Passivation Opening Structure to Prevent PI Corner Cracks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges with stress at the interface between polyimide (PI) layers and passivation layers, leading to cracks and degradation of device reliability due to the complexity and increased stress at corner interfaces.
Innovation Solution
A method is introduced that forms a patterned polyimide (PI) layer over passivation layers using a single photolithography step, ensuring no PI layer remains within the via openings, thereby avoiding stress and cracks by recessing the sidewalls from the corners, and simplifying the process by reducing the number of masks used.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyimide layer is formed over passivation layers in existing semiconductor manufacturing processes, then the device structure is completed, but stress at corner interfaces causes cracks and degrades device reliability
Solution Approach 1:
The patent extracts and removes the polyimide layer from the corner interfaces where stress concentration occurs. By forming openings in the polyimide layer that expose the contact features, the harmful polyimide material is taken out from the stress-prone corner regions, eliminating the source of stress-induced cracks while maintaining the structural integrity of the device.
Solution Approach 2:
The patent applies preliminary action by forming openings in the polyimide layer before final device assembly. This preliminary removal of polyimide material from corner interfaces prevents stress accumulation and crack formation in advance, ensuring device reliability from the outset rather than addressing cracks after they form.
2Manufacturing precision
If multiple masks are used for patterning the polyimide layer, then precise patterning is achieved, but manufacturing complexity and processing costs increase
Solution Approach 1:
The patent merges multiple patterning operations into a single photolithography step. By designing the polyimide layer openings to be formed concurrently with other patterned layers using the same mask, the process eliminates the need for separate patterning steps, reducing manufacturing complexity while maintaining the required patterning precision through careful mask design.
Solution Approach 2:
The patent applies universality by making the photolithography mask serve multiple functions: it patterns both the polyimide layer openings and other device layers in a single exposure step. This multi-functional approach to the mask reduces the total number of patterning operations required while achieving the necessary precision for all layers.
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
Enhances the reliability of the patterned PI layer by eliminating stress and potential cracks, while reducing processing costs through a simplified manufacturing process that uses a single mask for patterning.
Implementation Method 1
forming a patterned polyimide (PI) layer over passivation layers using a single photolithography step
Implementation Method 2
performing one or more etching processes to form a second opening that exposes a top surface of the upper contact feature
Data Source
AI summary
A semiconductor device and method including depositing a passivation layer over an upper contact feature. In some embodiments, a polyimide (PI) layer is formed over the passivation layer. In an example, the PI layer is patterned to form a patterned PI layer including a first opening that exposes a portion of the passivation layer over the upper contact feature. In an embodiment, one or more etching processes are performed to form a second opening that exposes a top surface of the upper contact feature. In some embodiments, the one or more etching processes etches the passivation layer through the first opening to form a patterned passivation layer. In some examples, the one or more etching processes also recesses sidewall surfaces of the patterned PI layer from corners of the patterned passivation layer defined along opposing surfaces of the second opening.