Semiconductor Contact Hole Etching via Segmented Mask

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Solution Overview

Problem

In semiconductor device manufacturing, simultaneously forming contact holes with varying opening areas by dry etching leads to insufficient etching with smaller holes and overetching with larger holes, causing increased contact resistance and potential short-circuits.

Innovation Solution

A method involving dry etching with a mask having first and second openings, where the second openings are closer and have the same or similar opening areas, allowing the formation of first and second holes that connect at their upper parts to create a comb-shaped second contact hole with a larger opening area, thereby controlling etching rates and preventing short-circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If dry etching is performed on contact holes with different opening areas, then contact holes can be formed simultaneously, but smaller holes have lower etching rate causing insufficient etching and larger holes have higher etching rate causing overetching

Engineering Contradiction:

Improvesimultaneous formation of multiple contact holesVSAvoidetching depth control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The mask pattern is segmented into two types: first openings for forming individual contact holes and second openings arranged closely for forming merged contact holes. This segmentation allows different etching behaviors for different regions, enabling simultaneous formation of contact holes with controlled etching rates for each type.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple contact holes formed under closely arranged second openings are merged together during etching to form a single larger contact hole structure. This merging approach allows the etching process to be optimized for larger openings while still forming the required contact connections.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If smaller opening area holes are etched, then contact resistance is reduced, but etching rate is lower causing insufficient etching

Engineering Contradiction:

Improvecontact resistanceVSAvoidetching rate

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Different mask opening configurations are used in different locations: first openings for individual contact holes and second openings for merged contact holes. This local differentiation allows optimization of etching parameters for specific regions, ensuring sufficient etching depth where needed while maintaining appropriate etching rates.

Inventive Principle:

Principle #3Local quality

3Productivity

If larger opening area holes are etched, then etching rate is increased, but overetching occurs causing short-circuits

Engineering Contradiction:

Improveetching rateVSAvoidshort-circuit prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The mask pattern is segmented into first openings for individual contact holes and second openings for merged contact holes. By controlling the arrangement and spacing of second openings, the etching process can achieve higher rates without causing overetching that would lead to short-circuits, as the merged structure provides better control over the etching boundaries.

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 allows for simultaneous formation of contact holes with controlled etching rates, preventing insufficient etching and overetching, thus reducing contact resistance and avoiding short-circuits between layers.

Implementation Method 1

dry etching an interlayer insulating layer provided on a foundation layer

Methodology Applied

Scientific EffectDry etching:

Data Source

PatentUS8617979B2Method for manufacturing semiconductor device and semiconductor device

Publication Date: 2013.12.31 KIOXIA CORP

AI summary

According to one embodiment, a method can include dry etching an interlayer insulating layer provided on a foundation layer by using a mask having a plurality of first openings and a plurality of second openings arranged more closely than the first openings to form simultaneously a first hole reaching the foundation layer under each of the first openings and a second hole reaching the foundation layer under the second openings. The first hole reaches the foundation layer without contacting any other first holes. After starting of the dry etching, a plurality of holes are formed under each of the plurality of second openings, and with the progress of the dry etching, the plurality of holes are connected with each other at least at their upper parts including their open ends to form the second hole having an opening area larger than an opening area of the first hole.