WO2000055888A1

WO2000055888A1 - Device for treating substrates

Info

Publication number: WO2000055888A1
Application number: PCT/EP2000/001984
Authority: WO
Inventors: Wolfgang Kroeber
Original assignee: Steag Microtech Gmbh
Priority date: 1999-03-12
Filing date: 2000-03-08
Publication date: 2000-09-21
Also published as: DE19911084C2; EP1161765A1; DE19911084A1; KR20010103049A; JP2002539334A; TW472316B

Abstract

The invention relates to a device for treating substrates, especially semiconductor wafers, with at least one processing container that is provided with an opening which can be closed from the exterior during the treatment with the substrate. The aim of the invention is to provide a simple and homogeneous treatment of a surface pertaining to a substrate. The aim of the invention is also to reduce the danger of damage between successive treatment steps. To this end, a second processing container is provided adjacent to the first processing container. The wall of said second processing container is at least partially the container wall of the first processing container, whereby said container wall is provided with the opening which can be closed from the side of the first processing container.

Description

Device for treating substrates

The present invention relates to a device for treating substrates, in particular semiconductor wafers, with a process container having at least one opening, in which the opening can be closed from the outside through the substrate.

A device for treating substrates is known, for example, from DE 198 59 470, which did not pre-publish and which goes back to the same applicant. This device has a process tank which is open at the top and through which a metal-containing electrolyte flows from bottom to top. On its way up, the electrolyte flows through an anode designed as an expanded metal. A semiconductor wafer to be plated with the metal in the electrolyte is held by a substrate holder over an upper edge of the process container so that a flow gap is formed therebetween. The electrolyte flowing through the process tank is brought to overflow between the upper edge of the process tank and the substrate and is brought into contact with the wafer.

By applying a voltage between the anode and the wafer, which is electrically contacted, the metal contained in the electrolyte is caused to be deposited on the wafer.

In the case of this device, as a result of the abovementioned flow onto the substrate in the outer edge regions of the wafer, in particular in the region of the gap between the wafer and the upper edge of the process container, there are higher flow rates than in the central region of the wafer. These inhomogeneities in flow create deposition inhomogeneities of the metal on the wafer. Gas bubbles formed during the deposition of the metal are generally entrained by the flow of the electrolyte, but can collect in areas of relative calm flow and impair further deposition of metal there. Since the electrical Trolyte flows through the anode opposite the wafer, this must have large flow openings, which affects the generation of a homogeneous electric field between the anode and the wafer. For a further treatment of the wafer, such as a rinsing process, the substrate has to be raised and, if necessary, a rinsing-drying unit, as described in DE 198 59 469, which was published by the same applicant and is not prepublished, has to be moved under the wafer.

From US-A-5,437,777 a device for treating substrates of the type mentioned is known, in which an opening of a process container is closed from the outside by a substrate to be treated. The opening is arranged in a vertical wall of the process container in order to achieve a uniform flow of treatment fluid onto the substrate during metal plating. After a plating process, the substrate has to be reloaded in a complex manner in order to be treated, for example rinsed, in a further process container. When reloading there is a risk of damage to the substrate due to the necessary handling steps. Furthermore, there is a risk during reloading that the treatment fluid dries due to the required reloading time and thereby damages the substrate.

The present invention is therefore based on the object of providing a device of the type mentioned at the outset which enables simple, homogeneous treatment of a surface of the substrate to be treated and reduces the risk of damage to the substrate between successive treatment steps.

The object is achieved according to the invention in that, in the device described at the outset, a second process container is provided adjacent to the first process container, one wall of which is at least partially the container wall of the first process container containing the opening. By providing the second process container which shares the wall containing the opening with the first process container during the treatment in the first process container, the substrate is arranged in the second process container and after the treatment in the first process container can be treated in the second container without further reloading. The time periods between successive treatment steps can be reduced considerably, as a result of which the risk of the treatment fluid drying on is considerably reduced. If the substrate does not seal the opening in the process containers, it is sealed from the first process container side to provide separation of the two process containers. The two separate process rooms also reduce media carryover. By closing the opening of the first process container from the outside through the substrate, it is ensured in a simple manner that only the surface of the substrate facing the process container comes into contact with a treatment fluid located in the process container, while the remaining areas of the substrate are insulated from it . Furthermore, a lateral flow against the substrate, which extends essentially parallel to the substrate surface, is made possible. This results in a uniform flow on the substrate surface and thus a uniform treatment.

In a particularly preferred embodiment of the invention, the opening is formed in a substantially vertical wall of the process container, as a result of which the substrate is completely wetted by a treatment fluid when the process container is filled and air pockets are avoided. Gases generated during the treatment are immediately discharged upwards due to the vertical arrangement of the substrate and cannot get caught in zones of relative flow calmness. In addition, the vertical arrangement allows the Marangoni effect to be used when the substrate dries.

In order to ensure a good and tight closing of the opening by the substrate, a sealing element forming the periphery of the opening is provided. The sealing element preferably has an undercut and a sealing lip which, according to one embodiment of the invention, is milled out sen of a sealing material forming the sealing element are formed. The sealing element can also be an O-ring.

In a preferred embodiment of the invention, a contact element for electrically contacting the surface of the substrate facing the process container is provided, which preferably extends into the region of the undercut of the sealing element in order to ensure good and reliable contact in the edge region of the substrate.

In a further preferred embodiment of the invention, the device provides an electrode opposite the opening for generating an electric field between the electrode and the substrate. The electrode is preferably an electrode plate which enables the application of a homogeneous electric field. In a preferred embodiment, the electrode plate has openings for passing at least one fluid, in particular a drying fluid, in order to enable a targeted, vertical fluid flow onto the substrate opposite the electrode. The electrode is preferably an anode.

According to a further preferred embodiment of the invention, the electrode can be moved towards and away from the opening in order to adjust the distance between the electrode and the substrate, if necessary. The opening of the process container can preferably be closed from the inside by the electrode in order to close off the process container from the environment when it is not closed by the substrate.

In order to ensure that the opening is sealed off by the electrode, at least one sealing element is provided on the electrode and / or on a container wall surrounding the opening. In order to prevent impairment of the electrical field generated by the electrode and to avoid impairment of a fluid flow on the substrate side, the sealing element preferably radially surrounds the electrode and projects axially over a surface of the electrode facing the opening. In a special embodiment of the device which is used for the metal plating of the substrate, at least one treatment fluid which can be introduced into the process container is an electrolyte containing metal and / or an etching medium.

The second process container preferably forms a rinsing and / or drying chamber and / or a surface conditioning chamber.

In a preferred embodiment of the invention, the substrate is held by a substrate holder with at least one vacuum finger that is movable relative to a main body of the substrate holder. The provision of a vacuum finger movable relative to the main body of the substrate holder enables the substrate to be loaded and unloaded at a distance from the main body of the substrate holder, so that a substrate handling device can move in between the substrate and the main body of the substrate holder. For a secure and uniform hold, the vacuum finger is preferably arranged centrally in a surface of the main body facing the substrate. To bring the main body of the substrate holder into contact with the substrate, the vacuum finger can preferably be countersunk into the main body.

In a preferred embodiment of the invention, a pressure sensor is provided in a vacuum line connected to the vacuum finger in order to inform a wafer handling device, which brings the substrate to the substrate holder, when the substrate is securely held on the vacuum finger.

In addition to the vacuum finger, the substrate holder preferably has a plurality of fixed vacuum openings in the surface of the main body facing the substrate in order to hold the substrate firmly on the substrate holder over larger areas. The vacuum openings surround preferably radial the vacuum finger. The vacuum openings can advantageously be subjected to negative pressure separately from the vacuum finger.

According to a preferred embodiment of the invention, at least one sealing element radially surrounding the vacuum openings is provided on the substrate holder in order to ensure a good seal of a vacuum region. The sealing element on the substrate holder is preferably elastic and lies opposite the sealing element on the circumference of the opening, in particular the sealing lip, in order to give the substrate a small freedom of movement in this region, thereby avoiding the substrate between the sealing element on the circumference of the opening and the substrate holder damaged, in particular crushed. Because the two seals lie opposite one another, the contact pressure is also transmitted directly vertically through the substrate without transverse forces or stresses occurring in the substrate.

The invention is explained below on the basis of preferred exemplary embodiments with reference to the figures. Show it:

1 shows a schematic illustration of an embodiment of the device according to the invention;

FIG. 2 shows an enlarged schematic illustration of a circular section according to FIG. 1;

Fig. 3 shows an alternative embodiment of the invention with two process containers.

1 shows a metal plating device 1 with a process container 2, an anode arrangement 3 movably arranged inside the process container 2 and a substrate carrier 4 arranged outside the process container 2.

The process container 2 is formed by a bottom wall 6, an upper wall 7 and corresponding side walls, of which a left side wall 8 and a right side wall 9 are shown. Between the walls of the pro zeßbehälters 2, a process room 10 is formed. In the bottom wall 6, a combined inlet / outlet opening 11 is provided adjacent to the right side wall 9, which is connected to a line 12. A treatment fluid can be introduced into and drained from the process container 2 via the line 12 or the opening 11. Instead of a combined inlet / outlet connection, two separate openings with corresponding lines could of course also be provided.

An opening 14 is provided in the upper wall 7 and is connected to an overflow line 15. The treatment fluid introduced from below overflows from the process container 2 through the opening 14 and the overflow line 15.

In the left side wall 8 there is a central opening 17 in which a sliding rod 19 of the anode arrangement 3 is arranged. The shift rod 19 of the anode arrangement 3 extends through the central opening 17 and is connected at its end outside the process container 2 to a linear movement unit, not shown. The end of the shift rod 19 located within the process container 2 is connected to an anode plate 20 which extends parallel to the side wall 8 and essentially perpendicular to the shift rod 19. The anode plate

20 is a closed plate with a flat top 21 facing the right side wall 9. Between the left side wall 8 and the back of the anode plate 20, a seal in the form of an O-ring 23 is provided, which either on the left side wall 8 or Back of the anode plate 20 is attached. The anode plate 20 is radially surrounded by an O-ring 25 which extends in the direction of the right side wall 9 over the surface

21 of the anode plate 20 protrudes. The reference numeral 26 shows a sealing bellows which is connected on its left side to the sliding rod 19 and on its right side to the first wall 8 of the container 10.

The right side wall 9 has a central opening 29 whose dimensions are smaller than the dimensions of a substrate to be treated, such as. B. of a semiconductor wafer 31. The periphery of the opening 29 is formed by a seal 32, which can best be seen in the detailed view in FIG. 2. The seal 32 is welded to an inner circumference of the right side wall 9 and has a curved surface 33 facing the opening 29. In the side of the seal 32 opposite the surface 33, an undercut 35 is formed, which is formed, for example, by milling out the material forming the seal 32 becomes.

A contact element 37 in the form of a contact spring is fastened to the outside of the container wall 9 by means of a screw. The contact element 37 extends into the region of the undercut 35 of the seal 32 and has a contact tip 39. The contact tip 39 serves to electrically contact an edge region of a surface 40 of the wafer 31 facing the process container 2. The electrically contacted edge region of the surface 40 of the wafer 31 is located radially outside of a contact region between the surface 40 and the seal 32 and is thus with respect to the inside of the process container 2 isolated.

The wafer 31 is carried by the substrate holder 4 and is movable with it towards the process container into a position in which the wafer 31 closes the opening 29 in the side wall 9 and can be moved away from the process container 2 into a position in which the wafer 31 does not close the opening 29.

The substrate holder 4 has a main body 42 and a slide rod 43 attached to it. The shift rod 43 can also be formed in one piece with the main body 42. A central vacuum finger 44 is arranged in the main body 42 and is connected to a vacuum line 45. A pressure sensor, not shown, is arranged in the vacuum line 45 and is used to determine whether a sufficient negative pressure is maintained between the vacuum finger 44 and the wafer 31 for holding the wafer. The vacuum finger 44 is laterally movable out of the main body 42 and retractable into it so that it is completely sunk in the main body 42.

In the main body 42 there are also a plurality of openings 47 radially surrounding the vacuum fingers 44, which are connected to a vacuum line 48 and can be subjected to negative pressure in order to pull the wafer 31 firmly against the base body 42 of the substrate holder 4. The vacuum lines 45 and 48 can be subjected to negative pressure separately from one another, although they can be connected to a common negative pressure source.

As can be seen in FIG. 2, a groove 50 is provided in the edge region of a surface of the main body 42 facing the wafer 31, in which a O-ring 51 is received. The O-ring 51 radially surrounds the vacuum openings 47 and thus provides a good radial seal for a vacuum region formed between the wafer 31 and the main body 42 of the substrate holder 4. The O-ring 51 lies in the area of the seal 32 on the side wall 9 of the process container 2.

The treatment of the wafer 31 in the device according to FIG. 1 is described below.

First, the substrate holder 4 is withdrawn from the process container 2 and spaced apart. The vacuum finger 44 has moved out of the main body 42 of the substrate holder 4 and receives a wafer 31 which is brought into the region of the substrate holder 4 by a handling device (not shown). The extended vacuum finger 44 enables the handling device to move into a space formed between the main body 42 and the substrate 31 and to be transferred to the vacuum finger 44. After the substrate has been picked up by the vacuum finger 44, the handling device is released and moved out of the area between the wafer 31 and the main body 42 of the substrate holder 4. Then the vacuum finger 44 is retracted into the main body 42 of the substrate holder 4. One side of the wafer 31 comes into contact with the main body 42, and a vacuum is applied to the vacuum openings 47 via the vacuum line 48 in order to ensure a secure hold of the wafer 31 on the main body 42.

The substrate holder 4 is then moved towards the process basin 2 until the surface 40 of the wafer 31 comes into contact with the seal 32 on the side wall 9 and thereby closes and seals the opening 29 in the side wall 9. At the same time, the surface 40 of the wafer 31 comes into contact with the contact tip 39 of the contact element 37 in its edge region.

The process container 2 is then filled with an electrolyte containing metal, the surface 40 of the wafer 31 being uniformly wetted with the electrolyte. A voltage is then applied between the anode plate 20 and the electrically contacted wafer 31 in order to cause the metal contained in the electrolyte to be deposited on the surface 40 of the wafer 31. In this case, electrolyte is continuously introduced into the process container 2 via the opening 11 and flows out of the process container 2 via the opening 14. After sufficient deposition of the metal, the electrolyte is let out of the process container 2 via the opening 11. When the substrate holder 4 is withdrawn from the process container 2, the anode plate 20 is moved through the process container 2 to the side wall 9 until the seal 25 comes into contact with an inside of the side wall 9. As a result, the opening 29 of the process container 2 is sealed from the inside and the entry of impurities into the process container 2 is prevented.

Alternatively, the substrate 31 can be rinsed and / or dried before the substrate holder 4 is moved away. To rinse the wafer 31, rinsing fluid is introduced into the process container 2 via the opening 11 or a separate opening and the surface 40 of the wafer 31 is rinsed. To dry the wafer 31, the rinsing liquid is slowly drained off, a solvent, such as an IPA layer, being applied beforehand to the surface of the rinsing liquid, so that drying takes place according to the Marangoni principle.

Alternatively, openings could be provided in the anode plate 20 for the passage of a drying fluid (as will be described below with reference to FIG. 3). Then, after draining the rinse fluid, the anode plate 20 would be moved to a position adjacent to the substrate 31 and drying fluid, such as N ₂ , would be passed through the openings onto the surface 40 of the substrate 31 to dry it.

Subsequently, the substrate holder 4 is moved away from the side wall 9, so that the wafer 31 can be removed from the substrate holder 4.

FIG. 3 shows an alternative embodiment of the invention, in which the metal plating device 1 is designed in the form of a vertical double process chamber. Insofar as this is expedient, the same reference numerals as in the exemplary embodiment according to FIG. 1 are used in FIG. 3 to denote the same or similar elements.

The device 1 has a first process container 2, which is essentially the same as the process container 2 according to FIG. 1, and a second process container 60.

The process container 2 has a bottom wall 6, an upper wall 7 and left and right side walls 8 and 9. In the bottom wall 6, a drain opening 62 is provided which is connected to a line 63.

In the side wall 8, an inlet opening 64 is provided in the region of the bottom wall 6, which is connected to an inlet line 65. In the side wall 8, an overflow opening 66 is also provided in the region of the upper wall 7, which is connected to a line 67.

A shift rod 19 of an anode arrangement 3 extends through a central opening 17 in the side wall 8 and is longitudinally displaceable within the process container 2.

A longitudinally extending line 70 is provided in the shift rod 19 and is connected to a fluid source, not shown.

An anode plate 20 of the anode arrangement 3 has lines 72 which extend radially outward and are connected to the line 70 in the slide rod 19. The lines 72 are connected to openings 74 in a surface 75 of the anode plate 20 facing the side wall 9. A fluid, such as N ₂ , can be passed through the anode arrangement 3 via the line 70, the lines 72 and the openings 74. The area formed by the openings is very small compared to the total area of the upper side 75 of the anode plate 20, so that the anode plate 20 can be regarded as an essentially closed plate. As in the first exemplary embodiment, the anode plate 20 is radially surrounded by an O-ring 25. Again, a sealing bellows 26 is provided, which is connected on one side to the sliding rod 19 and on the other side to the first wall 8 of the container 10.

The side wall 9 in turn has an opening 29, the circumference of which is determined by a seal 32. The opening 29 can in turn be closed from the outside by a wafer 31 and from the inside by the anode plate 20.

A process container 60 is provided adjacent to the first process container 2, the left side wall of which is formed by the right side wall 9 of the first process container 2 containing the opening 29. The second process container 60 has a bottom wall 76, an upper wall 77, the left side wall 9 and a right side wall 78. In the bottom wall 76 is one combined inlet / outlet opening 81 is provided which is connected to a line 82. Instead of a combined inlet / outlet opening, two separate openings can of course also be provided.

An opening 84 is provided in the upper wall 77 and communicates with a line 85.

In the right side wall 78 of the process container 60 there is a central opening 87 through which a sliding rod 43 of the substrate carrier 4 extends. At 91, a sealing bellows is shown, which is connected on one side to the displacement rod 43 of the substrate support 4 and on the other side to the right side wall 78 of the process container 60.

Arranged on or in the left side wall 9 of the second process container 60 is a nozzle 90 which points into the second process container 60 and via which a treatment fluid, such as, for example, a rinsing liquid, in particular deionized water, is introduced into the second process container 60. Instead of a single nozzle, a plurality of nozzles can also be provided.

The structure of the substrate holder 4 essentially corresponds to the structure of the substrate holder 4 according to FIG. 1, only the shape of the vacuum finger 44 and the shape of the vacuum openings 47 differing from the shapes shown in FIG. 1.

The functional sequence of the vertical double process chamber is as follows:

The wafer 31 is introduced vertically through a side opening (not shown) of the second process container 60 via a wafer handling device and is received on the substrate holder 4 in the manner described above. The substrate holder 4 is then moved in the direction of the wall 9 until the wafer surface 40 comes into contact with the seal 32 at the opening 29 and the process containers 2 and 60 seal against one another. At the same time, the wafer is processed in the manner described above and electrically contacted directly behind the seal 32 on its surface 40.

After the process chambers have been sealed, an electrolyte containing metal is introduced into the process container 2 via the opening 64 until it overflows via the opening 66. Thereafter, a voltage is applied between the wafer 31 and the anode plate 20, thereby causing metal deposition on the surface 40 of the wafer 31. After the deposition process has ended, the electrolyte is discharged from the process container via the opening 62.

Subsequently, the substrate holder 4 with the wafer 31 held thereon is moved away from the common wall 9 of the process chambers 2 and 60. At the same time, the anode arrangement 3 is moved in the direction of the wall 9 until the O-ring 25 comes into contact with the common wall 9 and the two process containers 2 and 60 are sealed off from one another by the anode arrangement 3.

Rinsing fluid, such as deionized water, for example, is now admitted into the second process container 60 via the nozzle 90 and / or the opening 81 and the wafer is rinsed. After sufficient rinsing, the deionized water is drained off. To dry the wafer, a drying fluid, such as N ₂ , is then introduced into the process container 60 through the openings in the anode and blown against the wafer. For drying, the distance between the anode plate and the wafer 31 can be reduced by moving the substrate holder 4 towards the wall 9.

The Marangoni principle could also be used as an alternative drying method. For this purpose, a solvent, such as. B. IPA, introduced into the process container 60. The deionized water is then drained off and the wafer 31 is dried in accordance with the Marangoni principle. Finally, the substrate treated and dried in this way is removed from the side opening of the container 60, not shown.

The invention was previously described with reference to preferred exemplary embodiments of the invention, but without being restricted to the special exemplary embodiments. For example, it is not necessary for the opening 29, which can be closed off by the wafer 31, to be formed in a vertical side wall. The opening 29 could, for example, also be formed in a bottom wall of a treatment device, the respective treatment fluid inlets and outlets having to be adapted accordingly. The movement of the substrate holder and the anode arrangement could be controlled such that the anode plate and / or the wafer closes the opening 29 at all times. In addition, the anode arrangement can be designed as a combined washing / drying unit, via which the washing and drying fluid is directed onto the wafer opposite the anode plate 20. The anode plate can have, for example, a structure with a centered rinsing fluid nozzle and drying fluid nozzles extending tangentially to it. The construction of such a combined rinsing / drying unit is described, for example, in DE 198 59 466, which is based on the same applicant and has not been previously published, and is thus made the subject of the present invention in order to avoid repetitions. The bottom walls, the upper walls and the side walls (not shown) of the process containers can be formed in one piece. Furthermore, the bottom walls can be funnel-shaped in order to achieve a better outflow of the respective treatment fluid. In particular, the respective chambers can also be used for different processes. For example, an etching medium can be introduced into the process chambers and the second chamber can be designed as a surface conditioning chamber.

Claims

claims

1. Device (1) for treating substrates (31), in particular semiconductor wafers, with a first process container (2) having at least one opening (29), the opening (29) being closable from the outside by the substrate (31), characterized by a second process container (60) provided adjacent to the process container (2), one wall (9) of which is at least partially the container wall (9) of the first process container (2) containing the opening, the opening (29) being from the Side of the first process container is closable ago.

2. Device (1) according to claim 1, characterized in that the opening (29) is formed in a substantially vertical wall (9) of the process container (2).

3. Device (1) according to one of the preceding claims, characterized by a sealing element (32) forming the circumference of the opening (29), which in particular has an undercut (35) and a sealing lip, which in particular by milling out the sealing element ( 32) forming sealing material is formed.

4. Device (1) according to one of the preceding claims, characterized by a contact element (37) for electrically contacting the process container (2) facing surface (40) of the substrate (31), which is particularly in the region of the undercut (35) of the sealing element (32) extends.

Device (1) according to one of the preceding claims, characterized by an electrode (20) opposite the opening (29), which is in particular an electrode plate (20) and openings (74) for passing at least one fluid through and in particular is an anode.

6. The device (1) according to claim 5, characterized in that the electrode (20) on the opening (29) to and from this is movable and in particular the opening (29) through the electrode (20) from the side of the first Process container is closable ago.

7. The device (1) according to claim 6, characterized by at least one sealing element (25) on the electrode (20) and / or an opening (29) surrounding the container wall (9), which in particular surrounds the electrode radially and axially via a Surface (29) facing surface protrudes.

8. Device (1) according to one of the preceding claims, characterized in that at least one treatment fluid which can be introduced into the process container (2) is an electrolyte containing metal and / or an etching medium.

9. Device (1) according to one of the preceding claims, characterized in that the second process container (60) forms a rinsing and / or drying chamber and / or a surface conditioning chamber.

10. The device (1) according to any one of the preceding claims, characterized by a substrate holder (4) with at least one vacuum finger (44) which is movable relative to a main body (42) of the substrate holder (4) and which is in particular centered in a to the substrate (31) facing surface of the main body (42) is arranged and in particular can be countersunk in the main body (42) of the substrate holder (4).

11. The device (1) according to claim 10, characterized by a pressure sensor in a vacuum line (45) connected to the vacuum finger (44).

12. The device (1) according to any one of claims 10 or 11, characterized by a plurality of fixed vacuum openings (47) in the surface of the main body (42) of the substrate holder (4) facing the substrate (31) which the vacuum finger (44) surrounded in particular radially and which can be acted upon by vacuum in particular separately from the vacuum finger (44).

13. The device (1) according to any one of claims 10 to 12, characterized by at least one radially surrounding the vacuum openings (47)

Sealing element (51) on the substrate holder (4), which is in particular elastic and lies opposite the sealing element (32) on the circumference of the opening (29), in particular the sealing lip.