Liquid Ejection Head Reticle Exposure Process
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Solution Overview
Problem
The challenge in producing liquid ejection heads with long ejection orifice arrays is that the entire chip cannot be exposed at once due to the limited reticle field angle, leading to reduced ejection orifice arranging accuracy and potential overexposure issues when using conventional photolithography methods.
Innovation Solution
A process involving multiple reticles for exposure and development, where a first reticle forms the ejection orifice array and a second reticle forms the side portions, such as electrode pads, allowing for alternating exposure and development of chips on a common substrate to overcome the limitations of the reticle field angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the entire chip is exposed at once using a single reticle, then the ejection orifice array can be formed with high accuracy, but the reticle field angle is insufficient to cover the entire long chip
Solution Approach 1:
The chip is divided into multiple regions (first region and second region) that are exposed separately using different reticles. The first reticle covers the first region while the second reticle covers the second region, allowing each region to be exposed within the limited field angle of individual reticles while collectively covering the entire long chip.
Solution Approach 2:
The exposure process transitions from a single-dimension approach (one reticle covering the entire chip length) to a multi-dimensional approach (multiple reticles arranged in a matrix pattern, each covering a specific region). This spatial reorganization allows comprehensive coverage of the long chip while maintaining the accuracy benefits of limited-field-angle exposure for each region.
2Area of stationary object
If the chip is divided into multiple regions for exposure, then the reticle field angle limitation is overcome, but the ejection orifice array may be overexposed due to multiple exposures
Solution Approach 1:
Different reticles are assigned to different regions of the chip based on their specific requirements. The first reticle is optimized for exposing the first region with the ejection orifice array, while the second reticle is optimized for the second region. This localized optimization ensures that each region receives appropriate exposure without overexposure, even though multiple reticles are used.
Solution Approach 2:
Multiple reticles are used as separate copying tools, each creating a precise pattern in its designated region. Instead of attempting to copy the entire chip pattern with a single oversized reticle that would compromise accuracy, multiple smaller reticles make localized copies, each within their optimal field angle, thereby preventing overexposure while achieving complete coverage.
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 enables the production of liquid ejection heads with improved ejection accuracy and reliability by ensuring the ejection orifice array is formed accurately without the need for divided exposure, maintaining high-quality image formation and preventing overexposure-related defects.
Implementation Method 1
a first reticle for forming at least the portion for ejection and a second reticle for forming only the side portion are used as the reticle, and wherein the exposure step comprises a first exposure treatment by the first reticle for at least the portion for ejection and a second exposure treatment by the second reticle for the side portion
Data Source
AI summary
A process for producing a liquid ejection head by providing, in one chip, a liquid ejection head having a portion for ejection in which an ejection orifice array is arranged and a side portion having no ejection orifice array, these portions being provided with a member of a photosensitive material, arranging the chip on a common substrate in such a chip array that these two portions are alternately arranged, and separating each chip from the substrate, the process including the steps of relatively moving a reticle of an aligner along the chip array for a photosensitive material on the substrate to expose each chip, and developing the material to obtain the member. A first reticle for forming the portion for ejection and a second reticle for forming only the side portion are used. The exposure includes a first and a second exposure treatment respectively by the first and second reticles.