WO2010057671A2

WO2010057671A2 - Method and device for handling a cut wafer block

Info

Publication number: WO2010057671A2
Application number: PCT/EP2009/008344
Authority: WO
Inventors: Reinhard Huber
Original assignee: Gebr. Schmid Gmbh & Co.
Priority date: 2008-11-24
Filing date: 2009-11-24
Publication date: 2010-05-27
Also published as: DE102008060014A1; TW201030881A; WO2010057671A3

Abstract

In a method for handling a wafer block cut into individual wafers while the block is being held by the carrier device, brushes having bristles as pressing means are moved up to the cut wafer block in horizontal position from both sides, reaching laterally up to the side edges of the wafers and into interspaces between the wafers so as to keep them at a distance. The bristles run along the cut wafer block and can be moved along said longitudinal extension. The cut wafer block is brought out of the horizontal position and into a vertical position while the bristles are pressed on at the same time. Then the bristles are moved away from the top down along the cut wafer block, and in doing so, the bristles are retracted from the interspaces between the individual wafers to lower the individual wafers directly onto one another without any interspaces to form a wafer stack.

Description

description

Method and device for handling a sawed-off wheel block

Field of application and state of the art

The invention relates to a method and to a device suitable for handling or for turning a sawn wafer block, in particular after the sawing of a wafer block into individual wafers for the production of solar cells.

From DE 102008053596.6 and DE 102008053598.2 it is known to saw a wafer block, which is glued along at least one side to a carrier and is secured to a support means with the carrier, into individual wafers and then to clean. As a result, sawing residues are eliminated. Furthermore, as described in DE 102008053598.2, the sawn wafer block or the individual wafers are then released from the carrier by dissolution or removal of the adhesive. The sawed wafer block is in a horizontal position, so the individual wafers are vertical. After releasing the bond with the carrier, the wafers are held in the carrier device or are fastened, preferably by abutment on lateral, elongate holders such as side brushes according to DE 102005028112 A1 or bar-like supports. In this carrier device, the wafers are then erected in a vertical position so that they lie flat. Thus, a stack is formed, from which the wafers can then be removed automatically. Alternatively, they can also be removed manually from the carrier device and rotated and fed to further processing, for example a batch production line.

However, manual handling of the wafers is considered disadvantageous because it often damages or destroys the wafers and is costly. A previous automatic turning into a vertical position is possible. However, loosening and draining the wafers into a stack of directly superimposed wafers is often also associated with the risk of damage or destruction since, above all, it can not be carried out in a precisely controlled manner.

Task and solution

The invention has for its object to provide an aforementioned method and a corresponding device with which the disadvantages of the prior art can be achieved and in particular the rotation of a sawn wafer block and forming a vertical stack of wafers, ie with a vertical position, to allow with little risk of damage to the wafer.

This object is achieved by a method having the features of claim 1 and a device having the features of claim 12. Advantageous and preferred embodiments of the invention are the subject of further claims and are explained in more detail below. Some of the features described below are mentioned only for the method or only for the device. However, they should be considered detached from both the method and the corresponding device. The wording of the claims is incorporated herein by express reference.

It is provided that the wafer block sawn into individual wafers or even the individual wafers are still held on the carrier device. This is advantageously done on at least two sides, preferably on opposite sides. According to the invention, pressing means, which are advantageously brushes with bristles or lamellae or a substantially closed soft surface of foam or the like, are moved onto the wafer block in a horizontal position from two opposite sides, in particular horizontally opposite one another. On white- sen. The pressing means keep the wafers as a whole and also at a distance from one another. This is done by pressing a soft surface against the side edge and, in a brush, not only reaching the bristles or fins laterally to the side edges of the wafers, but even into the interstices between the individual wafers for better spacing. By the pressure force of the bristles or fins not only the wafers can be kept at a distance, so the spaces are obtained, but also the wafers themselves are held in position. As with the pressing means with the very soft surface, this makes it possible to release the carrier device described later, without the wafers moving or falling down. The pressing means have a longitudinal extension along the sawn wafer block, so that they rest against all the wafers. They are movable along this longitudinal extension, in particular in the direction of this longitudinal extent. The sawed wafer block is brought with pressed-pressing means from the horizontal position in a vertical position, so erect. Then, the pressing means are moved from top to bottom either so that in some areas the pressing means are moved away from it or bristles or fins are partially moved out of the wafers, or over the entire length to the same extent. Advantageously, the pressing means are moved overall along the longitudinal direction from top to bottom and thus detach from the wafers or draw all the bristles or lamellae simultaneously from the intermediate spaces. As a result, the intervals or gaps are no longer obtained and the wafers can be lowered onto one another in order to form the wafer stack, in which the wafers rest directly on one another.

Thus, it is thus possible with the invention not only to hold the wafers of the sawn wafer block with the pressing means in order to bring them into a vertical position, but also to improve the stacking of the wafers spaced apart by the interspaces without mechanical damage. If the surface or the bristles or lamellae are soft enough and finely formed in the pressing means, they can both fill very thin spaces with simultaneous holding function as well as pull out a certain holding and distance-preserving function fulfill, even if the distance is still very much is less than at the beginning, so not more 100 microns to 200 microns, but 20 microns to 50 microns or microns .. Furthermore, such soft surfaces of foam or the like. or bristles or lamellae are moved laterally to the wafers and possibly moved into the interstices without damaging the side edges.

As an alternative to brushes, the pressing means may be provided with a surface which consists of very soft material, preferably foam material or soft neoprene. It may either be substantially closed or may have projections such as ribs or panels for abutment with the side edges of the wafers.

In a further embodiment of the invention, the erecting of the sawn wafer block from the horizontal position to the vertical position can be done in a water bath. For this purpose, the horizontal sawed wafer block can either be moved into a corresponding water bath or it can be formed around it.

In a further development of the invention, it is also possible to carry out the removal of the pressing means or the lowering or destacking of the individual wafers onto a wafer stack likewise in a water bath. Again, the above options apply to the water bath. The advantage of the movement or handling of the wafers or of the sawed wafer block in the water bath is that mechanical forces remain less due to the floating of the wafers. Above all, the lowering or stacking of the wafers on each other can be made more gentle and so to speak attenuated by the water bath. The further In the case of a stacking of the wafers in a water bath, the water level can be lowered at the same time.

Another advantage of pressing means in the form of downwardly moving brushes with downwardly moving bristles or lamellae is that they are pulled out on the one hand down and on the other hand, but also move the wafer down, so to speak. This results in a very precise controllable stacking, as the bristles or fins still lead the wafer.

In a further advantageous embodiment of the invention, the bristles or slats are uniformly pulled out of the spaces or the brushes are moved at a constant speed down. Alternatively, the speed can be reduced as the stacking process continues, in order to achieve as gentle a stacking as possible.

In a further embodiment of the invention is in addition to an advantageous to select elasticity and thickness of the bristles or fins make sure that they do not retract with an excessive proportion of their length in the spaces between the wafer. It can thereby be achieved that a still sufficient length of the bristles or lamellae remains outside the wafer in order to be bent downwards during movements. So they stand with not too oblique angle into the interstices. Indeed, this could adversely affect gradual stacking of the wafers because otherwise the sloped ends of the bristles or fins could otherwise force the wafers apart.

In one embodiment of the invention, the pressing means can not only be significantly longer than the wafer stack, but can even be formed circumferentially, that is, as a type of circumferential loop. Here, for example, training on the type of tapes with the very soft Surface, for example made of foam, or with the protruding bristles or lamellae, so to speak brush bands. They then abut against the wafers on the two opposite sides or, in the case of brushes, are pressed into the spaces with their bristles or lamellae. Even while they are turning, they can still touch the wafers.

Alternatively, pressing means such as bar brushes may be provided as moving brushes with a corresponding width, alternatively with a very soft surface. It can also be used over a certain width distributed two or three very narrow bands or bar brushes. The advantage of several such narrow bar brushes is that they can be moved up to the bristles or lamellae into the interstices not only with a movement directly on the wafer, but are moved very close with wegdrehrehten bristles or fins. By turning about its longitudinal axis, the bristles or lamellae can then be screwed in laterally, that is to say not only with the tip in advance in the longitudinal direction of the bristles are pressed, but with a certain length at the same time, allowing for easier retraction. A similar effect can be achieved if the brush is simultaneously moved parallel to the side edge of the wafer as it moves.

The pressing means should have a certain width, which is for example at least half as wide as the wafers, advantageously slightly wider. They should be moved in a central area to the sawed wafer block and applied to keep the wafer well and also to protect against tilting.

It is possible to form the pressing means as components of the carrier device, ie to fasten it to the carrier device. Then the erection of the sawed-wafer block and also the stacking takes place so to speak with the carrier device. Alternatively, the pressure Tel be arranged on a separate device and remove the sawed wafer block so to speak in the horizontal position of the support means for erecting and destacking.

These and other features will become apparent from the claims but also from the description and drawings, wherein the individual features each alone or more in the form of sub-combinations in an embodiment of the invention and in other fields be realized and advantageous and protectable Represent embodiments for which protection is claimed here. The subdivision of the application into individual sections and subheadings does not restrict the general validity of the statements made thereunder.

Brief description of the drawings

Embodiments of the invention are shown schematically in the drawings and will be explained in more detail below. In the drawings show:

1 is an oblique view of a sawed wafer block in a device according to the invention with two lateral brush belts,

FIG. 2 shows a highly schematic sectional view through the wafer stack from FIG. 1 with the application of the lateral brushes and. FIG

Fig. 3 is a schematic diagram of the stacking of the wafer in the vertically erected wafer stack by moving the brush belts.

Detailed description of the embodiments 1 shows a sawed wafer block 11 which, as FIGS. 2 and 3 make clear, consists of a large number of wafers 12 with lateral side edges 13. The wafers 12 each have gaps 14 with respect to one another. This is also apparent, for example, from the German patent application DE 102008060012.1 of the same Applicant, to which reference is expressly made.

The sawed-wafer block 11 is horizontal as shown in FIG. 1, which means that the individual wafers 12 are vertical. He is held in a support means 15 which has a frame-like upper plate 16a and a lower plate 16b. Such a carrier device is described in the aforementioned DE 102008053596.6, to which reference is expressly made.

In addition to support rods not shown, the support means 15 in the longitudinal direction of the wafer block 11 side brushes 18, as described in the aforementioned DE 102008053596.6 and DE 102005028112.5. These side brushes 18 also extend the length of the wafer block 11 and serve both to support and to space the wafers 12. While they may be rotatable, they are not movable along the wafer block.

Furthermore, pressing brushes 20, which have elongated bristles 21, are provided as pressing means. These bristles can be relatively thin, for example, thinner than 20 microns or even thinner than 10 microns, and have a length of a few centimeters. In Figs. 1 and 3, the pressure brushes 20 are formed as circumferential brush belts 23 which run around circulation rollers 24, wherein the circulation rollers 24 may be driven and supported on brush holders 25.

Alternative pressing means with a very soft surface, preferably made of plastic, which may be open-pored or closed-pored, may in principle be designed in the same way. The surface should be consistently But it does not have to be. It could also be divided into individual protruding ribs or fields for a smaller or point-like attack on the side edges of the wafers. These ribs or fields advantageously extend transversely to the longitudinal direction of the wafer stack or to the direction of movement.

In Fig. 2 is shown schematically, as shown at the left side edge 13 of the wafer 12, which is at this time still supported in the support means 15 and from this, the side brushes 18 abut the wafer block 11 and their bristles in Intervene gaps 14 between the wafers 12 intervene. The Andrückbürste 20 is still laterally next to it with a certain distance. This corresponds approximately to the representation according to FIG. 1, in which the brush belts 23 are relatively close to the sides of the wafer block 11, but do not yet rest.

In the next step, by moving the brush holder 25 toward each other, the pressing brush 20, as shown on the right side edge 13 of the wafer 12 in Fig. 2, brought in accordance with the thick arrow and is not only on the side edge 13 with the bristles 21. The bristles 21 penetrate into the intermediate spaces 14 between the individual wafers 12, which is easy to imagine. This penetration depth can be a few millimeters to a few centimeters.

This pressing movement of the pressure brushes can be carried out either in accordance with the illustrated thick arrow exactly on the side edge 13. Alternatively, at the same time, a certain visual rag movement can take place, for example, from top to bottom. By such an oblique movement, as is easily imagined, the retraction of the bristles 21 into the intermediate spaces 14 can be facilitated.

In a next step, the side brushes 18 of the carrier device 15 can be removed or moved away. In addition to this Also further support rods or the like. the carrier device are removed. In particular, it is possible that even the entire support means 15 is removed, which is usually not necessary and is technically difficult to implement due to the cage-like structure.

Subsequently, the wafers 12 are held only laterally by the pressure brushes 20 and no longer by the side brushes 18 or other lateral support rods of the support means 15. With an underside, they may continue to rest on support rods of the support means 15, but this is not absolutely necessary and could Even destacking.

Subsequently, the erecting of the horizontal wafer block 11 takes place in the vertical position shown in FIG. Of course, this is done with brush bands 23 on the brush holders 25 simultaneously with the carrier device 15 itself. This erection can, as described above, take place in a water bath, since it is then gentler possible.

Below the wafer block 11 is a holding plate 26. This can either already be present in the support means 15 or be introduced separately. In any case, it serves to deposit the individual wafers 12 on it, as will be explained in more detail below.

The procedure for depositing the wafers or destacking is as follows. The brushes 20 and the brush belts 23 move down at the side edges 13 of the wafer 12. As a result, on the one hand, all the wafers 12 are moved downwards and are thereby starting more and more successively from bottom to top on the holding plate 26. This is illustrated by the fact that in the upper area a wafer stack 28 is still shown with spacings between the wafers 12, which are at the same time already smaller than the intermediate spaces 14. In the lower area, a lowered position is already present on the holding plate 26. ter wafer stack 29 ago, in which the distances are only very small or, for example, at the very bottom, already no longer available.

Furthermore, as the brush belts 23 move downwardly, their bristles 21 slowly pull out of the spaces 14. This also serves to ensure that, as it were, fewer and fewer spacers are between the wafers 12 and that they approach one another more and more, which leads to the destacking described below. The advantage of this method is that the distance reduction is gradual. Furthermore, a guide or a guided movement of the wafer 12 is achieved during this reduction in distance by the brush belts 23 and their adjacent bristles 21.

As described above, the stacking, similar to the erection, can be done in a water bath or under water. As a result, a gentle process is possible, in particular because the water in the gaps 14 between the wafers 12 dampens the movement and prevents two wafers from colliding with their sides.

It is easy to imagine how instead of the rotating brush belts 23 elongated brushes can be used, which are rod-like design similar to the side brushes 18. For them then just a longitudinal guide is needed and a device to move them along. It is important in the invention namely that the bristles of the brushes are not simply moved laterally out of the spaces, similar to what has been described above for the side brush 18 by unscrewing in the cited prior art. The movement of the brushes and their bristles together with the wafer stack in the direction of stacking is advantageous for a gentle and controlled process. Instead of continuously rotating pressing means in the form of brush belts 23, which lie against the wafer stack 28 and 29 over their entire length during stacking, pressure rollers 31 shown in dashed lines could also be provided. These may be moved down the wafer block 11 beginning to descend, as illustrated by the double arrows. Simultaneously with this movement, the upper circulation rollers 24 can be moved away from the wafer block 11 and thereby, either alone or in addition to the circulation of the belt 23, pull the bristles 21 in the longitudinal direction of the spaces 14 of the wafer 12. Alternatively, such pressure rollers 31 could travel from the bottom upwards and then just the bottom circulation rollers 24 would be moved away laterally. Especially in the case of pressing devices with a soft surface, such a procedure is particularly advantageous. As a result, the installation of the very soft surface on the side edges of the wafer can not be achieved by running along, but by lateral movement away of the pressing means, which is even more gentle for the wafer.

After stacking to the lowered wafer stack 29, the brush holder 25 can move away laterally completely and the vertical stack of wafers 12 can be removed on the holding plate 26. It can then be transported on to a separation, as described in DE 102007061410 A1.

Claims

claims

1. A method for handling a sawn wafer block, wherein the wafer block is sawed into individual wafers and the individual wafers are held by a carrier device, characterized in that are moved from two sides to the sawed wafer block in a horizontal position pressing means and laterally to the side edges the wafers extend to keep them or at a distance, wherein the pressing means have a longitudinal extent along the sawed wafer block and are movable along this longitudinal extent, wherein the sawed wafer block is brought with simultaneously pressed-pressing means from the horizontal position to a vertical position and then the pressing means are moved from top to bottom along the sawn wafer block or their connection with the individual wafers is released from top to bottom for lowering the individual wafers directly to one another without a gap to a wafer stack.

2. The method according to claim 1, characterized in that the raising takes place from the horizontal position to the vertical position in a water bath.

3. The method according to claim 1 or 2, characterized in that the removal of the pressing means or lowering of the individual wafer is carried out on a wafer stack in a water bath.

4. The method according to any one of the preceding claims, characterized in that the pressing means are brushes with bristles or lamellae and in particular the bristles or lamellae zoom in laterally to the side edges of the wafer and in spaces between the wafers to keep them or keep at a distance.

5. The method according to claim 4, characterized in that the brushes are moved down along the sawn Wafer- blocks and thereby pull out their bristles or fins from the spaces between the individual wafers for lowering the individual wafers directly to each other without any gap to a wafer stack.

6. The method according to any one of claims 1 to 3, characterized in that the pressing means have a surface of soft material for application to the side edges of the wafer, preferably foam material or soft neoprene, in particular with a continuous surface.

7. The method according to any one of claims 2 to 6, characterized in that simultaneously with the stacking of the wafer by moving the pressing down or releasing the connection with the pressing means of the water level is lowered by draining water, preferably such that the formed wafer stack is always completely immersed.

8. The method according to any one of the preceding claims, characterized in that the pressing means are moved at a constant speed down.

9. The method according to any one of the preceding claims, characterized in that the pressing means are formed circumferentially, in particular in the manner of bands with the protruding bristles or lamellae, wherein they preferably at two opposite Overlying sides of the wafer stack to attack the individual wafers.

10. The method according to any one of the preceding claims, characterized in that the pressing means run exactly parallel to the side edges of the sawn wafer block.

11. The method according to any one of the preceding claims, characterized in that the sawed wafer block is introduced into a Abstapel- device having the pressing means, and in which both the pressing means are moved up to the sawed wafer and the sawed wafer block from a horizontal position is erected in the vertical position and then the individual wafers are stacked.

12. An apparatus for performing the method according to any one of the preceding claims, characterized in that it comprises at least one pressing means having a soft foam surface, protruding lamellae or bristles, wherein the fins or bristles are formed very thin.

13. The apparatus according to claim 12, characterized in that the pressure means comprise two brushes.

14. The apparatus of claim 12 or 13, characterized in that the pressing means are formed circumferentially, in particular in the manner of tapes with foam or the protruding bristles or lamellae, preferably having two pressing means to on two opposite sides of the wafer stack to the individual wafer attack.

5. Device according to one of claims 12 to 14, characterized in that the pressing means extend with its broad side parallel to the sides of the wafer, wherein preferably the pressing means are slightly less wide than the side edges of the wafer, in particular a little more than half as wide.