JP2016136565A - Semiconductor manufacturing device and semiconductor manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor manufacturing device capable of manufacturing an oxide semiconductor with high mobility by heating an oxide semiconductor precursor thin film at a low temperature.SOLUTION: A semiconductor manufacturing device 10 manufactures an oxide semiconductor by processing a workpiece W including a substrate S and an oxide semiconductor precursor thin film P formed on the substrate S. The semiconductor manufacturing device 10 comprises a processing container 12 for housing the workpiece W, a treatment board 14 provided in the processing container 12 and for placing the workpiece W, a low pressure mercury lamp 16 provided in the processing container 12 so as to face the treatment board 14, a heater 18 for heating the treatment board 14, and a steam feeder 20 for feeding a gas containing steam into the processing container 12. The processing container 12 is partitioned into the lamp chamber 44 in which the low pressure mercury lamp 16 is arranged and the processing chamber 46 in which the treatment board 14 is arranged by a partition plate 22 transmitting ultraviolet light.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a semiconductor manufacturing apparatus and a semiconductor manufacturing method for manufacturing an oxide semiconductor having high mobility by processing an oxide semiconductor precursor thin film formed on a substrate.

  When the oxide semiconductor precursor thin film coated or printed on the substrate is baked to exhibit semiconductor characteristics, heating in an electric furnace is mentioned as the most general and simple method. However, firing at a temperature exceeding 300 ° C. is necessary to realize highly functional semiconductor characteristics, and it has been difficult to produce an oxide semiconductor by coating or printing on a base material such as a flexible plastic. In order to produce an oxide semiconductor by coating or printing on a base material such as plastic, a low temperature heating process is required. It is also important to suppress variations in the performance of a plurality of semiconductor devices manufactured in the same plane.

JP 2014-207431 A JP 2000-351918 A

  The present invention has been made in view of such circumstances, and provides a semiconductor manufacturing apparatus and a semiconductor manufacturing method for manufacturing an oxide semiconductor with high mobility by heating an oxide semiconductor precursor thin film at a low temperature. Objective.

  The present inventor has made it possible to reduce the firing temperature, improve the semiconductor performance, and to manufacture the semiconductor in the same plane by simultaneously performing ultraviolet light irradiation and heating in a high-humidity atmosphere in the firing process of the coated oxide semiconductor. It was found that device performance variation can be suppressed.

  A semiconductor manufacturing apparatus of the present invention is a semiconductor manufacturing apparatus for manufacturing an oxide semiconductor by processing a target object including a base material and an oxide semiconductor precursor thin film formed on the base material. A processing container for housing a body, a processing table provided in the processing container for mounting a target object, an ultraviolet lamp provided in the processing container so as to face the processing table, and a heater for heating the processing table And a water vapor supply machine for supplying a gas containing water vapor into the processing vessel.

  In the semiconductor manufacturing apparatus of the present invention, the ultraviolet lamp is a low-pressure mercury lamp, and the processing vessel is divided into a lamp chamber in which the low-pressure mercury lamp is arranged and a processing chamber in which the treatment table is arranged, and a partition through which ultraviolet light is transmitted. It is preferable that a plate is provided in the processing container and further has a discharge mechanism for discharging ozone generated in the lamp chamber to the outside of the processing container. Moreover, in the semiconductor manufacturing apparatus of this invention, it is preferable to further have a temperature control mechanism which controls a heater and maintains a process stand at the predetermined temperature of 100 to 300 degreeC.

  A semiconductor manufacturing method of the present invention is a semiconductor manufacturing method for manufacturing an oxide semiconductor by processing a target object including a base material and an oxide semiconductor precursor thin film formed on the base material, and the relative humidity Irradiation process of irradiating the oxide semiconductor precursor thin film with ultraviolet light while maintaining the object to be processed at a predetermined temperature of 100 ° C. to 200 ° C. in an atmosphere of 80% or more, and the object to be processed obtained in the irradiation process And a firing step of firing while maintaining a predetermined temperature of 200 ° C to 300 ° C. In the semiconductor manufacturing method of the present invention, the oxide semiconductor precursor thin film may be formed by applying or printing an oxide semiconductor precursor liquid containing indium nitrate, gallium nitrate, and zinc nitrate on a substrate. preferable.

  According to the present invention, an oxide semiconductor with high mobility can be obtained by low-temperature heat treatment. Moreover, the variation in the performance of the semiconductor device manufactured in the same plane can be suppressed.

The cross-sectional schematic diagram of the semiconductor manufacturing apparatus which concerns on embodiment of this invention. The graph which shows the transfer characteristic of the oxide semiconductor thin film obtained in the Example. 6 is a graph showing transfer characteristics of the oxide thin film obtained in Comparative Example 1. The graph which shows the transfer characteristic of the oxide thin film obtained by the comparative example 2.

  Hereinafter, a semiconductor manufacturing apparatus and a semiconductor manufacturing method of the present invention will be described based on embodiments and examples with reference to the drawings. The drawings schematically show a semiconductor manufacturing apparatus, constituent members of the semiconductor manufacturing apparatus, and peripheral members of the semiconductor manufacturing apparatus, and the dimensions and dimensional ratios on the drawings are different from the actual ones. Note that repeated explanation is omitted as appropriate. In addition, when “˜” is described between two numerical values to represent a numerical range, the two numerical values are also included in the numerical range.

  FIG. 1 schematically shows a cross section of a semiconductor manufacturing apparatus 10 according to an embodiment of the present invention. The semiconductor manufacturing apparatus 10 is an apparatus for processing an object to be processed W to manufacture an oxide semiconductor. The workpiece W is a plate-like member whose upper and lower surfaces are polygons such as squares and rectangles or circles, and whose thickness is 10 mm or less. Moreover, the to-be-processed object W is equipped with the base material S which consists of silicon, glass, etc., and the oxide semiconductor precursor thin film P formed on the base material S. The composition and manufacturing method of the oxide semiconductor precursor thin film P will be described later.

  The semiconductor manufacturing apparatus 10 includes a processing container 12, a processing table 14, a low-pressure mercury lamp 16 that is an ultraviolet lamp, a heater 18, a water vapor feeder 20, a partition plate 22, and a discharge mechanism 24. The processing container 12 is made of a metal such as aluminum or stainless steel, and is a hollow member whose main outer shape is a cylinder or a rectangular parallelepiped. A workpiece W is accommodated inside the processing container 12. Specifically, the workpiece W is placed on the processing table 14 provided in the processing container 12. The processing table 14 is a cylindrical member or prismatic member whose upper surface is a polygon such as a square or a rectangle or a circle, and is made of a material having resistance to ultraviolet light and condensation.

The low-pressure mercury lamp 16 is provided so as to face the processing table 14, that is, above the processing container 12. Further, the low-pressure mercury lamp 16 is driven at 100 VAC and uses a high-density grid-shaped synthetic quartz glass as a tube material. Further, the low-pressure mercury lamp 16 has an irradiation light intensity of 28 mWcm ⁻² at a position 5 mm below and an area that can be uniformly irradiated is 200 mm × 200 mm or more, and can be turned on and off from outside the processing container 12. The low pressure mercury lamp 16 fed from the power source 26 irradiates the oxide semiconductor precursor thin film P of the workpiece W with ultraviolet light having emission lines at wavelengths of 84.9 nm and 253.7 nm. Instead of the low-pressure mercury lamp 16, an ultraviolet lamp that emits ultraviolet light having a bright line other than the wavelengths 84.9 nm and 253.7 nm may be used.

  The heater 18 heats the processing table 14. By heating the processing table 14, the oxide semiconductor precursor thin film P is heated from the base material S side of the workpiece W. The heater 18 is connected to a temperature control mechanism 28, operates at 100 VAC, and can heat an area of 200 mm × 200 mm or more. The processing table 14 can be maintained at a predetermined temperature of 100 ° C. to 300 ° C. by the heater 18 and the temperature control mechanism 28. For this reason, the processing temperature of the to-be-processed object W can be kept substantially constant. The predetermined temperature may have a width. Moreover, monitoring and control of the temperature of the processing table 14 can be performed from outside the processing container 12.

  The steam supply machine 20 supplies a gas containing water vapor into the processing container 12 through the introduction pipe 40 and the introduction valve 42. That is, the water vapor feeder 20 is configured to heat water to generate water vapor and to supply the water vapor into the processing container 12 by compressed air. Instead of heating the water, water may be irradiated with ultrasonic waves to generate water vapor. Further, after water is put into the gas cleaning bottle, compressed air is allowed to flow through the gas cleaning bottle to generate bubbles violently, and a gas containing water vapor generated here may be supplied into the processing container 12. The relative humidity around the workpiece W is controlled by adjusting the amount of water vapor supplied from the water vapor feeder 20 into the processing container 12. That is, the relative humidity around the workpiece W can be increased by the water vapor feeder 20. A humidity monitor (not shown) is installed in the processing container 12.

  The partition plate 22 is made of an ultraviolet light transmissive member such as synthetic quartz and is installed in the processing container 12. Specifically, the partition plate 22 is disposed so as to separate the lamp chamber 44 in which the low-pressure mercury lamp 16 is disposed from the processing chamber 46 in which the processing table 14 is disposed. Therefore, the low-pressure mercury lamp 16 can be isolated from the processing chamber 46 having a large amount of water vapor, for example, a relative humidity of 80% or more, and the low-pressure mercury lamp 16 can be prevented. Further, the partition plate 22 can separate the lamp chamber 44 including the partition plate 22 from the processing chamber 46. Therefore, maintenance of the lamp chamber 44 such as replacement of the low-pressure mercury lamp 16 and cleaning of the lamp chamber 44 is facilitated.

  Further, the partition plate 22 may have a box-type structure that covers the low-pressure mercury lamp 16. This is because when the relative humidity in the processing chamber 46 is high, it is possible to suppress the intrusion of water vapor into the lamp chamber 44 and the formation of condensation on the surface of the low-pressure mercury lamp 16. In addition, a condensation prevention heater 48 is provided on the surface of the partition plate 22 on the processing chamber 46 side to suppress condensation on the surface of the partition plate 22 on the processing chamber 46 side. For cleaning, the partition plate 22 can be removed and carried out of the processing container 12.

  The discharge mechanism 24 is provided on the wall of the lamp chamber 44 and the outside thereof in order to discharge ozone generated in the lamp chamber 44 by ultraviolet light irradiated from the low-pressure mercury lamp 16 to the outside of the processing container 12. The discharge mechanism 24 includes a discharge valve 50, a discharge pipe 52, and a blower 54. When ozone is generated in the lamp chamber 44, the discharge valve 50 is opened automatically or manually, and the blower 54 driven by, for example, AC 100V is operated to discharge ozone out of the processing vessel 12. An exhaust pump may be used instead of the blower 54. An exhaust valve 56 is provided on the wall of the processing chamber 46 to prevent pressurization in the processing chamber 46. That is, when the pressure in the processing chamber 46 becomes high, the exhaust valve 56 is automatically or manually opened, and the gas in the processing chamber 46 is discharged out of the processing container 12 through the exhaust pipe 58.

  The gas discharged includes gas generated when an oxide semiconductor thin film is generated from the oxide semiconductor precursor thin film P, for example, nitrogen oxide or ammonia when the oxide semiconductor precursor is a metal nitrate. It is. Further, the semiconductor manufacturing apparatus 10 is provided with a jack 70 as an elevating mechanism for elevating the processing table 14. Since the height of the processing table 14 is changed by the lifting mechanism, the distance between the low-pressure mercury lamp 16 and the upper surface of the workpiece W can be controlled within an appropriate range of, for example, 10 mm to 100 mm. The lifting mechanism is configured so that the workpiece W does not contact the partition plate 22. Further, the processing container 12 is provided with a door (not shown) for taking in and out the workpiece W and performing maintenance in the processing container 12. The inside of the processing container 12 is airtight with the door closed.

  The semiconductor manufacturing method according to the embodiment of the present invention is a method of manufacturing an oxide semiconductor by processing the object to be processed W. The object to be processed is a predetermined temperature of 100 ° C. to 200 ° C. in an atmosphere having a relative humidity of 80% or more. An irradiation step of irradiating the oxide semiconductor precursor thin film with ultraviolet light while maintaining the temperature, and a baking step of baking the object to be processed obtained in the irradiation step at a predetermined temperature of 200 ° C. to 300 ° C. It has. That is, in the irradiation process, the object to be processed W is heated at a relatively low temperature of 100 ° C. to 200 ° C., and in the baking process, the object to be processed W obtained in the irradiation process is heated at a relatively high temperature of 200 ° C. to 300 ° C. To do. In the firing step, the workpiece W may not be irradiated with ultraviolet light, and the periphery of the workpiece W may not be 80% or higher in relative humidity.

  Specifically, an oxide semiconductor is manufactured by the following procedure. First, the workpiece W is prepared. For example, the to-be-processed object W provided with the oxide semiconductor precursor thin film P on the surface is producible by apply | coating or printing the liquid containing an oxide semiconductor precursor to the base material S. Examples of the oxide semiconductor precursor include metal salts such as zinc, copper, nickel, indium, cadmium, gallium, tin, rhodium, aluminum, or strontium.

  Examples of the metal salt include metal hydrochloride, sulfate, acetate, nitrate, and the like. Of these, nitrates having high water solubility are preferred. In particular, an oxide semiconductor when a liquid containing indium nitrate, gallium nitrate, and zinc nitrate is used as the oxide semiconductor precursor liquid has high mobility. Next, the door of the processing chamber 46 is opened, the workpiece W is placed on the processing table 14, and the door is closed. Then, the processing table 14 is adjusted to a predetermined height. Thereafter, the heater 14 is used to set the treatment table 14 at a predetermined temperature of 100 ° C. to 200 ° C., for example, at a temperature at which the oxide semiconductor precursor thin film P is thinned under high humidity and ultraviolet light irradiation. maintain.

  Next, a gas containing water vapor is supplied from the water vapor feeder 20 into the processing container 12 so that the relative humidity in the processing chamber 46 is 80% or higher, preferably 90% or higher. Then, the dew condensation prevention heater 48 and the low-pressure mercury lamp 16 are operated to irradiate the oxide semiconductor precursor thin film P with ultraviolet light (irradiation process). Thereafter, the operation of the low-pressure mercury lamp 16 and the supply of the gas containing water vapor from the water vapor feeder 20 are stopped, and the oxide semiconductor precursor thin film P is completed at a temperature at which the oxide semiconductor thin film formation is completed, for example, 200 ° C. to 300 ° C. The object W is fired while maintaining the treatment table 14 at a predetermined temperature (firing step). In the present embodiment, the irradiation process and the baking process are performed under atmospheric pressure. As described above, an oxide semiconductor thin film is generated from the oxide semiconductor precursor thin film P through the irradiation process and the baking process.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The content of the present invention is not limited to this embodiment.

(Example)
First, 0.238 g of indium nitrate, 0.012 g of gallium nitrate, 0.089 g of zinc nitrate, 3 mL of water, and 7 mL of 2-trifluoroethanol were mixed and stirred to prepare an oxide semiconductor precursor solution. . Next, this oxide semiconductor precursor solution was spin-coated on the surface of a silicon wafer with a thermal oxide film, and the to-be-processed object W in which the oxide semiconductor precursor thin film P was formed was produced. Then, the object to be processed W is placed on the processing table 14 of the semiconductor manufacturing apparatus 10, the temperature of the processing table 14 is maintained at 130 ° C., and the relative humidity around the object to be processed W is maintained at 90% or more. Then, the oxide semiconductor precursor thin film P was irradiated with ultraviolet light for 30 minutes.

Thereafter, the supply of the gas containing water vapor to the processing chamber 46 and the irradiation with ultraviolet light are stopped, the temperature of the processing table 14 is raised to 300 ° C. while the workpiece W is placed, and the atmospheric pressure is maintained while maintaining this temperature for 60 minutes. The to-be-processed object W was baked and the oxide thin film based on an Example was produced. The transfer characteristics of the obtained oxide thin film are shown in FIG. As shown in FIG. 2, it was revealed that the obtained oxide thin film was an oxide semiconductor having a saturation mobility of 4 cm ² V ⁻¹ g ⁻¹ . Hydroxyl radicals generated from water vapor decomposed by ultraviolet light decomposed nitrate ions contained in the precursor thin film, and this was removed from the oxide thin film by subsequent heating. It is done. In addition, it is considered that an appropriate amount of hydroxy radicals are bonded to the surface of the oxide thin film, which controls the excessive carrier transport, and thus shows good semiconductor characteristics.

In addition, when the to-be-processed object in which the oxide semiconductor precursor thin film which consists of this metal nitrate was formed on the surface was baked at 300 degreeC using the conventional electric furnace, the saturation mobility of the obtained oxide thin film was 1 cm It was about ² V ^-1 g ^-1 . By using the semiconductor manufacturing apparatus and the semiconductor manufacturing method of the present invention, an oxide semiconductor having a mobility of 3 cm ² V ⁻¹ g ⁻¹ or higher can be obtained. In addition, when a plurality of semiconductor devices are manufactured in the same plane using the semiconductor manufacturing apparatus of the present invention, performance, for example, variation in threshold voltage and saturation mobility of an oxide thin film, and hysteresis in transfer characteristics are suppressed. Successful.

(Comparative Example 1)
The oxide thin film which concerns on the comparative example 1 was produced like the Example except the point which changed the conditions of 90% or more of relative humidity of the Example into the relative humidity 50%. The transfer characteristics of the obtained oxide thin film are shown in FIG. As shown in FIG. 3, the oxide thin film did not exhibit semiconductor characteristics. The amount of hydroxyl radicals generated from water vapor decomposed by ultraviolet light was small, so that hydroxyl groups did not adhere to the surface of the oxide thin film, and oxygen defects were generated in the thin film during the oxide thin film formation process. This is probably because the density has become abnormally large.

(Comparative Example 2)
The oxide thin film which concerns on the comparative example 2 was produced like the Example except the point which did not irradiate the ultraviolet light to the oxide semiconductor precursor thin film P of the Example. The transfer characteristic of the obtained oxide thin film is shown in FIG. As shown in FIG. 4, although this oxide thin film exhibited semiconductor characteristics, hysteresis was observed, and variations were observed in the threshold voltage and saturation mobility. It is considered that the above phenomenon was observed because nitrate ions contained in the precursor thin film were not decomposed because they were not irradiated with ultraviolet light, and were present as free substances.

  The semiconductor manufacturing apparatus and semiconductor manufacturing method of the present invention can be used in fields such as electronic device manufacturing and flexible electronics.

DESCRIPTION OF SYMBOLS 10 Semiconductor manufacturing apparatus 12 Processing container 14 Processing stand 16 Low pressure mercury lamp 18 Heater 20 Steam supply machine 22 Partition plate 24 Discharge mechanism 26 Power supply 28 Temperature control mechanism 40 Introducing pipe 42 Introducing valve 44 Lamp chamber 46 Processing chamber 48 Condensation prevention heater 50 Exhaust Valve 52 Discharge pipe 54 Blower 56 Exhaust valve 58 Exhaust pipe 70 Jack W Processed object S Base material P Oxide semiconductor precursor thin film

Claims (5)

A semiconductor manufacturing apparatus for manufacturing an oxide semiconductor by processing a target object including a base material and an oxide semiconductor precursor thin film formed on the base material,
A processing container for containing the object to be processed;
A processing table provided in the processing container and on which the object to be processed is placed;
An ultraviolet lamp provided in the processing container so as to face the processing table;
A heater for heating the processing table;
A water vapor supply machine for supplying a gas containing water vapor into the processing vessel;
A semiconductor manufacturing apparatus. In claim 1,
The ultraviolet lamp is a low-pressure mercury lamp,
The processing container is divided into a lamp chamber in which the low-pressure mercury lamp is disposed and a processing chamber in which the processing table is disposed, and a partition plate that transmits ultraviolet light is provided in the processing container.
A semiconductor manufacturing apparatus further comprising a discharge mechanism for discharging ozone generated in the lamp chamber out of the processing container. In claim 1 or 2,
The semiconductor manufacturing apparatus which further has a temperature control mechanism which controls the said heater and maintains the said process stand at the predetermined temperature of 100 to 300 degreeC. A semiconductor manufacturing method for manufacturing an oxide semiconductor by processing a target object including a base material and an oxide semiconductor precursor thin film formed on the base material,
An irradiation step of irradiating the oxide semiconductor precursor thin film with ultraviolet light while maintaining the object to be processed at a predetermined temperature of 100 ° C. to 200 ° C. in an atmosphere having a relative humidity of 80% or more;
A firing step in which the object to be processed obtained in the irradiation step is fired while being maintained at a predetermined temperature of 200 ° C. to 300 ° C .;
A semiconductor manufacturing method comprising: In claim 4,
The semiconductor manufacturing method by which the said oxide semiconductor precursor thin film is formed by apply | coating or printing on the said base material the oxide semiconductor precursor liquid containing an indium nitrate, a gallium nitrate, and a zinc nitrate.

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