TSV Insulation Ring Tapered Geometry Void Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The Bosch process for forming deep openings in semiconductor substrates results in scalloping on the side surfaces, which complicates the filling of insulation rings and can lead to voids and cracks, affecting manufacturing yield.
Innovation Solution
A semiconductor device with a through silicon via and an insulation ring that includes a tapered portion with a gradually decreasing sectional area and a vertical portion with a constant, smaller sectional area, both designed to facilitate the embedding of insulation films and prevent voids by controlling the etching cycles and bias power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the Bosch process is used to form deep openings with vertical shape, then the opening depth and vertical shape are improved, but scalloping is formed on the side surface which complicates insulation ring filling and causes voids and cracks
Solution Approach 1:
The patent applies preliminary action by forming a tapered portion at the upper end of the opening before filling the insulation ring. This tapered portion is created through controlled etching processes that modify the opening geometry in advance, providing a transition zone that facilitates smooth insulation film deposition and prevents void formation. The tapered shape is established before the insulation filling step, allowing subsequent processes to proceed without the scalloping-induced defects.
Solution Approach 2:
The patent applies local quality by creating different geometric characteristics at different locations within the opening. The upper end features a tapered portion with gradually changing cross-sectional area, while the lower end maintains a vertical shape with constant cross-sectional area. This localized differentiation allows the insulation ring filling process to occur smoothly in the tapered region without the scalloping problems that would affect a uniformly vertical opening, thereby improving overall reliability.
2Length of stationary object
If repeated etching and deposition cycles are performed to form deep openings, then the opening depth is improved, but the scalloping on side surface worsens
Solution Approach 1:
The patent applies segmentation by dividing the opening formation process into distinct stages that create different geometric features at different depths. The etching process is controlled to form a tapered portion in the upper region and a vertical portion in the lower region. This segmentation of the opening structure allows the upper tapered region to serve as a buffer zone that prevents scalloping from propagating through the entire opening, thereby maintaining side surface smoothness while achieving the required depth.
Solution Approach 2:
The patent applies preliminary action by intentionally creating the tapered portion through controlled etching cycles before the insulation filling process. This preliminary geometric modification establishes a favorable shape that prevents scalloping defects from developing during subsequent processing steps. The tapered portion is formed in advance as a preventive measure, allowing the vertical portion below it to maintain smooth sides without the harmful scalloping effects.
3Shape
If the insulation ring is filled to cover scalloping, then the side surface coverage is improved, but voids and cracks are formed affecting manufacturing yield
Solution Approach 1:
The patent applies preliminary action by forming the tapered portion before insulation ring filling to prevent void and crack formation. The tapered geometry is established in advance, creating a favorable shape that allows insulation material to deposit smoothly without forming defects. This preliminary shape control eliminates the need to fill over scalloping, as the tapered portion prevents scalloping from forming in the first place, thereby maintaining high manufacturing yield.
Solution Approach 2:
The patent applies local quality by concentrating the insulation ring filling issue in the upper tapered region where the geometry naturally prevents void formation. The tapered portion's gradual cross-sectional area reduction creates a favorable deposition environment, while the lower vertical portion remains free from filling defects. This localized quality differentiation ensures reliable insulation coverage without compromising manufacturing yield.
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 solution effectively prevents voids in the insulation ring, enhances the embedding characteristic of insulation films, and improves manufacturing yield by smoothing the tapered and vertical portions, ensuring reliable semiconductor device performance.
Implementation Method 1
a first opening 31-1 is formed by dry etching having high isotropy and using etching gas (first etching process)
Implementation Method 2
a deposition process of depositing a carbon polymer-based protective film on an inner wall of the opening alternately
Data Source
AI summary
A semiconductor device includes a semiconductor substrate having a first surface, a through silicon via (TSV) that is formed so that at least a part thereof penetrates through the semiconductor substrate, and an insulation ring. The insulation ring is formed so as to penetrate through the semiconductor substrate and so as to surround the TSV. The insulation ring includes a tapered portion and a vertical portion. The tapered portion has a sectional area which is gradually decreased from the first surface toward a thickness direction of the semiconductor substrate. The vertical portion has a constant sectional area smaller than the tapered portion.