Compliant Collet Locating Structure for Thermal Shift Restraint

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Solution Overview

Problem

Conventional methods for restricting positional shifts of a collet in semiconductor die bonding systems face challenges due to thermal expansion and friction, leading to misalignment and potential damage, with rigid stoppers either causing stress concentrations or failing to prevent shifts effectively.

Innovation Solution

A bond head assembly with a compliant locating structure featuring flexural elements that deflect to exert biasing forces against the collet, accommodating thermal expansion and misalignment, and distributing stress across a larger area to prevent positional shifts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If rigid stoppers are used to restrict positional shifts of the collet, then the collet is mechanically constrained to limit shifts, but the stoppers cause stress concentrations on the collet and may lead to cracking

Engineering Contradiction:

Improvepositional stability of colletVSAvoidstress concentration on collet

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces rigid stoppers with flexible lips that can deflect and accommodate thermal expansion of the collet. The flexible lips are formed from a single piece of material and positioned to contact the collet at multiple points, providing restraint without creating stress concentrations that would cause cracking.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the mechanical properties of the restraining structure from rigid to flexible. The flexible lips can dynamically adjust their stiffness and contact force based on thermal conditions, allowing them to accommodate thermal expansion while still preventing excessive positional shifts.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If rigid stoppers are positioned to contact the collet after thermal expansion, then positional shifts are restricted, but it is nearly impossible to ensure precise gap spacing leading to either cracking or residual gaps

Engineering Contradiction:

Improvegap spacing between stoppers and colletVSAvoidassembly complexity of rigid stoppers

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The flexible lips eliminate the need for precise gap spacing by accommodating thermal expansion through their flexibility. The lips are positioned to contact the collet and can deflect to allow for thermal growth without requiring exact pre-calculated gaps, significantly simplifying assembly.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The flexible lips automatically adjust their position and contact force in response to thermal expansion of the collet, eliminating the need for manual adjustment or precise pre-positioning. The structure self-regulates to maintain appropriate contact without causing stress concentrations.

Inventive Principle:

Principle #25Self-service

3Manufacturing precision

If the collet is continually repositioned relative to the heater to correct positional shifts, then alignment precision is improved, but the machine cycle time increases and throughput decreases

Engineering Contradiction:

Improvealignment precision of collet to dieVSAvoidmachine throughput

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The flexible lips are pre-positioned to contact the collet and prevent positional shifts before they occur during the bonding process. This proactive restraint eliminates the need for continual repositioning and alignment corrections, maintaining precision without reducing throughput.

Inventive Principle:

Principle #10Preliminary action

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 compliant locating structure enhances bonding quality and throughput by automatically aligning the collet, reducing the risk of damage and maintaining precise positioning during thermal cycles.

Implementation Method 1

Each of the first and second flexural elements is arranged such that a portion thereof is deflectable by movement of the collet against the flexural element, thereby causing the first or second flexural element to exert a biasing force

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

After the collet undergoes heating and cooling by the heater through multiple bonding cycles, it has been observed that the position of the collet relative to the heater may shift in different directions along a plane on which the collet is secured

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS20260018557A1Compliant locating structure for a bond head assembly

Publication Date: 2026.01.15 ASMPT SINGAPORE PTE LTD

AI summary

A bond head assembly includes a collet and a planar compliant locating structure having a plane. The collet is operative to hold a die during a bonding process. The planar compliant locating structure includes a first flexural element that is positioned to contact a first side surface of the collet and a second flexural element that is positioned to contact a second side surface of the collet. The first and second side surfaces of the collet are substantially orthogonal to each other. Each of the first and second flexural elements is arranged such that a portion thereof is deflectable by movement of the collet against the flexural element, thereby causing the first or second flexural element to exert a biasing force against the first or second side surface of the collet along the plane of the compliant locating structure to restrict positional shifts of the collet towards the flexural element.