Adjustable Shadow Mask Assembly for Solar Cell Ion Implantation

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Solution Overview

Problem

Current solar cell fabrication techniques face challenges in achieving precise and cost-effective patterned implant doping and deposition without the need for additional lithographic or external masking, particularly in forming well-defined doping patterns and atomic profiles for high-efficiency solar cells.

Innovation Solution

An adjustable shadow mask assembly that allows for selective ion implantation by adjusting between positions to enable the formation of multiple parallel lines with or without intersecting orientations, using a combination of occlusion masks and exposure regions to create smaller openings, and incorporating a moveable substrate holder and controller for velocity adjustment, enabling both homogeneous and selective implantation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional lithographic methods are used for patterned implant doping, then precise doping patterns can be achieved, but manufacturing costs increase significantly

Engineering Contradiction:

Improvedoping pattern precisionVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention extracts and eliminates the lithographic step from the conventional fabrication process by using a shadow mask assembly that directly defines the doping pattern through physical masking during ion implantation, thereby achieving precise patterning without the need for expensive lithographic equipment and processes

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The shadow mask assembly serves as an intermediary tool between the ion source and substrate, using occlusion masks with precisely positioned openings to define the doping pattern. This intermediary mechanism allows direct pattern transfer without requiring lithographic photoresist processing, reducing manufacturing complexity and cost while maintaining precision

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If multiple separate masking steps are used to create complex doping patterns, then pattern definition accuracy is maintained, but processing time and device complexity increase

Engineering Contradiction:

Improvepattern definition accuracyVSAvoidmasking process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention merges multiple masking functions into a single shadow mask assembly that can simultaneously define multiple doping regions and patterns. The occlusion masks are configured with multiple openings in specific arrangements that allow complex patterns to be created in one implantation step rather than requiring multiple sequential masking operations

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The shadow mask assembly incorporates adjustable occlusion masks that can be positioned and repositioned to create different doping patterns. This dynamic capability allows the same assembly to produce various patterns by adjusting mask positions, reducing the need for multiple fixed masks and simplifying the overall device complexity

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If fixed shadow mask positions are used, then device simplicity is maintained, but adaptability to different doping patterns is limited

Engineering Contradiction:

Improvedoping pattern versatilityVSAvoidmask assembly complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The shadow mask assembly is designed as a universal tool that can create multiple different doping patterns through adjustment of the occlusion masks. The same assembly structure serves multiple functions by configuring masks in different positions, eliminating the need for separate dedicated masks for each pattern type

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 achieves accurate and defined doping patterns, reduces manufacturing costs by avoiding expensive lithographic methods, and enhances solar cell performance by allowing for precise control of doping levels and resistivity, thereby improving efficiency and meeting the demands of future solar cell requirements.

Implementation Method 1

an ion source configured to provide ions; and an shadow mask assembly configured to selectively allow ions from the ion source to pass therethrough to a substrate where they are implanted

Methodology Applied

Scientific EffectIon implantation: Ion Implantation

Data Source

PatentEP2534674B1An adjustable shadow mask assembly for use in solar cell fabrications

Publication Date: 2016.04.06 INTEVAC INC

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AI summary

An adjustable shadow mask implantation system comprising: an ion source configured to provide ions; and an shadow mask assembly configured to selectively allow ions from the ion source to pass therethrough to a substrate where they are implanted, wherein the shadow mask assembly is configured to adjust between a first position and a second position, wherein the shadow mask assembly enables ion implantation of multiple substantially parallel lines absent any lines with an intersecting orientation with respect to the multiple substantially parallel lines when set in the first position, and wherein the shadow mask assembly enables ion implantation of multiple substantially parallel lines and a line with an intersecting orientation with respect to the multiple substantially parallel lines when set in the second position.