing the risk of cracking, includes a combination of longer first contact fingers for electrical contact and shorter second contact fingers for lift, which are configured to contact the carrier substrate and seed layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single type of contact finger is used, then the structure is simple, but it cannot simultaneously provide stable electrical contact and prevent substrate cracking

Engineering Contradiction:

Improvesubstrate crack preventionVSAvoidcontact finger structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The contact finger is divided into multiple segments with different lengths: first contact fingers extend further to contact the substrate for electrical connection, while second contact fingers are shorter to contact the carrier substrate for lift. This segmentation allows each segment to perform its specific function optimally without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the contact structure have different properties: the first contact fingers have greater length for stable electrical contact with the substrate, while the second contact fingers have shorter length for providing lift. This local differentiation of geometric properties enables simultaneous achievement of electrical connectivity and crack prevention.

Inventive Principle:

Principle #3Local quality

2Reliability

If longer contact fingers are used for electrical contact, then electrical connection is stable, but the risk of substrate cracking increases

Engineering Contradiction:

Improveelectrical connection stabilityVSAvoidsubstrate cracking risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The contact structure is segmented into first contact fingers (longer, for electrical contact) and second contact fingers (shorter, for lift). By separating these functions into distinct segments, the patent achieves stable electrical connection through the longer fingers while the shorter fingers provide lift to prevent cracking, resolving the contradiction between connection stability and crack prevention.

Inventive Principle:

Principle #1Segmentation

3Object-affected harmful factors

If shorter contact fingers are used for lift, then substrate cracking is prevented, but electrical connection stability decreases

Engineering Contradiction:

Improvesubstrate cracking preventionVSAvoidelectrical connection stability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The contact structure is segmented into first contact fingers (longer, for electrical contact) and second contact fingers (shorter, for lift). The longer first contact fingers ensure stable electrical connection to the substrate, while the shorter second contact fingers provide the necessary lift to prevent cracking, thus resolving the contradiction between crack prevention and connection stability.

Inventive Principle:

Principle #1Segmentation

4Ease of manufacture

If uniform contact fingers are used, then manufacturing is simple, but handling precision during thin substrate processing is insufficient

Engineering Contradiction:

Improvecontact finger manufacturingVSAvoidsubstrate handling precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The contact finger structure is segmented into multiple types with different lengths and functions. This segmentation enables precise control over substrate interaction: longer fingers for electrical contact and shorter fingers for lift, thereby achieving high handling precision for thin substrates while maintaining manufacturability through systematic design.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different segments of the contact structure have different geometric properties optimized for their specific functions. The first contact fingers have greater length for electrical contact stability, while the second contact fingers have shorter length for precise lift control. This local differentiation of properties enables precise substrate handling while remaining manufacturable.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20230175161A1Blended contact fingers for preventing cracks during thin substrate handling

Publication Date: 2023.06.08 LAM RES CORP

AI summary

A contact for providing a connection to a substrate in a substrate plating system includes a body having an arcuate shape. The arcuate shape of the body is configured to conform to a shape of at least a portion of a substrate arranged on a lip seal and a cup of the substrate plating system. A plurality of first contact fingers extend a first distance from the body. A plurality of second contact fingers extend a second distance from the body. The first distance is greater than the second distance.