Semiconductor Isolation Regions via Inverted Gate Stack Formation

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Solution Overview

Problem

The existing methods for forming semiconductor devices face challenges in reducing the area of isolation regions due to design rule limitations, making it difficult to increase the density of devices on a semiconductor substrate.

Innovation Solution

The method involves forming gate stack structures and an interlayer material layer on a semiconductor substrate, then defining isolation regions by removing portions of the interlayer material layer and substrate to create trenches, which are filled with insulating material, allowing for reduced isolation region area and simplified processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If isolation regions are formed before gate stack structures in conventional methods, then the isolation regions can be properly formed, but the area of isolation regions cannot be reduced due to design rule limitations

Engineering Contradiction:

Improvearea of isolation regionVSAvoidisolation region formation precision

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent inverts the conventional sequence by forming gate stack structures first and then forming isolation regions afterward. This reversal allows isolation regions to be defined based on the already-formed gate structures, enabling reduced isolation region area while maintaining proper formation precision through the gate structures serving as reference boundaries.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The gate stack structures are formed in advance before the isolation regions are created. This preliminary formation of gate structures provides established reference points that guide the subsequent isolation region formation process, ensuring precise positioning and reduced area while maintaining manufacturing precision.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the area of isolation regions is reduced to increase device density, then more devices can be formed in unit area, but design rule limitations make it difficult to reduce isolation region area further

Engineering Contradiction:

Improvedevice densityVSAvoidisolation region definition precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

By inverting the formation sequence to create isolation regions after gate stack structures, the patent enables reduced isolation region area that increases device density. The already-formed gate structures serve as precise boundaries, maintaining manufacturing precision even with smaller isolation regions.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the temporal parameter of the formation process by reversing the sequence of operations. This parameter change allows isolation region area to be reduced while maintaining precision, as the gate structures formed earlier provide stable reference boundaries for the reduced-size isolation regions.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If conventional isolation region formation methods are used, then the process follows standard procedures, but the processing complexity increases and efficiency decreases

Engineering Contradiction:

Improveprocessing simplicityVSAvoidprocessing efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent merges the isolation region formation process with the gate stack structure formation process by sequencing them to overlap in time and space. This combination simplifies the overall manufacturing process and improves efficiency by reducing the total number of separate processing steps required.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

By forming gate stack structures in advance, the patent creates a foundation that simplifies subsequent isolation region formation. This preliminary action reduces processing complexity by establishing clear boundaries and reference points before the isolation regions are created, making the overall process more efficient.

Inventive Principle:

Principle #10Preliminary action

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 precise formation of isolation regions, reducing their area and simplifying the process by utilizing the interlayer material layer for conductive contact holes, thereby enhancing device density and processing efficiency.

Implementation Method 1

the removing operation is performed by an isotropic etching process

Methodology Applied

Scientific EffectIsotropic etching:

Implementation Method 2

performing thermal processing, to convert the interlayer material layer into a conductive layer

Methodology Applied

Scientific EffectThermal processing: Heat Treatment

Data Source

PatentUS8637935B2Semiconductor device including embedded isolation regions and method for forming the same

Publication Date: 2014.01.28 INST OF MICROELECTRONICS CHINESE ACAD OF SCI LTD

AI summary

A method for forming a semiconductor device comprises: forming at least one gate stack structure and an interlayer material layer between the gate stack structures on a semiconductor substrate; defining isolation regions and removing a portion of the interlayer material layer and a portion of the semiconductor substrate which has a certain height in the regions, so as to form trenches; removing portions of the semiconductor substrate which carry the gate stack structures, in the regions; and filling the trenches with an insulating material. A semiconductor device is also provided. The area of the isolation regions may be reduced.