EP3472859A1

EP3472859A1 - Substrate support element for a support rack

Info

Publication number: EP3472859A1
Application number: EP17727519.5A
Authority: EP
Inventors: Thomas Piela; Larissa Von Riewel
Original assignee: Heraeus Noblelight GmbH
Current assignee: Heraeus Noblelight GmbH
Priority date: 2016-06-20
Filing date: 2017-05-22
Publication date: 2019-04-24
Also published as: WO2017220272A1; US20190333787A1; CN109314073A; JP2019525496A; DE102016111236A1; TW201801234A; TWI667727B; KR20190019132A

Abstract

Known substrate support elements for a support rack for the thermal treatment of a substrate have a supporting surface for the substrate. The aim of the invention is to, starting from this point, specify a substrate support element which permits the most homogenous heating of the substrate possible. This aim is achieved, according to the invention, in that the substrate support element is a composite element which comprises a first composite component and a second composite component, wherein the first composite component has a thermal conductivity in the range from 0.5 to 40 W/(m∙K) and the second composite component has a thermal conductivity in the range from 70 to 450 W/(m∙K).

Description

SUBSTRATE CARRIER ELEMENT FOR A CARRIER HORSE

Technical background

The present invention relates to a substrate carrier element for a carrier tray for the thermal treatment of a substrate, comprising a support surface for the substrate. Furthermore, the present invention relates to a carrier horde for the thermal treatment of a substrate, and a device for irradiating a substrate.

Carrier horroes in the sense of the invention are used for holding a plurality of substrates, in particular for holding semiconductor wafers. A common application of carrier hauls is the thermal treatment of silicon wafers in the semiconductor or photovoltaic industry. Known carrier hordes comprise a plurality of substrate carrier elements, on each of which a substrate can be placed. For this purpose, the substrate-carrier elements are often equipped with a support surface, for example in the form of a depression. State of the art

In the production and processing of silicon wafers, the silicon wafer is regularly subjected to a thermal treatment. Infrared radiators are usually used as the energy source for the thermal treatment.

Silicon wafers are thin, disk-shaped substrates that have a top and a bottom. A good, homogeneous thermal treatment of these substrates is achieved when the infrared radiators are assigned to the top and / or bottom of the substrate. However, this presupposes the presence of a comparatively large space above or below the wafer to be irradiated ahead.

A higher throughput in the thermal treatment of the wafers is achieved when the wafers are arranged in a carrier tray, which, supplied with wafers, is supplied to the thermal treatment.

Such carrier hordes are often vertical hordes; they consist essentially of an upper and a lower boundary plate, which are interconnected by a plurality of slotted cross bars. In semiconductor processing of wafers, these carrier trays are used, for example, in an oven, a coating or etching plant, but also for the transport and storage of wafers. Such Trägerhorde is known for example from DE 20 2005 001 721 IM.

A disadvantage of these carrier hordes, however, is that only a small amount of space remains between the wafers held in the carrier horde, which leads to the fact that the infrared heaters must be arranged laterally of the carrier horde. Such an arrangement has the consequence that the wafer edges are irradiated more strongly in comparison to the wafer center. Uneven irradiation of the wafers can affect the quality of the wafers. In addition, the process time depends on how long it takes for the wafer - including its center region - to reach the selected temperature. Lateral irradiation of the wafers is therefore associated with a prolonged process time.

In addition, carrier hordes are known which have several levels in the manner of a shelving system. In these carrier hordes, one or more substrates (wafers) are placed on the individual planes. Such carrier horden may be formed in one piece or several pieces, for example, a plurality of, each forming a separate plane support elements may be provided, which are held in a holding frame. In carrier shelves in the manner of a shelving system, the heat is supplied via two mechanisms, namely on the one hand directly by irradiation of the substrate and on the other hand indirectly by heat transfer from the respective shelf level. However, even when using shelf-like hordes, the problem basically arises that the infrared emitters lie next to the horde must be arranged, which often leads to an inhomogeneous substrate temperature distribution.

Technical task

The present invention is therefore based on the technical object of specifying a substrate carrier element for a carrier horde, which allows the most homogeneous possible heating of the substrate.

In addition, the present invention has for its object to provide a carrier horde or an irradiation device, which allow the most homogeneous possible heating of the substrate. General description of the invention

With regard to the substrate carrier element, this object is achieved on the basis of a substrate carrier element of the aforementioned type in that the substrate carrier element is a composite body comprising a first composite component and a second composite component, wherein the first composite component has a thermal conductivity in the range of 0.5 to 40 W / (mK) and the second composite component has a thermal conductivity in the range of 70 to 450 W / (mK).

Substrate support members used to thermally treat substrates are typically made from a single, homogeneous material characterized essentially by good thermal stability and good chemical resistance. Especially in semiconductor manufacturing, the yield and the electrical performance of semiconductor devices depend substantially on the extent to which it is possible in semiconductor manufacturing to prevent contamination of the semiconductor material by impurities. Such contamination can be caused, for example, by the equipment used.

In conventional substrate support members made of a single material, temperature variations often occur with lateral exposure observed on a substrate placed thereon. The reason for this is that these substrate carrier elements have an edge region and a central region, wherein the edge region of the substrate carrier element facing the radiation source is heated to a greater extent than, for example, the middle region. The associated temperature differences of the substrate-carrier element are also reflected in the substrate temperature.

According to the present invention, the substrate support member is a composite body comprising at least two composite components differing in thermal conductivity. Here, the first composite component has a thermal conductivity in the range of 0.5 to 40 W / (m-K), and the second composite component has a thermal conductivity in the range of 70 to 450 W / (m-K).

Thermal conductivity, also called heat conductivity, is understood to mean a substance-specific physical quantity; It is a measure of the heat transfer through heat conduction within a material. Prerequisite for the heat conduction is an existing temperature difference. Metals regularly have a good thermal conductivity, which is based on the fact that in metals heat energy can be transported well over the conduction electrons. Table 1 below lists by way of example the heat conductivities of some materials.

Table 1

Fabric thermal conductivity λ material thermal conductivity λ

[W / (m-K)] [W / (m-K)]

Silver 419 alumina 25 - 39

Copper 372 graphite 5 - 17

Gold 308 Quartz 1, 1

Aluminum 209 glass 0.6 - 1, 0

Platinum 70 In order to achieve the most homogeneous possible temperature distribution on the substrate, the composite components are chosen so that they work towards a temperature compensation.

In the simplest case, regions of the substrate carrier element which are comparatively exposed to high irradiation intensities and for which a high temperature is expected, are manufactured from the first composite component and regions for which a low temperature is expected from the second composite component.

By making portions of the substrate support member for which a low temperature is expected to be made of the second composite component having higher thermal conductivity, heat energy can be easily transported to and distributed evenly in those portions, for example, from the edge portion to the center portion. Although the regions of the substrate carrier element produced from the first composite component continue to be exposed to a high energy input, an immediate forwarding of the energy due to the low thermal conductivity of the first composite component is counteracted. Since the substrate carrier element according to the invention is a composite body, the thermal energy introduced into the first composite component can be distributed as evenly as possible over the entire substrate carrier element by means of the second composite component, whereby the occurrence of high-temperature regions on the substrate is simultaneously reduced.

For the properties of the composite body, the material properties and the geometry of the composite components are important. In particular, size effects often play a role. The connection of the first and second composite component takes place by material or positive connection or a combination of both. Since the size, shape and number of contact surface areas, which are made of the first and the second composite component, on the type of irradiation, in particular the irradiation power, the distance of the radiation source and the substrate to be irradiated depends, it is advantageous if this regularly the irradiation situation are adjusted. In a preferred embodiment of the substrate according to the invention

Carrier element is provided that the support surface of the second composite is made component, and that adjoins the support surface made of the first composite component edge region.

A bearing surface made of the second composite component contributes due to their good thermal conductivity to a uniform substrate temperature. The fact that the support surface is at least partially surrounded by an edge region which is made of the first composite component, for example, laterally introduced into the substrate support element heat energy due to the relatively low thermal conductivity of the first composite component initially stored in the edge region, to then by means of second composite component transported away in the direction of the support surface and to be evenly distributed there.

The support surface may be completely or partially surrounded by the edge region. In the simplest case, the edge region is associated with only one side, which is exposed directly to a heat input, for example, the side of the substrate-carrier element facing a radiation source.

Likewise advantageously, a bearing area completely enclosing edge area has been found. In this case, the edge area serves as an energy storage, is stored with the energy and evenly provided for heating the support surface. The energy transport is ensured by the support surface made of the second composite component. In this context, it has proved to be particularly favorable if the support surface is formed from a disc-shaped support element made of the second composite component, which has an upper and a lower side, and if the edge region at least partially overlaps the upper side and / or the lower side of the support element. The overlap of the edge area and the support element increases the contact area between the first and second composite components, so that a particularly efficient heat transfer from the first to the second composite component is made possible.

In another, equally preferred embodiment of the substrate carrier element according to the invention, the support surface comprises the first and the second composite component. Conventional substrate carrier elements are made of a single material, so that the bearing surface consists of the same material as the carrier element. A resting on substrate has regular temperature differences on irradiation. Here, in particular, the side of the substrate facing the radiation source and the substrate-carrier element are heated more strongly than, for example, the center region thereof.

In contrast, it has proved to be particularly favorable when the substrate carrier element according to the invention, a modified support surface is provided, the physical properties of which is adapted to the lateral irradiation of the support surface and a possibly placed thereon substrate.

In the simplest case, a region of the support surface for which a low corresponding substrate temperature is expected to be made of the second composite component with higher thermal conductivity. For example, this often applies to the center region of the support surface. If the bearing surface has good thermal conductivity in this region, heat energy can easily be transported into this region and distributed uniformly there, for example from an edge region into the middle region. Preferably, areas of the support surface, which are expected to be more heated due to their position relative to the radiation source, are manufactured from the first composite component. Although these areas are still exposed to a higher energy input, but a transfer of energy is counteracted by the low thermal conductivity. In this way, the area of high temperature areas on the substrate is minimized.

It has proved to be particularly favorable when the first composite component has a specific heat capacity at 20 ° C of at least 0.7 kJ / (kg-K), preferably a specific heat capacity at 20 ° C in the range of 0.7 kJ / (kg -K) to 1, 0 kJ / (kg-K).

The specific heat capacity of a substance is a measure of which amount of heat a given amount of a substance can absorb at a temperature change of 1 K, that is, to what extent the substance is able to absorb and store heat energy. If the first composite component has a heat capa- having at least 0.7 kJ / (kg-K), it can absorb a comparatively large amount of heat energy. This reduces the amount of heat absorbed by any substrate placed thereon. Therefore, the larger the heat capacity of the first composite component, the lower the amount of heat that can be absorbed by the substrate, and thus the lower the substrate temperature.

The first composite component is preferably associated with a region of the support surface for which a high corresponding substrate temperature is expected, for example an edge region of the support surface. Together with a suitable choice of the composite components based on their thermal conductivity, the use of a composite component with a heat capacity in the abovementioned range additionally contributes to equalizing the substrate temperature differences.

Table 2 below lists, by way of example, the specific heat capacities of some materials at T = 20 ° C. Table 2

In a preferred embodiment of the substrate support element according to the invention it is provided that the mass of the first composite component and the mass of the second composite component of the support surface are coordinated so that the heat capacity of the first composite component large It is higher than the heat capacity of the second composite component.

The heat capacity of the composite components depends, among other things, on their mass. The larger the mass of a composite component, the greater its heat capacity. In addition, the heat capacity of the composite component has an influence on the temperature distribution in a substrate placed on the support surface and irradiated with infrared radiation. The heat capacity of a composite component means the ratio of the amount of heat supplied to the heating achieved. The larger the heat capacity, the more energy must be added to the composite component to heat it by 1K. The first composite component is preferably associated with areas of the support surface for which a high corresponding substrate temperature is expected. If the heat capacity of the first composite component is greater than that of the second composite component, areas with the first composite component are heated less. Conversely, areas with the second composite component are heated more strongly. This contributes to a balance of substrate temperature differences. In this context, it has been proven that the heat capacity of the first composite component is at least 30% greater than the heat capacity of the second composite component. Preferably, the support surface is formed as a flat surface. A flat surface can be produced with little manufacturing effort, for example by grinding. It also has the advantage that a likewise flat substrate has the largest possible contact surface with the support surface. This contributes to the fact that the amount of heat over the support surface can be distributed as evenly as possible on the substrate. A placed on the support surface substrate can rest completely or partially on the support surface. Preferably, a substrate placed on the support surface lies completely on the support surface with its support side. This has the advantage that the temperature of the support side can be adjusted as far as possible over the support surface, so that a uniform possible heating of the substrate is made possible.

Preferably, the support surface for the substrate has a size in the range of 10,000 mm ² to 160,000 mm ² , more preferably in the range of 10,000 mm ² to 15,000 mm ² , on.

The larger the contact surface, the more difficult it is to produce a uniform temperature of the support surface. A bearing surface in the range of 10,000 mm ² to 160,000 mm ² is sufficiently large for accommodating common substrates such as semiconductor wafers. At the same time, the temperature of such a bearing surface can be kept sufficiently homogeneous. A contact surface of more than 160,000 mm ² is also expensive to manufacture.

It has proven particularly useful if the size of the bearing surface in the range of 10,000 mm ² to 15,000 mm ² . A bearing surface in this area is particularly suitable for receiving wafers, such as those used in the manufacture of electronic components, for example in the manufacture of integrated circuits. It has proved to be advantageous if the support surface has a square or round shape. In the case of a square bearing surface whose size is preferably between 100 mm x 100 mm and 122 mm x 122 mm; in a round bearing surface of the bearing surface diameter is preferably between 56 mm and 120 mm.

It has proven useful if the bearing surface comprises a first zone having the first composite component and a second zone having the second composite component.

The term zone is understood to mean a region of the contact surface which consists exclusively of the first composite component. In the simplest case, the first zone and the second zone directly adjoin one another. But they can also be spaced from each other. The use of zones has the advantage that they can be manufactured easily and inexpensively and connected to one another. The connection of the first and second zone is preferably carried out by positive locking, but can also be made cohesively, for example by welding or gluing. A combination of positive and cohesive connection is possible. A purely positive connection has the advantage that it is particularly easy to manufacture. Advantageously, the first zone has a section with an oval shape.

The temperature distribution pattern on a disk-shaped, planar substrate often has isotherms with an oval shape section. It has therefore been proven that even the first zone is adapted to the shape of the isotherms. Preferably, the second zone also has an oval shaped section. It is particularly favorable if the first and second zones directly adjoin one another and the first zone has an oval shaped section and the second zone has a second oval shaped section corresponding to the first shaped section. In a preferred embodiment of the substrate support element according to the invention, the first composite component is carbon, silicon carbide or blackened zirconium oxide.

The abovementioned materials, in addition to a thermal conductivity in the range indicated above, have good temperature stability and have good chemical stability.

In this connection, it has proven useful if the second composite component contains a metal, preferably aluminum or an alloy thereof or high-temperature steel.

Metals regularly have a high thermal conductivity, which is based on the fact that in metals energy can be transported via their conduction electrons. Aluminum in particular exhibits sufficient chemical stability at elevated temperatures and is therefore suitable for use as a composite component.

The substrate carrier element can advantageously be used in a known carrier horde for the thermal treatment of a semiconductor wafer. With regard to the Trägerhorde for thermal treatment of a substrate, the above object is achieved starting from a carrier horde of the aforementioned type in that it comprises a first substrate support member and a second substrate support member, wherein the first and second substrate support member are arranged that their respective Laying surfaces for the substrate parallel to each other.

The Trägerhorde invention is designed in particular for the thermal treatment of a semiconductor wafer (silicon wafer). In this case, bearing surfaces of the substrate carrier elements are arranged parallel to each other. Preferably, first and second carrier element are arranged in the manner of a shelf, which is designed for receiving substrates. The use of a shelf-like carrier horde has the advantage that the energy required for heating can be provided by two mechanisms, namely on the one hand directly by direct irradiation of the substrate and on the other hand indirectly by heat conduction through the carrier horde itself, which also heats up during the irradiation process. The Trägerhorde can be made in one piece or in several pieces. It has at least two substrate carrier elements.

In conventional substrate carrier elements, the support surface usually consists of the same material as the carrier element. In contrast, carrier elements in the form of a composite body are provided in the carrier horde according to the invention, which comprises at least two composite components which differ in their thermal conductivity. Here, the first composite component has a thermal conductivity in the range of 0.5 to 40 W / (m-K), and the second composite component has a thermal conductivity in the range of 70 to 450 W / (m-K). As explained above, the composite components are chosen so that they work towards a temperature compensation. This results in the most homogeneous possible temperature distribution on the substrate.

With regard to the device for irradiating a substrate, the above-mentioned object is achieved according to the invention in that it has at least one substrate carrier element and at least one infrared radiator for irradiating the substrate carrier element.

Such a device for irradiation of a semiconductor wafer (silicon wafer) suitable; it has at least one infrared radiation source and can be used for thermal treatment of substrates. The infrared radiator is used to irradiate the substrate carrier element, in particular the bearing surface and a designed on top of laid substrate. The infrared radiator preferably has a longitudinal axis which runs perpendicularly parallel or diagonally to the bearing surface of the substrate carrier element.

The device has at least one substrate carrier element within the meaning of the invention, which is provided with a modified bearing surface. This bearing surface comprises at least two composite components which differ in their thermal conductivity. Here, the first composite component has a thermal conductivity in the range of 0.5 to 40 W / (m-K), and the second composite component has a thermal conductivity in the range of 70 to 450 W / (m-K). The physical properties of the composite components are adapted to the lateral irradiation of the support surface and a possibly placed thereon substrate.

In order to achieve the most homogeneous possible temperature distribution on the substrate, the composite components are chosen so that they work towards a temperature compensation. In the simplest case, a region of the support surface for which a low corresponding substrate temperature is expected to be made of the second composite component with higher thermal conductivity. For example, this often applies to the center region of the support surface. If the bearing surface has a good thermal conductivity in this area, heat energy can be easily transported into this area and distributed uniformly there, for example from one edge area to the middle area. Preferably, areas of the support surface, which are expected to be more heated due to their position relative to the radiation source, are manufactured from the first composite component. Although these areas continue to be exposed to a higher energy input, the transmission of energy is counteracted by the low thermal conductivity. In this way, the size of high-temperature regions on the substrate is minimized and the most homogeneous possible heating of the substrate is possible.

It has proved to be favorable if the bearing surface of the substrate carrier element comprises a first zone having the first composite component and a second zone having the second composite component, and if it has a transverse side facing the infrared radiator and two longitudinal sides. has, wherein the first zone extends along the transverse side.

The transverse side is regularly assigned to the infrared radiator; It is therefore exposed to the highest irradiation levels. It has the smallest distance to the infrared radiator. A first zone extending along the transverse side helps to keep the temperature in the region of the transverse side as low as possible and to counteract the propagation of regions of high temperature.

In this context, it has proved to be particularly advantageous if the second zone extends along at least one of the longitudinal sides.

On the long sides, the temperature of the substrate is regularly higher than in the middle of the substrate. This has to do with the fact that a substrate usually heats up faster at its edges than in the middle. The fact that the second zone extends along at least one, preferably along both longitudinal sides, the heat can be dissipated from the edges in the middle. For this purpose, the second zone is made of the second composite component; With its high thermal conductivity, this contributes to rapid temperature compensation within the substrate.

embodiment

The invention will be explained in more detail with reference to embodiments and drawings. 1 shows an embodiment of a carrier horde according to the invention for the thermal treatment of a substrate, in which a plurality of substrate carrier elements according to the invention are stacked in the manner of a shelving system,

Figure 2 is a sectional view of an embodiment of an inventive

Device for irradiating a substrate,

FIG. 3 is a temperature distribution diagram showing the surface temperature of a silicon substrate on a carbon support surface. and a schematic representation for explaining the temperature distribution,

FIG. 4 shows a temperature distribution diagram which shows the surface temperature of a silicon substrate on an aluminum support surface, and a schematic representation for explaining the temperature distribution,

FIG. 5 shows a plan view of various embodiments of substrate carrier elements according to the invention, and

Figure 6 shows an embodiment of a substrate support element according to the invention in a plan view (A) and a sectional view (B).

FIG. 1 shows a perspective view of an embodiment of a carrier tray according to the invention, to which the reference numeral 100 is assigned overall. Carrier hanger 100 is designed for thermal treatment of silicon wafers in the semiconductor / photovoltaic industry. Such carrier shelves in the manner of a shelf are also referred to as "stacks" in the English-speaking language The carrier tray 100 comprises a plurality of substrate carrier elements 101. For simplifying the illustration, an arrangement of ten substrate carrier elements 101 is shown by way of example in FIG. Carrier elements 101 are of identical design The carrier tray 100 has five substrate carrier elements 101 stacked on one another in the vertical direction 103. In addition, the carrier carrier extends in the horizontal direction 102, in each case two substrate carrier elements 101 being arranged next to one another in each plane.

By way of example, one of the substrate carrier element 101 is described in more detail below:

The substrate support member 101 is made of carbon; it has two longitudinal sides 105 and two transverse sides 104. On the transverse sides 104 are each two projections 106, with which the substrate-carrier element 101 can be attached to the transverse bars 107. The cylindrical cross bars 107 are made of steel and each provided with an external thread. The substrate carrier element 101 has corresponding bores with an internal thread, so that the substrate carrier element 101 can be screwed to the transverse bars 107. The thread diameter is 8 mm. The transverse rods 107 have a circular radial cross-section, the diameter of the transverse rods is 8 mm. The substrate support member 101 has a length of 200 mm (corresponding to the longitudinal side 105 including the protrusions 106 having a protrusion length of 30 mm) and a width of 150 mm (corresponding to the lateral side 104). The thickness of the substrate support member 101 is 2 mm. On the upper side of the substrate support element 101, a support surface 108 for a semiconductor wafer in the form of a rectangular depression is provided.

The substrate support member 101 is made in the region of the support surface 108 of two composite components, namely from the first composite component carbon (thermal conductivity: 17 W / (m-K)) and the second composite component aluminum (thermal conductivity: 209 W / (m-K)); it is dimensioned such that a silicon wafer which is placed on the support surface 108 rests completely on the support surface with its underside.

The support surface 108 has a rectangular shape and has a length of 101 mm and a width of 101 mm.

FIG. 2 shows a sectional view of a device according to the invention for irradiating semiconductor wafers, to which the reference numeral 200 is assigned overall. The device 200 comprises four infrared radiator modules 201, 202, 203, 204, and a Trägerhorde 100 as described in Figure 1.

Insofar as the same reference numerals are used in FIG. 2 as in FIG. 1, the same or equivalent constituents of the carrier tray are described, as explained above with reference to FIG.

The infrared radiator modules 201, 202, 203, 204 are of identical design and emit infrared radiation having a maximum wavelength in the range from 1 .100 nm to 1 .400 nm. The radiator modules 201, 202, 203, 204 have a nominal total power of 12 kW. Each of the radiator modules is equipped with eight cylindrical infrared radiators 205. In the modules 201, 202, 203, 204 are the infrared radiators 205 are arranged such that their radiator tube longitudinal axes are perpendicular to the bearing surfaces 108 of the Trägerhorde 100.

In FIG. 2, the radiator modules 201, 202, 203, 204 are assigned to the transverse sides 104 of the substrate carrier elements 101. In an alternative embodiment of the device according to the invention (not shown), the radiator modules 201, 202, 203, 204 are assigned to the longitudinal sides 105 of the substrate carrier elements 101. This has the advantage that the radiator modules 201, 202, 203, 204 can be made larger, so that a higher irradiation power can be provided. The respective radiator tube of the infrared radiator 205 is made of quartz glass; it has an outer diameter of 14 mm, a wall thickness of 1 mm and a length of 300 mm. Within the radiator tube, a filament of tungsten is arranged in each case. In addition, the emitter tube of the infrared radiator 205 has a side 207 facing the semiconductor wafer 206a, 206b to be irradiated and an opposite side 208. The side of the radiator tube facing away from the semiconductor wafer 206a, 206b to be irradiated is provided with a layer of opaque quartz glass, which acts as a reflector.

With regard to the carrier horde 100, FIG. 2 shows a horizontal section through two substrate carrier elements 101. Each of the substrate carrier elements 101 has two transverse sides 104 and two longitudinal sides 105, wherein the infrared radiator modules 201, 202, 203, 204 are assigned to the transverse sides 104. By this arrangement, any applied to the bearing surfaces 108 semiconductor wafers are irradiated laterally from two sides. In this type of arrangement of the infrared radiator relative to the Trägerhorde 100 inserted substrates are on the one hand directly from the infrared radiator modules 201, 202, 203, 204 irradiated. On the other hand, the shelving system is made of carbon, which also absorbs radiation energy, so that a not insignificant part of the heat input into the substrate also takes place via the shelving system. In such an arrangement, in principle, the edges of an inserted substrate are exposed to higher infrared irradiances than the substrate center. To resulting differences of the To minimize substrate temperature, the support surface 108 is made of two composite components, such as aluminum and carbon.

Aluminum has a high thermal conductivity of 209 W / (m-K) and is therefore suitable for rapid removal and rapid redistribution of heat energy. In contrast, carbon has a comparatively low thermal conductivity; it is about 17 W / (m-K). As a result, the distribution of heat in carbon is slower. At the same time, however, the material carbon has a good heat capacity (0.71 kJ / kg-K at T = 20 ° C), so that carbon can absorb a certain amount of heat itself. A support surface 108, which is made according to the invention of a composite of these two aforementioned materials, aluminum and carbon, makes use of these different properties of the composite components. Possible embodiments of the support surface 108 with regard to the distribution of the composite components are shown in FIG. A placed on the support surface 108 semiconductor wafer is heated on the one hand directly from the infrared radiators and on the other hand indirectly from the Trägerhorde. The direct irradiation of the semiconductor wafers with infrared radiation means that their sections assigned to the transverse sides 104 are heated more strongly by the infrared radiators than the sections of the semiconductor wafers which are assigned to the longitudinal sides 105 and thus to the longitudinal sides of the support surface. Since a zone of the first composite component (carbon), which preferably extends along the respective transverse side of the support surface, is assigned to the transverse sides 104, part of the incident irradiation energy is absorbed by the carbon zone of the support surface 108.

Characterized in that between the carbon zones on the transverse sides 104, an intermediate zone of aluminum is arranged, a rapid heat distribution from the edges of the longitudinal support surface is achieved to the center of the aluminum zone, so that in particular any temperature differences within the substrate are compensated faster. In addition, the masses of the two composite components are chosen so that the heat capacity of the carbon content is greater than that of the aluminum content. The mass ratio is: 30% aluminum and 70% carbon.

FIG. 3A shows a simulation of the temperature distribution on a silicon substrate 300 after the silicon substrate 300 has been irradiated laterally with two infrared modules 301 a, 301 b with the nominal power 28 kW. The infrared modules 301 a, 301 b each have an infrared radiator. The infrared radiator has a cylindrical radiator tube of quartz glass with a radiator tube length of 1 m. The spotlight tube has an oval cross-section with the following external dimensions: 34 mm x 14 mm. The wall thickness of the spotlight tube is 1, 6 mm.

The silicon substrate 300 has a width of 100 mm, a length of 100 mm and a height of 2 mm. The corners of the silicon substrate 300 are rounded.

The simulation is based on the fact that the silicon substrate 300 rests with its underside on a carrier element whose contact surface is made entirely of carbon. The heat transfer to the substrate takes place by two mechanisms, namely by irradiation with infrared radiation and by heat transfer via the carrier element.

The substrate temperature is in the range of 490.5 ° C to 580.38 ° C. Since both low and high temperatures are represented by dark hues in FIG. 4 and only the transition regions between the minimum and maximum temperatures have lighter colors, FIG. 3B shows a simplified, schematic representation of the substrate of FIG. 3A, from which the lower, middle regions and high temperature are easily apparent. In it, areas of high temperature are darkly hatched, areas of medium temperature are shaded lighter and

Low temperature areas are shown in light hatching. FIG. 3B is intended to serve primarily to explain FIG. 3A.

FIG. 4A likewise shows a simulation of the temperature distribution as in FIG. 3A, with the difference that in the simulation according to FIG. 4A the silicon substrate 300 rests on a carrier element whose bearing surface is made of aluminum. nium is made. FIG. 4B serves - as already shown in FIG. 3B with reference to FIG. 3A - to explain FIG. 4A.

Figures 3 and 4 show that a support surface made of a single material can be associated with an inhomogeneity in the temperature distribution. The comparison of FIGS. 3 and 4 shows in particular that a bearing surface made of carbon is associated with a lower substrate temperature in comparison with a bearing surface made of aluminum [carbon: about 540 ° C .; Aluminum: about 780 ° C].

The lower substrate temperature can be explained by the fact that a carbon substrate carrier element itself has a large heat capacity, so that part of the heat is absorbed by the substrate carrier element itself and therefore a smaller amount of heat is available to heat the silicon substrate 300 stands.

FIG. 5 shows a top view of four different embodiments of substrate carrier elements 500, 520, 540, 560 according to the invention, which can be used in the carrier tray 100 according to FIG. The substrate carrier elements 500, 520, 540, 560 each have two transverse sides 502, 522, 542, 562 and two longitudinal sides 501, 521, 541, 561. The substrate carrier elements 500, 520, 540, 560 are designed for use in the device 200 from FIG. 2, wherein an infrared radiation source is assigned to the transverse sides 502, 522, 542, 562 in each case. The direction of radiation of the radiation emitted by the infrared radiation sources is shown by arrows 580.

The substrate support elements 500, 520, 540, 560 furthermore have a support surface 503, 523, 543, 563 for a substrate which comprises two composite components, namely as the first composite component carbon with a thermal conductivity in the range of 0.17 W / ( mK) and as a second composite component aluminum with a thermal conductivity of about 209 W / (mK). The bearing surfaces 503, 523, 543, 563 are divided into zones that are made of either the first composite component or the second composite component. The support surface 503 of the substrate support element 500 according to FIG. 5A has three zones I, II, III. Zones I and III are made of carbon and zone II is off Made of aluminum. The shape of Zones I and III is identical; they each have a section with a parabolic course. Zone II immediately adjoins zones I, III.

The bearing surface 523 of the substrate carrier element 520 (FIG. 5B) differs from the bearing surface 503 only in the form of the zones I, II, III. The zones I and III also have a section with a - albeit flattened - parabolic course. In addition, the zone II does not extend completely over the longitudinal side bearing surface.

Figure 5C shows an alternative arrangement of zones I, II and III of Figure 5A. The zones I, III are trapezoidal. Trapezoidal zones have straight sections and are therefore easy and inexpensive to manufacture.

In FIG. 5D, the support surface 563 has four zones I, IIa, IIb, III. The support surface 563 is divided into four equal zones I, IIa, IIb, III. Zones I, IIa, IIb, III are in the shape of an isosceles triangle. Such a zone distribution is particularly easy and inexpensive to manufacture.

FIG. 6A shows a plan view of the upper side of a substrate carrier element according to the invention, to which the reference numeral 600 is assigned; FIG. 6B shows the substrate carrier element 600 in a sectional illustration along the section axis A-A '.

The substrate carrier element 600 has a bearing surface 601 in the form of a depression, which comprises two interconnected components. The first composite component 603 is made of carbon and forms a kind of support frame for the second composite component 602. The second composite component is an aluminum plate; it has a length of 120 mm, a width of 120 mm and a height of 1 mm. The aluminum plate is inserted over the transverse side 605 in the receptacles 606 of the first composite component and connected to this materially. The aluminum plate is dimensioned such that a possibly placed on the support surface 601 substrate rests exclusively on the aluminum plate. If the substrate carrier element 600 is irradiated laterally with infrared radiation, especially the edge region 607 of the substrate carrier element 600 heats up. The edge regions 607 serve as energy store; the aluminum plate causes an energy transfer from the edge regions 607 into the central region 608 of the substrate carrier element. It exhibits a uniform, homogeneous temperature distribution and thus contributes to a uniform thermal treatment of any substrate placed on the support surface 601.

Claims

claims

1 . A substrate support member (101; 500; 520; 540; 560; 600) for a support tray (100) for thermal treatment of a substrate (300) comprising

Supporting surface (108; 503; 523; 543; 563; 601) for the substrate (300), characterized in that the substrate support member (101; 500; 520; 540; 560; 600) is a composite body comprising a first composite component and a second composite component, wherein the first composite component has a thermal conductivity in the range of 0.5 to 40 W / (mK) and the second composite component has a thermal conductivity in the range of 70 to 450 W / (mK).

The substrate support member (101; 500; 520; 540; 560; 600) according to claim 1, characterized in that the support surface (108; 503; 523; 543; 563; 601) is made of the second composite component, and that adjoining the support surface (108; 503; 523; 543; 563: 601) is an edge region made of the first composite component.

A substrate support member (101; 500; 520; 540; 560; 600) according to claim 1, characterized in that said support surface (108; 503; 523; 543; 563; 601) comprises said first and second composite components.

A substrate support member (101; 500; 520; 540; 560; 600) according to any one of the preceding claims, characterized in that the first composite component has a specific heat capacity at 20 ° C of at least 0.7 kJ / (kg-K). , preferably has a specific heat capacity at 20 ° C in the range of 0.7 kJ / (kg-K) to 1, 0 kJ / (kg-K).

5. Substrate carrier element (101; 500; 520; 540; 560; 600) according to one of the preceding claims, characterized in that the mass of the first composite component and the mass of the second composite component are coordinated so that the heat capacity of the first Ver - bund component is greater than the heat capacity of the second composite component.

6. Substrate support element (101; 500; 520; 540; 560; 600) according to one of the preceding claims 1 or 3 to 5, characterized in that the support surface (108; 503; 523; 543; 563; 601) is one of the first composite

5 nent first zone (I, III) and a second composite component having the second zone (II, IIa, IIb) comprises.

The substrate support member (101; 500; 520; 540; 560; 600) according to claim 6, characterized in that the first zone (I, III) has a portion of an oval shape.

The substrate support member (101; 500; 520; 540; 560; 600) according to any one of the preceding claims, characterized in that the first composite component is carbon, silicon carbide or blackened zirconia.

The substrate support member (101; 500; 520; 540; 560; 600) according to any one of the preceding claims, characterized in that the second composite component comprises a metal, preferably aluminum or an alloy thereof.

10. Substrate carrier element (101; 500; 520; 540; 560; 600) according to one of the preceding claims, characterized in that it is arranged in a carrier tray (100) for the thermal treatment of a semiconductor wafer (206a,

20 206b) can be used.

1 1. A carrier hanger (100) for thermal treatment of a substrate (300), comprising a first substrate carrier element (101; 500; 520; 540; 560; 600) according to one of the preceding claims 1 to 10 and a second substrate carrier element (101; ; 520; 540; 560; 600) according to any one of the preceding claims 1 to 10, wherein first and second substrate support members (101; 500; 520; 540; 560; 600) are arranged such that their respective bearing surfaces (FIGS. 108; 503; 523; 543; 563; 601) for the substrate (300) are parallel to one another.

12. Device (200) for irradiating a substrate (300), comprising min. at least one substrate carrier element (101; 500; 520; 540; 560; 600) according to one of the preceding claims 1 to 10 and at least one infrared radiator (205) for irradiating the substrate carrier element (101; 500; 520; 540; 560) 600).

The apparatus (200) according to claim 12, characterized in that the support surface (108; 503; 523; 543; 563; 601) of the substrate support member (101; 500; 520; 540; 560; 600) is one of the first Compound having first zone (I, III) and a second composite component having second zone (II, IIa, IIb), and that it a the infrared ray e) ler (205) facing the transverse side, and two longitudinal sides, wherein the first zone (I, III) extends along the transverse side.

14. Device (200) according to claim 13, characterized in that the second zone (II, IIa, IIb) extends along at least one of the longitudinal sides.