Light-Transmissive Substrate Patterning via Inverted Exposure
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Solution Overview
Problem
Current manufacturing methods for devices with structure bodies on substrates are costly due to the need for expensive exposure apparatuses with two-sided alignment functions and can result in quality defects during dicing processes.
Innovation Solution
A method involving a light-transmissive substrate with structure bodies on one surface and a negative-type photoresist on the opposing surface, where light is irradiated through the substrate to expose the photoresist, eliminating the need for two-sided alignment and reducing costs by patterning the photoresist using the structure bodies as a mask.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If two-sided alignment exposure apparatuses are used to pattern photoresist on both surfaces of substrate, then patterning coverage is improved, but manufacturing cost increases
Solution Approach 1:
Instead of irradiating light from the photoresist side (conventional approach), the patent inverts the approach by irradiating light from the opposite side of the substrate. The substrate itself serves as the mask, and the structure bodies on one surface block light to create the pattern on the photoresist applied to the other surface. This eliminates the need for expensive two-sided alignment apparatuses while achieving complete patterning coverage.
Solution Approach 2:
The substrate serves multiple functions: it acts as both the structural base and the masking layer for light exposure. The structure bodies on one surface serve as the pattern-defining elements that block light, eliminating the need for separate mask materials. This multi-functionality reduces the number of components and apparatuses required, thereby reducing manufacturing cost.
2Productivity
If dicing is performed on substrates with metal layers, then device separation is achieved, but quality defects occur due to metal burrs
Solution Approach 1:
The patent applies photoresist to the entire surface of the substrate before dicing, and the photoresist is removed after dicing. This preliminary application of photoresist protects the metal layers and substrate surfaces during the dicing process, preventing metal burrs and quality defects. The photoresist acts as a protective layer that is later removed to reveal clean, defect-free device surfaces.
3Loss of substance
If photoresist is applied only to specific regions, then material usage is reduced, but application complexity increases
Solution Approach 1:
The patent extracts the patterning function from the photoresist application process itself. Instead of applying photoresist only to specific regions through complex masking and alignment, the entire substrate surface is coated with photoresist. The pattern is then defined by light blocking from the structure bodies during exposure, not by selective photoresist application. This simplifies the application process while the photoresist is subsequently removed after serving its protective and patterning functions.
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 reduces manufacturing costs by eliminating the need for expensive exposure apparatuses and avoids dicing-related quality defects, while improving patterning precision and efficiency.
Implementation Method 1
The substrate is light-transmissive and has a second surface on a side opposite to the first surface
Implementation Method 2
A light transmissivity of the structure body is lower than a light transmissivity of the substrate
Implementation Method 3
irradiating the substrate with light to expose a portion of the photoresist by using the structure body as a mask
Data Source
AI summary
According to one embodiment, a method for manufacturing a device includes a first process, a second process, a third process, and a fourth process. The first process includes providing a structure body at a first surface of a substrate. The substrate is light-transmissive and has a second surface. A light transmissivity of the structure body is lower than a light transmissivity of the substrate. The second process includes providing a negative-type photoresist at the second surface. The third process includes irradiating the substrate with light to expose a portion of the photoresist. The light is irradiated in a first direction from the first surface toward the second surface. The light passes through the substrate. The fourth process includes developing the photoresist to remain the portion of the photoresist in a state of being adhered to the second surface and to remove other portion of the photoresist.