Semiconductor Package Redistribution Layer With Double-Exposure Damascene
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Solution Overview
Problem
Current packaging technologies for integrated circuits face challenges in forming efficient redistribution layers, particularly in achieving accurate pattern overlay and alignment, which affects the integration density and reliability of semiconductor packages.
Innovation Solution
A method involving a double exposure process using positive photo-sensitive materials, where two consecutive exposure processes with different energy doses form latent patterns that are then developed to create dual damascene openings, allowing for better pattern alignment and filling capabilities without the need for conventional photolithographic processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithographic processes are used to form redistribution layers, then the manufacturing process is well-established, but the pattern overlay and alignment precision deteriorates
Solution Approach 1:
The patent replaces conventional photolithographic processes with a direct laser writing approach. The laser beam directly writes patterns onto the photoresist layer without requiring complex photolithographic alignment systems, thereby improving pattern overlay and alignment precision while reducing process complexity.
Solution Approach 2:
The patent introduces a positive photo-sensitive material as an intermediary layer that enables direct laser writing. This photoresist layer acts as a mediator between the laser writing system and the underlying substrate, allowing for high-precision pattern formation through the photochemical reaction triggered by laser exposure.
2Ease of manufacture
If single exposure process is used, then the manufacturing process is simpler, but the filling capability of metal layers into openings deteriorates
Solution Approach 1:
The patent divides the exposure process into two sequential steps: first exposure to define the opening pattern, and second exposure to define the damascene pattern. This segmentation allows each exposure step to be optimized independently, improving metal layer filling capability while maintaining manufacturing simplicity through the use of a single photoresist layer.
Solution Approach 2:
The first exposure step creates a preliminary pattern of openings in the photoresist layer before the second exposure step defines the final damascene pattern. This preliminary action enables subsequent metal deposition to be precisely controlled, improving filling capability while keeping the overall process simple.
3Area of stationary object
If high integration density is achieved through fin-pitch redistribution layers, then the package size is reduced, but the alignment precision deteriorates
Solution Approach 1:
The patent replaces conventional photolithographic alignment systems with direct laser writing, which inherently provides superior alignment precision. The laser beam can be precisely controlled to write fin-pitch patterns at reduced package sizes without suffering from the alignment errors that plague conventional photolithographic methods.
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 enhances pattern overlay and alignment, improves the filling capability of metal layers into openings, and ensures better adhesion between damascene openings and redistribution patterns, leading to more reliable and densely integrated semiconductor packages.
Implementation Method 1
A first exposure process is performed with a first energy dose to form first exposure portions with a first depth in the dielectric material layer. A second exposure process is performed with a second energy dose to form second exposure portions with a second depth in the dielectric material layer.
Data Source
AI summary
A method of fabricating a semiconductor package includes providing a substrate having at least one contact and forming a redistribution layer on the substrate. The formation of the redistribution layer includes forming a dielectric material layer over the substrate and performing a double exposure process to the dielectric material layer. A development process is then performed and a dual damascene opening is formed in the dielectric material layer. A seed metallic layer is formed over the dual damascene opening and over the dielectric material layer. A metal layer is formed over the seed metallic layer. A redistribution pattern is formed in the first dual damascene opening and is electrically connected with the at least one contact.