DE4443740B4 - Device for coating substrates - Google Patents

Abstract

Device for coating substrates with an evacuable vacuum chamber (1) with coolable outer walls (2, 3), at least one substrate carrier (9, 10) arranged rotatably and in particular exchangeably within the vacuum chamber (1) and at least one substrate carrier (9 , 10) directed evaporator source (6), wherein in the vacuum chamber (1) at a distance from the coolable outer walls (2, 3) and to form an insulating, plasma-free space (4) provided at least substantially self-contained inner chamber (5) which is delimited by heating and wall sectors (7, 8) and at least one integrated evaporator source (6) and forms an isothermal coating space (12) accommodating the substrate carrier (9, 10),
characterized in that
- in the inner chamber (5) a plurality of at least substantially over the height of the inner chamber (5) extending evaporator (6) are provided,
- Wherein located between the evaporators (6) andungsbereiche the inner chamber (5) are at least partially formed as Strahlungsheizflächen (7) and
- in which...

Description

The The invention relates to a device for coating substrates with an evacuable vacuum chamber with coolable outer walls, at least one arranged within the vacuum chamber, rotating and in particular interchangeably mounted substrate carrier and at least one directed to the substrate carrier Evaporator source.

coaters of this type are known and are used, for example, layers to apply to tools whose characteristics and life improve significantly.

With However, these known devices are experiencing difficulties to ensure a clearly reproducible deposition of layers of high and highest quality. The causes of this unsatisfactory results are complex and have been so far not be eliminated. A disadvantage of the known, in particular at the after the arc technology Working devices is also that due to unavoidable plant cleaning operations not only disturbing high cleaning costs, but also expensive machine downtime and thus productivity losses must be accepted.

From the DE 38 29 260 A1 discloses a coating chamber having at least one consumable by an arc cathode and means for receiving objects, which are coated by precipitation of reacted with a gas atmosphere in the chamber, in the plasma state transferred cathode material. In this case, a screen is arranged in a space between the cathode and the objects, which is removable from the intermediate space. This makes it possible to use during the heating phase of the indirect heating of the substrates and at the same time to protect them from the deposition of droplets of the cathode material, but during the reaction phase to release the direct path from the cathodes to the substrates.

Out WO 92/14859 A1 is an apparatus for reducing droplets when coating surfaces with hard materials known by the PVD process, which is a double-walled, water-cooled chamber has, in a realized by heating coils radiation heating is provided in the region of the inner wall of the chamber. To heat up To avoid the inner wall of the reaction chamber are between the Heating elements and the inner wall reflectors provided. The radiant heating serves only to heat the to be coated Objects or the surface the objects to be coated before the start of the coating.

From the EP 0 489 659 A1 a coating device is known in which within a closed outer chamber, an inner chamber is provided with a comparatively large wall thickness, which consists of a thermally insulating material. At a distance from the walls of this inner chamber heating resistors are arranged, which allow to heat the parts to be coated to temperatures between 400 ° C and 1300 ° C.

From the DE 3 930 832 A1 a device is known which - represents the closest prior art - according to the preamble of claim 1-.

task The invention is a device of the type specified To create kind, which makes it possible with comparatively simple structure, qualitatively high quality, possible achieve compact and low-tension coatings with high productivity. Furthermore, elaborate Cleaning work inside the plant avoided and the required Reproducibility of the coatings can be guaranteed.

Is solved this object according to the invention essentially in that in the vacuum chamber at a distance from the coolable outer walls and forming an insulating, plasma-free space an at least substantially self-contained inner chamber is provided by heating and wall sectors and at least an integrated evaporator source is limited and receiving the substrate carrier forms isothermal coating space.

By the creation of one of the cooled outer walls the vacuum chamber through an insulating, plasma-free space separate inner chamber it becomes possible the coating processes in an isothermal plating space to perform the is called in a room where all Parts, that is also larger and smaller objects to be coated as well as the room limiting walls are practically at the same temperature and thus in this promoting the uniform plasma distribution Isothermal space is not disturbing Temperature gradient is present. A pronounced temperature gradient occurs only in the plasma-free space between the inner chamber and the Exterior walls of the Vacuum chamber on.

The presence of an isothermal plas Maraums has a very positive effect on the coating quality as well as on the stability of the coating process carried out in it.

From It is also essential that on the cooled outer walls the vacuum chamber no separation effects occur and thus also with conventional Plants consuming cleaning operations in the plant interior omitted. Located in the inner chamber in the form of hard solid particles From time to time, the coated areas that form form part of it can then sucked easily, for example by means of a vacuum cleaner become. This inventively achieved self-cleaning effect leads to a significant increase in productivity, because expensive machine downtime can be avoided.

The associated with the optically virtually dense inner chamber or walls of this inner chamber forming heating sectors are so dimensioned that the Heating the substrates to the target temperature almost exclusively by the generated radiant heat is achieved, with the interior of the chamber very fast to high Temperature can be brought, since the walls have only low heat capacity and especially not in contact with the cooled outer walls, but from these outer walls due to the evacuation very pronounced insulating space are separated.

The Walls of the inner chamber are according to the present invention at a bias voltage, to specifically achieve an ion-plating effect and on this To ensure that while avoiding any dust formation on the inner chamber walls A solid deposit is obtained after a certain maximum Layer thickness automatically peels off and thus removed problem-free can be.

When substrate carrier is preferably a fast interchangeable, in the inner chamber mounted turntable with a plurality of it also rotatable mounted and powered satellite plates used for workpiece holders, so that a triple rotation of the workpieces can be achieved.

Of the Inner chamber are preferably a plurality, extending over the chamber height, assigned vertically arranged evaporator sources that over the Scope of the turntable are distributed. Through the interaction of Radiation areas of these evaporator sources and the embodiment the substrate carrier array can fulfill the requirement be that each located in the inner chamber, multiple times rotating substrate at any point of its surface to be coated at least essentially at any time visual contact with at least one has the evaporator sources.

By This measure is achieved, especially in the central area of the substrate carrier no unwanted Plasma CVD reactions or plasma CVD-like reactions or other plasma inhomogeneities or Set plasma interference can and no annoying Hollow cathode effect may occur. It's going to be an excellent one instead plasma uniformity guaranteed in the entire inner chamber space.

Especially Cheap it is a substrate carrier assembly from a turntable and three rotatably mounted satellite dishes to use, since with such a configuration an optimum in terms the loading possibilities On the one hand and the coating uniformity on the other hand achievable is, since in this configuration in the interior of the substrate carrier no field-free space exists in which set undefined plasma conditions could.

For the practical Embodiment of the device according to the invention, it is advantageous if the evaporator sources in the stable outer walls of the vacuum chambers are held and by the insulating sheath forming a gap extend into the inner chamber or with their target surfaces boundary surfaces of the Form inner chamber. In this way, also a simple opening of the Achieve device for feeding purposes, as a large-scale swinging an outer wall area along with an associated area of the wall of the inner chamber can be done.

Further advantageous embodiments and features of the invention are in dependent claims and are used in conjunction with the description below of exemplary embodiments explained with reference to the drawing.

In the drawing shows:

1 a schematic cross-sectional view for explaining the basic concept of the structure of a device according to the invention,

2 a schematic representation of a possible embodiment of a device according to the invention with a three satellite Teler ler having rotary car, and

3 one of the 2 corresponding representation with a trolley with six satellites plates.

1 shows schematically the basic structure of a coating device according to the invention, which consists of a vacuum chamber 1 and one with respect to the cooled outer walls 2 . 3 the vacuum chamber 1 spaced inner chamber 5 for receiving one or more substrate carriers, wherein in 1 as a substrate carrier a turntable 9 is shown schematically.

The walls 2 the vacuum chamber 1 are partly from front and side doors 3 formed, and the vacuum chamber 1 is about a connection 13 connectable to a corresponding vacuum source, so that in the interior of the vacuum chamber 1 and thus also in the actual coating room 12 in the inner chamber 5 the required vacuum can be generated.

The inner chamber 5 related to the vacuum chamber 1 is made at least substantially optically dense, is limited by evaporator sources 6 , Heating sectors 7 and wall sectors 8th wherein the arrangement may be such that a polygonal or substantially cylindrical coating space 12 arises.

The heating sectors 7 are designed as powerful radiant heat sources, and the number of heating sectors used in each case 7 as well as the radiation sources used 6 can be selected depending on the intended use of the device.

In the embodiment according to 1 are two pairs of heating sectors opposite each other in a rectangular arrangement 7 provided, and in the corner areas are evaporator sources 6 arranged, which are also opposite in pairs and the height of the inner chamber 5 extend.

The centric in the inner chamber 5 arranged substrate carrier 9 consists of a still to be explained in detail rotary carriage, which is mounted quickly replaceable, for which the device is preferably formed according to swiveling.

The loading of the substrate carrier 9 takes place in each case outside the device, that is, it can be replaced in each case a substrate carrier with coated tools against a substrate carrier with uncoated tools in minutes, so that while thereby increasing the economic efficiency of the system is still enough time to load the tools outside the device available ,

By creating one of the cooled outer walls 2 . 3 the vacuum chamber 1 spaced and separated by an insulating, plasma-free space from this outer chamber 1 separate inner chamber 5 succeeds in conjunction with the interior chamber 5 associated heating segments 7 , a room 12 to which the plasma is confined and which forms an isothermal coating that can be heated and desorbed very rapidly, with the added benefit of having temperature control in this isothermal space 12 can be ensured comparatively easy and secure. A strong radiation heating and their safe control is essential for the operation of the device according to the invention.

The Inner chamber walls can be applied to a bias voltage, which ensures that the chamber walls to deposit compact hard material layers whose problem-free removal, for example, can be done specifically by that the Device over a few hours of the atmosphere is exposed, using water vapor and other air gases in the layers penetrate and cause them to flake off and thus a kind of self-cleaning effect is achieved.

Practically leads this Fact that a size Number of batches can be coated without any intermediate cleaning can and therefore conventional Equipment unavoidable cleaning costs and expensive machine downtime accounts.

As evaporator sources 6 Preferably, such sources are used as described in German Offenlegungsschrift 43 29 155.

Such magnetic field cathodes have a surface-trained target with a target center associated with the inner ring coil and at least one assigned to the Targetumfangsbereich outer ring coil, the inner ring coil enclosing a arranged in the target center permanent magnet and forms a Feldlinienkonzentrator together with this permanent magnet. Such a magnetic field cathode can be formed without problems in the form of a rectangle, which extends over the height of the coating chamber 12 extends and has a height comparatively small width.

It is also possible to use such evaporation sources 6 in the coating room 12 horizontal and in particular also on the ceiling side, if this leads to advantages for certain coating tasks.

The distance of the evaporator sources 6 to the on the substrate carrier 9 The supported substrates should preferably be at least about 150 mm to ensure that local electric fields close to the tools virtually do not alter the trajectory of the ions. It can thereby be achieved that the ionic flux density is uniform on all surfaces of the substrate and local thermal overloads, which could occur especially at points, and other surface modifications are prevented.

2 shows a schematic representation of a possible concrete embodiment of the device according to the invention, wherein in this embodiment, the vacuum chamber 1 has an octahedral cross-section and the isothermal coating space 12 enclosing inner chamber 5 is suitably adapted accordingly.

The evaporator sources 6 are in the outer walls 2 supported and thus accessible in an advantageous manner from the outside. They extend over the insulating space 4 into the inner chamber 5 and form with their target surfaces simultaneously boundary surfaces of this inner chamber 5 , There are two pairs of evaporator sources in this embodiment 6 provided, wherein the individual evaporator sources 6 diametrically opposed to each other. Between every two evaporation sources 6 each extends a heating sector 7 , the size of which can be chosen depending on the requirements in practice, and either the substantially entire area of the respective connecting wall between two evaporator sources 6 take or form part of this connection surface.

In the coating room 12 is a substrate carrier in the form of a turntable 9 and three satellite dishes rotatably mounted thereon 10 provided, these satellite dishes 10 mounted offset by 120 ° from each other and form the actual workpiece carrier. This substrate support arrangement is designed so that it is the best possible way in all directions for the plasma to eliminate shielding effects. The use of three satellite dishes in the manner shown is particularly advantageous, since in this arrangement, no field-free space is created in the central region, in which undefined plasma conditions and possibly interfering hollow cathode effects could form. The turntable center is accordingly open, which ensures that on the one hand already during the heating of the coating chamber 12 through heating surfaces 7 and on the other hand, especially during the subsequent etching and coating operations, each tool arranged on the satellite plates has visual contact with one of the radiation sources and, in particular, the evaporator sources at every point of its surface at all times, this criterion having to be realized in particular during the coating processes, in the heating but also beneficial.

In order to be able to ensure this criterion during the etching and coating processes, the device is preferably always equipped with a plurality of evaporators 6 operated, which essentially exceeds the height of the coating room 12 extend, and it is also ensured that the fastest possible rotation of turntable 9 and satellite dishes 10 is realized.

The drive of the substrate carrier unit, for example, such that the satellite dish 10 during a turn of the turntable 9 Turn around its axis about three to five times, with those on the satellite plates 10 provided tool carrier are in turn rotated at each rotation of the associated satellite dish over a certain angular range, so that in total results in a triple rotation of the substrates to be coated.

3 shows a modification of the device according to 2 , where the turntable 9 with six satellite plates distributed evenly around its circumference 10 is provided. Also in this embodiment, by suitable design and dimensioning of the satellite dish 10 for which in 3 the maximum possible diameter is shown graphically, the criterion is met that each tool at each point of its surface virtually at all times visual contact with at least one of the evaporator sources 6 has. Depending on the respective coating tasks, the diameter of the satellite dish 10 and also the number of satellite dishes used in each case, always taking care that the visual contact criterion can be met.

At the in 3 konkrekt shown embodiment with six satellite plates 10 , which are close to each other circumferentially, can be a field poor indoor area 14 inside the satellite dish 10 arise, and in this interior 14 For the purpose of avoiding unwanted plasma CVD reactions or plasma CVD-like reactions or other plasma inhomogeneities or plasma disturbances, it is preferable to provide at least one further source of evaporation which may be effective on all sides and may be fixedly supported relative to the rotating parts.

1

vacuum chamber

2

outer wall

3

doors

4

insulating gap

5

inner chamber

6

evaporation source

7

heating sector

8th

Wandungssektor

9

turntable

10

satellite dish

11

radiation range

12

isothermal coating room

13

vacuum port

14

interior

Claims (9)

Device for coating substrates with an evacuable vacuum chamber ( 1 ) with coolable outer walls ( 2 . 3 ), at least one within the vacuum chamber ( 1 ), rotatably and in particular exchangeably mounted substrate carrier ( 9 . 10 ) and at least one to the substrate carrier ( 9 . 10 ) directed evaporator source ( 6 ), wherein in the vacuum chamber ( 1 ) at a distance from their coolable outer walls ( 2 . 3 ) and forming an insulating, plasma-free intermediate space ( 4 ) an at least substantially self-contained inner chamber ( 5 ) of heating and wall sectors ( 7 . 8th ) and at least one integrated evaporator source ( 6 ) is limited and a substrate carrier ( 9 . 10 ) receiving isothermal coating space ( 12 ), characterized in that - in the inner chamber ( 5 ) at least substantially over the height of the inner chamber ( 5 ) extending evaporator ( 6 ), whereby the between the evaporators ( 6 ) located areas of the inner chamber ( 5 ) at least in part as radiant heating surfaces ( 7 ) and - the wall sectors ( 8th ) and the heating surfaces ( 7 ) to achieve ion-plating effects at a predetermined bias. Device according to claim 1, characterized in that the evaporators ( 6 ) are diametrically opposed and consist of magnetic field cathodes, which are in particular rectangular in shape compared to the height of small width. Device according to one of the preceding claims, characterized in that the inner chamber ( 5 ) is polygonal. Device according to one of the preceding claims, characterized in that the wall sectors forming no active functional areas ( 8th ) of the inner chamber ( 5 ) have a low heat capacity. Device according to one of the preceding claims, characterized in that the evaporator sources ( 6 ) in the outer walls ( 2 ) of the vacuum chamber ( 1 ) are held and about the space ( 4 ) into the inner chamber ( 5 ). Device according to one of the preceding claims, characterized in that at least a portion of the outer wall ( 2 ) of the vacuum chamber ( 1 ) in the form of a swing-up door ( 3 ) is formed and that with this door region a corresponding portion of the inner chamber ( 5 ) and thus the coating space ( 12 ) is accessible. Device according to one of the preceding claims, characterized in that the substrate carrier consists of a turntable ( 9 ) with in particular three arranged thereon, also rotatably mounted satellite plates ( 10 ), and that this substrate carrier arrangement with respect to the evaporator sources ( 6 ) is dimensioned and designed such that the turntable ( 9 ) of each radiation area ( 11 ) of the evaporator sources ( 6 ) is detected at least substantially over its entire diameter. Device according to one of the preceding claims, characterized in that in the inner chamber ( 5 ) in addition a central evaporator source is provided which extends into a free central region of the substrate carrier ( 9 . 10 ). Device according to one of the preceding claims, characterized in that as evaporator sources ( 6 ) exist according to the principle of the arc technique or the principle of arc discharge working sources.