Deposition Mask With Resistive Heating And Support Structures
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Solution Overview
Problem
Deposition masks with small openings and large aspect ratios face challenges in semiconductor processing, as the deposited material tends to pinch-off at the corners, preventing it from reaching the substrate due to the high aspect ratio, leading to inefficiencies in material distribution for small pixel sizes in image sensors.
Innovation Solution
A deposition mask with a thin mask layer and a resistive heating element is used, reducing the aspect ratio of the openings and minimizing material deposition on the mask, thereby preventing pinch-off and ensuring material reaches the substrate effectively. The mask layer is formed with tensile stress and aligned with the substrate opening, and a spacer layer provides mechanical support, while the resistive heating element reduces deposition by generating heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a mask with small openings and large aspect ratio is used for selective deposition, then the deposition pattern can achieve small pixel sizes, but the deposited material pinches off at the corners and cannot reach the substrate
Solution Approach 1:
The patent changes the geometric parameters of the mask openings by providing support structures at the corners, which effectively increases the opening width and reduces the aspect ratio. This parameter change allows material to reach the substrate while maintaining the ability to form small pixel patterns, resolving the contradiction between deposition precision and material delivery reliability
Solution Approach 2:
The patent segments the mask structure by adding separate support structures at the corners of each opening. These support structures are distinct from the mask layer itself, allowing them to provide structural support without interfering with the deposition pattern. This segmentation enables the mask to maintain both small opening dimensions for precision and sufficient material flow paths
2Manufacturing precision
If the mask opening size is reduced for small pixel deposition, then the deposition pattern precision improves, but the aspect ratio increases causing material pinch-off
Solution Approach 1:
The patent addresses the aspect ratio problem by adding a vertical dimension element - the support structures extend from the substrate surface up to support the mask layer at the corners. This dimensional addition provides mechanical support that allows the horizontal opening dimensions to be reduced for precision without proportionally reducing the vertical thickness, thereby maintaining a manageable aspect ratio
3Strength
If a traditional mask structure is used, then the mask provides structural support, but material deposition on the mask causes pinch-off at high aspect ratio openings
Solution Approach 1:
The patent segments the functional responsibilities by separating the mask layer (for pattern definition) from the support structures (for mechanical support and material guidance). The support structures at the corners provide structural integrity and guide material flow, while the mask layer maintains the precise deposition pattern. This segmentation prevents material accumulation that would cause pinch-off in traditional integrated structures
Solution Approach 2:
The support structures act as intermediaries between the substrate and the mask layer. They provide the necessary mechanical support and material flow paths without interfering with the precise pattern definition function of the mask layer. This intermediary structure allows material to reach the substrate through the openings while the mask maintains its structural integrity and patterning function
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 solution effectively reduces the risk of material pinch-off at the openings, ensuring that the deposited material reaches the substrate, improving the efficiency of material distribution for small pixel sizes and enhancing the semiconductor processing outcome.
Implementation Method 1
a resistive heating element reduces deposition by generating heat
Data Source
AI summary
Generally, examples described herein relate to deposition masks and methods of manufacturing and using such deposition masks. An example includes a method for forming a deposition mask. A mask layer is deposited on a substrate. Mask openings are patterned through the mask layer. A central portion of the substrate is removed to define a substrate opening through a periphery portion of the substrate. The mask layer with the mask openings through the mask layer extending across the substrate opening.