Semiconductor Cap Layer Rework via Acid Brush Module
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing method of forming cap layers in integrated circuits using electroless deposition often results in excess metal compound deposition on dielectric material, leading to electric shorts between conductive lines, which can cause leakage currents and circuit failures.
Innovation Solution
A method is developed to detect malfunctions in cap layer formation, involving the use of acid treatments and a brush module system to remove excess cap layer material, followed by a rework procedure to ensure proper deposition of a new cap layer, preventing electric shorts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electroless deposition is used to form cap layers, then cap layer formation is achieved, but excess metal compound deposits on dielectric material causing electric shorts
Solution Approach 1:
A mandrel layer is formed prior to cap layer deposition to control and limit the deposition area. The mandrel layer acts as a preliminary structure that defines where the cap layer should be deposited, preventing excess material from forming on adjacent dielectric surfaces.
Solution Approach 2:
The mandrel layer serves as an intermediary between the substrate and the cap layer. It provides a controlled interface that directs the electroless deposition process, ensuring metal compound deposits only where intended and preventing unwanted deposition on dielectric material.
2Quantity of substance
If feature sizes are reduced to increase circuit density, then more circuit elements fit on the same area, but current density increases leading to electromigration
Solution Approach 1:
The invention changes the physical parameters of the conductive structure by introducing cap layers with different material compositions and thicknesses. This modifies the electrical and mechanical properties of the interconnect, reducing current density and mitigating electromigration effects even as feature sizes decrease.
Solution Approach 2:
The patent employs composite material structures combining different metal compounds in the cap layer (e.g., cobalt tungsten phosphide, cobalt tungsten boride). These composite structures provide both electrical functionality and enhanced resistance to electromigration, allowing smaller feature sizes without compromising reliability.
3Area of stationary object
If cap layer material is deposited on dielectric material, then deposition coverage is increased, but electric shorts occur between conductive lines
Solution Approach 1:
The mandrel layer creates local quality differences across the substrate surface. Areas with mandrel layer receive cap layer deposition, while areas without mandrel layer (dielectric material) do not. This spatially selective deposition ensures coverage where needed while preventing shorts where not needed.
Solution Approach 2:
The deposition process is segmented into controlled zones defined by the mandrel layer pattern. The cap layer deposition is divided into discrete regions corresponding to individual conductive line locations, preventing continuous or excessive coverage that would cause shorts between adjacent lines.
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 approach effectively prevents electric shorts and ensures reliable cap layer formation, reducing the risk of circuit failures by removing excess cap layer material and allowing for a cleaner surface for subsequent deposition, thereby enhancing the integrity of the semiconductor structure.
Implementation Method 1
A method is developed to detect malfunctions in cap layer formation, involving the use of acid treatments and a brush module system to remove excess cap layer material
Implementation Method 2
The existing method of forming cap layers in integrated circuits using electroless deposition often results in excess metal compound deposition on dielectric material
Data Source
AI summary
The present invention allows correcting malfunctions occurring in the formation of a cap layer on an electrical element in a semiconductor substrate. It is detected whether a malfunction occurred in the formation of the cap layer. If a malfunction in the formation of the cap layer was detected, a rework procedure is performed. The rework procedure can comprise exposing the substrate to a first acid and a second acid.