DE102015105844B4 - Closure device, pyrometer arrangement and vacuum substrate treatment system - Google Patents

Abstract

A closure device comprising a housing (1) having two opposing openings (2) defining an optical axis through the housing (1), wherein in the housing (1) a prismatic cavity (3) having a prism axis is arranged, in that the prism axis is aligned transversely to the optical axis and in the cavity (3) a closure element (4) with at least two functional areas (5), of which at least a first functional area (5) is permeable to IR radiation, is displaceably arranged is that optionally exactly one functional area (5) of the at least two functional areas (5) is arranged in the optical axis.

Description

The invention relates to a closure device, a pyrometer arrangement and a vacuum substrate treatment system.

It is known to subject substrates in vacuum substrate treatment plants to processes that specifically influence the substrate surface or the substrate texture. It is thus possible to coat substrates in a vacuum, to remove layers of substrates or to temper substrates. As a rule, the substrates are placed on a substrate support or fixed in the vacuum space.

However, continuously operating vacuum substrate treatment systems are known in which the substrate is moved on the substrate support through the vacuum substrate treatment system. As a rule, the substrate support is designed as a substrate transport device, for example with transport rollers, of which at least some are designed as driven transport rollers.

An example of such vacuum substrate treatment plants are plants for the treatment of large-area plate-shaped substrates such as glass panes or belt-shaped substrates such as films or metal strips, for example for cleaning or / and coating of such substrates in a continuous process in which the substrates are introduced through an entrance lock into the system, by various Sections transported through the system and thereby undergo a treatment under atmospheric conditions or in a vacuum or in a process gas atmosphere and are discharged through an exit lock from the plant.

The successively arranged sections of such substrate treatment plants can be designed to carry out different process steps or to fulfill various other tasks, for example for transferring between the atmospheres outside and inside the substrate treatment plant, buffering (buffering) the substrates within the substrate treatment plant, heating or cooling the substrates, for evacuation or aeration of the plant chamber, for vacuum separation between successive process areas, for substrate treatment etc.

In some such sections within such substrate treatment plants very high temperatures are reached. In all vacuum treatment processes, the substrate temperature plays a crucial role. For example, in the case of a substrate coating, the layer properties are significantly influenced by the substrate temperature. In particular, in the case of large flat substrates which are coated in a vacuum substrate treatment plant and for this purpose are transported through the vacuum substrate treatment system, the homogeneity of the layer properties both in the longitudinal direction, that is in the transport direction of the substrates, as well as in the transverse direction plays a crucial role , In order to achieve a homogeneous layer properties, a targeted influence on the substrate temperature is absolutely necessary. This affects both the temperature itself and its lateral homogeneity.

It is known to coat flat substrates or webs in vacuum with metallic and non-metallic layers by thermal evaporation or sputtering of the application materials. As a rule, the surfaces to be coated must be pretreated for certain layer properties. For example, for a necessary adhesive strength of the deposited layer on the substrate, the substrates must have a temperature which can usually be produced by heating the substrate or in a plasma treatment. The temperature of the substrate must be adjusted within certain limits. For example, substrate temperatures of 280 ° C to 320 ° C are set for adherent aluminum layers on steel strip. When coating wafers with aluminum for solar cells 400 ° C should not be exceeded. In both cases, alloying aluminum into the base material must not occur. Often, coating occurs at variable substrate speeds. The process must be adapted to the substrate thickness, the substrate speed and the thickness of the applied layer. To adjust the process parameters, the temperature of the substrate must be measured before and after the coating. For example, it is possible to deduce from the temperature after the coating on the thickness of applied layers, which leads by their heat of condensation to a further heating of the substrate.

The use of pyrometers is known for measuring the substrate temperature and, consequently, for influencing them in a targeted manner.

The principle of temperature measurement by means of pyrometers is that the thermal radiation emanating from a body, in this case from the substrate, is measured and is closed by the measuring signal to the temperature of the substrate. This method requires knowledge of the emissivity of the body to be measured, that is to say of the emissive body. Furthermore, to obtain a sufficient measurement signal in the pyrometer, a minimum emission of the measured Body required. Highly reflective layers, such as sputtered metal layers, are unsuitable for this.

The method of pyrometric temperature measurement therefore requires that the measurement of the temperature of a substrate in a vacuum substrate treatment plant be such that the measurement result is not affected by the vacuum treatment itself, for example by a change in the emissivity due to the application of layers. Namely, the surface of the substrate changes its emissivity during the coating of substrates and / or their modification, such as selenization or sulfurization, depending on the location of the substrate in the vacuum substrate treatment plant. Thus, there is insufficient knowledge of the locally varying emissivity, which prevents a reliable and accurate temperature measurement of the substrate. With such a temperature measurement of substrates, it is possible to measure on surface parts of the substrate, that is to say receive the radiation from surface parts of the substrate which are not influenced by vacuum treatment processes. Thus, for example, in a temperature measurement in a coating of a substrate having a functional layer, the temperature of the substrate is detected by a measurement of the substrate back, since very often, for example, by a magnetron sputtering, the substrate is coated only from one side. The temperature differences between the substrate back and the applied layer are usually negligible, especially with thin glasses of only a few millimeters.

Out DE 10 2008 026 002 A1 For example, a method and associated apparatus for measuring temperature in continuous coating of planar substrates or webs under vacuum conditions are known.

It often proves to be problematic that the pyrometers are exposed to the stray steam in the process, whereby the measurement results are falsified.

An essential requirement in the use of pyrometers for temperature measurement is that contamination of the lens system of the pyrometer must be excluded. In particular, vacuum coating processes repeatedly lead to such contamination. Deposits on the lens system of the pyrometer only a few nanometers thick layer can already weaken the signal at the radiation receiver of the pyrometer so much that an accurate temperature detection is no longer possible.

To avoid this effect is in DE 10 2010 040 640 A1 in a substrate treatment plant for the treatment of substrates, which comprises at least one chamber chamber bounded by chamber walls with at least one substrate treatment device and at least one pyrometer for determining the substrate temperature, proposed that inside the at least one plant chamber a protective tube is arranged, which extends from the pyrometer on a Substrate to extend.

It is known that the pyrometer manufacturers provide a protective glass to protect the pyrometer optics. Since these protective glasses always cause a signal attenuation, the manufacturer calibrates the pyrometer together with the protective glass. With such a protective glass but only contaminants are kept away from the lens system of the pyrometer. The protective glass itself will continue to contaminate if no further measures are taken. Thus, the contamination of the protective glass again leads to an impairment of the measurement result. Although the protective glasses can be replaced, this can only be done as part of a system maintenance.

In order to be able to carry out the replacement of protective glass even outside the plant maintenance and to reduce contamination of the lens system or protective glass in pyrometers, which are caused by processes in vacuum substrate treatment plants, is in DE 20 2012 101 670 U1 for an arrangement of a pyrometer in a vacuum substrate treatment plant having a vacuum space separated from the atmosphere by a chamber wall, the assembly comprising a pyrometer outside the vacuum space communicating with the chamber wall via a tube tube is connected, that its measuring axis is directed through the tube interior to a measuring location in the vacuum space, wherein the Tubusrohr penetrates the chamber wall through a wall opening vacuum-tight and opens with its Tubusrohröffnung in the vacuum space, proposed that in the Tubusrohr outside the vacuum space between chamber wall and pyrometer a valve which is the vacuum space in front of the pyrometer vacuum-tight lockable, is arranged, which may be formed, for example, as a slide valve.

DE 10 2012 207 510 A1 describes an arrangement for measuring the temperature of substrates in a vacuum substrate treatment plant having a vacuum space separated from the atmosphere by a chamber wall and a substrate support, the assembly comprising a pyrometer outside the vacuum space communicating with the chamber wall via a tube tube is connected, that its measuring axis is directed through the tube interior to a measuring location on the substrate support, wherein the Tubusrohr penetrates the chamber wall through a wall opening and opens with its Tubusrohröffnung in the vacuum space, wherein a contamination entering the Tubusrohr preventing protective element is arranged outside the measuring times of the pyrometer can be pivoted into the measuring axis. For this purpose, for example, be arranged laterally next to the Pyrometer Tubusrohr arrangement a pivot drive having a shaft with an axis of rotation which is substantially parallel to the measuring axis, which penetrates the chamber wall by means of a vacuum-tight rotary feedthrough and at the vacuum-sided end of the protective element is arranged , which can be pivoted by the shaft in the measuring axis.

Out JP H03-97859 A there is known a vacuum coating machine with a viewing window, in front of which rotating disks are arranged, which have slots.

JP 2004-193340 A proposes to arrange one or more transparent elements over a chamber wall opening located directly under a substrate of a vacuum chamber to which a pyrometer is attached, and to position one of the transparent elements by turning or pivoting in front of the chamber wall opening.

Some disadvantages of the known solutions are that the fouling of the optics of the pyrometer can not be prevented, because in the measurement always scattered vapor particles can get on it. This repeatedly requires the removal and subsequent calibration of the pyrometer. High wear of the usual vacuum suitable slide valves means that they generally have to be replaced after about 50,000 to 100,000 switching operations.

These problems should be solved in particular for the temperature measurement by means of pyrometers in vacuum systems under very dirty conditions, with as many as 1,000,000 or more switching operations at a pressure of 10 ^-6 mbar should be achievable.

This object is achieved by a closure device having the features of claim 1, a pyrometer arrangement having the features of claim 9 and a vacuum substrate treatment system having the features of claim 11.

Proposed for this is first a closure device with a housing having two opposite openings defining an optical axis through the housing, wherein in the housing, a prismatic cavity with a prism axis is arranged so that the prism axis is aligned transversely to the optical axis and in the prismatic cavity a closure element having at least two functional areas, of which at least a first functional area for infrared radiation (IR radiation) is permeable, slidably arranged so that optionally arranged exactly one functional area of the at least two functional areas in the optical axis is.

The term "optical axis" describes a straight line extending between the two openings and indicating the direction in which IR radiation is directed through the housing as intended. The term "prismatic" encompasses any cavity which can be generated by parallel displacement of a planar figure, for example a polygon, along a straight line not lying in this plane in space, wherein a circle as a special case of a polygon with an infinite number of corners thereof is also included like other flat figures, for example an ellipse. A cylindrical cavity with a circular or elliptical cross section is therefore also to be regarded as a prismatic cavity in the sense of the disclosed teaching.

The proposed closure device can for example be connected to a pyrometer so that the optical axis of the closure device is identical to the measuring axis of the pyrometer. The closure device closes the access to the pyrometer, in particular to the optical components of the pyrometer, by means of the closure element arranged therein, which always lies with one of its functional regions in the optical axis, for scattered vapor particles. Since at least one functional region of the at least two functional regions of the closure element is permeable to IR radiation, the functionality of the pyrometer is ensured in the event that the at least one functional region permeable to IR radiation is arranged in the optical axis. If another functional region of the closure element is not transparent to IR radiation and this functional region is in the optical axis, i. arranged between the two openings of the housing, so no measurement can be performed with the pyrometer. Since measurements with the pyrometer are often not continuous but cyclical when used on a vacuum substrate treatment plant, this is harmless.

If no measurement is currently being carried out, only the scattered vapor particles incident on the functional region of the closure element are exposed, which in any case is for IR radiation is impermeable. If, on the other hand, a measurement is to be carried out, the closure element in the housing is displaced in such a way that, for the duration of the measurement, the or a functional region which is permeable to IR radiation is arranged in the optical axis, so that the IR radiation received is Radiation can penetrate to the pyrometer. Since such a measurement requires little time, only a few scattered vapor particles can strike the IR-transmissive functional region. When the measurement is complete, the closure element is displaced again so that the non-IR-permeable functional region lies in the optical axis.

For example, the closure element may also have two or more functional regions, all of which are IR-transmissive. If a functional area is excessively contaminated by scattered vapor particles, the closure element can be displaced so that another, non-contaminated, IR-transmissive functional area lies in the optical axis. Advantageously, the closure element may have a non-IR transmissive functional region and two or more IR-transmissive functional regions. The non-IR transmissive functional region may then always be located in the optical axis when no measurement is taken, and in the case of a measurement one of the IR-transmissive functional regions is moved into the optical axis. Multiple IR-transmissive functional regions allow the switch to a clean IR-transmissive functional region when the previously-used IR-transmissive functional region is already contaminated.

According to one embodiment, it can be provided that at least one functional region of the closure element has a depression which faces one of the two openings of the housing. For example, a non-IR transmissive functional region may have such a depression. In this depression, the incident scattering vapor particles collect, so that the mobility of the closure element in the cavity of the housing is not limited with increasing thickness of the resulting scattered vapor layer. For many applications, it is sufficient to arrange a depression in a non-IR-permeable functional region, since this is exposed to the scattering vapor for the most part. However, such a depression can also be arranged particularly advantageously in IR-transmissive functional regions.

The latter arises automatically in a configuration in which the closure element consists of a material that is impermeable to IR radiation, wherein the closure element in the at least one functional region, which is transparent to IR radiation, has a continuous opening running parallel to the optical axis and the opening is closed by an IR window element made of an IR radiation transmissive material.

For the closure member, a plastic such as the Murtfeldt "S" green material having extreme wear resistance, excellent sliding properties, good non-stick properties, very good chemical resistance and moisture absorption, or a comparable plastic can be preferably used.

The IR window element can advantageously be an IR-permeable plate, for example made of calcium fluoride, which is arranged and fixed in the through opening of the closure element, for example glued. Advantageously, the IR window element is releasably fixed by means of a O-ring on a arranged in the through hole paragraph or ledge to allow quick and easy replacement of soiled IR window elements. The remaining on both sides of the IR window element functional areas of the through hole form recesses, of which the remote from the pyrometer depression fulfills the described purpose of collecting scattered vapor particles.

Advantageously, it can further be provided that the closure element is secured against rotation in the cavity of the housing. An anti-rotation device can be realized, for example, in that the prismatic cavity and the closure element have non-circular cross-sections. However, since round cross-sections of cavity and closure element are particularly easy to manufacture, an anti-rotation can be realized even with circular cross-sections, for example, that the closure element has at least one parallel to the prism axis extending bore and in the cavity an engaging into the bore guide rod is arranged.

One goal is to seal the closure element in the cavity as much as possible. This can be achieved, for example, by a tight tolerance between the closure element and the cavity, but the mobility of the closure element in the cavity becomes narrower and narrower. Therefore, it is provided in a further embodiment that the closure element has on its outer side at least one acting on walls of the cavity of the housing sealing ring. For example, multiple sealing rings of a suitable elastomer such as DuPont Viton or the like may be disposed on the closure member such that each functional region is bounded by two sealing rings.

According to a further embodiment it is provided that the closure element is operatively connected to an adjusting device which is adapted to move each functional area of the closure element in the optical axis.

Such a control device may for example be a so-called multi-position cylinder, such as a pneumatic multi-position cylinder, as sold by Festo. The closure element is adapted to the actuator (or vice versa) so that each of the possible positions of the multi-position cylinder causes one of the functional regions of the closure element in the optical axis of the closure device, i. between the two openings of the housing, is arranged.

Furthermore, a pyrometer arrangement is proposed with a pyrometer having a measuring axis, and a measuring channel attached to the pyrometer with a longitudinal axis that is identical to the measuring axis of the pyrometer, wherein a part of the measuring channel is formed by a closure device of the type described, which is arranged so that its optical axis is also identical to the measuring axis of the pyrometer. The measuring channel can be formed, for example, by a tube which can be directed to a measuring location whose temperature is to be determined. The tube can be made in one or more parts, wherein the proposed closure device between two parts of the tube or between the pyrometer and the tube is arranged. For this example, all parts can be connected to each other via flange.

The proposed pyrometer arrangement can be further developed in that on the side facing away from the pyrometer of the closure device, a part of the measuring channel is formed by a slide valve. The slide valve can also be incorporated by flange into the measuring channel, as already described above. In particular, for vacuum applications, the spool valve allows the pyrometer (for example, for recalibration) or / and the closure device (for example, to replace the closure element or the IR window elements) to be removed during operation without having to ventilate the vacuum chamber. The slide valve must be operated only in these cases, and thus very rarely, so that over a very long period of time only a few switching operations are required. In normal operation, however, the gate valve may be permanently open because the pyrometer is permanently protected from stray vapor by the shutter, either by an IR-transmissive functional area of the shutter which allows measurement by the pyrometer or by a non-IR-transmissive functional one Range that does not allow a measurement of the pyrometer, but protects the pyrometer from unwanted pollution by scattered vapor.

The described closure device and the pyrometer arrangement are advantageously used in a vacuum substrate treatment plant with a vacuum chamber bounded by chamber walls, in which at least one substrate treatment device is arranged, wherein a pyrometer arrangement of the type described above is attached to the vacuum chamber such that the pyrometer and the closure means are disposed outside the vacuum chamber and a pyrometer-opposed end of the measurement channel is disposed within the vacuum chamber.

• 1 eine perspektivische Ansicht eines Ausführungsbeispiels einer erfindungsgemäßen Pyrometer-Anordnung,
• 2 die Pyrometer-Anordnung aus 1 in einer Seitenansicht,
• 3 die Pyrometer-Anordnung aus 1 in einer vertikalen Schnittdarstellung, und
• 4 die Pyrometer-Anordnung aus 1 in einer horizontalen Schnittdarstellung.

The invention will be explained in more detail with reference to an embodiment and associated drawings. Show

• 1 a perspective view of an embodiment of a pyrometer arrangement according to the invention,
• 2 the pyrometer arrangement off 1 in a side view,
• 3 the pyrometer arrangement off 1 in a vertical sectional view, and
• 4 the pyrometer arrangement off 1 in a horizontal sectional view.

In the exemplary embodiment, the pyrometer assembly includes a horizontally disposed spool valve from top to bottom 12 , a piece of pipe 13 , a closure device with an adjusting device 10 , and a pyrometer 14 ,

The slide valve 12 , the piece of pipe 13 and the closure device each have a flange in the selected representation on their respective upper side and on their respective lower side. The pyrometer 14 also has a flange on its upper side in the selected representation. The adjacent components are each via flange connections 15 their mutually facing flanges, which can be designed in a manner known per se as clamping rings, claws or the like, connected to each other.

The upper flange of the slide valve 12 is open. It may be used to attach the pyrometer assembly to a flange that attaches to, for example, an opening in a chamber wall of the vacuum chamber of a vacuum substrate treatment facility. This flange may also belong to a pyrometer thermowell fixedly or movably attached to the chamber wall and projects into the vacuum chamber and is directed to a measuring location in the interior of the vacuum chamber or can be addressed.

The valve spool of the slide valve 12 is horizontally arranged and thus suitable, the passage between the two flanges of the slide valve 12 optionally release or close.

Below the slide valve 12 and the tube piece arranged underneath 13 the closure device is arranged. This has a housing 1 with a prismatic cavity disposed therein 3 on. The housing is made of solid material with a square cross-section into which a hole has been made, which is the cavity 3 forms. The prism axis of this bore extends horizontally in the selected representations and thus at right angles to the measuring axis of the pyrometer 14 which runs vertically in the selected representations. In the measuring axis of the pyrometer 14 is the optical axis of the closure device, ie the connecting line between the upper and the lower opening 2 of the housing.

In the cavity 3 is a closure element 4 arranged, which is formed from a body having a generally cylindrical shape, so that the closure element 4 in the cavity 3 is displaceable. The closure element 4 is made of a plastic that is not permeable to IR. The closure element 4 exemplifies three different functional areas 5 on. Each of the three functional areas 5 has depressions 6 on each of which one the pyrometer 14 and one each the slide valve 12 is facing.

The in the representations of the 3 and 4 leftmost functional area 5 the closure element 4 , in the local representations straight in the optical axis, ie between the two openings 2 of the housing 1 is a non-IR transmissive functional region 5 , His pits 6 are formed by two blind holes, which enclose between them a portion of the non-IR-permeable plastic material. The two functional areas arranged to the right 5 are IR-transparent. They are as through holes of the closure element 4 formed, in each of which an IR window element 7 arranged in the form of a transparent plate made of calcium fluoride and on a shoulder of the bore with an O-ring 8th is fixed.

With the closure element 4 is an adjusting device 10 operatively connected, which is designed as a pneumatic multi-position cylinder, which has three possible positions. This makes it possible for each of the three functional areas 5 to move into the optical axis.

In the ground state, in the 3 and 4 is shown, is the non-IR-permeable functional region 5 in the optical axis, so that no measurement is possible, but the pyrometer 14 is protected from stray steam. If a measurement is to be carried out, then the closure element 4 through the adjusting device 10 so moved that the first functional area 5 which is IR transmissive, is moved in the optical axis. The incoming IR radiation from above can become a pyrometer 14 penetrate, with the pyrometer 14 However, it remains protected from scattered vapor. After completion of the measurement, the closure element 4 through the adjusting device 10 again so moved that the non-IR permeable functional area 5 is arranged in the optical axis. When several measurements were taken, it is the first IR-transmissive functional area 5 dirty, so before the next measurement, the closure element 4 through the adjusting device 10 so moved that for the measurement of the next IR-transmissive functional area 5 is moved in the optical axis.

In the connection area between the closure device and the adjusting device 10 An intermediate suction is arranged to prevent leakage from the surrounding atmosphere to the vacuum area.

LIST OF REFERENCE NUMBERS

1

casing

2

opening

3

cavity

4

closure element

5

functional area

6

deepening

7

IR window element

8th

O-ring

9

Corporate Office

10

setting device

11

interstage

12

spool valve

13

pipe section

14

pyrometer

15

flange

Claims (11)

A closure device comprising a housing (1) having two opposing openings (2) defining an optical axis through the housing (1), wherein in the housing (1) a prismatic cavity (3) having a prism axis is arranged, in that the prism axis is aligned transversely to the optical axis and in the cavity (3) a closure element (4) with at least two functional areas (5), of which at least one first functional area (5) is permeable to IR radiation, is displaceably arranged is that optionally exactly one functional area (5) of the at least two functional areas (5) is arranged in the optical axis. Locking device after Claim 1 , characterized in that at least one functional region (5) of the closure element (4) has a recess (6) which faces one of the two openings (2) of the housing (1). Locking device after Claim 1 or 2 , characterized in that the closure element (4) consists of an IR radiation-impermeable material, wherein the closure element (4) in the at least one functional region (5), which is transparent to IR radiation, extending parallel to the optical axis has through opening and the opening is closed by an IR window element (7), which consists of a permeable to IR radiation material. Locking device according to one of Claims 1 to 3 , characterized in that the closure element (4) in the cavity (3) of the housing (1) is secured against rotation. Locking device after Claim 4 , characterized in that the closure element (4) has at least one bore extending parallel to the prism axis and in the cavity (3) a guide rod (9) engaging in the bore is arranged. Locking device according to one of Claims 1 to 5 , characterized in that the closure element (4) has on its outer side at least one on walls of the cavity (3) of the housing (1) acting sealing ring. Locking device according to one of Claims 1 to 6 , characterized in that the closure element (4) is operatively connected to an actuating device (10) which is adapted to move each functional region (5) of the closure element (4) in the optical axis. Locking device after Claim 7 , characterized in that the adjusting device (10) is a multi-position cylinder. Pyrometer arrangement comprising a pyrometer (14) having a measuring axis, and a measuring channel fixed to the pyrometer (14) with a longitudinal axis which is identical to the measuring axis of the pyrometer (14), wherein a part of the measuring channel by a closure device according to one of the Claims 1 to 8th is formed, which is arranged so that its optical axis is also identical to the measuring axis of the pyrometer (14). Pyrometer arrangement after Claim 9 , characterized in that on the side facing away from the pyrometer (14) of the closure device, a part of the measuring channel is formed by a slide valve (12). Vacuum substrate treatment plant with a vacuum chamber bounded by chamber walls, in which at least one substrate treatment device is arranged, wherein a pyrometer arrangement according to Claim 9 or 10 is attached to the vacuum chamber so that the pyrometer (14) and the closure device are arranged outside the vacuum chamber and a pyrometer (14) opposite the end of the measuring channel is disposed within the vacuum chamber.

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