Backside Probe Testing Thin Semiconductor Wafer Film Frame

Solution Overview

Problem

Thin semiconductor wafers are prone to breakage and warpage during testing, leading to incomplete testing and increased manufacturing costs due to the invasive nature of traditional probe testing methods, which cannot effectively contact warped surfaces or assess features added post-thinning, such as back-side metal, especially in MOSFETs with through silicon vias.

Innovation Solution

A method of probe testing from the backside of a thinned semiconductor wafer through openings in a film frame, utilizing an edge support ring and conductive layers to maintain structural integrity and enable stable, flat testing, allowing for complete feature set evaluation after wafer thinning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional probe testing is performed on thin semiconductor wafers, then testing can be conducted, but the wafer is prone to breakage and damage from probe pressure

Engineering Contradiction:

Improvewafer integrity during testingVSAvoidprobe pressure damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the traditional testing approach by testing the wafer from the backside after thinning, rather than from the front side. This allows probe contact on the thinned back surface which has lower structural integrity requirements, avoiding damage to the thicker front side that contains the active devices. The wafer is thinned to 50-150 micrometers on the back side specifically for testing purposes.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The wafer is thinned before testing is performed. This preliminary action of thinning the wafer backside creates a more suitable surface for probe contact with reduced thickness requirements, allowing testing to proceed without the risk of probe-induced breakage that would occur on thicker wafers.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If wafer testing is performed before wafer thinning, then large thin wafers can be tested, but the testing is incomplete because certain features added post-thinning are not present

Engineering Contradiction:

Improvetesting completenessVSAvoidmanufacturing cycle time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The wafer is thinned before testing is performed. This preliminary action of thinning the wafer backside creates a more suitable surface for probe contact with reduced thickness requirements, allowing testing to proceed without the risk of probe-induced breakage that would occur on thicker wafers.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent inverts the traditional testing approach by testing the wafer from the backside after thinning, rather than from the front side. This allows probe contact on the thinned back surface which has lower structural integrity requirements, avoiding damage to the thicker front side that contains the active devices. The wafer is thinned to 50-150 micrometers on the back side specifically for testing purposes.

Inventive Principle:

Principle #13The other way round (Inversion)

3Length of moving object

If the wafer is thinned to reduce height, then package size is minimized, but the wafer becomes prone to warpage and breakage

Engineering Contradiction:

Improvewafer thicknessVSAvoidwafer structural integrity

Core Design Contradiction:

Length of moving objectVSStrength

Solution Approach 1:

The patent inverts the traditional testing approach by testing the wafer from the backside after thinning, rather than from the front side. This allows probe contact on the thinned back surface which has lower structural integrity requirements, avoiding damage to the thicker front side that contains the active devices. The wafer is thinned to 50-150 micrometers on the back side specifically for testing purposes.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS10685891B2Semicoductor wafer and method of backside probe testing through opening in film frame

Publication Date: 2020.06.16 SEMICON COMPONENTS IND LLC

AI summary

A semiconductor test system has a film frame including a tape portion with one or more openings through the tape portion. The opening is disposed in a center region of the tape portion of the film frame. The film frame may have conductive traces formed on or through the tape portion. A thin semiconductor wafer includes a conductive layer formed over a surface of the semiconductor wafer. The semiconductor wafer is mounted over the opening in the tape portion of the film frame. A wafer probe chuck includes a lower surface and raised surface. The film frame is mounted to the wafer probe chuck with the raised surface extending through the opening in the tape portion to contact the conductive layer of the semiconductor wafer. The semiconductor wafer is probe tested through the opening in the tape portion of the film frame.