Capillary Liquid Media Application Device for Semiconductor Substrates

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Solution Overview

Problem

Existing methods for applying liquid media to semiconductor substrates, such as screen printing, are limited by large dosing needle diameters, resulting in inadequate contact resistances and inability to produce small structural sizes effectively.

Innovation Solution

A device utilizing a capillary fluid guidance system with a small outer diameter, capable of flexible placement on the substrate, and a feed device for relative movement, allowing precise application of liquid media in narrow lines or patterns, using a fluid conveying device to maintain constant pressure and flow, enabling the production of small structures with high reliability and short processing times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a dosing needle with large diameter is used for screen printing, then the application process is simple and reliable, but the minimum structure size that can be achieved is large and contact resistance is high

Engineering Contradiction:
Improvestructure sizeVSAvoidcontact resistance
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent uses capillary forces (a hydraulic principle) to control liquid medium flow through the small-diameter capillary without requiring mechanical pressure systems. The capillary's small diameter (≤25 μm) creates sufficient capillary pressure to drive the liquid medium onto the substrate, enabling precise deposition of small structures while maintaining flow control and reliability

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes the critical parameter of capillary diameter from conventional large dimensions to extremely small dimensions (≤25 μm, preferably 5-15 μm). This parameter change enables the formation of small structure sizes while the capillary's surface properties and liquid medium viscosity are optimized to maintain reliable material flow and low contact resistance

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If a capillary with small outer diameter is used, then small structures can be produced, but the capillary is more fragile and difficult to handle

Engineering Contradiction:
Improvestructure sizeVSAvoidcapillary handling
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent protects the fragile small-diameter capillary by nesting it within a robust holder structure. The capillary is inserted into and supported by the holder, which provides mechanical strength and protection while allowing the capillary tip to extend for precise substrate contact. This nested arrangement protects the delicate capillary during handling and operation

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent employs a flexible membrane at the capillary tip area that can deform to maintain contact with the substrate surface during relative movement. This flexible element absorbs mechanical stresses and protects the rigid small-diameter capillary from damage while ensuring consistent liquid medium application

Inventive Principle:
Principle #30Flexible shells and thin films

3Manufacturing precision

If the capillary is placed in sliding contact with the substrate surface, then precise application is achieved, but damage to the substrate or capillary may occur

Engineering Contradiction:
Improveapplication precisionVSAvoidsubstrate damage
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent incorporates a flexible membrane element between the capillary and substrate that acts as a cushion. This flexible element deforms under contact pressure, distributing forces and preventing damage to both the fragile capillary and the substrate surface while maintaining precise liquid medium application

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent optimizes the physical parameters of the liquid medium (viscosity, surface tension) and capillary properties (diameter, surface treatment) to enable controlled flow at very low pressures. This parameter optimization allows the capillary to be placed in sliding contact with the substrate without applying sufficient force to cause damage, while still achieving precise material deposition

Inventive Principle:
Principle #35Parameter changes

4Productivity

If conventional screen printing is used, then the process is simple and robust, but processing time is long and throughput is low

Engineering Contradiction:
ImprovethroughputVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent uses capillary-driven liquid flow to eliminate the need for complex mechanical screen printing systems. The capillary's inherent capillary pressure enables automatic liquid medium flow and deposition without requiring complex pumping, pressure control, or screen mechanism systems, thereby increasing throughput while keeping the device relatively simple

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent replaces the mechanical screen printing system with a capillary-based liquid delivery system. Instead of using screens, squeegees, and mechanical pressure systems, the invention uses capillary forces to control liquid flow and deposition, simplifying the device while enabling faster processing and higher throughput

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

The solution enables the production of smaller, more reliable structures with lower contact resistances, potentially replacing conventional screen or pad printing in solar cell production, achieving higher throughput and improved conductivity of front contacts.

Implementation Method 1

a capillary (32) made of glass or quartz or plastic or containing such a capillary... The open end of the capillary intended for the exit of the liquid medium is guided in a sliding manner on the substrate surface

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP3736050B1Device and method for applying liquid media to a substrate surface
Publication Date: 2022.11.16 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3736050B1 patent drawingFigure 1~2
  • EP3736050B1 patent drawingFigure 3
  • EP3736050B1 patent drawingFigure 4

AI summary

The invention relates to a device for applying liquid media (6) to a substrate surface (21), comprising at least one fluid guidance device (3), at least one fluid conveying device (4), and at least one feed device (25) for generating relative movement at least between the substrate surface (21) and a part of the fluid guidance device (3), wherein the device further comprises at least one drive device (1) for changing the distance between the substrate surface (21) and a part of a second longitudinal section (32) of the fluid guidance device (3). The invention further relates to the use of such a device and a method for applying liquid media (6) to a substrate surface (21).