Element Chip Protective Film Formation Using High Vapor Pressure Solvents
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in manufacturing element chips is the difficulty in forming a uniform protective film on substrates with high water-repellency and fine asperities, leading to inadequate coverage of bumps and potential damage during plasma-etching due to insufficient drying of water-soluble resin solutions, which can cause mask burning and deformation.
Innovation Solution
A manufacturing process involving a mixture of water-soluble resin and an organic solvent with higher vapor pressure than water is applied to form a protective film, which is then dried using a spray-coating and spin-coating technique to ensure uniform coverage across convex and concave portions, even at low temperatures, preventing mask damage and debris adherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If water-soluble resin solution is applied on the substrate surface, then the protective film can be removed easily by water flushing, but the resin solution fails to cover the whole surface uniformly due to high water-repellency and fine asperities
Solution Approach 1:
The patent changes the solvent composition parameters by using an organic solvent with higher vapor pressure than water (such as ethanol, isopropanol, or acetone) instead of pure water. This parameter change allows the resin solution to wet the hydrophobic surface better and evaporate more quickly, preventing solution flow before drying completes, thereby achieving uniform coverage while maintaining easy removability.
Solution Approach 2:
The patent uses a composite solvent system combining water-soluble resin with organic solvents having higher vapor pressure than water. This composite material approach creates a solution that exhibits both the easy removability of water-soluble resins and the improved wetting/evaporation characteristics of organic solvents, resolving the contradiction between ease of removal and uniform coverage.
2Productivity
If the substrate is heated to accelerate drying of the resin solution, then the volatile components are removed quickly, but the holding sheet with heatproof temperature of 80°C or less cannot withstand the high temperature
Solution Approach 1:
The patent changes the vapor pressure parameter of the solvent by selecting organic solvents with higher vapor pressure than water (such as ethanol, isopropanol, acetone). This allows the solution to dry at lower temperatures (below 80°C) while still achieving rapid evaporation, thus maintaining both high drying speed and holding sheet reliability.
Solution Approach 2:
The organic solvent acts as an intermediary that facilitates rapid evaporation at low temperatures. By using a solvent with higher vapor pressure than water, the system achieves efficient volatile component removal without requiring high temperatures that would damage the holding sheet, thus mediating between the conflicting requirements of drying speed and thermal stability.
3Ease of manufacture
If the resin solution does not dry sufficiently, then the mask can be applied easily, but mask burning or mask deformation occurs during laser grooving and plasma-etching steps
Solution Approach 1:
The patent changes the evaporation rate parameter by using organic solvents with higher vapor pressure than water. This enables the resin solution to dry completely at lower temperatures, forming a sufficiently dried protective film that maintains its integrity during laser grooving and plasma-etching, preventing mask burning and deformation while still allowing easy application.
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 process ensures a uniform protective film formation across the substrate surface, minimizing damage from plasma exposure and debris, while maintaining the integrity of the dicing tape and preventing mask burning, thereby enhancing the reliability of the element chips.
Implementation Method 1
an organic solvent which is water-soluble and has a vapor pressure higher than water
Implementation Method 2
removing the protective film along the etching regions by irradiating a laser beam onto the protective film covering the etching regions
Implementation Method 3
plasma-etching the substrate from the first side along the etching regions while allowing the protective film to be maintained as a mask in the element regions
Data Source
AI summary
A manufacturing process of an element chip comprises steps of preparing a substrate including a plurality of etching regions and element regions each containing a plurality of convex and concave portions, holding the substrate and a frame with a holding sheet, forming a protective film by applying a first mixture to form a coated film above the substrate and by drying the coated film to form the protective film along the convex and concave portions, the first mixture containing a water-soluble first resin, water and a water-soluble organic solvent and has a vapor pressure higher than water, removing the protective film by irradiating a laser beam thereon to expose the substrate in the etching regions, plasma-etching the substrate along the etching regions while maintaining the protective film in the element regions to individualize the substrate, and removing the protective film by contacting the protective film with an aqueous rinse solution.