DE102013012082A1 - Device for the thermal treatment of a semiconductor substrate, in particular for applying a coating - Google Patents

Abstract

The invention relates to a device for the thermal treatment of a semiconductor substrate (15) having a susceptor (2) which can be heated by a heater (3) forming the bottom of a process chamber (1) and which has an upper side (5) facing the process chamber (1) Substrate carrier base (4), with a on the substrate support base (4) attachable transport ring (6) having a ring opening (7) surrounding the support shoulder (9) for supporting support of the edge (17) extending over the annular opening (7) Substrate (15), wherein the substrate (15) can be heated by heat transfer from the substrate carrier base (4) and through the transport ring (6). In order to increase the temperature homogeneity of the substrate surface, it is proposed that the ring opening (7) be filled by a plate (12) which lies between substrate (15) and substrate carrier base (4). In particular, lateral temperature gradients should be avoided.

Description

The invention relates to a device for the thermal treatment of a semiconductor substrate with a bottom of a process chamber forming, heatable by a heater susceptor having an upper side facing the process chamber substrate carrier base, with an attachable to the substrate support base transport ring having a surrounding a ring opening support shoulder for supporting the edge of a substrate extending over the ring opening, wherein the substrate can be heated by heat transport through the substrate carrier base and the transport ring.

A device of the type described above is in the DE 102 32 731 A1 described. A generic device is a CVD reactor having a gas-tight housing to the outside, within which there is a process chamber. The process chamber can be evacuated. In the process chamber gas supply lines open, are introduced by the provided by a gas mixing device process gases through a gas inlet member into the process chamber. The process chamber has a bottom that forms a susceptor. The susceptor is heated from below by means of a heater. The result is a permanent flow of heat from the heater to the process chamber, in which the process gas introduced by the gas inlet member in the process chamber is heated to a process temperature, decomposes, with decomposition products are deposited on a susceptor resting on the substrate and further decomposition products together with a carrier gas be led out of the process chamber. The process gas is a gas mixture which contains in particular a gas, which may be a V component and a III component, for example arsine, phosphine or ammonia. The process gas also contains a III component, for example trimethylindium or trimethylgallium. The process gases react on the surface of a semiconductor substrate resting on the susceptor such that a semiconductor layer consisting of, for example, gallium and nitrogen or gallium and arsenic grows on the surface of the semiconductor substrate. In order to load the susceptor with substrates, a loading plate is proposed in the cited prior art, which can be placed on a substrate support base of the susceptor. The loading plate forms a transport carrier ring with a ring opening, which is covered by the substrate. The edge of the substrate rests on a support shoulder, which surrounds the opening edge of the ring opening. The heat transport from the substrate carrier base heated by means of the heater to the substrate takes place through the edge portion of the carrier ring on which the susceptor rests and through a cavity between substrate base and substrate carrier base top or directly by contacting the substrate on the top of the substrate carrier base. The heat transfer is different in the central region from the heat transfer in the edge region of the substrate, so that the surface temperature of the substrate is location-dependent.

From the US 6,001,183 For example, a transport carrier is known in which the substrate is located above a cavity which is formed by a pocket of the substrate carrier forming a bottom.

The US 2011/0171380 A1 describes a CVD reactor in which the substrate rests on the edge of an annular opening of a substrate carrier, below which there is a pedestal of an intermediate plate. A resting on the edge portion of an opening edge of a transport ring intermediate plate which carries the substrate, shows the EP 10 94 502 A2 , An annular substrate holder also describes the US 6,217,663 B1 ,

The DE 10 2012 106 796 describes a generic device in which the substrate support base extends into the ring opening, so that the substrate rests on the substrate support base.

The object of the invention is to increase the temperature homogeneity of the substrate surface. In particular, lateral temperature gradients should be avoided.

The object is achieved by the invention specified in the claims, wherein initially and essentially proposed that the ring opening is filled by a plate. It is a center plate, which lies in the center of the ring and the edge of which protrudes up to the opening edge of the ring opening. The material thickness of the plate is preferably only slightly smaller than the distance between the underside of the substrate and the top of the substrate carrier base. The heat transfer property of the plate resting on the substrate carrier is adapted to the heat transfer property of the support shoulder forming portion of the transporting ring resting on the substrate carrier base. As a result of this adaptation, the heating of the substrate carrier base by means of a heater disposed below the substrate carrier base results in that the surface temperature of the substrate in the substrate center is substantially the same as in the substrate edge region. The base may be in a pocket of a susceptor, below which the heater is located. The heater may be an infrared heater, an RF heater, or a resistance heater that heats the susceptor. In the bag in which Substrate support base rests, a Traggasstrom can be fed, which holds the circular disk-shaped substrate support base in a floating position and rotatably drives the substrate support base. The substrate carrier pedestal may have a flat upper surface on which the transport ring and the center plate lie. The annular gap between the peripheral wall of the middle plate and the annular opening may be selected such that a wall portion of the center plate is partially engaged, so that the center plate is removable together with the transport ring from the substrate carrier base. This can be done with a gripper arm of an end effector. The gripper arm may have fork-like gripping ridges, which engage under the edge region of the support ring. When the support ring is raised, the edge of the center plate is engaged by a portion of the opening edge of the support plate, so that the entire ensemble, which carries the substrate, can be removed from the process chamber. It proves to be advantageous that the center plate can exert a heat storage function. If the substrate is taken out of a process chamber, edge region and central region of the substrate cool substantially uniformly since during transport both the edge region and the central region of the substrate lie above a warm body, namely above the heated middle plate and above the transport ring. It is advantageous if almost the entire space surrounded by the opening wall of the ring opening is filled by the center plate. The transport ring and the plate may rest on top of a substrate carrier pedestal. The top of the substrate carrier socket may have a recess which is designed so that it creates a clearance to the bottom of the center plate. This results in a large, complementary heat transfer zone, with which the heat flow from the substrate support base to the substrate is fine tuned. The center plate can be supported on an edge portion of this recess. But it is also possible that the center plate is supported on a radially inwardly facing projection of the wall of the ring opening. The invention also includes such arrangements in which the center plate can not be carried by the support ring, so that the center plate remains when lifting the substrate carrier ring on the substrate support base. However, what is essential is the gap between the underside of the middle plate and the top of the substrate carrier socket which forms a heat transfer barrier from the substrate carrier pedestal to the central plate, which substantially corresponds to the heat transfer barrier forming the joint between the underside of the carrier ring and the top of the substrate carrier pedestal. The plate forms a sort of filler, which modifies the heat transfer. The radial extent of the center plate is subject to a large variation spectrum. Thus, embodiments are conceivable in which only the central region of the substrate carrier base is covered by a plate and more than 50 percent of the radial region is covered by the transport ring. At least a small ring opening is necessary to separate the substrate from the transport ring. For this purpose, the transport ring, as also described in the aforementioned prior art, is set over pins that pass through the ring opening and support the substrate, so that it can be grasped at the edge by the arms of another gripper. If the center plate is lifted together with the transport ring from the substrate carrier base, this arrangement is also placed on a vertical pin arrangement. The center plate is supported on central vertical pins. Upon further lowering of the gripper, which grips the transport ring at the edge, the carrier shoulder moves away from the edge of the substrate, so that the edge of the substrate can be grasped by the gripping arms of another gripper, with which the substrate can be lifted off the middle plate. In a further embodiment, the center plate may have a maximum diameter, so that only one edge of the substrate required for carrying the substrate rests on a carrier shoulder of the transport ring. The substrate carrier socket can be rotated. For this purpose, a centering pin protrude from the bottom of a receiving pocket. This centering pin can project through an opening of the substrate carrier base and protrude into an opening in the middle plate. With the centering thus centering of the center plate is possible. A centering of the substrate or the center plate can be carried out with a device such as the DE 10 2012 111 167 describes. The content of this document is therefore incorporated in full in the disclosure of this application, in particular also to claim technical features of this description.

Embodiments of the invention are explained below with reference to accompanying drawings. Show it:

1 schematically a vertical section through a CVD reactor,

2 an exploded view of the in the 1 illustrated substrate carrier assembly,

3 similar to a vertical section 1 by a second embodiment of a substrate carrier arrangement,

4 a representation according to 3 a third embodiment,

5 a substrate carrier assembly of a fourth embodiment,

6 a substrate carrier assembly of a fifth embodiment,

7 a substrate carrier assembly of a sixth embodiment,

8th a substrate carrier assembly of a seventh embodiment,

9 the enlarged section IX in FIG 8th .

10 a representation according to 9 an eighth embodiment,

11 a representation according to 9 a ninth embodiment,

12 a separation device for separating a substrate from the transport ring and

13 a section along the line XIII-XIII in 12 ,

The 1 shows schematically the cross section through a reactor housing of a CVD reactor, wherein the outwardly gas-tight housing walls are not shown. Not shown are also gas supply lines and gas discharges, but only a process chamber ceiling 31 , which forms a gas inlet member through which process gases into the process chamber 1 be initiated. The latter is located vertically below the process chamber ceiling 31 , The bottom of the process chamber 1 is made of a susceptor consisting of, for example, graphite, molybdenum, quartz, or other suitable material 2 educated. Below the susceptor 3 there is a heater 3 , It can be a resistance heater, an infrared heater or even a radio frequency heater. The to the process chamber 1 pointing top of susceptor 2 forms a bag 18 from, in the flow channels, not shown, lead to the passage of a Traggasstromes. With the Traggasstrom can create a gas cushion on which a circular disk-shaped substrate support base 4 is carried floating and turning.

In the in the 1 to 4 illustrated embodiments has the top of the substrate carrier socket 4 a flat surface. On the edge of the flat surface rests a transport ring 6 , the protrusions projecting beyond the rim 11 can have. In the 1 is the level of the top of the susceptor 2 lower than the level of the top of the transport ring 6 and in particular the top of the annular transport ring 6 surrounding ledge 11 , In the in the 3 and 4 variants shown is the radially projecting projection 11 completely in the bag 18 one, leaving the top of the susceptor 2 with the top of the transport ring 6 runs flush.

Radially inward of the ledge 11 makes the transport ring 6 a recessed annular shoulder. This ring shoulder forms a shoulder 9 on the edge 17 of a substrate 15 rests. The circular disc-shaped substrate 15 extends completely over a ring opening 7 of the transport ring 6 that from an opening wall 8th is surrounded. The shoulder 9 is the measure of the material thickness of the substrate 15 opposite the top of the transport ring 6 set lower, leaving the surface of the substrate 15 is flush with the top of the transport ring 6 ,

Between the shoulder 9 and the bottom of the transport ring 6 with which the transport ring 6 on the edge of the top 5 the substrate carrier socket 4 rests, there is a height difference, so that between top 5 and the bottom of the substrate 15 forms a cavity, the side of the opening wall 8th the ring opening 7 is limited. According to the invention, this cavity of the ring opening 7 from a plate 12 filled. Because of this plate 12 in the center of the ring opening 7 is, it is a middle plate.

With the heater 3 becomes the susceptor 2 heated from below. The in the susceptor 2 fed heat is in the substrate carrier socket 4 transported. The heat transfer is essentially heat conduction. Depending on the gas pressure in the process chamber 1 is the heat transfer between the bottom of the bag 18 and bottom of the substrate carrier socket 4 but also heat radiation. From the top 5 of the transport carrier socket 4 Heat is transferred to the transport ring 6 directed. This is done through the joint between the underside of the transport ring 6 and the top 5 the substrate carrier socket 4 ,

The plate 12 forms a heat transfer plate, because through it heat from the top 5 of the transport carrier socket 4 towards the substrate 15 is transported. The gap between the opening wall 8th and peripheral wall of the plate 12 is minimal, so that on the substrate 5 transferred heat is essentially the heat that passes through the plate 12 and the transport ring 6 to the substrate 15 is transmitted. The substrate 15 gives its heat to the gas in the process chamber 1 its heat radiates from the process chamber ceiling 31 , which is colder than the temperature of the substrate 15 ,

The heat transfer characteristic of the transport ring 6 and the plate 12 are coordinated so that the edge 17 of the substrate 15 and the central area 16 of the substrate 15 heat up in about the same way, that the surface temperature of the substrate in the edge area 17 essentially the surface temperature of the substrate 15 in the central area 16 equivalent. The lateral, in particular extending in the radial direction temperature gradient is thereby reduced to a level which has no technological significance. The heat transfer properties can be achieved by choosing a suitable material for the plate 12 be set. But it is also possible, the heat transfer properties by the material thickness of the plate 12 to adjust or by being below the bottom 14 the plate 12 a depression 22 in the substrate carrier socket 4 is introduced, which acts as an additional heat transport barrier.

The substrate 15 can on the top 13 the plate 12 rest. But it is also envisaged that the substrate is higher, so that between the bottom of the substrate 15 and top 13 the plate 12 a free space remains.

In the in the 1 to 7 illustrated embodiments, the gap between the peripheral wall of the plate 12 and the opening wall 8th the ring opening 7 designed so that the plate 12 on the top 5 the substrate carrier socket 4 remains lying when the transport ring 6 is lifted. To the transport carrier 6 To raise, a gripper, not shown engages under the radial annular projection 11 , Because the edge 17 of the substrate 15 on a shoulder 9 is, the substrate is raised with.

The in the 3 to 7 illustrated embodiments differ essentially in that the middle plate 12 having different diameters.

With the in the 5 illustrated embodiment, a lift-off function is also possible. For this purpose are the transport ring 6 and the plate 12 on surveys 32 extending from the flat top of the substrate carrier socket 4 protrude. Between transport ring 6 or plate 12 and substrate carrier socket 4 a slight gap forms, which is the lifting of the transport ring 6 facilitated. In the embodiment, the surveys 32 formed by balls which engage in blind holes such that a portion of the spherical surface protrudes from the blind bore. The diameter of the ball is slightly larger than the depth of the blind hole. In a variant, not shown, but the surveys and the same material from the substrate carrier base 4 be educated.

The figures also show a the bottom of the bag 8th springing centering pin 19 , the one opening 20 the substrate carrier socket 4 reaches through and into a sack opening 21 the plate 12 engages so that the location of the plate 12 with the help of the pin 19 is centerable.

In the in the 8th and 9 illustrated embodiment forms the peripheral wall of the plate 12 a radially projecting edge 24 from that of a section of the opening wall 8th can be attacked. The opening wall 8th thus forms a radially inwardly directed projection, which under the radially outwardly directed edge portion 24 the plate 12 lies. This has the consequence that when lifting the transport ring 6 the plate 12 with raised.

The in the 7 and 11 illustrated embodiments show a transport ring 6 , the down-facing ring-shaped process 23 having. This serves to increase the heat transfer from the susceptor to the transport ring 6 , In the in the 7 . 10 and 11 illustrated embodiments is at least a portion of the substrate carrier socket 4 in one below the ring opening 7 arranged further annular cavity of the transport ring 6 , Again, as in the in the 1 to 6 illustrated embodiments of the diameter of the substrate carrier socket 4 greater than the diameter of the center plate 12 so that the transport ring 6 at least with a radially inwardly located annular portion on the upper side of the substrate carrier base 4 supported.

In the in the 7 . 10 and 11 illustrated embodiments is the edge portion 12 ' the middle plate 12 also on a ring step 29 of the ring process 23 on, so he together with the transport ring 6 from the substrate carrier socket 4 is liftable. The ring process 23 relies on a recessed ring step 28 the substrate carrier socket 4 from. The ring step 28 surrounds the central region of the substrate carrier socket 4 ,

At the in 11 illustrated embodiment, a central region of the substrate carrier socket 4 also from a ring process 23 surrounded by the transport ring. Again, there is a border section 12 ' the plate 12 on a ring step 29 on, which forms a parallel plane to the shoulder 9 or to the underside of the transport ring or to the top of the transport ring. However, here forms the edge area 12 ' a grading.

The 12 and 13 show a separator with which a substrate 15 from the transport ring 6 is separable. From a base plate of the separator 25 protrude different lengths vertical pins 26 . 27 from. The longer pins grouped around the center of the base plate 26 grab through the ring opening 7 of the transport ring 6 through, so when Putting on a substrate 15 carrying transport ring 6 on the pins 26 the substrate 5 from the transport ring 6 is lifted. The transport ring 6 can be on the shorter, radially outer pins 27 be put on.

The substrate 15 can then be taken with another gripper on its edge to be transported.

The in the 12 and 13 illustrated device 25 is also suitable for the substrate 15 to separate from an arrangement in which the plate 12 together with the transport ring 6 from the substrate carrier socket 4 is lifted. In this case, the plate is supported 12 on the inner pins 26 from. The edge of the substrate 15 But dominates the edge of the plate 12 so that the substrate 15 can be bordered by a gripper.

The transport of the plate 12 together with the transport ring 6 is beneficial if the substrate 15 from a still hot process chamber 1 to be taken. The plate 12 then not only has the function of a heat transport member during the process, but also the function of a heat capacity. While during thermal treatment of the substrate 15 in the process chamber 1 the thermal transition is important, with the ring opening 7 of the transport ring 6 filling plate 12 has the same thermal transition as the ring 6 , is the plate during transport of the wafer 15 able to store heat as a temperature capacity, leaving the substrate 15 in the central area 16 cooling at about the same speed as in the central area 17 , Thus, even during transport, only a slight lateral temperature gradient forms on the surface of the substrate or in the volume of the substrate.

With the solution according to the invention, the temperature behavior of the substrate during transport has also been improved over the prior art. Homogeneous cooling of the substrate is possible since the substrate is cooled by way of the plate, which consists in particular of graphite. Within the process chamber, the substrate is also heated more homogeneously than is possible in the prior art. Nevertheless, because of the edge-side projection of the substrate 15 over the plate 12 a simple separation of the substrate from the carrier device possible.

The plate-like plate 12 may consist of the same material, from which also the substrate carrier socket 4 or the transport ring 6 consists. As a material is graphite, molybdenum or quartz or other suitable material into consideration.

All disclosed features are essential to the invention. The disclosure of the associated / attached priority documents (copy of the prior application) is hereby also incorporated in full in the disclosure of the application, also for the purpose of including features of these documents in claims of the present application. The subclaims characterize in their optionally sibling version independent inventive developments of the prior art, in particular to make on the basis of these claims divisional applications.

LIST OF REFERENCE NUMBERS

1

process chamber

2

susceptor

3

heater

4

Substrate support pedestal

5

top

6

transport ring

7

ring opening

8th

aperture wall

9

supporting shoulder

10

wall

11

head Start

12

center plate

12 '

edge section

13

top

14

bottom

15

substratum

16

Central area

17

border area

18

bag

19

spigot

20

opening

21

opening

22

deepening

23

Annular extension

24

edge

25

separating device

26

pen

27

pen

28

annular step

29

annular step

30

flank

31

Process chamber ceiling / gas inlet

32

survey

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10232731 A1 [0002]
• US6001183 [0003]
• US 2011/0171380 A1 [0004]
• EP 1094502 A2 [0004]
• US 6217663 B1 [0004]
• DE 102012106796 [0005]
• DE 102012111167 [0007]

Claims (10)

Device for thermal treatment of a semiconductor substrate ( 15 ) with a bottom of a process chamber ( 1 ), from a heater ( 3 ) heatable susceptor ( 2 ), one to process chamber ( 1 ) facing top ( 5 ) having substrate carrier base ( 4 ), with one on the substrate carrier base ( 4 ) attachable transport ring ( 6 ), which has a ring opening ( 7 ) surrounding shoulder ( 9 ) has to support the edge ( 17 ) one over the ring opening ( 7 ) extending substrate ( 15 ), the substrate ( 15 ) by heat transport from the substrate carrier base ( 4 ) and through the transport ring ( 6 ) is heated, characterized in that the ring opening ( 7 ) from a plate ( 12 ) between substrate ( 15 ) and substrate carrier socket ( 4 ) lies. Device according to claim 1 or in particular according thereto, characterized in that the heat transfer property of the plate ( 12 ) so the heat transfer property of the on the base ( 4 ), the shoulder ( 9 ) forming section of the transport ring ( 6 ) is adapted such that, when heated from the process chamber bottom, the surface temperature of the substrate ( 5 ) in the region of the substrate center ( 16 ) substantially the surface temperature of the substrate edge ( 17 ) corresponds. Device according to one or more of the preceding claims or in particular according thereto, characterized in that the material thickness of the plate ( 12 ) is slightly smaller than the distance of the top of the substrate carrier base ( 4 ) from the bottom ( 14 ) of the substrate ( 15 ). Device according to one or more of the preceding claims or in particular according thereto, characterized in that the plate ( 12 ) together with the transport ring ( 6 ) from the substrate carrier base ( 4 ) is removable. Device according to one or more of the preceding claims or in particular according thereto, characterized in that the edge ( 24 ) of the plate ( 12 ) the opening edge ( 8th ) of the transport ring ( 6 ) slightly overlaps. Device according to one or more of the preceding claims or in particular according thereto, characterized by an annular extension ( 23 ) of the transport ring ( 6 ) standing on an annular step ( 28 ) of the substrate carrier pedestal ( 4 ) and a step edge ( 30 ) of a central region of the substrate carrier base ( 4 ) surrounds. Device according to one or more of the preceding claims or in particular according thereto, characterized by a in a central opening ( 21 ) of the plate ( 12 ) projecting centering pin ( 19 ). Device according to one or more of the preceding claims or in particular according thereto, characterized in that the substrate carrier base ( 4 ) is a disc-shaped body which is in a bag ( 18 ) of a susceptor ( 2 ), which from below by means of a heater ( 3 ) is heated. Device according to one or more of the preceding claims or in particular according thereto, characterized in that the transport ring ( 6 ) and the plate ( 12 ) on a substantially planar surface of the substrate support base ( 4 ) rest. Device according to one or more of the preceding claims or in particular according thereto, characterized in that the otherwise flat surface of the upper side of the substrate carrier base ( 4 ) local surveys ( 32 ) comprising the transport ring ( 6 ) or the plate ( 12 ) with respect to the surface of the substrate carrier pedestal ( 4 ) spaced in particular 0.1 to 0.5 mm.

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