TSV Capacitance Variability via N-type Implant Layer
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Solution Overview
Problem
Through-silicon via (TSV) structures experience poor substrate contact and variability in electrical characteristics due to depletion regions caused by plasma processing, affecting the ability to carry moderate to high frequency signals.
Innovation Solution
The implementation of an N-type implant layer in the substrate adjacent to the TSV, combined with an insulator sidewall and conductive fill material, forms improved electrical contacts that stabilize capacitance across frequencies by converting the p-type substrate to n-type, reducing impedance variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma processing is used to form TSV, then via structure is created, but depletion region forms causing poor substrate contact and capacitance variability
Solution Approach 1:
The patent applies preliminary anti-action by forming an n-type implant layer in advance before TSV formation. This pre-established n-type region counteracts the depletion effect that will occur during subsequent plasma processing, preventing the formation of poor-quality substrate contacts and capacitance variability before they can occur.
Solution Approach 2:
The n-type implant layer is formed as a preliminary action before the TSV structure is created. This preparatory step ensures that when plasma processing occurs, the substrate already has the appropriate doping characteristics to maintain good electrical contact and stable capacitance, rather than having to correct the depletion region afterward.
2Manufacturing precision
If plasma processing is used to form TSV, then via structure is created, but impedance variability increases affecting high frequency signal transmission
Solution Approach 1:
The n-type implant layer serves as a preliminary countermeasure that prevents the plasma-induced depletion region from forming in the first place. By having the n-type doping already in place, the plasma processing cannot create the impedance variability that would otherwise occur, thus maintaining stable electrical characteristics for high-frequency signals.
3Reliability
If n-type implant layer is added to substrate, then substrate contact and capacitance uniformity improve, but device complexity increases
Solution Approach 1:
The n-type implant layer is applied locally only in the regions where TSV structures will be formed, not across the entire substrate. This localized approach improves substrate contact quality and capacitance uniformity precisely where needed, while minimizing the overall added complexity and avoiding unnecessary modifications to other areas of the device.
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 results in uniform TSV capacitance and reduced impedance variability from die to die and across all frequencies, enhancing the reliability of high-frequency signal transmission.
Implementation Method 1
converting the p-type substrate to n-type during formation of a via structure
Data Source
AI summary
The present disclosure relates to semiconductor structures and, more particularly, to Through-Silicon Via (TSV) structures with improved substrate contact and methods of manufacture. The structure includes: a substrate of a first species type; a layer of different species type on the substrate; a through substrate via formed through the substrate and comprising an insulator sidewall and conductive fill material; a second species type adjacent the through substrate via; a first contact in electrical contact with the layer of different species type; and a second contact in electrical contact with the conductive fill material of the through substrate via.