JP2009224447A - Substrate cleaning method, method of manufacturing semiconductor apparatus, and substrate cleaning apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To raise a manufacturing yield of a semiconductor apparatus by removing films deposited on a bevel portion of a semiconductor substrate by a cleaning. <P>SOLUTION: A substrate cleaning method includes the steps of: rotating the semiconductor substrate around a rotation axis; cooling the bevel portion at a perimeter of the rotating semiconductor substrate by means of a cooling mechanism formed in a primary angular position to the rotation axis; and heating the bevel portion of the rotating semiconductor substrate by means of a heating mechanism formed in a secondary angular position different from the primary angular position to the rotation axis, wherein the films deposited on a front surface of the semiconductor substrate in the bevel portion are peeled off by alternately heating and cooling the bevel portion of the semiconductor substrate. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates generally to the manufacture of semiconductor devices, and more particularly to a technique for cleaning the outer periphery of a semiconductor wafer.

In the manufacturing process of a semiconductor device, various films are formed on a semiconductor wafer. These films include, for example, organic films such as resist films, and low dielectric constant insulating films such as SiC films and SiOCH films. The organic film is generally formed by a coating method, while the low dielectric constant insulating film is formed by a coating method or an MOCVD method.
JP-A-6-53199 JP 2004-119715 A

  In any of these film formation methods, film formation occurs not only on the main surface of the wafer but also on the end side surface (bevel portion). The film formed on the wafer bevel portion in this way is used during substrate handling. It is desirable to remove it because it easily peels off due to contact and impact and becomes the main particle source.

  A technique for directly polishing the wafer bevel portion with a dedicated brush or polishing tape has been proposed for cleaning to remove the film formed on the wafer bevel portion. However, this technique cannot be applied to a process in the middle of a wafer process in which moisture cannot be used because the wafer surface is covered with pure water during processing.

  A technique for removing the film from the wafer bevel portion by selectively dry-etching the wafer bevel portion has also been proposed, but this method requires a vacuum device and a plasma generator, and the required device configuration becomes large. In addition, there is a problem that costs increase.

  According to one aspect, the present invention provides a method for rotating a semiconductor substrate around a rotation axis and a cooling mechanism formed at a first angular position with respect to the rotation axis. The step of cooling the outer peripheral portion and the outer peripheral portion of the rotating semiconductor substrate are heated by a heating mechanism formed at a second angular position different from the first angular position with respect to the rotation axis. And a step of cleaning the substrate.

  According to another aspect, the present invention provides a rotation mechanism for rotating a semiconductor substrate around a rotation axis, a first angular position with respect to the rotation axis, and dry ice on the outer periphery of the semiconductor substrate. A cooling mechanism for biasing, and a heating mechanism that is formed at a second angular position different from the first angular position with respect to the rotation axis and that heats the outer peripheral portion of the semiconductor substrate, and rotates. There is provided a substrate cleaning apparatus, wherein the outer peripheral portion of the semiconductor substrate is cooled and heated alternately by the cooling mechanism and the heating mechanism.

  According to the present invention, the bevel portion on the outer periphery of the rotating semiconductor substrate is alternately and repeatedly heated and cooled by the cooling mechanism and the heating mechanism, thereby peeling the film formed on the outer peripheral bevel portion with a simple configuration. -It can be removed. As a result, the generation of particles in the subsequent processes is reduced, and the manufacturing yield of the semiconductor device is improved.

  FIG. 1 shows a configuration of a substrate cleaning apparatus 10 according to an embodiment of the present invention.

  Referring to FIG. 1, the substrate cleaning apparatus 10 includes a processing container 11 having an exhaust port 11E formed therein, and a stage 11B that is rotated around a rotation axis X by a motor 11M in the processing container 11. The substrate to be processed W is held on the stage 11B. Examples of the substrate W to be processed include a silicon wafer having a diameter of 200 mm or 300 mm.

  The processing container 11 further includes a detachable lid member 11A that is movable up and down as indicated by an arrow. When the lid member 11A is attached to the processing container 11, together with the processing container 11, a processing space is provided. Define 11S.

  The lid member 11A is provided with a nozzle 11N that blows a jet of dry gas such as nitrogen gas, dry air, Ar gas, etc., substantially coincident with the rotation axis X, and the dry gas emitted from the nozzle 11N is The surface of the substrate W to be processed flows in the radial direction and is discharged from the exhaust port 11E.

  In the substrate cleaning apparatus 10 of FIG. 1, the dry ice block 11C held by the holder 11F abuts on the bevel portion (portion “A” in FIG. 2) of the outer periphery of the substrate W to be cooled. To do. That is, the dry ice block 11C and the holder 11F constitute a cooling mechanism 11G for the bevel portion. In the substrate cleaning apparatus 10, a heating mechanism 11H made of, for example, a resistance heater is disposed at a position opposite to the rotation axis X with respect to the position where the dry ice block 11C abuts. The cooling mechanism 11G is driven by another motor 11D in a direction approaching / separating the substrate to be processed W as indicated by an arrow in FIG. 1, whereby the dry ice block 11C is moved to the substrate to be processed W. It is energized by the bevel part.

  FIG. 2 is a plan view showing the periphery of the substrate W to be processed in the substrate cleaning apparatus 10 of FIG.

  Referring to FIG. 2, the dry ice block 11 </ b> C extends along the outer periphery of the substrate W to be processed, for example, over a length L of 50 to 100 mm, and is on the rotation axis X of the dry ice block 11 </ b> C. On the other hand, it can be seen that the heating mechanism 11H is provided on the opposite side, that is, at a position separated by an angular distance of 180 ° from the dry ice block 11C.

  Therefore, when the substrate to be processed W is rotated around the rotation axis X in such a configuration, the temperature at the point A in the outer peripheral bevel portion of the substrate to be processed W increases with time as shown in FIG.・ Repeat descending alternately.

  FIG. 4 is an enlarged view showing the peeling process of the film 12 by cooling and heating at the point A. As shown in FIG.

  Referring to FIG. 4, the substrate W to be processed includes an organic film such as a resist film or a film 12 made of a low dielectric constant insulating film such as a SiC film or a SiOCH film in the state (I). As shown in the state of (II), it is formed not only in the main part of the bevel part Wb along the outer periphery but also in part of the bevel part Wb. In the bevel portion Wb, a part of the film 12 contracts and becomes brittle at the same time, and a crack 12c is generated. When the substrate to be processed W is a silicon wafer, the thickness t of the wafer W is typically 750 μm, and the bevel portion Wb is formed on the outer periphery of the wafer W with a width r of, for example, 0.3 mm. Yes.

  In the state (II) of FIG. 4, dry ice particles enter the crack 12c from the dry ice block 11C. The intruded dry ice particles are vaporized and expanded by being heated by the heating mechanism 11H. The film 12 is peeled from the wafer W. The peeled film 12 is quickly removed from the surface of the wafer W to the exhaust port 11E by the dry gas jet from the nozzle 11N, and the substrate cleaning apparatus 10 performs a desired substrate cleaning.

  Thus, in this embodiment, the film 12 can be efficiently peeled off from the bevel portion Wb by alternately performing cooling and heating.

  FIG. 5 is a diagram showing how the dry ice block 11C comes into contact with the bevel portion Wb.

  Referring to FIG. 5, the dry ice block 11C is held in a holder 11F (not shown) such that the angle θ with respect to the surface P of the wafer W can be changed from + 180 ° to −180 °. By driving the motor 11D, the bevel portion Wb is urged at the selected angle θ. In the illustrated example, the film 12 is formed only on the upper half of the bevel portion Wb, so the angle θ is set to about 45 °. On the other hand, if the film 12 is formed on the upper and lower surfaces of the bevel portion Wb, the desired substrate cleaning is simultaneously performed on the upper and lower surfaces of the bevel portion Wb by setting the angle θ to 90 °. be able to. If the film 12 is mainly formed in the lower half of the bevel portion Wb, the substrate can be preferentially cleaned in the lower half by setting the angle θ to, for example, 135 °. .

  When the dry ice block 11C is brought into contact with the bevel portion Wb in this manner, the initial dry ice block 11C changes to a shape having a recess 11c that matches the shape of the bevel portion Wb, as shown in FIG. The substrate cleaning apparatus 10 in FIG. 1 can be applied to the substrate W to be processed having bevel portions Wb of various shapes.

  In the substrate cleaning apparatus 10 of FIG. 1, when the rotational speed of the substrate W to be processed, that is, the rotational speed of the motor 11M is too large, the temperature change shown in FIG. 3 is reduced, and the peeling effect due to the desired film thermal expansion is reduced. . On the other hand, if the rotational speed of the motor 11M is too low, the throughput of substrate processing is reduced. For this reason, the rotation speed of the motor 11M in the substrate cleaning apparatus 10, and hence the rotation speed of the substrate W to be processed, is preferably set to 200 rpm or more and 1000 rpm or less in the case of a 300 mm diameter silicon wafer.

  The heater 11H is driven according to the rotational speed of the substrate W to be processed. More specifically, in the temperature change pattern of FIG. 3, the maximum temperature of the bevel portion Wb does not exceed 400 ° C. Driven. For this reason, the substrate cleaning apparatus 10 of FIG. 1 is provided with a controller 15 that detects the rotational speed of the motor 11M and controls the drive current of the heater 11H. For example, the controller 15 holds the correspondence relationship between the rotational speed of the motor 11M and the optimum driving current value of the heater 11H corresponding to this in the form of a lookup table, and detects the rotational speed of the motor 11M. The heater 11H is controlled with the corresponding optimum driving current.

  FIG. 7 shows a configuration of a substrate cleaning apparatus 10B according to a modification of the substrate cleaning apparatus 10 of FIG.

  Referring to FIG. 7, in the substrate cleaning apparatus 10B, the first cooling mechanism 11G1 having the same configuration as the cooling mechanism 11G including the dry ice block is formed at the first corner position, and the second corner position is at the second corner position. A heating mechanism 11H1 having the same configuration as the heating mechanism 11H including a heater is formed. Furthermore, a second cooling mechanism 11G2 having the same configuration as the cooling mechanism 11H is provided at a third angular position between the first angular position and the second angular position, and the first angular position A second heating mechanism 11H2 having a configuration similar to that of the heating mechanism 11H is provided at a fourth corner position between the third corner positions, and the third corner with respect to the second corner position. A third cooling mechanism 11G3 having the same configuration as the cooling mechanism 11G is provided at a fifth corner position on the opposite side of the position, and is opposite to the second corner position with respect to the fifth corner position. A third heating mechanism 11H3 having a configuration similar to that of the heating mechanism 11H is provided at the sixth corner position, and a seventh corner opposite to the fifth corner position with respect to the sixth corner position. The fourth cooling mechanism 11G4 having the same configuration as the cooling mechanism 11G is provided at the position, and the seventh angular position The eighth angular position of between the first angular position, the heating mechanism 11H similar to the fourth heating mechanism is provided.

  In the substrate cleaning apparatus 10B having such a configuration, since the number of heating mechanisms and cooling mechanisms provided around the substrate to be processed W is four times that of the configuration in FIG. 1, the substrate to be processed W is rotated at the same speed. In this case, as shown in FIG. 8, the temperature change at the point A corresponding to the bevel portion Wb occurs in a short period of 1/4 that in the case of FIG.

  When heating and cooling are repeated in such a short cycle, the temperature change of the bevel portion Wb is actually averaged, and there is a possibility that a sufficient temperature difference cannot be secured. The rotational speed of the substrate to be processed W needs to be set to 1/4 or less of the substrate cleaning apparatus 10 in FIG.

  FIG. 9 shows a part of a manufacturing process of a semiconductor device using the substrate cleaning apparatus 10 or 10B of FIG. 1 or FIG.

  Referring to FIG. 9, a resist film or a low-K film is formed in step 1 on a semiconductor substrate such as a silicon wafer on which elements such as transistors and capacitors are formed in the previous process. Then, in step 2, the semiconductor substrate on which the film or the low-K film is formed is introduced into the processing container 11 of the substrate cleaning apparatus 10 of FIG. 1 or the substrate cleaning apparatus 10B of FIG. Cleaning is performed.

  As described above, the cleaning process of the wafer bevel portion using the substrate cleaning apparatus of FIG. 1 or FIG. 7 is performed after the film forming process of the semiconductor device, particularly the resist film coating process and the low-K film forming process. Thus, the problem of a decrease in semiconductor device manufacturing yield due to particles detached from the bevel portion is effectively suppressed.

As mentioned above, although this invention was described about preferable embodiment, this invention is not limited to this specific embodiment, A various deformation | transformation and change are possible within the summary described in the claim.
(Appendix 1)
Rotating the semiconductor substrate around a rotation axis;
Cooling the outer peripheral portion of the rotating semiconductor substrate by a cooling mechanism formed at a first angular position with respect to the rotation axis;
Heating the outer peripheral portion of the rotating semiconductor substrate by a heating mechanism formed at a second angular position different from the first angular position with respect to the rotation axis;
A substrate cleaning method comprising:
(Appendix 2)
2. The substrate cleaning method according to claim 1, wherein, in the cooling step, the cooling mechanism biases dry ice to the outer peripheral portion of the semiconductor substrate.
(Appendix 3)
Furthermore, the board | substrate washing | cleaning method of Additional remark 1 or 2 including the process of spraying dry gas on the surface of the said semiconductor substrate rotating between the said cooling process and the said heating process.
(Appendix 4)
The substrate cleaning method according to claim 1, wherein the cooling mechanism and the heating mechanism are provided at positions facing each other across the semiconductor substrate.
(Appendix 5)
A method for manufacturing a semiconductor device, comprising a substrate cleaning step using the substrate cleaning method according to any one of appendices 1 to 4.
(Appendix 6)
A rotation mechanism for rotating the semiconductor substrate around the rotation axis;
A cooling mechanism that is formed at a first angular position with respect to the rotation axis and that urges dry ice to the outer periphery of the semiconductor substrate;
A heating mechanism that is formed at a second angular position different from the first angular position with respect to the rotation axis, and that heats the outer peripheral portion of the semiconductor substrate;
With
A substrate cleaning apparatus, wherein the outer peripheral portion of the rotating semiconductor substrate is alternately cooled and heated by the cooling mechanism and the heating mechanism.
(Appendix 7)
7. The substrate cleaning apparatus according to claim 6, wherein the cooling mechanism holds the dry ice such that an angle formed by the dry ice with respect to a surface of the semiconductor substrate can be changed.

It is a figure which shows the structure of the board | substrate cleaning apparatus by one Embodiment of this invention. It is a top view which shows the outline of the board | substrate cleaning apparatus of FIG. It is a figure which shows the temperature change induced | guided | derived to a bevel part by the board | substrate cleaning apparatus of FIG. It is a figure explaining the mode of cleaning of the bevel part by the substrate cleaning device of FIG. It is a figure which shows the mode of the contact of the dry ice block to the bevel part in the board | substrate cleaning apparatus of FIG. It is a figure which shows the example of the shape change of the dry ice block produced by contact | abutting to a bevel part. It is a figure which shows the modification of the board | substrate cleaning apparatus of FIG. It is a figure which shows the temperature change induced | guided | derived to a bevel part by the board | substrate cleaning apparatus of FIG. It is a flowchart which shows the manufacturing process of the semiconductor device including the board | substrate cleaning process of a bevel part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Substrate cleaning apparatus 11 Processing container 11A Lid member 11B Stage 11C Dry ice block 11c Concave part 11D Drive motor 11E Exhaust port 11F Dry ice holder 11G, 11G1-11G4 Cooling mechanism 11H, 11H1-11H4 Heating mechanism 11M Motor 11N Drying gas nozzle 11S Processing Space 12 Film 12c Crack W Wafer Wb Bevel

Claims (6)

Rotating the semiconductor substrate around a rotation axis;
Cooling the outer peripheral portion of the rotating semiconductor substrate by a cooling mechanism formed at a first angular position with respect to the rotation axis;
Heating the outer peripheral portion of the rotating semiconductor substrate by a heating mechanism formed at a second angular position different from the first angular position with respect to the rotation axis;
A substrate cleaning method comprising:   2. The substrate cleaning method according to claim 1, wherein in the cooling step, the cooling mechanism biases dry ice to the outer peripheral portion of the semiconductor substrate.   The substrate cleaning method according to claim 1, further comprising a step of blowing a dry gas on a surface of the rotating semiconductor substrate between the cooling step and the heating step.   The substrate cleaning method according to claim 1, wherein the cooling mechanism and the heating mechanism are provided at positions facing each other across the semiconductor substrate.   A method for manufacturing a semiconductor device, comprising a substrate cleaning step using the substrate cleaning method according to claim 1. A rotation mechanism for rotating the semiconductor substrate around the rotation axis;
A cooling mechanism that is formed at a first angular position with respect to the rotation axis and that urges dry ice to the outer periphery of the semiconductor substrate;
A heating mechanism that is formed at a second angular position different from the first angular position with respect to the rotation axis, and that heats the outer peripheral portion of the semiconductor substrate;
With
A substrate cleaning apparatus, wherein the outer peripheral portion of the rotating semiconductor substrate is alternately cooled and heated by the cooling mechanism and the heating mechanism.