Two-Stage Through-Hole Semiconductor Device
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Solution Overview
Problem
Current methods for manufacturing through-electrodes in semiconductor devices are costly and complex, leading to reduced yield rates and reliability due to the need for multiple processes and exposure to plasma, which can damage the semiconductor elements.
Innovation Solution
A semiconductor device with a two-stage through-hole structure, featuring a tapered first hole and a perpendicular cylindrical second hole, allows for the formation of a uniform high-quality inorganic insulating film and through-electrode using chemical vapor deposition and dry-etching, reducing manufacturing costs and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dry-etching is used to form through-holes with etching depth of 20 to 500 μm, then through-electrodes can be formed for multi-layer lamination, but plasma exposure causes temperature rise and defects in semiconductor elements
Solution Approach 1:
The through-hole formation process is divided into two distinct stages: first forming a tapered hole to a intermediate depth, then forming a cylindrical hole to the final depth. This segmentation allows each stage to be optimized independently, reducing the cumulative plasma exposure time while maintaining formation quality.
Solution Approach 2:
The tapered first hole is formed in advance as a preliminary structure, providing a foundation for the second cylindrical hole. This preliminary action enables the second hole to be formed with reduced plasma exposure since the etching starts from an already-created opening rather than from the surface.
2Productivity
If chemical mechanical polishing or back surface etching is used to reduce substrate thickness, then through-hole formation time is shortened, but manufacturing costs increase
Solution Approach 1:
The tapered first hole structure serves a dual purpose: it is both an intermediate structural element and a self-aligned mask for forming the second cylindrical hole. The photoresist pattern used to define the first hole automatically serves as the mask for the second hole, eliminating the need for additional masking layers or alignment steps that would increase manufacturing complexity and cost.
3Reliability
If multiple processes are used to form through-electrodes, then connection reliability can be improved, but manufacturing complexity and cost increase
Solution Approach 1:
The formation of the tapered first hole and cylindrical second hole are merged into a single continuous dry-etching process using one photoresist pattern. This merging maintains the reliability benefits of a two-stage structure while eliminating the manufacturing complexity of separate processes, multiple masks, and additional alignment 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
The method enables the production of semiconductor devices with high-quality through-electrodes at lower costs and improved reliability by simplifying the manufacturing process and minimizing exposure to damaging plasma.
Implementation Method 1
an inorganic insulating film is formed on the inner wall surface of the two-stage through-hole by a chemical vapor deposition method
Implementation Method 2
overall dry-etching is performed on the insulating film, thereby a structure is formed in which the insulating film located on the I/O pad is removed
Data Source
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AI summary
A semiconductor device is provided that includes a semiconductor substrate including a first surface in which an integrated circuit and an I/O pad electrically connected to the integrated circuit are formed, and a second surface which is an opposite side to the first surface, that includes a two-stage through-hole formed in the semiconductor substrate, including a first shape portion having a tapered shape which has a wall surface and of which a diameter of an opening becomes smaller toward a bottom of the hole from the second surface side to a predetermined position of the semiconductor substrate in a thickness direction, and including a second shape portion having a cylindrical shape which extends from the first shape portion to the I/O pad on the first surface side, that includes an inorganic insulating film which is formed on the wall surface of the two-stage through-hole and the second surface, that includes a through-electrode of a metal layer which is formed on the I/O pad and the wall surface of the two-stage through-hole; and that includes a wiring pattern formed on the second surface and connected to the through-electrode.