Fine-Pitch HBM Test Apparatus Alignment

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Solution Overview

Problem

The challenge lies in accurately aligning and testing high-bandwidth memory (HBM) devices with small bumps and narrow pitches, as the distance from the edge to the center of the bumps is not uniform, leading to defective GPU configurations due to improper alignment during the sawing process.

Innovation Solution

A test apparatus featuring a vacuum chuck with alignment capabilities along X, Y, and θ axes, coupled with loading and unloading pickers, ensures precise alignment and electrical contact, utilizing primary and secondary vacuum pressures to maintain device position and temperature control, and includes a posture correction mechanism to adjust for machining and assembly tolerances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If devices with small bumps and narrow pitch are produced through sawing process, then high-performance HBM devices are manufactured, but the distance from edge to bump center becomes non-uniform causing alignment failure

Engineering Contradiction:

Improvebump pitch uniformityVSAvoidalignment accuracy

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent replaces manual alignment operations with an automated alignment system that uses vision sensors to detect bump positions and motorized stages to adjust device positions. This mechanical-to-automated substitution enables precise alignment despite non-uniform bump spacing from the sawing process.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The alignment system performs self-alignment by automatically detecting bump positions through vision sensors and adjusting device positions without external intervention. The system serves itself by using the bump patterns as reference markers for automatic position correction.

Inventive Principle:

Principle #25Self-service

2Reliability

If alignment is performed manually for devices with non-uniform bump spacing, then alignment might be achieved, but testing cannot proceed due to time consumption and complexity

Engineering Contradiction:

Improvealignment reliabilityVSAvoidtesting cycle time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

Manual alignment operations are replaced with an automated system combining vision sensors for detection and motorized stages for positioning. This substitution dramatically reduces alignment time while maintaining or improving alignment reliability through consistent automated execution.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The alignment and testing processes are integrated into a continuous automated workflow without manual intervention steps. Devices are automatically aligned, positioned, and tested in sequence, eliminating idle time and maintaining continuous productive action throughout the process.

Inventive Principle:

Principle #20Continuity of useful action

3Device complexity

If alignment parts and pickers are disposed on one side only, then device structure is simple, but testing cycle time increases due to sequential operations

Engineering Contradiction:

Improveapparatus structureVSAvoidtesting throughput

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent employs asymmetric positioning of alignment parts on one side while placing pickers on both sides of the apparatus. This asymmetric configuration enables parallel loading and unloading operations, doubling the throughput capability without requiring symmetric complexity throughout the entire system.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The system transitions from sequential single-side operations to parallel multi-side operations by utilizing both left and right sides of the apparatus for loading and unloading. This spatial dimensionality change allows simultaneous operations that double productivity without proportionally increasing overall system complexity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

This solution enables accurate performance testing of HBMs with fine pitches by ensuring consistent alignment, reducing cycle time, and minimizing alignment tolerance, thereby preventing defective GPU configurations.

Implementation Method 1

a vacuum chuck having vacuum holes respectively formed at seating points of the devices which are adsorbed and moved by means of the loading picker

Methodology Applied

Scientific EffectVacuum: Vacuum

Data Source

PatentUS11828792B2Test apparatus for semiconductor chips with fine-pitch bumps

Publication Date: 2023.11.28 AMT CO LTD(KR)

AI summary

A test apparatus for devices having fine pitches, includes a loading picker provided on one side of a loading part so as to sequentially adsorb devices to be tested, thereby putting the adsorbed devices on the upper surface of a vacuum chuck, a device alignment part, which is provided at an upper portion of a loading zone for aligning the devices, tester for testing a performance of the devices for a set time as the vacuum chuck positioned in the test position moves and comes into electrical contact with bumps of respective devices, and an unloading picker, which is provided at one side of an unloading zone so as to adsorb tested devices from the vacuum chuck, sorts the tested devices into good products and bad products, and unloads the tested devices as sorted on a tray of an unloading part.