Dummy Patterns in Aluminum Pad Layers for Etching Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The conventional method of forming aluminum pads in semiconductor processes faces issues with insufficient process window and aluminum erosion due to low pattern density, leading to defects and reliability concerns during plasma etching.
Innovation Solution
Introducing dummy patterns between aluminum pads and routings to increase pattern density, which are evenly distributed and strategically placed to prevent erosion and improve etching reliability, using materials like aluminum, aluminum copper alloy, or aluminum silicon copper alloy, and determining their placement based on a known dark/clear ratio to optimize the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma etching is used to remove aluminum film layers in conventional semiconductor processes, then aluminum pads can be formed, but the low pattern density causes insufficient process window and aluminum erosion
Solution Approach 1:
Dummy patterns are added to the aluminum pad layer before etching to pre-establish the required pattern density. This preliminary action ensures that the etching process operates within its optimal process window, preventing aluminum erosion and improving etching precision and reliability.
Solution Approach 2:
The pattern density parameter of the aluminum pad layer is modified by introducing dummy patterns. This changes the etching conditions from low pattern density (causing erosion) to optimal pattern density (ensuring precise and reliable etching).
2Quantity of substance
If large areas of aluminum film are removed to form aluminum pads, then aluminum pads can be created, but copper separates out and defects increase
Solution Approach 1:
Dummy patterns are introduced before the etching process to establish optimal pattern density. This preliminary configuration prevents copper segregation and defect formation during the etching of large aluminum areas.
3Reliability
If aluminum is used as solder pad material instead of copper, then oxidation and contamination issues are reduced, but the hardness is lower and testing reliability decreases
Solution Approach 1:
The pattern density parameter is changed by adding dummy patterns, which improves the etching process window and prevents aluminum erosion. This ensures that the aluminum pad layer maintains its structural integrity and hardness, thereby improving testing reliability while preserving the bonding reliability advantages of aluminum.
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 effectively increases pattern density, reduces the probability of defects, and enhances the reliability of the aluminum pad layer by preventing erosion and improving the uniformity and performance of the semiconductor device.
Implementation Method 1
an aluminum film layer is first formed and then the aluminum film layer is processed with plasma etching
Implementation Method 2
large amount of the plasma gas needs to be used for removing large areas of aluminum film
Data Source
AI summary
A method of disposing dummy patterns is described, which is used for increasing the pattern density of an aluminum pad layer. A substrate is provided, and an aluminum pad material layer is formed on the substrate. Then, the aluminum pad material layer is patterned to form the aluminum pad layer which includes a plurality of aluminum pads and a plurality of dummy patterns, wherein the dummy patterns are distributed in the spaces between the aluminum pads. Besides, routings can be further disposed in the aluminum pad layer and the dummy patterns are distributed in the spaces between the aluminum pads, between the aluminum pads and the routings, or between the routings.