Shielded Substrate Holder for Dual-Side Sputtering
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Solution Overview
Problem
The challenge is to form transparent conductive oxide layers on both sides of a heterojunction solar battery substrate without causing a short-circuit, while also reducing manufacturing costs and enhancing conversion efficiency.
Innovation Solution
A film formation apparatus with a vacuum chamber and a substrate-holder conveyance mechanism that allows for simultaneous sputtering on both surfaces of a substrate, using a single annular conveyance path and shielded substrate holders to prevent edge deposition, eliminating the need for masks and maximizing layer area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transparent conductive oxide layers are formed over the entire surfaces on both sides of the n-type crystalline silicon substrate by sputtering, then the conversion efficiency is enhanced, but materials deposited onto the side surfaces of the substrate may cause a short-circuit between the transparent conductive oxide layers
Solution Approach 1:
A substrate holder is introduced as an intermediary component between the sputtering source and the substrate. The substrate holder includes shield portions that extend toward the substrate to block film formation materials from depositing on the side surfaces, thereby preventing short-circuits while allowing full-surface deposition on the front and back surfaces
Solution Approach 2:
The solution moves from a two-dimensional deposition problem (front and back surfaces) to a three-dimensional spatial arrangement by positioning the substrate holder with shield portions at specific heights and angles, creating vertical shielding zones that prevent lateral deposition on side surfaces
2Object-affected harmful factors
If a mask is used to form transparent conductive oxide layers on both sides of the substrate to avoid short-circuits, then short-circuits are prevented, but manufacturing cost increases
Solution Approach 1:
The substrate holder with integrated shield portions replaces expensive reusable masks. The shield portions are simple structural components that can be easily manufactured and replaced if needed, eliminating the cost of mask materials and the complexity of mask alignment and replacement procedures
Solution Approach 2:
The shielding function is merged into the substrate holder structure itself rather than being a separate mask component. This integration eliminates the need for additional mask handling steps and reduces the total number of components required in the sputtering process
3Object-affected harmful factors
If transparent conductive oxide layers are formed over the entire surface on one side while forming another layer on the other side over a region other than the edge region using a mask, then short-circuits are avoided, but the area of the transparent conductive oxide layer is reduced
Solution Approach 1:
The substrate holder acts as a mediator that enables full-surface deposition on both front and back surfaces while preventing side-surface deposition through its shield portions, thereby maximizing the active area of transparent conductive oxide layers without requiring edge-region exclusion
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 method prevents short-circuits between sputtered films, reduces manufacturing costs by eliminating mask usage, and enhances conversion efficiency by maximizing transparent conductive oxide layer area on heterojunction solar batteries.
Implementation Method 1
a first sputtering source for performing film formation on a first surface of a film-formation target substrate; a second sputtering source for performing film formation on a second surface of a film-formation target substrate
Data Source
AI summary
The present invention provides a technique for performing film formation at low cost without causing a short-circuit between sputtered films formed on opposite surfaces of a film-formation target substrate. According to the present invention, in a substrate-holder conveyance mechanism 3, a substrate holder 11 is conveyed by a first conveyance portion so that the substrate holder 11 passes through a first film formation region; film formation is performed by sputtering on a first surface of a film-formation target substrate 50 held by the substrate holder 11; the substrate holder 11 is conveyed from the first conveyance portion to a second conveyance portion in such a manner as to make a turn with the up/down orientation of the substrate holder 11 maintained; the substrate holder 11 is conveyed by the second conveyance portion in a direction opposite to the direction of conveyance by the first conveyance portion so that the substrate holder 11 passes through a second film formation region; and film formation is performed by sputtering on a second surface of the film-formation target substrate 50. The substrate holder 11 has openings 14 and 15 through which first and second surfaces of the film-formation target substrate 50 are exposed, and includes a shield portion 16 for shielding an edge portion of the film-formation target substrate 50 from a film formation material supplied from a second sputtering source.