Patent Application
20050081791
The invention relates to a vacuum treatment installation for flat rectangular or square substrates in an at least substantially perpendicular position, comprising a vacuum chamber with at least two treatment chambers distributed on the circumference of the vacuum chamber and open at the chamber side, a charging interlock, a discharging interlock and a rotatable arrangement of substrate holders within the vacuum chamber, with a driving mechanism for the sequential rotation and the advance and retraction of the substrate holders relative to the treatment chambers.
Continuously operating treatment or coating installations, which are operated under vacuum up to the performance limit of the vacuum motor pump sets and in which different treatments are carried out in individual treatment stations on so-called substrates, include, as a rule, the following assemblages:
To the extent installations with rotary and optionally radial transport paths are involved and treatment stations or chambers connected to at least one, at least substantially rotationally symmetric, main vacuum chamber, such installations are also referred to as “cluster installations”.
In the treatment processes are employed preheating (outgassing) and cooling of the substrates, vacuum vapor deposition, cathode sputtering, plasma treatment (for example incandescence for cleaning and adhesion promotion), PVD, CVD, and PCVD processes. For these processes numerous process parameters and device components are known. “P” denotes here “physical”, “C” chemical, “V” “vacuum” and “D” “deposition”. Some of these processes, for which the designations have become internationally established usage, can be completed reactively (with the supply of reaction gases or gas mixtures) or nonreactively (in the presence of inert gases). Added to these are etching processes for surface treatment including generation of specific “background [surface] pattern” and contact lines on the substrates. Depending on the requirements made of the end products, all of these process steps and device components are also appropriate for the subject matter of the invention.
In their historical development the continuous “cluster installations” were initially applied in the case of relatively small substrates such as disks, chips, data stores and wafers. However, the further development in reference to larger substrates, such as window panes and displays, encountered considerable problems, such as for example the dimensions of the installation, the space requirement for handling the substrates and optionally the substrate holders, for example raising substrates supplied in the horizontal position into a substantially perpendicular position, the hazard of elastic deformation, breakage and/or mechanical damage of the substrates and/or their coatings and contamination, especially through the accumulation of coatings on components continuously or temporarily in the installations, and spalling of these contaminations due to different process parameters, especially through temperature changes or mechanical effects.
For example, according to EP 0 136 562 B1, which will be discussed later, each substrate is supplied to an interlock system lying horizontally; in it is first raised upwardly by means of a lifting device and subsequently swiveled with a pivot device into a perpendicular position, in which it is secured on a substrate holder. During the transport out in a second interlock system, the sequence of these steps is subsequently reversed. In the case of large-area rectangular substrates this would lead to considerable space problems, large interlock and chamber volumes as well as long evacuation times and/or high evacuation performances of the vacuum pumps.
EP 0 136 562 B1 disclosed forming in a continuous cathode sputtering installation for small circular disk-form substrates such as disks, semiconductors and wafers, a vacuum chamber of two pot-form chambers, namely of a pentagonal outer chamber and a concentric cylindrical inner chamber, both of which are connected with one another fixedly and vacuum-tight by an annular upper cover. The bottoms have a small vertical distance from one another. The outer chamber is provided on the circumference equidistantly with an interlock installation and four chamber-form treatment stations. Such installations are also generally referred to as “cluster installations.
Between outer and inner chamber is rotatably disposed a further polygonal pot, on whose body five substrate holders are disposed by means of leaf springs, which in the operating position close the interlock installation as well as the processing chambers by means of seals and a valve function. The substrate holder pot also has a bottom disposed between the bottoms of outer and inner chamber. The radial movements of the substrate holders, which remain continuously in the vacuum chamber, are generated synchronously through a central cone and five slide rods, which are guided in the body of the inner chamber and through its wall at approximately half its height and which, consequently, cannot take part in the rotation. The drive unit with its cone is also stationary.
The substrate holder pot is rotated stepwise by a further drive unit. In order to be able to rotate the substrate holder pot within the vacuum chamber from station to station, said slide rods must be cyclically retracted from their circular or cylindrical movement path of the substrate holder pot and be advanced again. Since during the rotation of the substrate holders from station to station the openings of the treatment stations are made clear, coating material escapes at half its height into the space between outer and inner chamber and there condenses on the surfaces, thus also on the ends of the slide rods, its guides and on the leaf springs on the substrate holder pot. The layer thickness of these condensates, which increases from operating cycle to operating cycle, from time to time becomes spalled off in the form of particles and leads to contaminations, and specifically also on the surface of the rotatingly guided substrates, which thereby become unusable and consequently represent expensive rejects. Especially damaging are the peeling processes of the condensates at the inner ends of the slide rods.
It is asserted that in this structuring and operating manner the contaminations of the substrates through spalled off particles coming from above of collected layer material are said to be avoided; however, this applies at best to an absolutely perpendicular position of the substrate surfaces on the entire transport path within the vacuum chamber. But this presupposes the securement of the relatively small substrates on their holders.
Through EP 0 665 193 B1 and DE 695 04 716 T2 it is known in a cluster installation for the purpose of the delimiting placement areas and chamber volumes to transport through an interlock substrates comprised of glass for large-area flat and rectangular or square displays with dimensions of 450 mm×550 mm and greater in continuously perpendicular position by means of one substrate holder each from the environment into a system of vacuum chambers and to transport them out again to the environment by means of the same substrate holder together with it. Between a central buffer chamber and the individual treatment chambers valve gates are disposed in each instance. In the buffer chamber is disposed concentrically and with vertical axis a rotary table, with which the substrates with their holders and with their main planes, thus nearly radially, oriented toward the particular treatment chamber and from this position are moved into the treatment chambers and retracted again. However, the rotary table does not have substrate holders of its own. For transporting the substrate holders, in each treatment chamber and on the rotary table, separate from each other and driven separately, conveying facilities with rollers are disposed for the substrate holders. The constructional expenditures and the driving and control facilities are considerable; in particular, on the rotary table several conveying facilities with rollers can also be disposed independently of one another. If a circle is drawn about the rotational axis of the rotary table, which also includes the radially projecting treatment chambers, a large requirement of placement area for the complete device results, especially also because the substrates are held “standing on one of their points” in the large-area substrate holders such that the diagonal dimensions of the substrates determine the diameter of said circle. The problem is thereby not eliminated of repeated transport of all substrate holders between the environment and the interior of the installation with the consequence of the spalling off of accumulated layers due to temperature changes in the installation.
DE 200 22 564 U1 discloses transferring carriers with substrates for coating purposes through a first interlock into a vacuum, guiding them continuously on a circular or partially circular path and, lastly, after the coating transferring them out again through a second interlock. Radial movements or movements with a radial component of the carriers within the vacuum chamber and opposite to the coating stations, deviating from the circular path, are not provided. The return transport of the empty carriers from the discharging interlock to the charging interlock outside of the vacuum chamber should take place on the shortest possible path or as rapidly as possible in order to limit the spalling of the layers accumulating on the carriers within the vacuum chamber due to temperature fluctuations.
DE 102 05 167 C1 discloses connecting in an in-line vacuum coating installation two buffer chambers with rotatable exchange units for carriers with substrates with one another through two linear transport paths of variable length, in order to be able to change the number of coating stations. The carriers can be transported in perpendicular or minimally inclined positions. The one transport path is provided for discontinuous transport and has at both ends, adjoining onto the buffer chambers, one interlock chamber each with two valves, and in front of it or following it a loading and an unloading station for the carriers. The other transport path is provided for the continuous transport and has at both ends, adjoining the buffer chambers via valves, one transfer region each for the carriers, each with the substrates. Means for a carrier movement transversely to the direction of transport within the installation are not provided and specifically neither on the linear transport paths nor in the buffer chambers, nor in the transfer regions. The buffer chambers are only provided with means for heating and cooling.
It is known from US 2002/0078892 A1 to transport large-area rectangular substrates with dimensions of 1 m×1.2 m and greater for LCD displays pairwise and perpendicularly parallel to one another or at the upper edges inclined toward one another at an acute angle on different transport paths from atmosphere to atmosphere through vacuum installations—including cluster installations. For this purpose serve substrate holders with a horizontal plate, on the upper side of which, disposed mirror symmetrically, two frames, open at the inside, are disposed as substrate holders and at whose under side along the plane of symmetry a bracket plate with bilateral toothed bars is disposed, by means of which the substrate holders can be driven by series of pinions driven by toothed belts, in different and changing directions.
Again, as the central part of the transport device serves here also a rotationally symmetric throughpassage or buffer chamber with a rotary table, on whose underside such a pinion drive is disposed with six pinions and a motor for guidance, change of displacement direction and for the radial displacement of the substrate holders. On the circumference of the buffer chamber are disposed, separated via gate valves, an interlock system and at least three treatment chambers for diverse vacuum processes. The substrate holders are moved in the radial longitudinal direction into the treatment chambers, which, consequently, must have the corresponding radial dimensions, such that an imaginary circle about the entire installation has a large diameter, leading to a correspondingly large placement area. The longitudinal displacement and corresponding drive units in the treatment chambers are also required for the reason that such treatment chambers can also be arranged serially in radial directions.
As prior art is described in US 2002/0078892 A1 a rotary table with a transfer robot and two grippers, which are actuated in the radial direction via articulation members in the manner of a scissors articulation. However, the patent expressly states that herein the substrates are held on the entire transport path eccentrically and in the horizontal position and that with increasing dimensions of the substrates for displays, for example, for wall display screens, this leads to space and volume problems as well as longer pumping times and to flexure or breaking under their own weight of the substrates which are only 0.7 mm thick. An enlargement of the horizontal dimensions of the substrates leads to the twofold value of the diameter enlargement, for example beyond 2 m, which is tied to additional enlargements of the interlock valves and to problems of mass during acceleration and delay and to tolerance problems.
US 2002/0078892 A1 further specifies that the bracket plate of the rotary table can be raised from a guidance rail by means of a magnetic lifting drive unit in order to avoid dust development through abrasion. However, not addressed is the problem of avoidance of dust formation through the spalling off of layer material cumulatively collected on the substrate holders due to the transport from atmosphere to atmosphere and heating within the vacuum chambers, as well as through abrasion from the pinion drive units. A further significant disadvantage of the known configuration is, however, that with the number of the treatment chambers connected to the central or buffer chamber, the number grows of transport mechanisms in the interior of the chamber, which must be compatible with the transport mechanism of the rotary table in the buffer chamber in order for the transfer into and out of the treatment chambers to be possible at all.
In conjunction with the above prior art it was shown that, due to the continual enlargement of the substrate dimensions and the decrease of the inherent shape stability and nondeformability due to the decrease of the substrate thickness, with advancing development new problems were generated, which have led to highly complex and expensive constructional principles and complicated operating sequences, and yet, nevertheless, the problem of placement area and of contamination of the substrates through particles of accumulated layers on installation components could not be successfully solved to satisfaction.
The invention therefore addresses the problem of specifying constructional principles and operation sequences leading to a further decrease of the placement area, the chamber volumes, the evacuation times and to a further simplification of the “handling” of the substrates outside and within the vacuum chamber and yet especially to a marked reduction of the contamination hazard of the substrates through particles of spalled off layer packets.
The solution of the posed problem is achieved according to the invention through the characteristics in the characterizing clause of patent claim 1, namely thereby that the substrate holders are connected in their lower regions via pivotable connecting rod configurations with the driving mechanism and that at least the lower pivot bearings of the connecting rod configurations are disposed below a horizontal center line of the height of the bearing surface of the substrate holders.
Through this solution the posed overall problem is fully solved to satisfaction, in particular constructional principles and operation sequences are specified, which lead to a further decrease of the placement area, the chamber volumes, the evacuation times and to a further simplification of the “handling” of the substrates outside and within the vacuum chamber and yet lead especially to a marked decrease of the contamination hazard of the substrates through particles of spalled off layer packets. The constructional expenditure and the number of rejects are decreased and the product quality is considerably enhanced.
In the course of further implementations of the invention it is especially advantageous if, either singly or in combination:
In the following two embodiment examples of the subject matter of the invention and their operational function will be explained in further detail in conjunction with FIGS. 1 to 10. In the drawing depict:
In
On the extension arms 4, which pairwise extend parallel toward one another and form a right-angled cross, are downwardly suspended overall eight parallelogram connecting rod configurations 8 via upper fixed pivot bearings. The lower ends of the parallelogram connecting rod configurations 8 are pivotably supported on horizontal U-form stirrups 9 with shanks 9a pairwise parallel to one another, whose outwardly directed ends are connected by one crosstie bar 10 each. Each of the crosstie bars 10 carries at least two projecting rollers 11, which serve as supports for substrates, not shown here, and are optionally drivable and/or arrestable. Each of the crosstie bars 10 supports toward the top a frame structure 12, directed obliquely and upwardly at an angle between 3 and 15 degrees with respect to the vertical with longitudinal and transverse struts in the manner of a framework, which is braced via vertical uprights 12a on the particular stirrup 9.
The outsides of the crosstie bars 10 and of the frame structure 12 are disposed in a common plane, whose outline corresponds at least substantially to the outline of the particular substrate. These parts thereby form a dimensionally stable substrate holder 13. In the direction of their said planes these [holders] have a height “H” and define in their midpoints (H/2) a horizontal virtual center line “M”, below which all connecting rod configurations and their pivot articulations are disposed.
The two substrate holders 13 shown are thereby movable oppositely in the direction of arrows 14 and essentially radially toward one another. It must be emphasized that only two of the substrate holders 13 are shown. The two remaining substrate holders disposed in front of and behind the driving mechanism 1 are not depicted for the sake of clarity. They are also radially movable in opposite directions and specifically at right angles to the two arrows 14.
The frame structures 12 are perforated at numerous sites and connected to a (not shown) gas source, such that the substrates can be loaded in the charging position in the manner of an “air cushion vehicle” free of friction and preserving form onto the particular substrate holder 13 guided by the rollers 11. The gas supply is subsequently interrupted in order for the gas atmospheres in the individual treatment chambers not to be impaired.
The vacuum chamber 15 comprises furthermore an outer chamber component 22 in the form of a square truncated pyramid with a bottom 23, through which is guided under vacuum seal the lower end region 24 of the driving mechanism 1. The inner and the outer chamber component 16 or 22 are connected vacuum-tight through a roof 25. The walls of the outer chamber component 22 are provided with four equidistantly distributed rectangular openings 26, of which here also only two diametrically opposite openings 26 are evident. Onto the openings 26 are set treatment chambers 27 and 28, which can be equipped with (not shown) facilities for the most diverse vacuum processes. The outer walls 27a and 28a of the treatment chambers 27 and 28 are provided with ribbings 50 for absorbing the forces of atmospheric pressure (esp.
Between the horizontal bottoms 17 and 23 are located the essential rotatable parts of driving mechanism 1, which will be explained in further detail in conjunction with
The driving mechanism 1 comprises a coaxial shaft 32 passing through bottoms 17 and 23, which shaft is guided by means of a first vacuum-tight rotational leadthrough 33 through the upper bottom 17, and by means of a second vacuum-tight rotational leadthrough 34 and through a radial bearing 35 through the lower bottom 23. A group of connection fittings 36 serves for supplying treatment media and, if required, also for the current feed.
The linear stepwise transport direction of the substrates in oblique position or guided in oblique position without substrate holder through the interlock series 37 is indicated by the series of arrows 42. Opposite to the transfer chamber 39 is a further treatment chamber 43. In the interior of the annular space 29 the movement sequences are indicated by thick arrow lines. Starting at the transfer chamber 39, the stepwise rotational movement takes place by 90 degrees in each instance along the closed arrow line 44. At each of the four stopping points directly in front of the transfer chamber 39 and the treatment chambers 27, 43 and 28 the advance and retraction of the substrates are indicated by radial double arrows 45. The advance of the substrates takes place up to immediately in front of shielding frame-form screens 46 disposed in the opening regions of the treatment chambers 27, 43 and 28. However, a sealing effect between the substrates and these screens 46 is not required for the reason alone that the extremely thin substrates cannot or must not perform a [sealing] contribution. As soon as the rearward movements of the substrate holders are completed, these are rotated by 90 degrees in front of the particular next treatment chamber, and at the end of the treatment, in front of the transfer chamber 39 for further transport into the discharging interlock 40.
The highly compact implementation of the installation saving space and volume is especially evident in
By lifting the shaft 56, which includes a bearing flange 63, via connecting rods 64 (
Thereby the extension arms 61 are pulled in and the substrate holders 13 secured thereon standing in oblique position. The layout of the trapezoidal connecting rod configurations 57 is made such that a vertical component of the radial movement is minimal. At the end of the radial movement the substrate holders 13 assume the positions 13a, indicated in
In conjunction with
It is clearly evident that through the lifting of the shaft 56 in the direction of arrow 75 the entire trapezoidal connecting rod configurations 57, and therewith the substrate holders 13, are synchronously displaceable via the angle levers 59 and the distance connecting rods 62 in the direction of arrow 76, since the extension arms 61 are articulatedly pivoted on the lower ends of the connecting rods 65a fixedly connected with the members 65.
| Number | Date | Country | Kind |
|---|---|---|---|
| 103 48 281.4-45 | Oct 2003 | DE | national |
