JP5080157B2 - Equipment for processing flat, fragile substrates - Google Patents

Description

The present invention is an apparatus for processing flat fragile substrates, particularly for the semiconductor and solar energy industries,
a) a processing chamber in which processing liquid can be supplied to the substrate;
b) a transfer device capable of guiding the substrate horizontally through the processing chamber in a number of tracks parallel to each other;
c) at least one acting on the upwardly facing side of the substrate to prevent lifting from the transfer device and having a connected shaft over a plurality of tracks, to which a number of pressing members are fixed Presser device;
The present invention relates to a device having

  In the semiconductor and solar energy industries, there are often very flat substrates such as silicon disks (wafers), silicon plates and glass plates that have to be subjected to various wet processes. The treatment method is, for example, chemical treatment and electrochemical treatment, cleaning treatment and drying treatment. The treatment liquid can be applied by either a spraying method or an immersion method.

  Substrates of the type described above are very vulnerable to breakage and therefore need to be transferred very carefully through one or more processing chambers.

  Known horizontal pass electroplating equipment, such as that used for conductor plate electroplating, cannot be used on the substrates mentioned herein. They use rollers as pressing members that are also often used here as contact members, which are mounted on a common shaft that spans the track. Here, slight thickness fluctuations of the conductor plate do not act very strongly on the pressing force of the pressing member; slight thickness fluctuations can be absorbed by the hard shaft and there is no risk of breakage of the conductor plate. Furthermore, in the known horizontal-pass electroplating equipment, since the current flowing therethrough is high, a strong pressing force of the pressing member is required to keep the contact resistance low. This strong pressure contact force destroys the fragile substrate.

In particular, roller transfer devices formed for processing fragile substrates are described in the prior art (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3). However, the formation of the presser device is very complicated here.
International Publication No. 2005 / 093788A1 Specification International Publication No. 03 / 086913A1 Specification International Publication No. 03 / 086914A1 Specification

  The object of the present invention is to provide an apparatus of the kind mentioned at the outset, which is capable of carefully transferring a substrate by simple means.

According to the present invention, this problem is
d) The presser device is as follows, that is, the individual presser members can be moved vertically independently of each other, so that a pressure substantially independent of their thickness can be applied on the substrate. It is solved by being formed in this way.

  The present invention is based on the recognition that the breakage of a substrate is often caused by a slight difference in thickness between the substrates. If a plurality of pressing members are arranged on the same hard axis and the pressure applied to the thinnest substrate is just enough to hold down, the break limit may be exceeded for thicker substrates. Accordingly, in the present invention, the individual pressing members associated with the same connected shaft have a certain degree of movement upward and downward, so that the difference in the thickness of the individual substrates in the individual tracks can be reduced. There is a possibility that it can follow and avoid the formation of an unacceptably high pressing force.

  This is because, in the simplest case, the shaft on which the pressing member is arranged is flexible and, in addition, flexes elastically when an upward force is supplied by the individual pressing member. This is already achieved by the fact that the force that the presser member acts on the substrate remains below the break limit.

  When the shaft material is metal, for example, shaft diameters between 1 mm and 3 mm are suitable.

  An alternative to this is that the presser member is fixed to a swing arm that can swing relative to the shaft. In this embodiment, the movement possibilities of the various pressing members associated with the same shaft are further independent of each other. The placement force of the contact member on the substrate surface can be adjusted by a counterweight provided on the swing arm in some cases.

  In an electroplating facility, it is common that the pressing member is simultaneously used as a contact member for supplying current to the substrate, and the shaft is formed as a current supply portion to the pressing member. This is possible even with very thin shafts in the device according to the invention. This is because the current to be transmitted here is much smaller than in the case of equipment for processing conductor plates.

  The pressing member is preferably a roller. This is because the rollers are connected with slight friction and are particularly carefully attached to the substrate.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  As an example of “processing” in the gist of interest here, an application example based on the solar energy industry is described below:

  To form a solar cell, a silicon plate about 0.2 mm thick is used, which is deposited on a later “sun-active” side or screen printed thin metal electrical plate. It has a conductor track. This conductor track must be reinforced by electroplating to a layer thickness of 1-20 μm. The reinforcing material can be copper, tin, silver or gold. The opposite side of the substrate is provided with a contact surface required for that, for example in the form of contact strips and / or contact windows, which is vapor-deposited or screen-printed on the “active to the sun” side. It is electrically connected to the electrical conductor track.

  FIG. 1 shows an apparatus, generally designated by reference numeral 1, which can reinforce a deposited conductor track of this type of silicon substrate. In FIG. 1, three silicon substrates are shown and denoted by reference numerals 2a, 2b and 2c. These silicon substrates 2a, 2b and 2c are guided through the electroplating bath liquid 4 by a roller transport system having a number of driven rollers 3a, 3b, 3c and 3d. The direction of transport is indicated by arrow 4. The liquid surface 15 of the electroplating bath liquid 14 is 0.1 to 10 mm above the silicon substrates 2a, 2b and 2c. Accordingly, the silicon substrates 2a, 2b and 2c are completely immersed in the bath liquid 14 when passing through the electroplating bath. In that case, the “active to the sun” side faces downward and the side with the contact surface of the silicon substrates 2a, 2b and 2c faces upward.

  A plate-shaped anode 5 extends along and below the movement paths of the silicon substrates 2a, 2b and 2c, and the anode is connected to a positive electrode of an electroplating current source (not shown). Since the reinforcing material is copper, tin or silver, a soluble consumed anode 5 can be used. However, in the case of a gold bath, it is operated with an insoluble anode 5.

  Counter rollers 7a, 7b, 7c and 7d are arranged on the sides of the silicon substrates 2a, 2b and 2c facing the transfer rollers 3a, 3b, 3c and 3d. These counter rollers 7a, 7b, 7c and 7d are used for two functions: for one, they push the silicon substrates 2a, 2b and 2c softly downwards, thereby the level of the bath liquid 14 15 below. On the other hand, the counter rollers 7a, 7b and 7c are used as contact devices, and by means of the contact devices, the silicon substrates 2a, 2b and 2c and accompanyingly vapor-deposited or screen-printed conductor paths are used in the usual way. , And can be electrically connected to the negative electrode of an electroplating current source (not shown).

  As can be seen in particular from FIG. 2, the installation 1 has two parallel “tracks”, and the silicon substrates 2 respectively arranged in the tracks can be guided through the treatment liquid 14. Each of these tracks has a number of transfer rollers 3, which face each other in pairs and are connected to each other by a shaft 6 within the pair. A lateral roller 20 having a conical shape is disposed outside the lateral side of the transfer roller 3, similarly to the shaft 6, or structurally integrated with the transfer roller 3. The lower side of the substrate 2 is placed on the transfer roller 3 on the edge side. The transfer roller 3 has an O-ring 21 that improves friction on the peripheral surface thereof.

  FIG. 2 further shows that a set of counter rollers 7 is associated with each “track” of the facility 1. Counter rollers 7 of different tracks at the same “height” in the transfer direction 4 roll on a common shaft 22 and in particular approximately in the middle between the two transfer rollers 3 on the upper side of the silicon substrate. It is mounted in an axial position so that it can. The shaft 22 is supported in the bearing 23 on both sides. The shaft is used not only to hold the counter roller 7 but also to supply current to it.

  The shaft 22 is made flexible by the choice of its material and by the choice of its geometry. That is, the shaft 22 can bend immediately upon receiving a small force. As a result, as shown in FIG. 2, the vertical positions of the two counter rollers 7 on the same shaft 22 do not need to be the same. For example, when the upper side of the silicon substrate 2 shown on the right in FIG. 2 is slightly higher than the upper side of the silicon substrate 2 shown on the left, the counter roller 7 shown on the right is subjected to some elastic deformation of the shaft 22. Can be displaced upward, and the counter roller 7 shown on the left continues to contact the upper side of the associated silicon substrate 2. In this way, even if the silicon substrates 2 are geometrically displaced with respect to each other, the silicon substrate 2 can be carefully guided through the bath solution 14, so that the breakage of the silicon substrate 2 is eliminated.

In the application field of interest here, the current to be guided to the silicon substrate 2 is relatively small, so a narrow cross section of the shaft 22 is quite sufficient to guide this current. For example, in the case of solar cell plates having dimensions of 180 × 80 mm having a surface which conducts approximately 0.25Dm ² is at a current density of 0.5A / dm ^2, unless transfer of current 0.125A Don't be. If the device 1 has, for example, six parallel tracks, it will be 0.75 A per axis 22. At this low current, a slight pressing force of the counter roller 7 is sufficient, which leads to a careful passage of the silicon substrate 2. If the shaft 22 is made of metal, in particular special steel, the diameter of the shaft 22 can be in the region between about 1 mm and about 4 mm.

  FIG. 3 shows a second embodiment of the present invention in a cross section corresponding to the cross section of FIG. The two embodiments are very similar to each other; therefore, the corresponding components in FIG. 3 are shown with the same reference numerals as in FIG. The only difference is that the two rolling on the same axis 22 on the edge side on the silicon substrate 102 rather than the only (central) counter roller 7 per “track” as in the embodiment of FIG. One counter roller 107, 107 'is provided. This embodiment is used in larger dimension silicon substrates 102 and prevents bending in its central region.

  A third embodiment of an apparatus 201 for strengthening a metal conductor track applied on a silicon substrate 202 by electroplating is the subject of FIGS. This third embodiment is also very similar to the two embodiments described above. Insofar as the parts in FIGS. 4 to 6 correspond to the parts of the embodiment of FIGS. 1 and 2, these parts are denoted by the same reference numerals plus 200.

  The formation of the two “tracks” of the transfer system having the transfer roller 203, the side guide rollers 220 and the shaft 206 connecting them together corresponds completely to that of the two embodiments described above. The difference is only in the method in which the counter roller 207 is held.

  The embodiment of FIGS. 4 to 6 is only as long as each track is associated with only one set of counter rollers 207 that roll about the center of the transfer roller 203 on the surface of the silicon substrate 202. And 2 are more similar to the second embodiment. However, the counter roller 207 is not directly coupled to the shaft 202 as in the two above-described embodiments. Rather, the counter roller is supported in the fork-shaped end region of the swing arm 240, and the end on the opposite side of the swing arm is rotatable or swingable about the shaft 222. It is attached. The shaft 222 may be stiff in this embodiment, and therefore need not be flexible to avoid excessive forces acting on the silicon substrate 202. As can be seen from the figure, the two counter rollers 207 can move vertically independently of each other under a suitable swinging movement about the shaft 222, so that the silicon substrate 202 and the device 201 can be moved. Enables a pressure force that is largely independent of the geometrical deviation within itself.

  The force with which the counter roller 207 is placed on the silicon substrate 202 is substantially determined by the weight of the swingable unit having the swing arm 240 and the counter roller 207 supported therein. The force can be adjusted by a counterweight in some cases.

FIG. 1 is a side view schematically showing an apparatus for electrically strengthening a metal conductor track applied on a silicon substrate. 2 is a vertical cross-sectional view of the apparatus of FIG. 1 perpendicular to the drawing plane. FIG. 3 is a cross-sectional view similar to FIG. 2, showing a second embodiment of this type of apparatus. FIG. 4 is a cross-sectional view similar to FIGS. 2 and 3 showing a third embodiment of this type of apparatus. FIG. 5 is a top view showing a part of the apparatus of FIG. FIG. 6 shows the details of the apparatus of FIGS. 4 and 5 in enlarged dimensions.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Processing apparatus 2 Silicon substrate 3 Drive roller (transfer apparatus)
4 Transfer direction 5 Anode 7 Counter roller (contact device, presser device)
14 Electroplating bath solution

Claims (5)

An apparatus for processing flat fragile substrates, particularly for the semiconductor and solar energy industries,
a) a processing chamber in which processing liquid can be supplied to the substrate;
b) a transfer device capable of guiding the substrate to pass horizontally through the processing chamber in a number of tracks parallel to each other;
c) Acts on the upwardly facing side of the substrate to prevent lifting from the transfer device, and has a connecting shaft extending over the plurality of tracks, and a number of pressing members are fixed to the shaft. At least one presser device;
In what has
d) The pressing device (7, 22; 107, 122; 207, 222) is movable as follows, that is, the individual pressing members (7; 107; 207) are movable in the vertical direction independently of each other. As a result, the substrate (2; 102; 202) is formed so as to be able to exert a pressure substantially independent of its thickness.
Equipment for processing flat, fragile substrates. The shaft (22; 122) to which the pressing member (7, 107) is attached is flexible, and in addition, an upward force is supplied by the individual pressing member (7; 107). in thinness that can flex elastically when are formed, and the pressing member (7; 107) said substrate; force acting against (2 102), of the substrate The processing apparatus according to claim 1, wherein the processing apparatus stays below a breaking limit.   The processing apparatus according to claim 1, wherein the pressing member (207) is fixed to a swing arm (240) swingable with respect to the shaft (222).   The pressing member (7; 107; 207) is simultaneously used as a contact member for supplying current to the substrate (2; 102; 202), and the shaft (22; 122; 222) is used as the pressing member. The processing apparatus according to claim 1, wherein the processing apparatus is formed as a current supply unit to (7; 107; 207).   The processing device according to claim 1, wherein the pressing member is a roller (7; 107; 207).

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