Platinum Patterning with a Sacrificial Layer for Precise Features
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Solution Overview
Problem
Conventional methods for patterning platinum layers in integrated circuits face challenges such as unreliable feature size production and contamination, leading to corrosion and short circuits due to humidity exposure, and inefficient platinum recycling.
Innovation Solution
A method involving a sacrificial aluminum layer, photoresist patterning, and selective etching is used to deposit and pattern platinum, where the sacrificial layer reacts faster with etchants than platinum, allowing precise removal of unwanted platinum portions and reducing contamination, enabling improved critical dimensions and platinum recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photoresist patterning is used for platinum, then the process is simple, but the feature size precision is poor and contamination occurs
Solution Approach 1:
The patterning process is divided into multiple stages: first forming a sacrificial layer pattern, then depositing platinum, and finally removing the sacrificial layer to reveal the final pattern. This segmentation allows precise feature size control while managing process complexity through systematic breakdown of steps.
Solution Approach 2:
The sacrificial layer is deposited and patterned in advance before the platinum layer is formed. This preliminary action establishes a precise template that guides the subsequent platinum deposition, ensuring accurate feature dimensions are achieved before the final metal structure is created.
2Reliability
If platinum is used as metallization layer, then corrosion resistance is improved, but patterning reliability deteriorates
Solution Approach 1:
A sacrificial layer acts as an intermediary material that facilitates the patterning process. This intermediate layer is easily patterned and removed, leaving behind the precisely patterned platinum structure. The intermediary enables reliable platinum patterning by decoupling the patterning difficulty from the final metal structure.
Solution Approach 2:
The sacrificial layer is a temporary, disposable structure used only during the patterning process. It is intentionally designed to be removed after serving its guiding function, enabling precise platinum patterning without requiring the platinum itself to be manipulated during the critical patterning steps.
3Manufacturing precision
If platinum is deposited over patterned sacrificial layer, then feature size precision is improved, but process time increases
Solution Approach 1:
Multiple functions are merged into the platinum deposition step: the platinum is deposited conformally over the sacrificial layer, simultaneously forming the metal structure and defining the final pattern. This merging of deposition and patterning functions achieves precise critical dimensions while reducing the number of separate process steps required.
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 achieves reliable patterning with precise feature sizes, reduces contamination, and facilitates efficient platinum recycling, enhancing the reliability and performance of platinum metallization in integrated circuits.
Implementation Method 1
An etching process is performed using a wet etching agent that begins to etch through the platinum layer. The etchant etches through the platinum layer where the platinum layer is the thinnest. Once an opening is formed in the platinum layer, the etchant is then able to etch the underlying sacrificial layer. The sacrificial layer reacts with the etchant at a faster rate than the platinum layer and, thus the sacrificial layer is etched more rapidly than the platinum layer.
Implementation Method 2
the platinum layer is sputter deposited on top of the substrate, wherein the platinum layer covers the patterned sacrificial layer and the exposed portion of the top surface of
Data Source
Figure 1A~1B
Figure 1C
Figure 1D
AI summary
At least one embodiment includes a method of patterning platinum (105B) on a substrate (101). An adhesive layer (102) is deposited over the substrate (101), a sacrificial layer (103) is deposited over the adhesive layer (102), and a patterned photoresist layer is formed over the sacrificial layer (103). Then, the sacrificial layer (103) is patterned utilizing the photoresist layer as a mask, such that at least a portion of the adhesive layer (102) is exposed. Subsequently, the top and sidewall surfaces of the patterned sacrificial layer (103) and the first portion of the adhesive layer (102) are covered by a platinum layer (105A). Finally, the sacrificial layer (103) and a portion of the platinum layer (105A) covering the top and sidewall surfaces of the sacrificial layer (103) are etched, thereby leaving a remaining portion of the platinum layer to form a patterned platinum layer (105B) on the substrate (101).