DEVICE AND METHOD FOR TREATING WAFERS

Abstract

The present invention relates to a device and a method for the treatment of wafers. Proposed is a transport of the wafers in vertical alignment through the process solution which is used for the treatment of the wafers, whereby an increase of the throughput, a simplified aftertreatment of the exhaust air as well as a reduction of the consumption of components of the process solution are made possible. The invention can, inter alia, be used in the production of solar cells or also of printed boards, for example printed boards for the electrical industry.

Claims

1. A device for the treatment of wafers with a chemical process solution, wherein the device comprises means of transport and holding-down means as well as at least one process basin for holding the chemical process solution, wherein the process basin on at least one side is limited by an impounding device, wherein the impounding device is designed such that between the means of transport and the holding-down means vertically aligned wafers in horizontal movement direction can be guided into the process basin and out of the process basin.

2. The device according to claim 1, wherein the impounding device is provided with at least one vertically running slot for guiding through the vertically aligned wafers.

3. The device according to claim 2, wherein the slots have a height in a range of 10 mm to 1000 mm.

4. The device according to claim 3, wherein the slots have a width in a range of 220 μm to 1000 μm.

5. The device according to claim 1, wherein the impounding device is provided with 2 to 1000 vertically running slots for guiding through the vertically aligned wafers.

6. The device according to claim 5, wherein the distance of the slots from each other is 2 times to 100 times the width of the slots.

7. The device according to at least one of claim 5, wherein the distance of the slots from each other is 0.4 mm to 40 mm.

8. The device according to claim 1, wherein the impounding device is arranged in a movable manner such that the impounding device can assume an open position and a closed position, wherein the open position allows the guidance of the vertically aligned wafers into the process basin and/or the guidance of the vertically aligned wafers out of the process basin.

9. The device according to claim 1, wherein the distance between the means of transport and the holding-down means is in a range of 10 mm to 1000 mm.

10. The device according to claim 1, wherein the means of transport and/or the holding-down means comprise at least one recess for holding the wafers.

11. The device according to claim 1, wherein the impounding device is designed in the form of two impounding devices which are present on opposite sides of the process basin.

12. An inline method for the treatment of wafers with a chemical process solution comprising the following steps: a) providing of vertically aligned wafers, b) providing of a process basin with process solution being present therein, c) guiding of the vertically aligned wafers into the process basin, d) guiding of the vertically aligned wafers through the process basin and the process solution being present therein so that the wafers are contacted with the process solution, e) guiding of the vertically aligned wafers out of the process basin, wherein the guiding into, guiding through and guiding out of steps according to the steps c) to e) are conducted in substantially horizontal movement direction.

13. The method according to claim 12, wherein 2 to 1000 rows of wafers at the same time side by side are transported through the process basin.

14. The method according to claim 13, wherein the distance of two rows of wafers from each other which are transported at the same time side by side through the process basin is 0.4 mm to 40 mm.

15. The method according to claim 1 for the production of solar cells and/or printed boards using the device.

16. The device according to claim 3, wherein the slots have a width in a range of 220 μm to 1000 μm.

17. The device according to claim 6, wherein the distance of the slits from one another is from 0.4 mm to 40 mm.

Description

DESCRIPTION OF THE FIGURES

[0063] FIG. 1 shows a cross-section through a device of prior art. The wafers (1) are transported in horizontal alignment through the device. The process basin (4) is limited by the transport rolls (2) and the holding-down rolls (3). Overflowing medium is returned into a tank (5) through a pipe, and from there by means of a pump (6) it is again pumped into the process basin (4). The arrows show the flow direction of the medium.

[0064] FIG. 2 shows a cross-section through a device of the present invention. The wafers (1) are transported in vertical alignment through the device. The device comprises a process basin (4) for holding the chemical process solution. The process basin (4) is limited on two sides by an impounding device (21). Overflowing medium is returned into a tank (5) through a pipe, and from there by means of a pump (6) it is again pumped into the process basin (4). The arrows show the flow direction of the medium. The treatment of the wafers (1) with the chemical process solution is achieved by guiding the wafers (1) through the process basin (4) with the process solution being present therein. The impounding device (21) is designed such that between the means of transport (2) and the holding-down means (3) vertically aligned wafers (1) in horizontal movement direction can be guided into the process basin (4) and out of the process basin (4).

[0065] FIG. 3 shows a front view of an impounding device (21) with slots (22) as passage for the wafers which are transported in vertical alignment.

[0066] FIG. 4 shows a front view of the transport rolls (2) and the holding-down rolls (3) with wafers (1) being vertically aligned between them.

[0067] FIG. 5 shows a perspective view of a device of the present invention. The impounding device (21) is designed such that between the means of transport (2) and the holding-down means vertically aligned wafers (1) in horizontal movement direction can be guided into the process basin (4) and out of the process basin (4). For reasons of clarity, the holding-down means are not shown.

[0068] FIG. 6 shows a cross-section through a device of the present invention with wafers (1) which are transported through the device in vertical alignment. The impounding device (21) is designed such that between the means of transport (2) and the holding-down means (3) vertically aligned wafers (1) in horizontal movement direction can be guided into the process basin (4) and out of the process basin (4), Shown is an embodiment in which the impounding device (21) is designed such that via two weirs 21a and 21b a loading region and via two weirs 21c and 21d an unloading region are formed. The weirs 21a, 21b, 21c and 21d each are retractable weirs. For loading and unloading, at first, the weirs 21a and 21c are lowered so that wafers can be moved into the loading and unloading region (FIG. 6A). Subsequently, the weirs 21a and 21c are transferred into the closed position so that the arrangement shown in FIG. 6B results. After transferring the weirs 21b and 21d into the opened position the wafer to be loaded (1) is transported into the process region, while the wafer to be unloaded ( ) leaves the unloading region (FIGS. 6C and 6D). When the loading and unloading regions are unoccupied again, then the weirs 21b and 21d are transferred into the closed position and the weirs 21a and 21b are transferred into the opened position so that the next wafers (1) each can be moved into the loading and unloading region, and again the arrangement shown in FIG. 6A results.

DETAILED DESCRIPTION OF THE INVENTION

EXAMPLES

[0069] Transport of vertically aligned wafers through a process plant

[0070] For the transport, in an edgewise and surface-parallel manner wafers are moved through a process plant. So, the space required per wafer is reduced from about 160×160 mm.sup.2 to 160×5 mm.sup.2 which results in a significant increase of the wafers being treated in parallel manner and thus in a significant increase of the throughput of the plant.

[0071] In contrast to prior art in which a horizontal alignment of the wafers during the transport is envisaged, in the present method an impounding of the process solution only by the transport and holding-down rolls is no longer possible, because now the distance between both rolls corresponds to the edge length of the wafers (156 mm). Therefore, the additional installation of an impounding device (21) is necessary. This impounding device (21) is provided with a number of slots (22) (which corresponds to the number of the wafers) through which the wafers can be moved into the impounded process solution. In the present case, 50 wafers are treated in parallel manner so that the impounding device (21) is provided with 50 slots (22).

[0072] For achieving a vertical alignment of the wafers which is as exact as possible, the transport rolls (2) and the holding-down rolls (3) are provided with a profile so that the wafers are guided in small recesses of the rolls and are protected against lateral tilting.

[0073] By the transport of the wafers in vertical alignment the throughput can significantly be increased.

[0074] Besides the higher throughput, the bath surface in relation to the number of the wafers which are treated at the same time is substantially smaller. So, oxides of nitrogen are released into the exhaust air in a more concentrated form which simplifies the aftertreatment thereof.

[0075] Furthermore, by the smaller bath surface the total load of oxides of nitrogen in the exhaust air is reduced. A part of the oxides of nitrogen remains in the process solution, and there it is reacted further. So, the consumption of nitric acid in the etching process is reduced.