Device and method for application of an even thin fluid layer to substrates

Abstract

The invention relates to a device (10), for application of an even thin fluid, namely phosphoric acid, layer to silicon cells (12) for photovoltaic application, provided with a process chamber (14), with a fluid trough (16) and a high-frequency ultrasound device (11) for conversion of the fluid into a fluid mist (15) and with a transport device (13) for the silicon cells (12) arranged below the fluid mist dropping shaft (25) of the process chamber (14). According to the invention, such a device (10) permitting a more homogeneous application of fluid to the relevant silicon cells with relationto both the surface and the amount applied, may be achieved, whereby the fluid mist dropping shaft (25) of the process chamber (14) has a tapering of the open cross-section thereof in the direction ofthe transport device (13) and opens out in a through shaft arrangement (40) for the substrates (12) covering the transport device (13) and the open cross-sections of the opening of the fluid mist dropping shaft (25) and the through shaft arrangement (40) match each other and are preferably essentially the same.

Description

technical field [0001] The present invention relates to a device for applying a uniform thin liquid layer, especially a phosphoric acid layer, to a substrate, especially a silicon cell for photovoltaic applications, and to a device for applying A method of applying a uniform thin liquid layer, especially a phosphoric acid layer, to a wafer - especially silicon cells for photovoltaic applications. Background technique [0002] In order to be able to manufacture photovoltaic cells made of silicon, it is first necessary to dope the unfinished cell with phosphorus. In this first step, the cell is wetted with phosphoric acid and the wetted cell is placed in a high temperature furnace at about 800°C to 900°C where phosphorus diffuses from the dried acid into the silicon substrate. The coating is designed to be very homogeneous to obtain an even distribution during diffusion, and the coating is also designed in an economical manner, since excess phosphoric acid melts onto the cell...

AI Technical Summary

Problems solved by technology

A disadvantage of this known device is that it does not guarantee an even distribution of the mist, since even a slight air flow is sufficient to "blow" the mist

Additionally, the configuration of the processing chamber results in damaging condensation dripping onto the silicon cells, which can prevent uniform wetting or even coating results

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