Backside Substrate Openings for Buried Metal Layer Testing

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The complexity of semiconductor integrated circuits makes it difficult to access and analyze metal layers from the front side, especially when they are buried under multiple layers, requiring high-performance equipment for cutting and repair, which is impractical and damaging.

Innovation Solution

A method involving forming openings from the back side of the substrate to expose metal layers through non-functional regions, using focused ion beam systems to mill openings and deposit conductive layers for electrical connection, allowing analysis without disturbing functional regions or requiring specialized equipment for metal layer cutting and repair.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If openings are formed from the front side to access buried metal layers, then metal layers can be exposed for analysis, but functional regions are damaged and high-performance equipment is required for cutting and repair

Engineering Contradiction:

Improveaccess to metal layersVSAvoiddamage to functional regions

Core Design Contradiction:

Difficulty of detecting and measuringVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional approach by forming openings from the back side of the substrate rather than the front side. This allows metal layers to be accessed and exposed for analysis without cutting through or damaging the functional regions on the front side, thereby resolving the contradiction between accessibility and damage prevention

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent segments the substrate access into two separate openings: a first opening from the front side and a second opening from the back side. These openings are formed at different locations and connected through the substrate, allowing independent formation and avoiding the need for a single large cutting operation that would damage functional regions

Inventive Principle:

Principle #1Segmentation

2Difficulty of detecting and measuring

If high-performance equipment is used to cut and repair metal layers from the front side, then metal layers can be accessed, but the process becomes impractical and damaging

Engineering Contradiction:

Improveaccess to buried metal layersVSAvoidpracticality of analysis process

Core Design Contradiction:

Difficulty of detecting and measuringVSEase of manufacture

Solution Approach 1:

By inverting the access direction to form openings from the back side, the patent eliminates the need for complex high-performance cutting and repair equipment required for front-side access, making the analysis process more practical and easier to manufacture

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent extracts the metal layer access function from the front side and relocates it to the back side. This separation allows the analysis process to be performed independently without requiring expensive specialized equipment for cutting and repairing metal layers on the front side

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If multiple metal layers are buried under the substrate, then circuit functionality is maintained, but access for analysis becomes increasingly difficult

Engineering Contradiction:

Improvecircuit functionalityVSAvoidaccess to buried metal layers

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent maintains circuit functionality by keeping multiple metal layers buried on the front side while inverting the access approach to form openings from the back side. This allows deep burial of metal layers for reliability while maintaining easy access for analysis through the back-side openings

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the dimensional approach by accessing metal layers from the vertical dimension (back side) rather than horizontally cutting through the front side. This allows multiple buried metal layers to remain intact for functionality while providing direct vertical access to any desired metal layer for analysis

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

Enables efficient analysis and investigation of semiconductor devices by exposing metal layers through the substrate from the back side, reducing damage to functional regions and eliminating the need for high-performance equipment to cut and reconnect metal layers.

Implementation Method 1

using focused ion beam systems to mill openings

Methodology Applied

Scientific EffectIon beam milling: Ion Beam

Implementation Method 2

using focused ion beam systems to mill openings and deposit conductive layers

Methodology Applied

Scientific EffectIon beam deposition: Ion Beam

Data Source

PatentUS11982709B2Methods and structures for semiconductor device testing

Publication Date: 2024.05.14 YANGTZE MEMORY TECH CO LTD

AI summary

A structure for performing analysis includes a first opening formed on a back side of a substrate and passing through the substrate, a second opening connected with a bottom of the first opening and penetrating into a first dielectric layer formed on a front side of the substrate, a first conductive layer formed on a sidewall of the second opening and a contact element in the first dielectric layer, and a second conductive layer formed on a second dielectric layer. The first conductive layer contacts the second conductive layer electrically.