Semiconductor Epitaxial Layer Formation via Disposal Spacer Removal
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Solution Overview
Problem
The formation of silicon seeds on a disposal material layer during the manufacturing process of semiconductor devices leads to yield reduction and improper epitaxial layer formation, as these seeds can grow during etching and form on unintended places, affecting the quality and accuracy of the device.
Innovation Solution
A method is introduced where a disposal material layer and silicon seeds are entirely removed during an additional etching process, using a combination of oxygen treatments and etching processes to prevent silicon seed growth and ensure precise epitaxial layer formation within defined regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxygen treatment is performed to prepare the disposal material layer, then the surface is activated for subsequent processing, but silicon seeds are formed on the disposal material layer which affect manufacturing yield
Solution Approach 1:
An additional etching process is performed after the first oxygen treatment to remove the disposal material layer and silicon seeds before they can cause problems during subsequent etching processes. This preliminary removal action prevents the silicon seeds from growing and affecting manufacturing yield in later steps.
Solution Approach 2:
The disposal material layer and silicon seeds are completely removed through an additional etching process, extracting the harmful elements from the system before they can interfere with the epitaxial layer formation and subsequent device manufacturing.
2Manufacturing precision
If disposal material layer is retained to protect sidewalls during etching, then sidewall protection is provided, but silicon seeds grow on the disposal material layer causing improper epitaxial layer formation
Solution Approach 1:
The disposal material layer is removed in advance through an additional etching process before the epitaxial layer formation step. This ensures that no silicon seeds are present on sidewalls that could cause improper epitaxial layer formation, while the sidewalls remain protected by spacers formed in previous steps.
Solution Approach 2:
The disposal material layer serving as a temporary protective structure is completely removed after it has fulfilled its protective function, eliminating the source of silicon seed formation that would otherwise contaminate the sidewalls and affect epitaxial layer precision.
3Productivity
If additional etching process is performed to remove disposal material layer and silicon seeds, then manufacturing yield is improved, but process complexity increases
Solution Approach 1:
The additional etching process combines multiple functions: removing the disposal material layer, eliminating silicon seeds, and preparing the surface for subsequent steps. By merging these removal functions into a single process step, the increase in process complexity is minimized while achieving the desired yield improvement.
Solution Approach 2:
The additional etching process is integrated into the continuous manufacturing flow, maintaining the production rhythm while removing harmful elements. The process is designed to be performed at a specific point in the sequence where it prevents future defects without creating bottlenecks or requiring separate handling steps.
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 effectively resolves the issue of silicon seed growth, enhancing the manufacturing process yield by preventing unwanted epitaxial layer formation on sidewalls and ensuring accurate placement of epitaxial layers, thereby improving the overall quality and precision of semiconductor devices.
Implementation Method 1
a first oxygen treatment P1 is performed, and a plurality of silicon seeds 24 will be formed on the disposal material layer 22
Implementation Method 2
the disposal material layer 22 and the silicon seeds 24 are entirely removed during the additional etching process E2
Data Source
AI summary
The present invention provides a method for forming a semiconductor device, comprising the following steps: firstly, a substrate is provided, having a NMOS region and a PMOS region defined thereon, next, a gate structure is formed on the substrate within the NMOS region, and a disposal spacer is formed on two sides of the gate structure, afterwards, a mask layer is formed on the PMOS region to expose the NMOS region, next, a recess is formed on two sides of the gate structure spaced from the gate structure by the disposal spacer within the NMOS region, the disposal spacer is then removed after the recess is formed, and an epitaxial layer is formed into the recess.