JP2011216591A - Sample carry-in/out operation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve sample production efficiency by eliminating as much moisture as possible remaining in a gas in the load lock chamber by introducing a dry nitrogen gas when carrying the sample between the load lock chamber of a semiconductor processing apparatus and an atmospheric carry-in/out means since reduction of foreign objects with a minute particle diameter is called for that are produced from a semiconductor manufacturing apparatus in association with miniaturization of the semiconductor elements, substantially controlling condensed water produced by temperature change of the gas at the time of pressure reduction and evacuation, and reducing faulty patterns arising from foreign objects adherent to the sample by the dripping of the condensed water.SOLUTION: For the sample carry-in/out operation between a load lock chamber 9a and an atmospheric carry-in/out means, a dry nitrogen gas is introduced and humidity in the load lock chamber 9a is reduced, and the gas introduction member 40, made up of a porous material when introducing the dry nitrogen gas, is set up on the top surface of the load lock chamber lid 21 that faces the sample table 14a.

Description

  The present invention relates to a sample transport processing method in a semiconductor manufacturing apparatus, and more particularly, to a sample transport processing method for reducing transport foreign matters at the time of loading / unloading of a sample in a processing apparatus.

  In the manufacture of semiconductor devices, foreign matter on the submicron level affects each manufacturing process. For example, in a semiconductor device manufacturing process, foreign matter attached on a sample forming a semiconductor device serves as a mask and an accurate pattern is not formed, which may result in a decrease in manufacturing yield.

  The foreign matter is generated due to various factors. For example, there is a case where a minute particle or the like falls from the inside of the semiconductor manufacturing apparatus during transportation in the semiconductor manufacturing apparatus and becomes a foreign matter on the sample.

  Some semiconductor manufacturing apparatuses perform sample processing under reduced pressure. At that time, in order to shorten the transport processing time for the transport processing of the sample, there is a case where a rapid exhaust process is performed during a decompression processing operation from the atmospheric pressure.

  At this time, the gas during decompression and exhaustion may be subjected to a rapid decompression process to lower the gas temperature and cause condensation of moisture. When moisture in the gas is condensed, the condensed moisture particles fall on the sample. The sample is then subjected to a predetermined process, but during the quality inspection of the sample, traces of condensed water that have fallen on the sample are regarded as a defective pattern of the sample, which is a cause of reducing the yield of the product.

  As described above, there is a further demand for reduction of fine particle size foreign substances generated from a semiconductor manufacturing apparatus as semiconductor elements are miniaturized.

  The present invention has been made in order to solve the above-mentioned problems, and the object of the present invention is to introduce dry nitrogen gas during the sample loading / unloading process between the load lock chamber and the atmospheric transfer means of the semiconductor processing apparatus, Moisture remaining in the gas in the load lock chamber is eliminated as much as possible, generation of condensed water due to gas temperature change during decompression exhaust is greatly suppressed, and pattern defects due to foreign substances adhering to the sample due to falling condensed water are reduced. However, it is to improve the production efficiency of the sample.

  The object is to introduce dry nitrogen gas into the sample loading / unloading processing operation between the load lock chamber and the atmospheric transfer means to reduce the humidity in the load lock chamber.

  In addition, a gas introduction member made of a porous material is installed on the upper surface facing the sample when dry nitrogen gas is introduced.

In the present invention, the productivity of the sample can be improved by the above means without increasing the amount of fine particulate foreign matter adhering to the surface of the sample.

  As described above, according to the present invention, it is possible to improve the productivity of the sample while suppressing the minute adhered foreign matter remaining on the sample surface after the plasma treatment. Therefore, it is possible to manufacture a semiconductor device with high reliability and high production efficiency.

FIG. 1 is a plan view showing a schematic configuration of a semiconductor manufacturing apparatus used in the present invention. (Example 1) FIG. 2 is a cross-sectional view showing a schematic configuration of a vacuum transfer container disposed in the semiconductor manufacturing apparatus used in the present invention. (Example 1) FIG. 3 is a graph showing the relationship between water temperature and water vapor pressure. (Example 1) FIG. 4 is a diagram showing the relationship between relative humidity and atmospheric pressure dew point. (Example 1) FIG. 5 is a graph showing the relationship between the elapsed time during decompression and gas temperature. (Example 1) FIG. 6 is a schematic configuration diagram (normal gas supply arrangement) showing a cross section of the load lock chamber. (Conventional example) FIG. 7 is a schematic configuration diagram showing a cross section of the load lock chamber (when a gas supply member is installed with a large area porous material). (Example 1)

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a semiconductor manufacturing apparatus having a vacuum transfer container according to the present invention. The semiconductor manufacturing apparatus 1 shown in FIG. 1 includes two processing units, that is, an atmospheric processing unit 17 and a vacuum processing unit 19 in which a cassette is installed. The vacuum side processing unit 19 carries the sample 2 into the vacuum transfer container 6 for vacuum processing the sample 2 (2a, 2b, 2c), the plurality of vacuum processing chambers 7 (7a, 7b, 7c, 7d), and the vacuum processing chamber 7. A load lock chamber 9 (9a, 9b) that can be switched between an air atmosphere and a vacuum atmosphere is provided.

  The vacuum processing chamber 7 (7a, 7b, 7c, 7d) and the load lock chamber 9 (9a, 9b) are vacuum chambers in which the inside is reduced to a vacuum level equivalent to the inside of the vacuum transfer container 6 and the pressure is maintained. A mounting table 12 having a mounting surface on which a sample to be processed is mounted is arranged on the upper surface of the vacuum processing chamber. In particular, the sample is processed in a state where it is mounted on a mounting table 12 (12a, 12b, 12c, 12d) disposed in the vacuum processing chamber 7 (7a, 7b, 7c, 7d).

  Within the vacuum transfer container 6, there are mounting tables 12 (12 a, 12 b, 12 c, 12 d) and load lock chambers 9 (9 a, 9 b) disposed in the respective vacuum processing chambers 7 (7 a, 7 b, 7 c, 7 d). A vacuum transfer robot 8 for transferring a sample to and from the sample stage 14 (14a, 14b) is disposed. The vacuum transfer robot 8 includes two robot arms (8a, 8b), each of which carries a sample on its upper surface and transfers the sample between the mounting tables.

  Further, the vacuum processing chamber 7 (7a, 7b, 7c, 7d) and the load lock chamber 9 (9a, 9b) and the vacuum transfer container 6 are partitioned so that the sample is transferred in the opening. A gate unit 16 (16a, 16b, 16c, 16d, 16e, 16f) having a gate and a gate valve for opening and closing the gate is disposed.

  The atmosphere-side processing unit 17 is arranged under atmospheric pressure, and has a plurality of cassette mounting tables 10 (10a, 10b, 10c) on which the cassettes 3 (3a, 3b, 3c) that can store a plurality of samples are placed on the upper surface. And a vertical direction, left and right so that a sample in a cassette placed on a cassette placing table 10 placed in the atmospheric carrying container 11 can be inserted and removed. An atmospheric transfer means 4 such as a robot arm configured to be movable in a direction, a mechanism 5 for aligning a sample, a vacuum transfer container 6 and an atmospheric transfer container 11 are connected to each other to obtain an atmospheric pressure and a vacuum pressure. And a plurality of load lock chambers 9 (9a, 9b) that can be switched to each other.

  The load lock chamber 9 (9a, 9b) is connected to the atmospheric transfer container 11. The inside of the load lock chamber 9 (9a, 9b) is configured so that the pressure can be changed between a pressure equivalent to the atmospheric pressure (atmospheric pressure) outside the apparatus and a pressure equivalent to that in the vacuum transfer container 6. ing.

  Between the load lock chamber 9 (9a, 9b) and the atmospheric transfer container 11, gate units 18 (18a, 18b) are arranged, respectively, via the gates in the gate units 18 (18a, 18b). The gate can be opened and closed by driving the gate valve provided in the gate unit 18 while communicating with the atmospheric transfer container.

  FIG. 2 shows a schematic configuration of the vacuum transfer container 6, the load lock chamber 9, the vacuum side gate unit 16, and the atmosphere side gate unit 18. The vacuum transfer container 6 includes a vacuum transfer container body 6a, a lid 6b, and a vacuum transfer robot 8. A part of the vacuum transfer container 6 is used for exchanging a sample with the load lock chamber 9 (9a, 9b). A vacuum side gate unit 16 (16e, 16f) is installed, and an atmosphere side gate unit 18 (18a, 18b) is installed at the other end of the load lock chamber 9 (9a, 9b).

  Embodiments of the present invention will be described with reference to FIGS. An example of the flow of sample processing when using a semiconductor manufacturing apparatus is shown below. One sample 2a to be processed is taken out from the cassette 3a mounted on the cassette mounting table 10a by the atmospheric transfer means 4 and passed through the mechanism 5 for aligning the sample, and the load lock chamber 9a adjusted to atmospheric pressure. Is carried in by the atmospheric transfer means 4 through the atmospheric gate unit 18a.

  The load lock chamber 9a is evacuated by an evacuation unit (not shown), and is decompressed to a pressure equivalent to that of the vacuum transfer container 6 that has been evacuated to a predetermined pressure in advance. Thereafter, the sample is taken out from the sample mounting table 14a in the load lock chamber by the vacuum transfer robot 8 provided in the vacuum transfer container 6 through the vacuum side gate unit 16e, and for example, the vacuum processing chamber 7b through the vacuum side gate unit 16b. Is mounted on a sample mounting table 12b.

  A sample processed under a predetermined condition in the vacuum processing chamber 7b is taken from above the sample mounting table 12b in the vacuum processing chamber 7b by a vacuum transfer robot 8 provided in the vacuum transfer container 6 via the vacuum side gate unit 16b. For example, the sample is taken out and placed on the sample placing table 14b provided in the load lock chamber 9b through the vacuum side gate unit 16f.

  Thereafter, the load lock chamber 9b is pressurized to atmospheric pressure by a purge means (not shown). The sample returned to the atmospheric pressure is carried out from the wafer mounting table 14b installed in the load lock chamber 9b by the atmospheric transfer means 4 via the atmospheric gate unit 18b, and is mounted on, for example, the cassette mounting table 10c. A series of processing is completed after being stored in the cassette 3c.

  In the present invention, the amount of foreign matter generated on the sample during sample transport in the semiconductor manufacturing apparatus is reduced, and the load lock chamber 9 (9a, 9b) and the atmospheric transport means 4 shown in FIG. And the decompression / evacuation process in the load lock chamber.

  FIG. 3 shows the relationship between the temperature of water and the water vapor pressure, and FIG. 4 shows the relationship between the relative humidity and the atmospheric dew point when the semiconductor manufacturing apparatus is installed in a room at room temperature of 25 ° C.

  The semiconductor manufacturing equipment was installed in a clean room, and the gate valve was opened in the atmosphere-side load lock chamber and the humidity in the load lock chamber during sample transport was measured. The measured humidity was approximately 3.5% in this case.

  Moisture in the gas at a temperature range where the atmospheric dew point is lower than the intersection (about −19 ° C.) where the broken line indicating the relationship between the relative humidity and the atmospheric dew point shown in FIG. Is likely to condense.

  FIG. 5 shows an example showing the relationship between the elapsed time (arbitrary unit) of the decompression exhaust processing time of the load lock chamber 9 (9a, 9b) and the gas temperature in the load lock chamber 9. FIG. 5 shows the relationship between the elapsed exhaust time and the gas temperature when the diameter of the orifice installed in the exhaust pipe (not shown) is 6 mm. The gas temperature during the decompression process is lowered to about −38 ° C. at the lowest temperature, which causes a considerable temperature drop.

  According to the result shown in FIG. 5, the gas temperature in the load lock chamber 9 is lowered to about −38 ° C., and it is estimated that condensation of moisture contained in the gas occurs.

  On the other hand, if the humidity in the load lock chamber 9 is moved to a lower humidity side, the moisture contained in the gas becomes a very small amount, and it can be expected to prevent condensation of moisture during the vacuum exhaust treatment.

  In order to prevent moisture from condensing during the vacuum exhaust process, dry nitrogen gas is introduced so as to keep the indoor humidity at 1% or less before the load lock chamber 9 is vacuum exhausted.

  When loading / unloading the sample 2 into / from the load lock chamber 9 (9a, 9b), from the opening operation of the gate unit 18 to the loading / unloading of the sample 2 in the chamber by the conveying means and the closing operation of the gate unit 18 During this time, dry nitrogen gas is continuously introduced into the load lock chamber 9 so that atmospheric gas flows into the load lock chamber and moisture in the chamber does not increase. By maintaining the humidity of the load lock chamber 9 before decompression exhaust at 1% or less, condensation of moisture in the gas during decompression exhaust can be almost eliminated. For this reason, it is possible to significantly suppress the generation of condensed moisture in the load lock chamber gas, and to obtain an effect of reducing pattern defects due to adhered foreign matters on the sample due to the fall of condensed water.

  As shown in FIG. 7, when introducing dry nitrogen gas from the gas supply pipe 30 into the load lock chamber 9a, a gas introduction member 40 made of a porous material is provided on the sample mounting table 14a in the load lock chamber 9a. Installed on the load lock chamber lid 21 so as to face each other.

  The gas supply amount per unit area is suppressed by installing the gas introduction member 40 and increasing the gas supply area. For this reason, compared with the case where a gas supply pipe (including a gas filter (not shown)) having an outer diameter of about 6 mm is used for the load lock chamber lid 20 of FIG. 6 without using a porous material, the per unit area of the gas supply surface. This makes it possible to suppress the gas supply rate.

  Fluid energy to the foreign matter due to the gas flow rate of the dry nitrogen gas supplied into the load lock chamber 9 is suppressed, so that the foreign matter that adheres to the wall or falls on the bottom surface of the container can be suppressed. For this reason, the effect which can suppress further the generation amount of the foreign material which falls on a sample is acquired.

DESCRIPTION OF SYMBOLS 1 Semiconductor manufacturing apparatus 2 Sample 3 Cassette 4 Atmospheric transfer means 5 Wafer alignment mechanism 6 Vacuum transfer container 7 Vacuum processing chamber 8 Vacuum transfer robot 9 Load lock chamber 9a Load lock chamber 9b Load lock chamber 10 Cassette mounting table 11 Atmospheric transfer container 12 Wafer mounting table 14 Wafer mounting table 14a Wafer mounting table 14b Wafer mounting table 16 Gate unit 17 Atmosphere side processing unit 18 Gate unit 19 Vacuum side processing unit 20 Load lock chamber lid 21 Load lock chamber lid 30 Gas supply piping 40 Gas introduction member

Claims (2)

  In a sample transfer processing method between a load lock chamber and an atmospheric transfer means of a semiconductor processing apparatus for plasma processing a sample, the sample is transferred between the atmospheric transfer means while flowing dry nitrogen gas into the load lock chamber. A sample transport method characterized by the above.   2. The sample transport processing method according to claim 1, wherein when the dry nitrogen gas is introduced, a gas introduction member made of a porous material is installed on an upper surface of a load lock chamber lid facing the sample, and the gas introduction member is The dry nitrogen gas is introduced into the load lock chamber through a sample transporting method.

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