Through-Silicon Via Copper Fill Tungsten Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The semiconductor industry faces challenges in producing reliable electrically conductive connections, particularly through-silicon-vias, due to adhesion and corrosion issues with copper fillings caused by electrochemical reactions with tungsten slurry used for removing conductive layers from semiconductor substrates.
Innovation Solution
A method involving the production of a hole in a semiconductor substrate, forming a tungsten conductive layer, removing it from the surface before filling with copper, and thinning the substrate, which avoids adhesion and corrosion problems by ensuring the tungsten layer remains with reduced thickness inside the hole, allowing for effective copper filling and substrate thinning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tungsten conductive layer is formed on the surface of the hole and then removed from the first surface, then adhesion and corrosion issues are prevented, but the manufacturing process complexity increases
Solution Approach 1:
The tungsten conductive layer is formed in advance on the surface of the hole before copper filling, and then selectively removed from the first surface while maintaining reduced thickness inside the hole. This preliminary action prevents adhesion and corrosion issues between copper and tungsten slurry, thereby improving reliability of the electrically conductive connections without significantly complicating the overall manufacturing process
Solution Approach 2:
The tungsten conductive layer is differentially treated across different locations: it is completely removed from the first surface (opening area) but retained with reduced thickness inside the hole. This local quality differentiation allows the copper filling to be deposited without adhesion issues on the surface while maintaining the conductive path through the hole, resolving the contradiction between reliability improvement and process complexity
2Reliability
If the electrically conductive layer is removed before filling with copper, then electrochemical reactions are avoided, but the manufacturing time increases
Solution Approach 1:
The removal of the electrically conductive layer from the first surface is performed as a preliminary step before copper filling. This timing optimization allows the subsequent copper deposition to proceed immediately without waiting for corrosion issues to develop, thereby maintaining stability of the conductive path while minimizing the overall manufacturing time
Solution Approach 2:
The method skips the problematic electrochemical reaction phase by removing the tungsten layer from the surface before copper filling. This rushing through the critical timing window prevents adhesion and corrosion issues from developing, maintaining conductive path stability while reducing the time the system remains in a vulnerable state
3Reliability
If the substrate is thinned after copper filling, then the hole remains uncovered at the second surface for connection, but the mechanical strength decreases
Solution Approach 1:
The substrate thinning is performed as a preliminary action after copper filling but before final assembly. This timing allows the copper connection to be established and verified while the substrate is still relatively thick and mechanically strong, and then the substrate is thinned to uncover the hole at the second surface for connection, achieving both connection reliability and maintaining adequate mechanical strength during processing
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 method significantly increases the reliability of electrically conductive connections by preventing adhesion and corrosion issues, ensuring a stable and continuous conductive path through the substrate, thereby enhancing manufacturing reliability.
Implementation Method 1
adhesion and corrosion issues with copper fillings caused by electrochemical reactions with tungsten slurry
Data Source
AI summary
A method for producing an electrically conductive connection between a first surface of a semiconductor substrate and a second surface of the semiconductor substrate includes producing a hole, forming an electrically conductive layer that includes tungsten, removing the electrically conductive layer from the first surface of the semiconductor substrate, filling the hole with copper and thinning the semiconductor substrate. The hole is produced from the first surface of the semiconductor substrate into the semiconductor substrate. The electrically conductive layer is removed from the first surface of the semiconductor substrate, wherein the electrically conductive layer remains at least with reduced thickness in the hole. The semiconductor substrate is thinned starting from a surface, which is an opposite surface of the first surface of the semiconductor substrate, to obtain the second surface of the semiconductor substrate with the hole being uncovered at the second surface of the semiconductor substrate.