Bipolar Dummy Electrode for Uniform Silicide Formation
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Solution Overview
Problem
The existing method for manufacturing semiconductor devices with bipolar transistors and insulated gate field effect transistors results in inconsistent silicide film thickness due to variations in protection film thickness, leading to unreliable transistor characteristics.
Innovation Solution
Incorporating a bipolar dummy electrode on the semiconductor substrate's isolation structures and using a specific patterning and deposition process to ensure uniform silicide film formation on bipolar transistors while preventing silicide formation on insulated gate field effect transistors, thereby maintaining uniformity and functionality across different transistor types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a protection film is formed to cover all transistors and then patterned to expose only bipolar transistors and first insulated gate field effect transistors, then selective silicide formation can be achieved, but the protection film thickness varies by position causing inconsistent silicide film thickness
Solution Approach 1:
The patent applies local quality by forming a bipolar dummy electrode specifically at the bipolar transistor region to compensate for protection film thickness variations only in that local area. This creates a localized solution that equalizes the effective thickness without requiring uniform treatment across the entire semiconductor substrate, thereby resolving the contradiction between selective silicide formation and thickness uniformity.
Solution Approach 2:
The patent changes the physical parameter of electrode height by forming a bipolar dummy electrode with a height that compensates for the protection film thickness variation. By adjusting this height parameter, the effective thickness becomes uniform across different regions, enabling consistent silicide film formation while maintaining the protective coverage for insulated gate field effect transistors.
2Reliability
If the protection film is made thicker to ensure complete coverage, then protection is improved, but silicide film thickness becomes inconsistent due to position-dependent variation
Solution Approach 1:
The bipolar dummy electrode provides a localized compensation mechanism specifically for the bipolar transistor region where protection film thickness variation occurs. This allows the protection film to be uniformly thick across the entire substrate for reliable coverage, while the dummy electrode locally adjusts the effective thickness to ensure consistent silicide formation only where needed.
Solution Approach 2:
The bipolar dummy electrode acts as an intermediary structure that mediates between the protection film and the silicide formation process. It absorbs the thickness variation effect, allowing the protection film to maintain its thick, uniform protective coverage while enabling precise and consistent silicide film formation on the bipolar transistor and first insulated gate field effect transistor.
3Adaptability or versatility
If selective exposure is achieved by patterning the protection film, then different transistor types can have different silicide characteristics, but protection film remnants may remain on bipolar transistors affecting silicide quality
Solution Approach 1:
The bipolar dummy electrode performs a preliminary action by pre-compensating for protection film thickness variation before the silicide formation process. This preliminary structural adjustment ensures that when the protection film is patterned and removed, the underlying surface is at the correct height, preventing remnants and enabling high-quality silicide formation with the desired adaptability for different transistor types.
Solution Approach 2:
The bipolar dummy electrode creates equipotentiality in terms of surface height by compensating for the protection film thickness variation. This ensures that the effective thickness is uniform across the bipolar transistor region, allowing clean removal of the protection film without remnants and enabling consistent silicide formation while maintaining the ability to have different characteristics for different transistor types.
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 ensures consistent silicide film thickness and characteristics for bipolar transistors, improving the reliability and performance of semiconductor devices by preventing protection film remnants and ensuring uniform silicide formation across various transistor types.
Implementation Method 1
a metal film is formed on the bipolar transistor and the first insulated gate field effect transistor, and the metal film is subjected to heat treatment. As a result, a silicide film is formed on an emitter region of the bipolar transistor and on a gate electrode of the first insulated gate field effect transistor
Data Source
AI summary
A semiconductor device includes a first insulated gate field effect transistor, a second insulated gate field effect transistor, a bipolar transistor, a first element isolation structure formed on a main surface above a pn junction formed between an emitter region and a base region, a second element isolation structure formed on the main surface above a pn junction formed between the base region and a collector region, and a third element isolation structure formed on the main surface opposite to the second element isolation structure relative to the collector region, in which the semiconductor device further includes a bipolar dummy electrode formed on at least one of the first element isolation structure, the second element isolation structure and the third element isolation structure and having a floating potential.