JP2010258317A - Heat treatment device, and method of manufacturing heat-treated wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique capable of improving treatment efficiency while preventing degradation of quality due to a dopant element in a wafer. <P>SOLUTION: In an anneal treatment device 1 including a treatment chamber 10 for executing an anneal treatment to a waver W mounted on a boat 33, a scavenger 21 arranged adjacently to the treatment chamber 10 for temporarily housing a leaked gas, and a transfer chamber 32 for transferring the wafer W to the boat 33 extracted from the treatment chamber 10, packing pieces 19, 20, 22 of the scavenger 21 are each formed with a member having phosphorus concentration not larger than predetermined concentration, and a step of housing the boat 33 in the treatment chamber 10, an anneal treatment step of executing an anneal treatment and a step of moving the boat 33 with the wafer W after the anneal treatment mounted thereon from the treatment chamber 10 to the transfer chamber 32 are executed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heat treatment apparatus that heats a wafer and performs a predetermined process, and a heat-treated wafer manufacturing method that manufactures a heat-treated wafer that has been heated and subjected to a predetermined process.

  2. Description of the Related Art Conventionally, a heat treatment apparatus is known that heats a wafer and performs a predetermined heat treatment such as annealing, epitaxial treatment, or oxidation treatment.

  For example, the annealing process is a process for increasing the crystal integrity of the wafer surface by setting the wafer at a high temperature of about 1200 degrees in an argon atmosphere. In this annealing treatment, it is desirable to make the surface resistivity distribution of the annealed wafer (annealed wafer) flat (uniform).

  Further, in the heat treatment apparatus, it is required to shorten the time required for the heat treatment and improve the wafer production efficiency.

  For example, a technique for improving the production capacity by cooling a wafer by injecting a cooling fluid onto the wafer is known (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 7-130752

  For example, by pulling out a heat treatment chamber in a heat treatment apparatus in a relatively high temperature state, the treatment chamber can be opened quickly and the wafer can be quickly cooled, so that the throughput in the heat treatment apparatus is improved. It is possible.

  However, when the wafer is pulled out at a relatively high temperature in the heat treatment apparatus, for example, the surface resistivity distribution of the wafer depends on an element (dopant element) serving as a dopant such as P (phosphorus) or B (boron). There was a problem that the flatness was not achieved and the quality deteriorated.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique capable of improving the efficiency of processing while preventing deterioration in quality due to a dopant element in a wafer.

  In order to achieve the above object, the present invention has been made paying attention to the possibility that the quality of the wafer may be deteriorated due to the influence of members other than the heat treatment chamber, and the first aspect of the present invention. The heat treatment apparatus includes a heat treatment chamber for performing heat treatment on wafers placed on a boat, a transfer chamber for transferring wafers to the boat taken out from the heat treatment chamber, and a boat from the heat treatment chamber to the transfer chamber. And a scavenger for storing gas leaked during heat treatment so as not to leak into the transfer chamber, around the range of movement of the boat from the heat treatment chamber to the transfer chamber. The scavenger located is constituted by a member having a predetermined dopant element concentration of a predetermined concentration or less. According to the heat treatment apparatus, when the boat is moved from the heat treatment chamber to the transfer chamber, generation (sublimation) of a predetermined dopant element from the scavenger member can be appropriately reduced. It is possible to appropriately reduce the adhesion of the dopant element to the dummy wafer or the like. For this reason, it can reduce that a dopant element is spread | diffused to a wafer in the heat processing with respect to a subsequent wafer, and can suppress the fall of the quality of a wafer.

  In the heat treatment apparatus, the predetermined concentration may be a concentration of 150 ppm or less. According to such a heat treatment apparatus, generation of dopant elements can be effectively reduced. In the heat treatment apparatus, the predetermined concentration may be a concentration of 50 ppm or less. Generation of dopant elements can be reduced more effectively.

  In order to achieve the above object, a heat treatment apparatus according to the second aspect of the present invention heats a wafer placed on a boat to perform a predetermined process, and transfers the wafer to the boat. In the heat treatment apparatus including the transfer chamber, the members around the range of movement of the boat from the heat treatment chamber to the transfer chamber are configured by members having a predetermined dopant element concentration of a predetermined concentration or less. According to the heat treatment apparatus, when the boat is moved from the heat treatment chamber to the transfer chamber, it is possible to appropriately reduce generation (sublimation) of a predetermined dopant element from members around the boat movement range. It is possible to appropriately reduce the adhesion of the dopant element to the like. For this reason, it can reduce that a dopant element is spread | diffused to a wafer in the heat processing with respect to a subsequent wafer, and can suppress the fall of the quality of a wafer.

  In order to achieve the above object, a heat treatment apparatus according to the third aspect of the present invention is for performing a heat treatment on a wafer placed on a boat and transferring the wafer to the boat taken out from the heat treatment chamber. And a scavenger provided around the range of movement of the boat from the heat treatment chamber to the transfer chamber and for accommodating gas leaked during heat treatment so as not to leak into the transfer chamber. In the heat treatment, the packing member for preventing gas leakage from the scavenger to the outside is formed of a member having a predetermined dopant element concentration of a predetermined concentration or less.

  In order to achieve the above object, a heat-treated wafer manufacturing method according to a fourth aspect of the present invention is a heat-treated wafer manufacturing method for manufacturing a desired wafer by performing a heat treatment on a wafer with a heat treatment apparatus. The apparatus includes a heat treatment chamber for performing heat treatment on wafers placed on the boat, a transfer chamber for transferring wafers to the boat taken out of the heat treatment chamber, and a range of movement of the boat from the heat treatment chamber to the transfer chamber. And a scavenger for temporarily storing gas leaked during heat treatment so as not to leak into the transfer chamber, and a packing member for preventing gas leakage from the scavenger to the outside is a predetermined dopant. A housing step for housing the boat in which the concentration of the element is less than a predetermined concentration and the wafer is placed in the heat treatment chamber; To have a heat treatment step of performing a predetermined heat treatment, and after the process moving step of moving the boat wafer heat treatment is performed is placed in the transfer chamber from the heat treatment chamber. According to such a heat-treated wafer manufacturing method, when the boat is moved from the heat treatment chamber to the transfer chamber, generation (sublimation) of a predetermined dopant element from members around the boat movement range can be appropriately reduced. It is possible to appropriately reduce the adhesion of the dopant element to the boat or the like. For this reason, it can reduce that a dopant element is spread | diffused to a wafer in the heat processing with respect to a wafer, and can suppress the fall of the quality of a wafer.

  In the heat treatment wafer manufacturing method, the post-treatment moving step may move the boat from the heat treatment chamber to the transfer chamber when the temperature of the wafer reaches a temperature near 700 degrees. According to the heat treated wafer manufacturing method, since the boat is moved from the heat treatment chamber to the transfer chamber with the wafer temperature in the vicinity of 700 ° C., the processing for taking out the wafer from the boat can be started at an early stage, and the wafer processing is performed. Efficiency can be improved.

It is a schematic block diagram of the annealing treatment apparatus which concerns on one Embodiment of this invention. It is a figure explaining the member of the scavenger of the annealing treatment apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows each process of the annealing wafer manufacturing method by the annealing treatment apparatus which concerns on one Embodiment of this invention. It is a figure explaining the annealed wafer manufactured by the annealed wafer manufacturing method concerning one embodiment of the present invention, and the annealed wafer manufactured by the annealed wafer manufacturing method concerning a comparative example. It is a figure which shows the outline | summary of the contamination mechanism of the annealed wafer manufactured by the annealed wafer manufacturing method which concerns on a comparative example.

  Embodiments of the present invention will be described with reference to the drawings. The embodiments described below do not limit the invention according to the claims, and all the elements and combinations described in the embodiments are essential for the solution of the invention. Is not limited.

  First, a vertical annealing apparatus which is an example of a heat treatment apparatus according to an embodiment of the present invention will be described.

  FIG. 1 is a schematic configuration diagram of an annealing apparatus according to an embodiment of the present invention.

  The annealing apparatus 1 includes a reaction tube 11 that accommodates a wafer W (for example, a diameter of 300 mm) and forms a processing chamber (heat treatment chamber) 10 for performing the annealing process. The reaction tube 11 is formed in, for example, a cylindrical shape made of quartz (SiO 2) with the upper end closed and the lower end opened. In the present embodiment, the boat 33 on which a plurality of wafers W are placed is accommodated in the processing chamber 10 and the annealing process is executed. Therefore, the inner diameter of the reaction tube 11 is larger than the diameter (for example, 300 mm) of the wafer W to be processed.

  A heat equalizing tube (liner tube) 12 for making the heat distribution in the reaction tube 11 uniform is provided outside the reaction tube 11 so as to surround the reaction tube 11. Further, a gas introduction pipe 15 for introducing a process gas used for the external annealing process into the processing chamber 10 is inserted in the approximate center of the upper part of the reaction tube 11. A heater 13 for heating the inside of the reaction tube 11 is provided outside the soaking tube 12.

  The lower end of the reaction tube 11 is supported by a substantially cylindrical flange 14 via, for example, an O-ring (not shown). The reaction tube 11 and the flange 14 may be integrated.

  A gas exhaust pipe 16 for exhausting gas from the inside of the processing chamber 10 is connected to the side wall of the flange 14. The gas introduction pipe 15 is disposed in the upper part of the reaction pipe 11 through the vicinity of the flange 14.

  A scavenger 21 is provided so as to surround the outer periphery of the flange 14 so as not to leak a gas related to processing. The scavenger 21 is mounted below the wall portion 17 so as to surround the periphery of the outer periphery of the flange 14 and the wall portion 17, and seals the space formed by the outer periphery of the flange 14 and the wall portion 17. Scavenger cover 18.

  FIG. 2 is a view for explaining a scavenger cover of the annealing apparatus according to one embodiment of the present invention.

  The scavenger cover 18 closely contacts the side surface of the flange 14 and the scavenger cover 18, and causes the ring-shaped ring packing 19 to prevent gas leakage from the periphery of the flange 14, and the scavenger cover 18 and the wall portion 17. A scavenger packing 20 for preventing gas leakage from a joint portion between the scavenger cover 18 and the wall portion 17, a window plate portion 21 for closing a window portion that can be confirmed without removing the scavenger cover 18, It has a cover packing 22 for bringing the window plate portion 21 into close contact with the window portion and preventing gas leakage. In the present embodiment, the packings 19, 20, and 22 are positioned around the movement range of the boat 33 when the annealed boat 33 is moved from the processing chamber 10 to the transfer chamber 32. It is easily affected by heat from the boat 33 and the like. In particular, the ring packing 19 is susceptible to heat because the boat 33 moves inside the ring packing 19. Therefore, in the present embodiment, the phosphorus (doping element) concentration for each of the packings 19, 20, and 22 is set to a predetermined concentration or less to reduce the generation of phosphorus. As the predetermined concentration, for example, a concentration of 150 ppm or less is preferable, and a concentration of 50 ppm or less is more preferable.

  Returning to the description of FIG. 1, a transfer chamber 32 defined by a casing 31 is formed below the processing chamber 10. In the transfer chamber 32, the wafer W is transferred to the boat 33, that is, the wafer W to be processed is loaded into the boat 33, and the wafer W (annealed wafer) that has been annealed is removed from the boat 33. Processing is performed.

  The boat 33 can be loaded with a plurality of wafers W. In the boat 33, for example, dummy wafers DW are placed at one or more upper wafer placement positions and one or more lower wafer placement positions, and a wafer to be processed is placed at a wafer placement position in an intermediate portion. W is placed. The dummy wafer DW is continuously placed over a plurality of batches. The boat 33 is supported by a heat insulating mechanism 39 for blocking heat transfer between the boat 33 and the lower side. At the lower end of the heat insulating mechanism 39, a seal cap 34 is provided for contacting the lower surface of the flange 14 and sealing the processing chamber 10.

  The seal cap 34 is supported below by a support arm 35 of the boat elevator 36. The support arm 35 is connected to the elevating unit 38. The elevating part 38 is formed with a thread groove, and is movable in the vertical direction in which a motor (not shown) rotates the feed screw shaft 37. Therefore, the boat 33 can be moved in the vertical direction.

  Thereby, the boat 33 can be raised and accommodated in the processing chamber 10 from the transfer chamber 32, and the boat 33 in the processing chamber 10 can be lowered and carried out to the transfer chamber 32.

  Next, an annealed wafer manufacturing method will be described.

  FIG. 3 is a flowchart showing each step of the annealed wafer manufacturing method by the anneal processing apparatus according to the embodiment of the present invention. This annealing wafer manufacturing method is repeatedly executed for each batch.

  First, in the transfer chamber 32, a plurality of wafers W to be processed are transferred (loaded) to the boat 33 (step S1).

  Next, the boat 33 is raised by the boat elevator 36 to accommodate the boat 33 in the processing chamber 10 (step S2). At this time, the seal cap 34 of the boat 33 is pressed against the lower surface of the flange 14, and the processing chamber 10 is hermetically sealed.

  Next, while the argon gas is introduced, the temperature inside the processing chamber 10 is increased, and after reaching a predetermined temperature (for example, 1000 degrees or more), an annealing process is performed (step S3).

  Next, after executing the annealing process for a predetermined time, when the temperature of the wafer subjected to the annealing process (processed wafer: annealed wafer) becomes equal to or lower than a predetermined temperature (approximately 700 degrees), the boat elevator 36 33 is lowered to move the boat 33 from the processing chamber 10 to the transfer chamber 32 (step S4), and in the transfer chamber 32, the wafer W is cooled after waiting for a predetermined time (for example, 30 minutes) (step S5). Thereafter, the annealed wafer W is taken out from the boat 33 (step S6). Here, in this embodiment, since the phosphorus concentration of each packing 19, 20, and 22 of the scavenger 21 is set to a predetermined concentration or less, even if the boat 33 passes through the vicinity of each packing 19, 20, and 22 The amount of phosphorus generated can be suppressed.

  FIG. 4 is a diagram illustrating an annealed wafer manufactured by the annealed wafer manufacturing method according to one embodiment of the present invention and an annealed wafer manufactured by the annealed wafer manufacturing method according to the comparative example.

  In the present embodiment, in the annealing apparatus 1 using a packing having a phosphorus concentration of 50 ppm or less as the packings 19, 20, and 22 of the scavenger 21, the wafer W to be processed is placed on the boat 33 and the boat 33 is placed in the processing chamber. 10, the annealing process is performed, and after the temperature of the wafer W reaches 700 ° C. after the annealing process, the boat 33 is lowered from the processing chamber 10 and moved to the transfer chamber 32. A series of processes for extracting W was repeatedly performed.

  In Comparative Example 1, in the annealing apparatus using the packing having a phosphorus concentration of 1800 ppm as the scavenger packing, the wafer W to be processed is placed on the boat 33, the boat 33 is moved to the processing chamber, and the annealing process is performed. After the annealing process, the temperature of the wafer W reaches 500 degrees, and then the boat 33 is lowered from the processing chamber and moved to the transfer chamber 32, and then a series of processing for taking out the wafer W from the boat 33 is repeated. Executed.

  In Comparative Example 2, in the annealing apparatus using the packing having a phosphorus concentration of 1800 ppm as the scavenger packing, the wafer W to be processed is placed on the boat 33, the boat 33 is moved to the processing chamber, and the annealing process is performed. After the annealing process, the temperature of the wafer W reaches 700 ° C., and then the boat 33 is lowered from the processing chamber 10 and moved to the transfer chamber 32. Thereafter, a series of processing for taking out the wafer W from the boat 33 is performed. Repeatedly executed.

  As shown in FIG. 4, the manufactured annealed wafer according to this example has a value S (σ / AVE) obtained by dividing the standard deviation of the in-plane resistivity by the average of the in-plane resistivity. 27%, which is much lower than the value S (35.5%) of the annealed wafer of Comparative Example 2, and lower than the value S (3.11%) of the annealed wafer of Comparative Example 1. is there. From this, it can be seen that the in-plane resistivity of the annealed wafer obtained by this example is more uniform than that of the annealed wafer obtained by Comparative Example 1 and Comparative Example 2.

  Further, as shown in FIG. 4, the manufactured annealed wafer according to the present example has a ratio of the surface layer resistivity to the bulk resistivity of 1.00, and the value of the annealed wafer of Comparative Example 2 (35. 73), which is much lower than the value (1.05) of the annealed wafer of Comparative Example 1. From this, it can be seen that the annealed wafer obtained in this example has a more uniform resistivity in the depth direction than the annealed wafer obtained in Comparative Example 1 and Comparative Example 2.

  In addition, the annealed wafer manufactured according to the embodiment can make the in-plane resistivity and the resistivity in the depth direction uniform, and can maintain a high extraction temperature. Can be kept high.

  FIG. 5 is a diagram showing an outline of a contamination mechanism of an annealed wafer manufactured by the annealed wafer manufacturing method according to the comparative example. In the figure, phosphorus is indicated by a circle.

  When the boat 33 is lowered into the transfer chamber 32 after the annealing process, the boat 33 passes near the scavenger 21 packing (in particular, the ring packing 19) as shown in FIG. 5A. . At this time, since the temperature of the packing rises due to the influence of the temperature of the boat 33, the higher the concentration of phosphorus contained in the packing, the more phosphorus is generated from the packing, and the higher the temperature of the boat 33, the more It can be estimated that the amount of increases. Thus, when phosphorus is generated, it can be estimated that phosphorus drifts in the transfer chamber 32 and the processing chamber 10.

  As a result, phosphorus drifting in the transfer chamber 32 adheres to the boat 33, the heat insulating mechanism 39, and the dummy wafer DW, and the wafer W to be processed (next batch) is transferred to the boat 33 as shown in FIG. 5B. At the time of transfer, phosphorus may adhere to the boat 33, the heat insulating mechanism 39, and the dummy wafer DW, or may adhere to the wall surface of the processing chamber 10 (the inner surface of the reaction tube 12).

  For this reason, as shown in FIG. 5C, when the boat 33 on which the wafer W is placed is accommodated in the processing chamber 10 and the annealing process is executed, the boat 33, the heat insulating mechanism 39, the dummy wafer DW, the reaction tube 12 and the like are attached. It can be inferred that the phosphorus that has been scattered scatters, adheres to and diffuses on the wafer W, and degrades the quality of the wafer W.

  For this reason, as described above, by setting the concentration of phosphorus in the packing to a predetermined concentration or less, generation of phosphorus from the packing when the boat 33 passes can be reduced, and the deterioration of the quality of the wafer W can be reduced. The take-out temperature when taking out the boat 33 can be kept high, and the production efficiency of the wafer W can be improved.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not restricted to embodiment mentioned above, It can apply to other various aspects.

  For example, in the above embodiment, the phosphorus concentration of each packing 19, 20, 22 is set to a predetermined concentration or less. However, the present invention is not limited to this, and all members constituting the scavenger 21 are set to a predetermined concentration. The following may be used. Moreover, although the example which makes the member of a scavenger below predetermined density | concentration was shown in the said embodiment, for example, like the member of the transfer chamber 32, all the members desired in the movement range of the boat 33 are predetermined density | concentration. The following may be used.

  In the above embodiment, the packings 19, 20, and 22 are set to a predetermined concentration or less. However, for example, only some packings (for example, the ring packing 19) that have a large influence on the contamination of the wafer W are phosphorylated. In this case, the quality of the wafer W can be reduced.

  In the above embodiment, the phosphorus concentration of each member is set to a predetermined concentration or less. However, the present invention is not limited to this, and other doping elements such as boron instead of phosphorus or together with phosphorus. You may make it make it below a predetermined density | concentration about (element used for doping).

  In the above-described embodiment, the example in which the present invention is applied to the annealing apparatus has been described. However, the present invention is not limited to this. For example, an oxidation apparatus that oxidizes a wafer or an epitaxial growth that grows an epitaxial layer on the wafer. The present invention can also be applied to an apparatus. In short, the present invention can be applied to any heat treatment apparatus that performs heat treatment.

DESCRIPTION OF SYMBOLS 1 Annealing apparatus, 11 Reaction tube, 12 Soaking tube, 13 Heater, 14 Flange, 15 Gas introduction tube, 16 Gas exhaust tube, 17 Wall part, 18 Scavenger cover, 19 Ring packing, 20 Scavenger packing, 21 Scavenger, 31 Case Body, 32 transfer chamber, 33 boat, 34 seal cap, 35 support arm, 36 boat elevator, 37 feed screw shaft, 38 elevating part, 39 heat insulation mechanism, W wafer, DW dummy wafer.

Claims (7)

A heat treatment chamber for heat-treating the wafers placed on the boat; a transfer chamber for transferring the wafer to the boat taken out from the heat treatment chamber; and the boat from the heat treatment chamber to the transfer chamber In a heat treatment apparatus provided with a scavenger provided around the moving range of the gas, and containing gas leaked during the heat treatment so as not to leak into the transfer chamber,
The heat processing apparatus which comprises the said scavenger located in the vicinity of the moving range of the said boat from the said heat processing chamber to the said transfer chamber by the member whose density | concentration of a predetermined dopant element is below a predetermined density | concentration. The heat treatment apparatus according to claim 1, wherein the predetermined concentration is a concentration of 150 ppm or less. The heat treatment apparatus according to claim 2, wherein the predetermined concentration is a concentration of 50 ppm or less. In a heat treatment apparatus comprising a heat treatment chamber for performing a predetermined process by heating a wafer placed on a boat, and a transfer chamber for transferring a wafer to the boat,
The heat processing apparatus which comprises the member around the movement range of the said boat from the said heat processing chamber to the said transfer chamber by the member whose density | concentration of a predetermined dopant element is below a predetermined density | concentration. A heat treatment chamber for performing heat treatment on the wafer placed on the boat; a transfer chamber for performing transfer of the wafer to the boat taken out from the heat treatment chamber; and the boat from the heat treatment chamber to the transfer chamber. A scavenger provided around the moving range, and for containing the gas leaked during the heat treatment so as not to leak into the transfer chamber,
A heat treatment apparatus in which, during the heat treatment, a packing member for preventing gas leakage from the scavenger to the outside is formed of a member having a predetermined dopant element concentration of a predetermined concentration or less. A heat treatment wafer manufacturing method for manufacturing a desired wafer by performing heat treatment on a wafer by a heat treatment apparatus,
The heat treatment apparatus includes: a heat treatment chamber for performing heat treatment on wafers placed on a boat; a transfer chamber for transferring wafers to the boat taken out from the heat treatment chamber; and a transfer chamber from the heat treatment chamber to the transfer chamber. A scavenger provided around the range of movement of the boat to temporarily store the gas leaked during the heat treatment so as not to leak into the transfer chamber, and to prevent gas leakage from the scavenger to the outside. The packing member for preventing is composed of a member having a predetermined dopant element concentration of a predetermined concentration or less,
A housing step for housing the boat on which the wafer is placed in the heat treatment chamber;
A heat treatment step of heating the wafer and performing a predetermined heat treatment;
And a post-treatment moving step of moving the boat on which the heat-treated wafer is placed from the heat treatment chamber to the transfer chamber. The heat treatment wafer manufacturing method according to claim 6, wherein, in the post-treatment moving step, the boat is moved from the heat treatment chamber to the transfer chamber when the temperature of the wafer reaches a temperature in the vicinity of 700 degrees.

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