DE102018111868A1 - substrate carrier - Google Patents

Abstract

The present invention relates to a substrate carrier for receiving at least one substrate and for processing substrates in a plurality of successively passing substrate carrier processing continuous system, in particular a PECVD coating system for coating a plurality of rows and columns arranged on the substrate carrier solar wafer, wherein the substrate carrier a essentially two-dimensional grid has, wherein between profiles of the grid is in each case a partially open Substratnest formed for receiving a substrate. It is therefore the object of the present invention to propose a substrate carrier with good processing area utilization and at the same time high processing quality. The object is achieved by a substrate carrier in which the grating has a narrow edge section and / or a narrow rear edge profile viewed in a passage direction of the substrate carrier in the continuous system, wherein the edge profiles of the two-dimensional grid in front of an outer front edge of the substrate and extend to an outer rear substrate edge, and wherein the substrate carrier has at least one projecting from the two-dimensional grid in a third dimension and extending laterally along the front and / or rear edge profile shielding element.

Description

The present invention relates to a substrate support for receiving at least one substrate and for processing substrates in a continuous system, in particular a PECVD coating system for coating a plurality of arranged in rows and columns on the substrate carrier solar wafers, wherein the continuous system several substrate carriers pass through successively wherein the substrate carrier has a substantially two-dimensional grid, and wherein in each case a partially open Substratnest is formed for receiving a substrate between profiles of the grid.

Such substrate carriers are used, for example, in continuous systems for coating solar cells. On planar, approximately two-dimensional substrate carriers, in various embodiments, for example, 5 × 6 = 30 or 6 × 7 = 42 substrates are placed in the form of solar wafers. During operation of the continuous flow system for the production of coated substrates, a plurality of substrate carriers are traversed in succession through the continuous flow system. Various sections or individual chambers of the continuous system are regularly separated from one another by chamber valves, which are also referred to as gate valves, wherein the use of gate valves constructively requires a distance between two substrate carriers. In contrast, processing tools arranged in a processing chamber, for example plasma-assisted vapor deposition microwave plasma sources (PECVD), are operated continuously. If there are gaps between two substrate carriers, the processing tools continue to run.

The resources of the continuous system and the processing source are optimally utilized at a time only when substrates are being processed. However, if just wide edges of a substrate carrier or gaps between two substrate carriers pass by the processing tool, there is no immediate substrate processing for a short time. In order to limit the processing effect of the processing tool largely on the planned processing area, for example the front side of a solar wafer, despite the gap between two substrate applications with active processing tool, a certain minimum width of the substrate carrier at its front and rear edge is usually required. Substrate surfaces, for which no processing by the machining tool is provided, for example, the backs of solar wafers, however, should be shielded from the machining tool. In the case of edges which are too narrow, on the other hand, the processing effect can be encroached on the side of the substrate facing away from the machining tool and a quality reduction caused thereby. In practice, a compromise between a high system utilization for narrow edges of the substrate carrier and a high quality due to homogeneous substrate processing at wide margins of the substrate carrier is partially set, whereby a higher throughput of the continuous system is paid for with quality losses. For example, the front and back row of solar wafers are so inhomogeneously coated that they do not pass a subsequent quality test and must be classified as inferior products.

It is therefore the object of the present invention to propose a substrate carrier which enables a high throughput of the continuous-flow installation employing the substrate carrier while at the same time offering high quality of processing.

The object is achieved by a substrate carrier in which the grid has a front narrow edge profile and / or a narrow rear edge profile viewed in a direction of passage of the substrate carrier in the pass-through system, wherein the edge profiles of the two-dimensional grid in front of an outer front edge of the substrate and extend to an outer rear edge of the substrate, and wherein the substrate carrier has at least one of the two-dimensional grid, in particular in a third dimension projecting and extending laterally along the front and / or rear edge profile shielding element.

The terms front edge profile and rear edge profile resulting from the position of the substrate carrier in its intended use in a continuous system along the passage direction made therein. The substrate carrier to which the invention relates is not a closed plate but a perforated grid in which the substrate nests are not closed but have openings between profiles of the grid, so that both sides of the disc-shaped substrates can be processed with the substrate carrier. Only at small support points or bearing surfaces no or reduced substrate processing takes place on the resting or more generally on the recorded substrate side. The substrate carrier can have, in addition to the grid, further components, for example lateral rails, which are supported and driven by rollers of the continuous system. Between the individual adjacent substrate nests, the profiles of the grid can be thin rods. On the edge of the substrate carrier, however, the profiles have larger widths, so that the edge profiles of the grid can also be referred to as surface areas or edge profiles of the grid. The term grid also includes the case that the Substrate carrier is formed for only a single, very large substrate and is actually an existing only of edge profiles frame. The front edge profile and the rear edge profile of the substrate carrier according to the invention are narrower in a plan view than in conventional substrate applications.

The narrower edge profiles result in greater plant throughput because the ratio of processed substrate surfaces to other areas adjacent to the substrates is increased. Due to the narrower edges, a higher throughput is realized, so it can be processed more substrates per unit time. For example, instead of a conventional 6 × 7 substrate support, a 7 × 7 substrate support according to the invention can be used in the same continuous installation and the same transport parameters, resulting in a correspondingly increased throughput.

The narrow edge profiles would lead to quality losses by Randumgriffe in conventional substrate applications. For example, a silicon nitride coating carried out on the front side would not only coat the front of the solar wafers, but also the backsides on the front edge of the front row substrates on the substrate support and also the back edges of the back row substrates on the substrate support. The intended editing page is hereby referred to as a front page for illustration, although this term may be inaccurate in other respects. The same applies to the term back. The unwanted coating of partial surfaces of the backs of the substrates can in various cases lead to functional and / or aesthetic quality losses. The substrate carrier according to the invention has at least one shielding element on the front or the rear edge profile and thereby enables substrate processing which, despite narrow edge profiles, satisfies existing quality specifications. There may also be two shielding elements, for example one on the front and one on the rear edge profile, or more than two shielding elements.

Two shielding elements may also be mounted on the front or the rear edge profile on both sides of the two-dimensional grid, for example in the case of a horizontally used substrate carrier on its upper side and on its underside. The substrate carrier according to the invention can also have at its front and rear edge profile in each case two opposing shielding on both sides of the grid so a total of four shielding. For example, the shielding member may be mounted from above on the unprocessed lower side in a one-sided processing using the substrate carrier. With an arrangement of the shielding element on the actually unprocessed side of the substrate carrier, the influence of the shielding element on the processing result on the processing side is minimal. Two mutually opposite shielding elements (for example, above and below a front edge profile) may be arranged next to the substrate carrier to avoid Randumgriffen at two-sided processing processes and / or the spatial distribution of Abschirmeffektes with limited passage widths.

A first row of substrate nests of the substrate carrier according to the invention may be covered by a holey fabric in addition to the shielding element. The provision of the holey fabric may be a means for further reducing the edge hemming and further increasing the quality of the machining process adjacent the front and / or rear edge profile of the substrate carrier. The holey tissue shields on the one hand diagonally arriving machining particles or gas molecules and gas ions. In the case of ions, electrostatic charges and repulsive forces may exacerbate the shielding effect. On the other hand, the fabric is substantially transparent to thermal radiation directed across the substrate support so that even heat distribution on the substrate support is not affected by the fabric. The homogeneous heat distribution contributes to a uniform substrate processing and a high substrate quality.

Pieces of tissue can cover the entire front and the entire back row of substrate nests. However, a first row of substrate nests next to the shielding element can also be only partially covered by a holey fabric. The width of the fabric cover can be adapted to the width of the Bearbeitungsumgriffes, this being dependent, for example, on average free path lengths and lifetimes of machining particles. With only partial coverage, on the one hand, the desired shielding effect is achieved and, on the other hand, the thermal influence of the fabric on the machining is minimized.

In a very specific embodiment, a first row of substrate nests is covered next to the shielding with a quarter of its width from the tissue. The width of one-quarter is the result of an optimization that takes due account of the conflicting goals of uniform substrate heating and good shielding. The fabric may be a mesh of stainless steel wire. Stainless steel is a cost-effective, durable and chemically resistant material. It is also possible to use other materials which have existing process engineering, meet mechanical and chemical requirements, such as other metals or carbon fiber materials (CFRP).

A first row of substrate nests may be at least partially covered by a plate in addition to the shielding element. Full or partial coverage of substrate nests with a plate is an alternative to covering with a tissue. Advantageous characteristics of the plate are complete avoidance of gas passage through the plate and good mechanical stability. With a suitable material selection and dimensioning of the plate, a sufficiently homogeneous heating of the substrate carrier is achieved despite the plate. In one embodiment, the plate is a 0.5 mm thick diaphragm made of a carbon fiber composite (CFRP). CFRP is a stable material that also transmits heat radiation well.

The reinforcing element may be a strip with a triangular cross-section and with decreasing thickness in the direction of the substrate. The reinforcing element may also be referred to as a spoiler. With the simple triangular cross-sectional shape, the reinforcing element is easy to manufacture and well adapted to the existing tasks. Near the substrate, the thickness of the shielding is small, so that there substrate processing is hardly disturbed. At the edge of the substrate carrier, the thickness is greater, so that correspondingly the shielding effect at the edge of the substrate carrier is large. Such a reinforcing element is 5 mm high (in the third dimension) and between 5 mm and 10 mm wide in some embodiments. The narrow edge profile of the substrate carrier according to the invention may be 2 cm narrow. Both edge profiles, the front and the rear, can be the same width. In some embodiments, for example, in particles incident obliquely from the machining tool but also different optimized widths front and rear can be present.

The shielding element can also be movably mounted on the grid. With a drive mechanism cooperating with the movable shielding element, the shielding element can be brought, for example, next to a chamber valve into a position not projecting along the direction of passage and into a protruding or otherwise better shielding position in processing positions. In some embodiments, the shield is foldably and / or slidably mounted to the grid.

The various described options of the invention may be combined at the discretion of one skilled in the art without departing from the scope of the disclosure. Randomly described options must not be misinterpreted as a mandatory combination of features.

• 1 einen erfindungsgemäßen Substratträger in Draufsicht;
• 2 einen erfindungsgemäßen Substratträger in einer Querschnittsansicht;
• 3 einen erfindungsgemäßen Substratträger mit Gewebe-Abdeckungen und
• 4 einen erfindungsgemäßen Substratträger mit Platten-Abdeckungen von Teilen von Substratnestern.

The present invention will be further explained below with reference to figures; show it:

• 1 a substrate carrier according to the invention in plan view;
• 2 a substrate carrier according to the invention in a cross-sectional view;
• 3 a substrate carrier according to the invention with tissue covers and
• 4 a substrate carrier according to the invention with plate covers of parts of substrate nests.

figure 1 schematically shows a plan view of a substrate carrier according to the invention 1 of which in this view only the grate 2 is visible. profiles 3 of the grate 2 define substrate nests 4 in which substrates are receivable, so that a substrate carrier loaded with substrates 1 can be processed in the pass-through facility as a unit. Between two adjacent substrate nests 4 are the profiles 3 thinner than the edge profiles 5 . 6 at the edge of the substrate carrier 1 , For a high productivity as many substrates as possible 9 on the substrate carrier 1 Find a place. In the case of the substrate carrier according to the invention, these are along the passage direction 7 front edge profile 5 and the rear edge profile 6 narrower than comparable conventional, not shown substrate carriers 1 , As a result, ultimately more substrates per unit time can be processed or the throughput of the continuous system is greater when using the substrate carrier according to the invention than with conventional substrate carriers.

Like reference numerals designate the same or similar objects in different figures. Descriptions of a figure are also to be considered in the descriptions of the other figures for their understanding.

In 2 is the substrate carrier 1 in a non-scale sketch of a cross section along the direction of passage 7 shown. As compared with 1 becomes clear, are in 2 the individual profiles 3 and the edge profiles 5 . 6 in relation to the width of the substrates non-scale, but too broadly sketched to the supports of the substrates in the substrate nests 4 to show better. In the illustrated substrate carrier 1 it is a substrate carrier intended for horizontal use 1 in which the individual substrates 9 on the grid 2 rest and lie by gravity in the recessed substrate pockets. Details of various possible substrate supports in The substrate nests are not an object of the present invention and are therefore not further described in the. In other unrepresented variants, the substrate carriers are designed for vertical or other non-horizontal orientations and are provided with suitable substrate holders. In the cross section of 2 are the in 1 concealed shielding elements 8th visible. The grate 2 is an approximately two-dimensional body, because its in 2 visible thickness is much smaller than the in 1 visible to other dimensions. The shielding elements 8th are not in the plane of the grid 2 but they extend out of this plane. In the illustrated embodiment is below the front edge profile 5 and below the rear edge profile 6 in each case a shielding element 8th attached. In the illustrated embodiment, the substrate carrier 1 a metallic substrate carrier 1 namely one made of stainless steel. The also made of a stainless steel shielding 8th are welded. In non-illustrated embodiments, the shielding elements 8th integral as components of the grid 2 manufactured. The main task of the shielding elements 8th is the Umgriff a processing medium from one side of the substrate carrier 1 To reduce the other side of the same, so to reduce a grip of the machining tool from top to bottom or from bottom to top. The desired effect is on the one hand by the longer path, the machining particles to the shielding 8th have to travel around. On the other hand, the effect is also due to a change in flow due to the shielding 8th supported. Because of their influence on flows in a processing chamber of a continuous system, the shielding elements 8th partly also referred to as spoiler.

The processing chamber is, for example, a PECVD deposition chamber for dielectric, semiconductive or conductive layers. The processing chamber may also be another chamber for layer production, surface treatment or Schichtabtragen. The movement of machining particles in the processing chamber depends on various factors. An important factor is the processing pressure used, because the smaller the gas pressure in a vacuum, the lower the number of particles per unit volume, and the greater the mean free path lengths that particles can travel before colliding with other particles. Other important parameters are set flow rates, flow directions, chemical reactivities, directional characteristics of plasma sources, and other plant-specific quantities.

3 shows a substrate carrier according to the invention 1' in which the front, parallel to the front edge profile 5 extending row of substrate nests 4 and the rear, parallel to the rear edge profile 6 extending row of substrate nests 4 each on the bottom through a holey fabric 10 is covered. The holey fabric is shown in sections in addition to the cross section in a plan view. If, in one exemplary embodiment, the substrate front sides are coated with a SiNx layer from above by PECVD and heated from below by radiant heaters, then the coating plasma is already attracted to the underside of the substrate carrier by the shielding elements 8th reduced. The front and back strips of the back of the substrate carrier 1' , on which in the areas of the front and the back row of substrate nests 4 by the encirclement of the coating plasma in the coating chamber also takes place a backside coating, here are through the strips of holey fabric 10 additionally screened so that the backside coating of the substrates 9 even further reduced. Since the tissues barely represent a barrier to radiant heat from below, the substrates in the front and the back row are heated sufficiently uniformly. The result is largely a one-sided coating from above with good homogeneity and almost no coating from below. In the illustrated embodiment, the strips cover holes in the fabric 10 each from a whole substrate width. In other embodiments, the tissue is 10 narrower, eg a quarter substrate width narrow, or wider than the substrate width. The tissue 10 In the illustrated embodiment, a stainless steel wire mesh, which is welded to a stainless steel mesh. In other embodiments, other materials and other fastening methods, such as screws, rivets or gluing are used.

In 4 is a substrate carrier according to the invention 1" shown in a plan view, in which at the bottom of the grid 3 strip-shaped plates 11 cause additional shielding, similar to the fabric strips in 3 , The plates are in the illustrated embodiment, 0.5 mm thick, a quarter of the width of the substrate wide CFRP plates, which are glued to a CFK substrate carrier.

LIST OF REFERENCE NUMBERS

1, 1 ', 1 "

substrate carrier

2

grating

3

Profiles of the gridiron

4

substrate nest

5

front edge profile

6

rear edge profile

7

Throughput direction

8th

shielding

9

substratum

10

holey fabric

11

plate

Claims (12)

Substrate carrier (1, 1 ', 1 ") for receiving a plurality of substrates (9) and for processing the substrates (9) on the substrate carrier (1) in a continuous system, in particular a PECVD coating system for coating several in rows and in columns Solar wafer arranged on the substrate carrier (1), the continuous system passing through a plurality of substrate carriers (1) in succession, the substrate carrier (1) having a substantially two-dimensional grid (2), and wherein between profiles (3) of the grid grid (2) each a partially open Substratnest (4) for receiving a substrate (9) is formed, characterized in that the grating (2), viewed in a passage direction (7) of the substrate carrier (1) in the continuous system, front narrow edge profile (5 ) and / or a narrow rear edge profile (6), wherein the edge profiles (5, 6) of the two-dimensional grid (2) along the passage direction (7) in front of an outer front n substrate edge and after an outer rear substrate edge, and that the substrate carrier (1) at least one of the two-dimensional grid (2) in particular in a third dimension projecting and laterally along the front and / or rear edge profile (5, 6) extending shielding (8). Substrate carrier after Claim 1 , characterized in that the substrate carrier has at its front and / or rear edge profile (5, 6) in each case two mutually opposite shielding elements (8) on both sides of the grid (2). Substrate carrier after Claim 1 , characterized in that a first row of substrate nests (4) adjacent to the shielding element (8) is covered by a holey fabric (10). Substrate carrier after Claim 3 , characterized in that a first row of substrate nests (4) next to the shielding element (8) is covered by a quarter of its width from the fabric (10). Substrate carrier after Claim 3 or 4 , characterized in that the fabric (10) is a mesh of stainless steel wire. Substrate carrier after Claim 1 , characterized in that a first row of substrate nests (4) adjacent to the shielding element (8) is at least partially covered by a plate (11). Substrate carrier after Claim 6 , characterized in that the plate (11) is a 0.5 mm thick diaphragm made of a carbon fiber plastic composite (CFRP). Substrate carrier after Claim 1 , characterized in that the shielding element (8) is a strip of triangular cross-section and in the direction of the substrate (9) of decreasing thickness. Substrate carrier after Claim 8 , characterized in that the shielding element (8) is 5 mm high and between 5 mm and 10 mm wide. Substrate carrier after Claim 1 , characterized in that the narrow edge profile (5, 6) is 2cm narrow. Substrate carrier after Claim 1 , Characterized in that the screening element (8) is movably mounted on the grate (2). Substrate carrier after Claim 11 , characterized in that the shielding element (8) on the grate (2) is mounted hinged and / or displaceable.

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