Intermediate suction support and its utilisation or producing a thin film structure

Abstract

A substrate holder is provided with two kinds of grooves (clearances) in the absorbing surface thereof. One kind of groove is made of a suitable depth so as to be able to quickly exhaust air and reduce pressure to thereby vacuum mount a substrate, and the other kind of groove is formed with a very small depth within such a range that there is no influence of dust being interposed between the holder and the substrate, in order to better the heat conduction between the substrate and the substrate holder. In addition, the area of the latter is made large as compared with the area of the former.

Description

[0001] The present invention relates to an intermediate suction support and its utilisation for producing a thin film structure.STATE OF PRIOR ART[0002] The introduction of gaseous species into a solid material can be carried out advantageously by ionic implantation. Thus, the document FR-A-2 681 472 (corresponding to the U.S. Pat. No. 5,374,564) describes a method for manufacturing thin films of semiconductor material. This document reveals that the implantation of a rare gas or hydrogen in a substrate in a semiconductor material is capable of inducing, under certain conditions, the formation of micro-cavities or platelets (micro-bubbles) at a depth close to the average depth of penetration of the implanted ions. If this substrate is put into intimate contact, on its implanted face, with a stiffener and a heat treatment is applied at a suitable temperature, there is interaction between the micro-cavities or platelets resulting in separation of the semiconductor substrate into two p...

AI Technical Summary

Benefits of technology

[0014] The present invention makes it possible to compensate for the disadvantages of prior art. It makes it possible to obtain a structure comprising thin films deposited on a low cost substrate (for example glass, ceramic or plastic). It enables the consumption of semiconducting material to be reduced to the minimum. It is simple to implement and to industrialise. It allows the substrate providing the thin films to be reused many times. It enables collective production of photovoltaic cells.

[0017] The support according to the invention makes it possible to avoid the formation of blisters and therefore to avoid recuperating the film in the form of chips. The suction support according to the invention thus plays a role of maintenance and of stiffener, and furthermore aids separation, for example by applying stresses in certain cases at the level of the embrittled layer.

[0023] The suction surface can have a dished shape, convex or concave, making it possible to produce a mechanical stress on the film during its separation from the rest of the substrate. These shapes facilitate separation.

[0031] The contact between the first face of the substrate and the suction surface of the intermediate support can be strengthened by molecular adherence. This adherence can be controlled by appropriate treatment to allow sticking reversibility.

Problems solved by technology

However, the present solution which consists of using sticking by molecular adhesion requires a surface preparation which can be delicate and costly.

Furthermore, gluing a support with glue does not allow later high temperature operations on the thin film, in particular because of the temperature hold limit of organic glues, and the restrictions involved in high temperature operations and contaminations in the case of inorganic glues.

However, at present it is not known how to produce this type of structure at a cost compatible with the cost of photovoltaic cells.

This method has several disadvantages; consumption of silicon (the porous layers are sacrificed), the porous layers are formed in several stages in order to obtain three different porosities, and the method is certainly difficult to industrialise.

This solution certainly poses the problem of re-using the substrate a large number of times.

They refer to technologies that are often delicate to implement.

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