TW201320222A - Solar cell process carrier - Google Patents

Abstract

A process carrier for solar cells includes a pair of parallel spaced apart endwalls with a plurality of cell supports configured as rods extending therebetween. Each cell support includes a post with a plurality of teeth extending outwardly therefrom defining slots for receiving solar cells. Each adjacent pair of teeth on a rod, along with corresponding pairs of teeth on each of the other rods, define a slot. Means for shifting each solar cell can be provided to shift the solar cells in the slots so that they are predominantly towards one side of the slots or are tilted in the slots or are otherwise in a more constrained position. This can create a larger open region for flow of processing fluid on one side of each portion of the solar cell that is within a slot at a particular rod. Fluid flow non-uniformities therefore can be controlled to occur only on one side of each portion within the slot, which reduces the amount of boat marks occurring on the solar cell and can position the remaining boat marks at more preferable locations, for example on a nonactive side of the cell.

Description

Solar cell process carrier

The invention relates to processing substrates. More particularly, the present invention relates to a process carrier suitable for holding a silicon wafer (particularly, a solar cell wafer) during processing of a processing bath.

As a part of the processing of the germanium wafer, the wafer is immersed in various solutions in a carrier often referred to as a boat. See, for example, the prior art FIG. 1a of US Pat. Such substrate process carrier 20 has a pair of end walls 22 and 24 with a plurality of tubular rails 30, and the tubular rails 30 have integral teeth 32 for engaging a substrate extending between the end walls. The teeth extend inwardly from the tubular rail toward the substrate 34. Such a process boat can use a polymer like a fluoropolymer to resist the corrosive process fluid used in the processing steps. The reinforcing member 36 can be embedded in the elongated tubular rail, such as by welding the tubular polymeric rail of the carrier to the end wall.

The specific treatment of solar cells (also known as photovoltaic cells) has traditionally used such boats or carriers. Substrate carriers (including solar cell process carriers) have contact areas on the teeth on the tracks to support and constrain the substrate. It is believed that the minimization of these contact areas is advantageous. There are ways in which these contact areas can cause non-uniformities in the action of fluids on these areas. Process fluid will adhere to the carrier on these areas, and After removing the carrier and substrate from its fluid, the carrier engages the cells at these regions, where the contact time of the fluid with the substrate is prolonged, thereby causing non-uniform interaction of fluids in these regions. Sex. In addition, when the carrier and substrate are immersed, the contact areas may also reduce fluid flow on the surface of the substrate at the contact area, causing further non-uniformity in its processing.

Furthermore, the proximity of the support rails causes disruption and interference of fluid flow at the edges of the substrate (especially the battery), which can affect further non-uniformity of fluid handling. These inhomogeneities can result in processing defects that are often visible along the edge of the solar cell and are referred to as "boat marks." The teeth on each of the support rails have the same spacing, i.e., they are aligned with corresponding teeth on the other rails. Conventionally, the teeth are uniformly formed between all the rails and are symmetrical with respect to each side of each tooth, and each side of each tooth defines a portion of the slot for the solar cell. . Conventionally, the contact areas, i.e., the spacing between corresponding adjacent pairs of teeth, are uniform around the solar cell, thus causing wafer traces to appear on each of the support rails on both sides of the solar cell. It is most desirable to reduce the likelihood of etch defects like boat traces through the vehicle design while complying with informal industry standardization (especially rail position).

A process carrier for a solar cell includes a pair of parallel spaced end walls having a plurality of battery supports disposed therebetween to be rods. Each The battery support includes a post having a plurality of teeth extending outward therefrom, and the plurality of teeth define a slot for receiving the solar cell. Each adjacent pair of teeth on the rod, together with the corresponding pair of teeth on each of the other rods, define a slot. Means may be provided for displacing each solar cell to displace the solar cells in the slots such that they are either significantly toward one side of the slots, or are inclined in the slots, or are in a more constrained manner position. Thus, for the flow of the treatment fluid, a larger open area is created on one side of each of the solar cells in the tank on the particular rod. Therefore, the fluid flow non-uniformity can be controlled so that it only occurs on one side of each part of the groove, so that the number of boat traces occurring on the solar cell can be reduced, and the remaining boat traces can be positioned at Preferably, for example, on the non-active side of the battery.

In a particular embodiment of the invention, the teeth are asymmetric such that for each slot on each rod, between the teeth, and between the opposite sides of each of the solar cells The facing relationship is different, thus providing different process fluid flow characteristics on each side of the rod.

A feature and advantage of a particular embodiment of the invention is that the upper support bar has a different spacing or alignment than the lower support bar and the side support bar. Therefore, the teeth of the upper support rod are offset from the teeth of the other support rods, thus causing the solar cell to be displaced to one side of the groove. This results in minimal traces of boating on one side of the solar cell.

Another feature and advantage of a specific embodiment of the present invention is that the support rod has unevenness The uniform teeth, for example, have a first side of each tooth having an angle greater than the other side, including a plurality of angles or a curved profile, and the second side of each tooth is generally vertical. This applies to the alignment of the mobile battery to one side of the slot, thus having a larger area for fluid flow on one side of the solar cell, resulting in a minimum of boating marks on that side.

Another feature and advantage of a particular embodiment of the invention is that the upper support bar has a helical cam on its end portion that is inserted into the end wall of the carrier. When the upper support bar is inserted into the carrier, it can rotate along the helical cam, thus causing the teeth of the upper support bar to be offset from the teeth of the other support bars. This causes the solar cells to be displaced or tilted to one side of the respective slots such that a minimum of boating marks are formed at a particular location on one side of the solar cell.

Another feature and advantage of a particular embodiment of the present invention is that the upper support bar has a plurality of teeth that are rotatable at an angle relative to an end portion of the support bar, or an end portion of the support bar and a post. The rotation of the teeth causes the teeth of the upper support rod to be offset from the teeth of the other support rods, thereby moving the battery to one side of the slot. Therefore, a minimum of boat traces are formed on one side of the solar cell.

Although specific embodiments are described herein in the context of process carriers for solar cells, the configurations herein are also intended for use with other silicon wafer process carriers, and carriers for substrates other than germanium.

2 depicts a process carrier 100 for holding a substrate during a process immersion processing substrate (particularly, a solar cell substrate) 102. Usually, when Insert and withdraw solar cells when they are in a vertical position and the battery is horizontal. When immersed in the process fluid, the carrier is typically in a horizontal position as shown in FIG.

The process carrier 100 includes a pair of parallel spaced end walls having a plurality of battery supports 104 extending therebetween for configuration into rails, and more particularly rods. The substrate support bar includes: a lower support rail or rod 106 on the bottom side of the process carrier 100 (relative to the horizontal position of the carrier during processing), a side support rail configured with rails or rods on each side of the carrier 100 108, and an upper support rail 110 disposed on the top side of the carrier 100 as a rod. The end wall 104 can include a plurality of receiving apertures 112 for receiving and aligning the substrate support bars. Each of the substrate support rails or rods is defined by a post 113 having a plurality of spaced apart teeth 114, and the plurality of spaced apart teeth 114 define a slot for holding the battery or substrate 102.

FIG. 3 depicts the upper support bar 110 and the lower support bar 106 supporting the solar cell substrate 102. A plurality of teeth 114 can extend axially along each of the support rods. The solar cell substrate 102 can be inserted into the process carrier into the slots 122 defined between the spaced apart teeth 114 of the battery support bars to rest against the contact surfaces 116 of the teeth. The substrate 102 can be stacked in an axially spaced relationship defined by a plurality of teeth 114. Alignment and configuration of the various types of teeth and supports that can be used in the specific examples of the present invention are described in PCT Application No. PCT/US2011/026, the entire disclosure of which is incorporated herein by reference. Also, see PCT/US2012/042749 and the Provisional Application (US) No. 61/497,371, which is incorporated herein by reference. Rails; incorporated herein by reference, and such applications describe suitable attachment means for rail-to-end walls.

Referring again to FIG. 3, it can be seen that the upper support bar 106 and its associated teeth 114 can have an off-set pitch for the teeth 114 of the lower support bar 110. Although not depicted, the side support bars 108 can have the same spacing as the lower support bars 110. Thus, each end of the solar cell substrate 12 is displaced toward one side of its respective groove 122, and a slope or inclination of the solar cell substrate 102 can be generated. In another option, the solar cell substrate 102 as a whole may extend vertically and horizontally between the support rods. Thus, in the region 108 on one side of the solar cell substrate 102, a closer contact is made between the solar cell substrate 102 and the teeth 114, and on the other side of the solar cell substrate 102, the teeth 114 and the solar energy A larger, more open region 120 is created between the battery substrates 102. This results in a relatively large non-uniformity of fluid flow near region 118, but provides minimal non-uniformity near region 120. In this regard, at each of the support bars, a boat trace is generated only on one side of the solar cell substrate 102.

4a-4f depict various embodiments of the present invention in which the solar cell substrate 102 is aligned within the slot 122 by virtue of the design of the teeth 114 rather than the distance between the support bars. Figures 4a and 4b show a specific example in which the teeth 114 have different angles on their first side 124 and second side 126. Thus, a larger area 120 is created between the solar cell substrate 102 and the first side 124, and a between the solar cell substrate 102 and the second side 126 is created. The smaller area 118 results in the same effect as described above, wherein the unevenness and associated boating traces are minimized on one side adjacent to the larger area 120. Figures 4c and 4d depict another embodiment in which the first side 124 of the tooth 114 is provided with multiple angles relative to the generally perpendicular second side 124 that produces the smaller region 118. A larger area 120 of at least the boat trace. Yet another embodiment is depicted in Figures 4e and 4f, which utilizes a first side 124 of the tooth 114 having a curved profile to create a larger area 120, and a second, substantially vertical side 126 to produce a smaller Area 118. In one embodiment, the teeth 114 in each of the lower support bar 106, the side support bar 108, and the upper support bar 110 can have the same tooth profile. In another embodiment, only the teeth 114 in the upper support bar 106 have an uneven configuration.

Referring now to Figures 5a and 5b, another embodiment of the present invention transforms the alignment of the solar cells with a movable (in this case, rotatable) upper support bar or rail 110. In one embodiment, the support rod 110 can use standard symmetrical teeth 114. The support bar 110 can include a helical cam 132 on one or both of its end portions 130. When the support rod 110 is inserted into the receiving hole 112 of the end wall 104 as shown in FIG. 2, it can be rotated in the hole 112 via the cam 132, and the tooth 114 of the support rod 110 is offset relative to the other support rods. Alignment. This allows the solar cell substrate inserted into the carrier to be displaced to one side of the slots to provide minimal non-uniformity of fluid flow as described above, and to be provided at the support rod at one of each solar cell Final result on the side Boat boat traces.

Figures 6a-6c illustrate an upper support rail or rod 110 that can be used in a carrier for another embodiment of the present invention. The teeth 114 of the support rod 110 can be rotated at an angle 134 to offset the teeth of the other support rods to displace the solar cells to position them toward one side of the slot 12. In one embodiment, the post 113 is rotated with the teeth 114 relative to the end portion 130 of the support bar 110 that is inserted into the receiving aperture 112 of the end wall 104 of the carrier 100. In another embodiment, only the teeth 114 are rotated, and they are rotated relative to both the strut 113 and the end portion 130. The reinforcing member 131 can provide enhanced rigidity to the rail, and a base can be provided when the outer sleeve 133 having teeth rotates in a particular embodiment instead of rotating the entire rail.

Referring to Figures 7a and 7b, the respective strip slots 140 defining the integral slots 144 before and after the displacement are produced at the uppermost strip slots 146. The dashed line in Fig. 7b indicates the original position of the teeth and the strip grooves before the displacement, and the strip teeth 150 in the middle thereof are schematically shown as being curved. The right side teeth 156 of the middle and upper rods are in very tightly facing engagement and may be in contact with the battery. The lower, middle right strip teeth 160 are not as tight as they are facing the battery. Position the battery to the left of the upper rod. In this configuration, for the upper middle strip, it is expected that there will be a boat trace on the right edge of the battery, but not on the left edge of the battery. Also, it is expected that there will be a trace of the boat on the upper left side of the upper groove.

Although describing the process load for immersing the solar cell in the process immersion liquid Yes, however, it should be noted that the support members described herein may also be used in transporting the carrier and any other type of container for supporting the solar cell substrate. Likewise, although described with respect to solar cells, the invention can be used with substrates of any other type, such as semiconductor wafers. The present invention can be assembled by partially welding together shaped tubular polymer (e.g., fluoropolymer) rails and welding them to the end walls to insert a rigid insert into the tubular member. For a suitable structural detail, see U.S. Patent No. 4,872,554, incorporated herein by reference.

The present invention may be embodied in other specific forms without departing from the spirit and scope of the invention. Therefore, the specific examples are to be considered in all respects as illustrative and not

Related applications:

The present application claims the benefit of U.S. Provisional Patent Application Serial No. 61/500,529, filed on Jun. 23, 2011, the entire disclosure of which is incorporated herein by reference.

20‧‧‧Substrate process carrier

22‧‧‧End wall

24‧‧‧End wall

30‧‧‧ tubular rail

32‧‧‧ teeth

34‧‧‧Substrate

36‧‧‧Strengthened components

100‧‧‧(process) vehicle

102‧‧‧(Solar cell) substrate; battery

104‧‧‧End wall

106‧‧‧(bottom) support rail; (bottom) support rod

108‧‧‧(side) support rail; (side) support rod

110‧‧‧(top) support rail; (top) support rod

112‧‧‧ accommodating holes

113‧‧‧ pillar

114‧‧‧ teeth

116‧‧‧Contact surface

118‧‧ (smaller) area

120‧‧ (larger, more open) area

122‧‧‧ slot

124‧‧‧ first side

126‧‧‧ second side

130‧‧‧ (support rod) end section

131‧‧‧Reinforcement components

132‧‧‧ spiral cam

133‧‧‧(outer) sleeve

134‧‧ (rotation) angle

140‧‧‧(strip) slot

144‧‧ (integral) slot

146‧‧‧(top, strip) slot

150‧‧‧ (middle, strip) teeth

156‧‧‧ (right) teeth

160‧‧‧ (lower, middle) (right, strip) teeth

Figure 1a is a prior art substrate process carrier.

Figure 1b is a cross-sectional view of the rail base portion and teeth of the prior art carrier of Figure 1a.

2 is a perspective view of a solar cell process carrier of a specific example of the present invention.

3 is a solar cell supporting a solar cell according to a specific example of the present invention; Schematic diagram of the process carrier.

Fig. 4a is a partial view of a solar cell support rod of a specific example of the present invention.

Figure 4b is a partial view of the solar cell support rod of Figure 4a.

Figure 4c is a partial view of a solar cell support rod of a specific example of the present invention.

Figure 4d is a partial view of the solar cell support rod of Figure 4a.

Figure 4e is a partial view of a solar cell support rod of a specific example of the present invention.

Figure 4f is a partial view of the solar cell support rod of Figure 4a.

Fig. 5a is a partial view of a solar cell support rod of a specific example of the present invention.

Figure 5b is a partial view of the solar cell support rod of Figure 5a.

Fig. 6a is a side view of a solar cell support rod of a specific example of the present invention.

Figure 6b is an opposite side view of the solar cell support rod of Figure 6a.

Figure 6c is a cross-sectional view of the solar cell support rod taken along line 6c-6c of Figure 6b.

Figure 7a is a schematic cross-sectional view taken along line 7-7 of Figure 2.

Figure 7b is a schematic cross-sectional view of Figure 7a with wafer displacement provided by the movement of the upper trench.

110‧‧‧(top) support rail; (top) support rod

113‧‧‧ pillar

114‧‧‧ teeth

122‧‧‧ slot

130‧‧‧ (support rod) end section

134‧‧ (rotation) angle

Claims (21)

A method of processing a substrate and controlling process traces produced on the solar cell substrate during processing, the method comprising: inserting a plurality of solar cell substrates into a substrate crystal having a plurality of vertical grooves defined by a plurality of toothed tracks In the boat, thereby providing a plurality of aligned arrays of solar cell substrates; the movable track of the teeth is mounted in the substrate boat, and the teeth of the movable rails are arranged in the solar cell substrate of the batch alignment array Mutual engagement; all of the solar cell substrates in the batch of solar cell substrate arrays are tilted in a common direction in their respective grooves via the intermeshing teeth of the upper rail; and the substrate crystal having the inclined solar cells The boat is immersed in the process immersion liquid. The method of claim 1, wherein the step of tilting all of the solar cell substrates in the array of solar cell substrates is achieved by rotation of the movable rails, and the teeth are oriented in a common direction Push each solar cell substrate. A method according to any one of the preceding claims, wherein the step of tilting all of the solar cell substrates is achieved by camming of the teeth, the teeth having a helical cam surface. The method of any of the preceding claims, wherein the step of tilting all of the solar cell substrates is achieved by axial movement of the movable rails in the common direction. The method of claim 4, wherein the axial movement is achieved by engagement of a helical surface, and the engagement of the helical surface acts as the movable rail and an end wall supporting the upper rail. One part of the meshing. A substrate process carrier having a pair of end walls supporting a plurality of toothed rails, and the toothed rails define a plurality of slots for holding a plurality of arrays of solar cell substrates, the plurality of slots Each of the slots of at least one of the toothed rails has a first side and a second side, and each side is defined by teeth protruding from the toothed rail; the teeth present in the substrate in the slots The facing surface, and wherein the dentations are configured such that the facing surfaces are different on each of the first side and the second side of each slot. The substrate process carrier of claim 6, wherein the trough is configured to provide a first position of each substrate in each slot when a plurality of substrates are loaded into the slots, and At least one of the toothed rails is movable, and a tilted state is applied to each of the substrates in each slot to place each substrate in a second position, the second position being A position is tilted out. A substrate process carrier according to any of the preceding claims, wherein each toothed rail has a rigid reinforcing member inserted therein. A substrate process carrier having a pair of end walls supporting a plurality of toothed rails, the toothed rails defining a plurality of slots for holding a plurality of solar cell substrate arrays; the solar cell Process carrier has The means of minimizing the processing traces caused by the toothed rails. A substrate process carrier according to any one of the preceding claims, wherein, for at least one toothed rail having a plurality of slots, each slot has a tip end, and one side of the slot presents a different side than the other The side surface of one side is a side surface that is steep and extends from the tip end. The substrate process carrier of claim 9, wherein the means for minimizing the treatment trace comprises at least one of the following groups: an axially movable toothed rail for Tilting the substrate in the slot; a rotatable toothed rail having a plurality of teeth, and when rotating the rotatable toothed rail, the teeth tilt the substrate in the slot; having a plurality of teeth a rotatable toothed rail having a helical cam surface for tilting the substrate when the rotatable toothed rail is rotated; and a plurality of slots defined by a plurality of tooth portions, Thus, each slot has a steep side surface that extends to a tip end and a less steep side surface that extends to the tip end. A method of loading a substrate into a carrier, comprising: inserting a plurality of solar cell substrates into a substrate wafer boat having a plurality of vertical slots defined by a plurality of toothed rails, thereby providing a plurality of alignments An array of solar cell substrates; a toothed movable rail is mounted in the substrate boat, and a plurality of teeth of the movable rail are interdigitated in the array of aligned solar cell substrates And the intermeshing teeth via the upper rails cause all of the solar cell substrates in the batch of solar cell substrate arrays to be displaced in a common direction in their respective slots. The method of claim 12, wherein the step of displacing all of the solar cell substrates is achieved by rotation of the toothed movable rail such that a helical cam surface is axially moved to The toothed movable rail. The method of claim 12, wherein the step of displacing all of the solar cell substrates is achieved by rotation of the toothed movable rail such that a spiral cam surface on each of the teeth The respective substrates are pushed in the common direction. A substrate process carrier having a pair of end walls to which a plurality of toothed rails are immovably fixed and to which at least one movable toothed rail is attached; The toothed rail defines a plurality of slots for holding a plurality of arrays of solar cell substrates; the movable toothed rail has a plurality of teeth, and when moving the movable toothed rail, the The teeth will shift the batch of solar cell substrate arrays in a common direction. The substrate process carrier of claim 15 wherein the movable toothed rail is removable from the end walls, allowing the substrate to be inserted into and removed from the slot. A substrate process carrier having a pair of end walls for a plurality of rails Immovably fixed thereto, and attaching at least one movable rail to the pair of end walls; the fixed rails defining a plurality of slots for holding a plurality of arrays of solar cell substrates; the movable The rails are engageable with the array of solar cell substrates to displace the substrates in a common direction as the movable rail is moved. The substrate process carrier of claim 17, wherein the movable rail is rotatably fixed to the pair of end walls and has a plurality of spiral surfaces, and the spiral surfaces are engaged with the substrate. And the substrates are displaced in a common direction while rotating the rail. The substrate process carrier of claim 17, wherein the movable rail is attachable to and detachable from the end walls, and when attached to the end walls, The movable rails engage the substrates in the slots and move the substrates in a common direction. The substrate process carrier of claim 19, wherein the rail applies a tilted state to the substrate when the substrate is moved by the movable rail. The substrate process carrier of claim 17, wherein the movable rail comprises a plurality of teeth movable on the rail base, and the teeth are movable to shift the substrate in the slot.