Hybrid Wafer Bonding After Probe Mark Planarization

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Solution Overview

Problem

The challenge in the semiconductor industry is that pre-bonding electrical testing of wafers often damages the test pads, leading to structural defects and potential voids or bubbles in hybrid bonding layers, which can result in sub-quality products and waste, as testing is typically done after bonding, making it difficult to evaluate wafer quality before bonding.

Innovation Solution

A method that involves planarizing the wafer surface after testing by using techniques like CMP or etching to reduce or remove probe marks, and forming additional insulating or conductive layers to ensure a flat surface for hybrid bonding, allowing for pre-bonding electrical testing and evaluation of wafers without compromising the bonding process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pre-bonding electrical testing is performed on wafers using probe needles, then wafer quality can be evaluated before bonding, but structural defects and probe marks are created on test pads that compromise hybrid bonding quality

Engineering Contradiction:

Improvewafer quality evaluationVSAvoidhybrid bonding quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent performs electrical testing on wafers before hybrid bonding to identify defective regions. By conducting the testing action in advance, the system can evaluate wafer quality and determine which regions are suitable for bonding, preventing defective areas from being bonded and thus ensuring high bonding quality without compromising reliability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent divides the wafer into tested regions with identified good and defective areas. By segmenting the wafer based on test results, the system can selectively bond only the good regions, isolating the probe marks and structural defects in non-bonded areas, thereby resolving the contradiction between testing reliability and bonding precision

Inventive Principle:

Principle #1Segmentation

2Stability of the object's composition

If testing is performed after bonding, then hybrid bonding structure is complete, but it becomes difficult to evaluate and separate defective regions, leading to waste of good regions

Engineering Contradiction:

Improvebonding structure completenessVSAvoiddefect evaluation and separation

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent performs electrical testing before hybrid bonding to identify defective regions. By conducting the testing action in advance, the system can evaluate wafer quality and determine which regions are suitable for bonding, preventing defective areas from being bonded and thus ensuring high bonding quality without compromising reliability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

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 approach enables pre-bonding electrical testing, improving yield and quality control by ensuring a flat surface for hybrid bonding, reducing the risk of defective products and allowing for selective bonding of good wafer regions, thus enhancing manufacturing efficiency and reducing waste.

Implementation Method 1

The structure defect of the test pad induced by a test probe during the wafer testing is repaired by a planarizing structure

Methodology Applied

Scientific EffectPlanarization:

Data Source

PatentUS12176320B2Semiconductor structure and methods for bonding tested wafers and testing pre-bonded wafers

Publication Date: 2024.12.24 AP MEMORY TECH CORP

AI summary

A method for bonding tested wafers is provided. The method includes the following operations. A first wafer having a first surface is received, and the first wafer includes a test pad and a conductive pad at the first surface of the first wafer and the test pad has a recess caused by a test probe and the conductive pad is electrically connected to the test pad. The first surface of the first wafer is planarized. A first hybrid bonding layer is formed over the first surface of the first wafer. The first wafer and a second wafer are bonded to connect the first hybrid bonding layer and a second hybrid bonding layer on the second water. A semiconductor structure and a method for testing pre-bonded wafers are also provided.