High-Aspect-Ratio TSV Structure for Thick Semiconductor Bases
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional TSV processes support only small substrate thicknesses, limiting their use in applications requiring package-level matching due to low aspect ratios.
Innovation Solution
A method for manufacturing a TSV electrical interconnect structure with a high aspect ratio, involving bonding a semiconductor base to carriers, forming backside and front-side vias, and creating a rewiring layer to connect the front and backside, allowing for a thickness greater than or equal to 150 μm and an aspect ratio higher than 20.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If conventional TSV processes are used, then manufacturing simplicity is maintained, but substrate thickness is limited to small values with aspect ratios below 20
Solution Approach 1:
The TSV formation process is divided into two separate stages: first forming a backside via extending from the backside surface to a first depth, then forming a frontside via extending from the frontside surface to a second depth. These two vias meet or overlap in the middle to form the complete through-silicon via. This segmentation allows each via to have a lower individual aspect ratio while achieving a high overall substrate thickness, resolving the contradiction between thick substrate support and manageable process complexity.
2Reliability
If substrate thickness is increased to meet package-level matching requirements, then electrical connection reliability is improved, but conventional TSV processes cannot achieve the required aspect ratio
Solution Approach 1:
The via formation is segmented into backside via and frontside via formation steps, each with controlled depth and aspect ratio. The backside via is formed first with a predetermined depth, then the frontside via is formed to meet or overlap with it. This segmentation reduces the manufacturing precision requirements for each individual via compared to forming a single via through the entire thickness, while still achieving reliable electrical connection through the thick substrate.
Solution Approach 2:
The backside via is formed in advance before completing the frontside processing. This preliminary action allows the backside via to serve as a guide and reference for subsequent frontside via formation, ensuring proper alignment and depth control. The backside via's position and depth are predetermined, which simplifies the overall manufacturing precision requirements while achieving the required thick substrate penetration.
3Length of stationary object
If high aspect ratio TSVs are formed, then package-level matching is achieved, but manufacturing complexity increases significantly
Solution Approach 1:
The manufacturing process is segmented into distinct steps: backside preparation and via formation, frontside preparation and via formation, and final integration. Each segment handles a specific portion of the via formation with controlled complexity. The backside via is formed with predetermined parameters, then the frontside via is formed to complete the connection. This segmentation makes high aspect ratio TSV formation manufacturable by breaking down the complex single-step process into manageable stages.
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 reliable electrical connection between the front and backside of a thick semiconductor base, meeting package-level matching requirements while minimizing area impact and ensuring structural integrity.
Implementation Method 1
bonding the semiconductor base to a first carrier so that the backside of the semiconductor base remains exposed
Implementation Method 2
bonding the semiconductor base to a first carrier
Data Source
AI summary
The present invention relates to a TSV electrical interconnect structure having a high aspect ratio and method of manufacturing it. In the method, a backside via and a backside contact pad connected to the backside via are formed on a backside of the semiconductor base. A front-side via connected to the backside via is then formed in the front side of the semiconductor base, obtaining a TSV which electrically connects the front side and backside of the semiconductor base that has a thickness greater than or equal to 150 μm. The TSV has an aspect ratio higher than 20, which can meet the requirements of package-level matching. The TSV electrical interconnect structure having a high aspect ratio can be connected to a package substrate or a PCB board through the backside contact pad. A rewiring layer on the front side of the semiconductor base is connected to the front-side via, and the TSV electrical interconnect structure having a high aspect ratio can provide an interconnection through the rewiring layer. Moreover, one or more other semiconductor bases may be stacked on the front side.