Semiconductor Package Stitching Zones for Fine-Pitch Lithography
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving high integration density and fine-pitch patterning due to physical limits in photolithography, particularly with warpage in wafers and the complexity of ultra-large packages, which affects the resolution and depth of focus during the manufacturing process.
Innovation Solution
A multi-exposure photolithography process is employed to create stitching zones within semiconductor packages, using negative-type photo-sensitive materials that undergo chemical changes to form ridge structures, enabling more flexible manufacturing and improved patterning capabilities, especially suited for FinFETs and system-in-package applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional single-exposure photolithography is used, then the manufacturing process is simple, but the integration density and feature size are limited by resolution and depth of focus
Solution Approach 1:
The photolithography process is divided into multiple sequential exposures, where each exposure creates a portion of the final pattern. The first exposure forms initial patterns, and the second exposure forms additional patterns that overlap with the first, creating stitching zones where the patterns are combined to achieve higher integration density and finer features than a single exposure could produce.
Solution Approach 2:
The patent extends the photolithography process from a single exposure in one dimension to multiple exposures in a temporal sequence, adding a time dimension to the patterning process. This allows the accumulation of multiple pattern layers through stitching zones, effectively increasing the complexity and precision of the final pattern beyond what a single exposure could achieve.
2Manufacturing precision
If fine-pitch patterning is performed on wafers with warpage or ultra-large packages, then high integration density is achieved, but the photolithography process becomes challenging due to resolution and depth of focus limits
Solution Approach 1:
The manufacturing process is segmented into multiple exposure steps, allowing each exposure to cover a smaller, more manageable area with controlled focus. By dividing the large package into multiple exposure zones and stitching them together, the process accommodates wafer warpage and ultra-large package dimensions while maintaining fine-pitch patterning precision that would be unachievable in a single exposure.
3Productivity
If multiple exposures are performed to create stitching zones, then integration density and feature size are improved, but the manufacturing process complexity increases
Solution Approach 1:
The multi-exposure process is segmented into distinct, repeatable steps: first exposure to form initial patterns, development, second exposure to form additional patterns, and final development to create stitching zones. This segmentation transforms a complex single-step process into multiple manageable steps, each contributing to the overall integration density while maintaining process control.
Solution Approach 2:
The photo-sensitive material layer serves as an intermediary that accumulates patterns from multiple exposures. Each exposure deposits a pattern into this intermediate layer, and the sequential exposures build upon each other, with the stitching zones forming where patterns overlap. This intermediary layer mediates the combination of multiple exposures into a unified high-density pattern.
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 allows for enhanced integration density and finer feature sizes, overcoming the limitations of traditional photolithography by creating ridge structures that improve the manufacturing process, particularly in large packages and those with warpage, thereby increasing the efficiency and precision of semiconductor package production.
Implementation Method 1
using negative-type photo-sensitive materials that undergo chemical changes to form ridge structures
Data Source
AI summary
A semiconductor package including a plurality of semiconductor devices, an insulating layer, and a redistribution layer is provided. The insulating layer is disposed over the semiconductor device. The redistribution layer is disposed over the insulating layer and electrically connected to the semiconductor device. The redistribution layer includes a conductive line portion. The semiconductor package has a stitching zone, and the insulating layer has a ridge structure on a surface away from the semiconductor device and positioned within the stitching zone.