Wafer Level Test Socket With Anisotropic Conductive Film

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Solution Overview

Problem

Current semiconductor packaging technologies, such as BGA, flip chip, and CSP, face challenges in inspecting solder joints and reworking circuit boards due to non-replaceable components, which complicates problem correction and reduces reliability, especially as package size decreases.

Innovation Solution

A test board with small sockets and anisotropic conductive films is introduced, allowing for precise electrical connections and easy replacement of chips during testing, featuring a base member with a central opening for an anisotropic conductive film and a cover member attached with screws.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional BGA packaging is used to achieve higher connection densities, then manufacturing yield improves, but solder joint inspection and circuit board rework become difficult

Engineering Contradiction:

Improvemanufacturing yieldVSAvoidsolder joint inspection difficulty

Core Design Contradiction:

ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The invention divides the packaging structure into separate functional components: a substrate with conductive pads, a socket assembly with contact elements, and a separate chip. This segmentation allows the socket to be removed and replaced independently, enabling inspection and rework of solder joints on the substrate without affecting the chip, thus resolving the inspection difficulty while maintaining high connection density

Inventive Principle:

Principle #1Segmentation

2Productivity

If conventional BGA packaging is used to achieve higher connection densities, then manufacturing yield improves, but circuit board rework becomes difficult

Engineering Contradiction:

Improvemanufacturing yieldVSAvoidcircuit board rework ease

Core Design Contradiction:

ProductivityVSEase of repair

Solution Approach 1:

The packaging is segmented into a substrate portion with solder joints and a separate socket assembly. The socket can be detached from the substrate, allowing the substrate to be replaced or reworked on the circuit board without removing the chip, thus enabling easy repair while maintaining high connection density through the BGA architecture

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The socket assembly acts as an intermediary between the chip and the substrate/circuit board. This intermediate component can be independently removed and replaced, facilitating rework of the circuit board or substrate without affecting the chip, thus improving ease of repair while maintaining the high connection density benefits of BGA packaging

Inventive Principle:

Principle #24Intermediary (Mediator)

3Volume of moving object

If package size is reduced to achieve smaller devices, then device compactness improves, but reliability of solder joints and rework capability deteriorate

Engineering Contradiction:

Improvedevice compactnessVSAvoidsolder joint reliability

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The invention segments the packaging into a substrate with conductive pads and a separate socket assembly with contact elements. This segmentation maintains compact device size while improving reliability by allowing the socket to be independently tested, removed, and replaced without affecting the chip or substrate solder joints, thus enabling rework capability in a compact form factor

Inventive Principle:

Principle #1Segmentation

4Volume of moving object

If package size is reduced to achieve smaller devices, then device compactness improves, but ease of rework deteriorates

Engineering Contradiction:

Improvedevice compactnessVSAvoidrework ease

Core Design Contradiction:

Volume of moving objectVSEase of repair

Solution Approach 1:

The packaging is segmented into a substrate portion and a separate socket assembly. The socket can be independently removed from the substrate, allowing rework of the substrate or replacement of the socket in compact devices, thus maintaining ease of repair while achieving device compactness

Inventive Principle:

Principle #1Segmentation

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 precise alignment of solder balls with conductive pads, facilitates easy maintenance and replacement of chips, and improves the reliability of semiconductor testing by allowing for effective rework and inspection of solder joints.

Implementation Method 1

an anisotropic conductive film (614) on an upper surface thereof. Each test socket includes a base member (518 or 618) configured for attachment to the test board (500)

Methodology Applied

Scientific EffectAnisotropic conduction: Anisotropy

Data Source

PatentUS7576551B2Test socket and test board for wafer level semiconductor testing

Publication Date: 2009.08.18 VISERA TECH CO LTD

AI summary

A test board for wafer level semiconductor testing is disclosed. The test board comprises a plurality of wires and microelectronic devices; and a plurality of test sockets on an upper surface of the test board. Each test socket comprises: a base member configured for attachment to the test board with a first set of screws, wherein the base member has a central opening exposing a portion of the underlying test board; an anisotropic conductive film disposed within the central opening of the base member; a chip to be tested, disposed on the anisotropic conductive film within the central opening of the base member; and a cover member overlying the chip, attached to the base member with a second set of screws.