Through-Substrate Via Filling With Integrated Backside Interconnects
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Solution Overview
Problem
Current integration techniques for forming via openings in substrates result in open bottoms, necessitating additional steps to close them before material deposition, which increases complexity and reduces yield.
Innovation Solution
A method involving forming through via openings from the backside of the substrate to the front side, exposing front side metal interconnects, and filling these openings to create through vias while simultaneously forming back side metal interconnects, using copper plating and seed layers to facilitate deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If via openings are formed through substrate before filling with conductive material, then interconnection pathways are created, but additional steps are required to close open bottoms reducing yield
Solution Approach 1:
The front side metal interconnects are formed in advance before via opening formation. This preliminary action creates a bottom closure for the via openings automatically, eliminating the need for separate bottom closure steps and improving yield while reducing process complexity
Solution Approach 2:
The conventional sequence of forming via openings then closing bottoms is inverted. Instead, the patent forms through via openings after front side interconnects are already in place, so the interconnects themselves serve as the bottom closure, reversing the traditional approach to eliminate defective open-bottomed vias
2Productivity
If through via openings are formed from back side to front side, then front side metal interconnects are exposed, but simultaneous filling and back side patterning must be integrated
Solution Approach 1:
The filling of through via openings and the patterning of back side metal interconnects are merged into a single copper plating process. This combination allows both operations to be performed simultaneously, improving productivity while the process integration manages the complexity through unified process control
Solution Approach 2:
The copper plating process serves multiple functions: it fills the through via openings to create conductive pathways and simultaneously forms the back side metal interconnects. This multi-functionality improves productivity by eliminating separate processing 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
Reduces process steps, enhances integration robustness, and improves yield by integrating via opening filling with back side patterning, thus reducing stress on patterned layers.
Implementation Method 1
using a copper plating process to fill the through via openings to form through vias and to form back side copper interconnects
Data Source
AI summary
Methods of processing a substrate are provided herein. In some embodiments, a method for processing a substrate includes: forming through via openings in a substrate from a back side of the substrate to a front side of the substrate, the substrate having front side metal interconnects disposed on the front side of the substrate that are exposed by the through via openings; and filling the through via openings to form through vias and forming back side metal interconnects on the back side of the substrate, wherein the back side metal interconnects are electrically coupled to the front side metal interconnects by the through vias.