Substrate processing apparatus, substrate processing method, method for producing semiconductor device, and program

Abstract

Provided is a technology that enables suppression of temperature rise of a substrate.　The present invention comprises: a low-order mode resonator in which a substrate is disposed in a direction perpendicular to an electric field; an oscillator that supplies microwave power to the resonator in a pulsed manner; a thermometer that measures the temperature of the substrate; and a control unit configured to be able to control the oscillator such that the temperature of the substrate reaches a prescribed temperature.

Description

Substrate processing apparatus, substrate processing method, semiconductor device manufacturing method, and program

[0001] The present disclosure relates to a substrate processing apparatus, a substrate processing method, a method for manufacturing a semiconductor device, and a program.

[0002] One process in the manufacturing process of semiconductor devices is a modification process, typically an annealing process, in which a substrate in a processing chamber is heated using a heating device to change the composition or crystalline structure of a thin film formed on the surface of the substrate or to repair crystal defects in the formed thin film. A heat treatment method using microwave irradiation, as disclosed in Patent Document 1, for example, has been considered as a modification process.

[0003] JP 2015-070045 A

[0004] When the microwave irradiation method is a multi-mode method in which a plurality of electromagnetic field modes coexist, the electric field and the magnetic field are related, and there is a possibility that the substrate itself will be heated by magnetic field heating.

[0005] The present disclosure provides a technique that enables substrate processing while suppressing a temperature rise in the substrate.

[0006] According to one aspect of the present disclosure, there is provided a technology including: a low-mode resonator in which a substrate is positioned perpendicular to an electric field; an oscillator that supplies microwave power to the resonator in pulses; a thermometer that measures the temperature of the substrate; and a control unit configured to be able to control the oscillator so that the temperature of the substrate becomes a predetermined temperature.

[0007] According to the present disclosure, it is possible to process a substrate while suppressing a temperature rise in the substrate.

[0008] Fig. 4 is a diagram illustrating the configuration of a microwave irradiation device in one aspect of the present disclosure. Fig. 5 is a diagram illustrating an example of a waveform in which microwave output is pulse-controlled, used in the microwave irradiation device shown in Fig. 1. Fig. 6 is a diagram illustrating the effect of annealing by the microwave irradiation device shown in Fig. 1. Fig. 7 is a diagram illustrating the configuration of a microwave irradiation device in another aspect of the present disclosure. Fig. 8 is a top view of the microwave irradiation device shown in Fig. 4.

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that all drawings used in the following description are schematic, and the dimensional relationships, ratios, etc. of the elements shown in the drawings do not necessarily correspond to the actual ones. Furthermore, the dimensional relationships, ratios, etc. of the elements do not necessarily correspond between multiple drawings. Furthermore, substantially identical elements between multiple drawings are assigned the same reference numerals, and each element is described in the drawing in which it first appears, and its description is omitted in subsequent drawings unless otherwise necessary. Unless otherwise specified in the specification, each element is not limited to one, and multiple elements may be present.

[0010] The configuration of a microwave irradiation apparatus as a substrate processing apparatus according to one embodiment of the present disclosure will be described with reference to FIG.

[0011] The microwave irradiation device 10 includes an oscillator 101, a semiconductor amplifier 102, a power monitor 103, a slug tuner 104, a resonator 110, a thermometer 111, and a controller 120. The oscillator 101 and the semiconductor amplifier 102 constitute a solid-state microwave source (semiconductor microwave source, semiconductor power supply) 100. The solid-state microwave source 100 may also include the power monitor 103 and the slug tuner 104.

[0012] The oscillator 101 oscillates microwaves, performs frequency / pulse control and output control, and supplies pulsed power. The semiconductor amplifier 102 amplifies the output of the oscillator 101. The power monitor 103 measures the microwaves (traveling waves) and reflected waves input to the resonator 110. The slug tuner 104 is an impedance matching device that transmits microwaves and matches impedance.

[0013] The resonator 110 is a cavity resonator that excites a low-order mode. The resonator 110 separates the electric field and magnetic field distribution in space and excites a low-order mode in which the electric field is at the center. Examples of low-order modes include the TM0n0 mode (n is a natural number equal to or less than 3) and the TE10n mode (n is a natural number equal to or less than 3). These modes are called single modes. The resonator 110 is also called a single-mode cavity (single-mode resonator).

[0014] The substrate W is placed so that the direction of the electric field (E) is perpendicular to the surface of the substrate W. For example, the resonator 110 has a cylindrical shape, and in the TM010 mode, the electric field direction is the axial direction of the cylinder (the left-right direction in FIG. 1). In the TE101 mode, the electric field direction is the up-down direction in FIG. 1. The resonator 110 constitutes a processing chamber for processing the substrate W.

[0015] The thermometer 111 serving as the thermometer side section is constituted by, for example, a radiation thermometer, and measures the temperature of the substrate W. The radiation thermometer is a non-contact type thermometer that can be placed outside the resonator 110, and is capable of suppressing the influence of heating by microwaves and also suppressing the influence on the microwaves. The measured temperature is sent to the controller 120. The controller 120 serving as a control section is capable of adjusting the frequency, pulse frequency, duty ratio, and output of the microwaves oscillated by the oscillator 101 based on the measured temperature. This allows the temperature of the substrate W to be maintained at a preset temperature.

[0016] The TM010 mode can be used for substrates W having a size (diameter) of about 20 mm or less, and the TE101 mode can be used for substrates W having a diameter of about 100 mm or less.

[0017] The substrate W is a semiconductor substrate (wafer), such as a silicon (Si) substrate, a silicon carbide (SiC) substrate, a gallium nitride (GaN) substrate, or a diamond (SP3) substrate.

[0018] The frequency of the microwave generated by the oscillator 101 is preferably controlled to be in the frequency range of 13.56 MHz to 24.125 GHz, more preferably 2.45 GHz or 5.8 GHz.

[0019] The controller 120 is configured as a computer including a CPU (Central Processing Unit) and a storage device. The storage device is configured as a computer-readable recording medium.

[0020] The storage device readably stores a control program for controlling the operation of the substrate processing apparatus, a process recipe describing the procedures and conditions for the annealing (modification) process, and the like. The process recipe is a combination of procedures in the substrate processing step that are executed by the controller 120 to obtain a predetermined result, and functions as a program. Hereinafter, the process recipe, control program, and the like are collectively referred to simply as a program. In this specification, the term "program" may refer to only a process recipe, only a control program, or both.

[0021] The CPU is configured to read and execute a control program from the storage device and to read a process recipe, and to control the output adjustment operation of the oscillator 101 based on the thermometer 111, the ON / OFF operation of the microwave output from the oscillator 101, and the like, in accordance with the contents of the read process recipe.

[0022] As shown in FIG. 2 , the oscillator 101 supplies microwaves in a pulsed manner, with the oscillator 101 being ON for a first predetermined time (T1) and OFF for a second predetermined time (T2). The first and second predetermined times are variable. For example, the pulse frequency can be set from 1 to 100 kHz. In other words, the pulse period (T = T1 + T2) can be set from 10 microseconds to 1 second. Furthermore, the duty ratio (D = T1 / T) can be set from 10 to 90%, for example. With this setting, microwaves are output at a frequency equal to the semiconductor power supply frequency (e.g., 2.45 GHz), and the output power per unit time decreases depending on the duty ratio.

[0023] The pulse frequency and duty ratio of the microwave output from the oscillator 101 can be set from the input / output device of the controller 120. In this setting, the operator first checks the parameter settings, then inputs the pulse value (pulse frequency) and duty ratio, and finally checks the semiconductor power supply output.

[0024] 1 , an example of a method for modifying (crystallizing) a film (processing target film) that is to be subjected to a heat treatment (modification treatment) formed on a substrate W will be described. In the following description, the operation of each component of the microwave irradiation device 10 is controlled by a controller (control unit) 120.

[0025] In this example, a Si wafer (hereinafter simply referred to as a wafer) is used as the substrate W. A film to be processed is formed on the wafer. The film to be processed is, for example, an amorphous silicon (Si) film to which a dopant (impurity) is added. The dopant is, for example, phosphorus (P) or boron (B). The film to be processed is formed on the wafer in a substrate processing apparatus other than the microwave irradiation apparatus 10, for example, a batch-type substrate processing apparatus or an ion implantation apparatus.

[0026] The term "wafer" used in this specification may refer to the wafer itself or to a laminate of the wafer and a predetermined layer or film formed on its surface. The term "surface of a wafer" used in this specification may refer to the surface of the wafer itself or to the surface of a predetermined layer or the like formed on the wafer. When described in this specification, "forming a predetermined layer on a wafer" may mean forming a predetermined layer directly on the surface of the wafer itself or forming a predetermined layer on a layer or the like formed on the wafer. When used in this specification, the term "substrate" is synonymous with the term "wafer".

[0027] First, the wafer is loaded (prepared) into the resonator 110 (hereinafter referred to as the processing chamber). After the wafer has been loaded into the processing chamber, the atmosphere in the processing chamber is controlled to a predetermined pressure (a pressure lower than standard atmospheric pressure). Once the pressure in the processing chamber is controlled to a predetermined value, an inert gas such as nitrogen gas is supplied. At this time, the pressure in the processing chamber is also adjusted to a predetermined value.

[0028] Next, when the processing chamber reaches a predetermined pressure, the oscillator 101 supplies microwaves to the processing chamber 110. The microwave output is smaller than the microwave output in the modification process described below, and a preheating process (preheating) is performed to heat the wafer by repeating an ON period of the microwave supply and an OFF period shorter than the ON period a predetermined number of times or for a predetermined period of time. This allows the wafer temperature to rise gradually, thereby preventing warping and cracking of the wafer.

[0029] Next, while maintaining the processing chamber at a predetermined pressure, the oscillator 101 supplies pulsed microwaves to the processing chamber to process the wafer (perform a modification process). Microwave pulse irradiation is performed by repeatedly turning the microwave supply OFF before thermal conduction and then ON to maintain temperature rise and heating (thermal equilibrium). In other words, the rate of temperature rise is suppressed, and heating is performed while maintaining thermal equilibrium until internal heat conduction (selective heating and internal heating) occurs. If the continuous microwave irradiation time is long, Joule heating (thermal conduction) becomes dominant, but microwave pulse irradiation suppresses this until internal heat conduction occurs.

[0030] As shown in FIG. 2 , the oscillator 101 can vary the ON time, which is a first predetermined time (T1), and the OFF time, which is a second predetermined time (T2), thereby supplying pulsed microwaves that repeatedly turn ON and OFF in short cycles. This maintains thermal equilibrium, which is expected to maintain heating selectivity. To suppress thermal diffusion, the ON time is preferably set to the order of 1 microsecond. The controller 120 is configured to control the oscillator 101 so that it turns on the microwave pulse irradiation to heat the dopant in the film to be processed by the microwave pulse irradiation, and turns off the microwave irradiation before the wafer is heated, i.e., so that the wafer is not heated. In this way, a process (procedure) of supplying pulsed microwaves to a substrate W loaded into the resonator (processing chamber) 110 to perform a modification process is performed.

[0031] For example, the frequency of the microwave power supply is 2.45 GHz. For example, the wafer is heated by repeating an ON period of microwave supply and an OFF period longer than the ON period a predetermined number of times or for a predetermined period of time. Here, the pulse period and duty ratio are adjusted, and the ON period is preferably 0.6 to 10 microseconds. If the ON period is 0.6 microseconds or less, heating is insufficient and the dopant is not activated. If the ON period is 10 microseconds or more, heating due to thermal conduction becomes dominant. Preferably, the duty ratio is 10 to 15%. If the duty ratio is 10% or less, heating is insufficient, resulting in insufficient dopant activation, and the film to be processed is not sufficiently heated. Furthermore, if the duty ratio is 15% or more, heating due to thermal conduction becomes dominant, resulting in heating of the substrate.

[0032] In this specification, when a numerical range such as "0.6 to 10 microseconds" is expressed, it means that the lower limit and upper limit are included in the range. Therefore, for example, "0.6 to 10 microseconds" means "0.6 microseconds or more and 10 microseconds or less." The same applies to other numerical ranges.

[0033] An example of the experimental results obtained by performing pulse irradiation as shown in Fig. 2 using the microwave irradiation device shown in Fig. 1 will be described with reference to Fig. 3. In Fig. 3, the horizontal axis represents the substrate temperature (Temp.) [°C], and the vertical axis represents the sheet resistance (Rs) [ohm / sq].

[0034] The experimental conditions were as follows: inner diameter of resonator 110: approximately 15 mm, oscillation frequency: 2.45 GHz, pulse period: 10 microseconds, duty ratio: 10%, microwave output: 100 W, irradiation time: 1200 seconds, substrate: ion-implanted 7×7 mm square substrate (Si substrate), dopant: BF ２ Implantation energy: 8 keV Electric field strength: 2.2×10 １５ V / m

[0035] In modification processes using heater heating (thermal) or RTP (rapid thermal process), the substrate temperature at which good activation (Rs ≈ 125) can be achieved is 600° C. As shown in Figure 3, the substrate temperature at which Rs ≈ 125 can be achieved is approximately 550° C. in multi-mode (MM: dashed line) and approximately 470° C. in single-mode (SM: solid line).

[0036] The electric field strength was set to 2.0×10 near the surface of the substrate W by a 2.45 GHz microwave resonator (for example, TM010 mode). ５ V / m (input power 100 W) or more. The output of the oscillator 101 is then controlled to pulse the microwave irradiation (pulse period: several tens of microseconds, duty ratio: 10-15%) rather than continuously. This allows the substrate to be heated to 470°C or below, while still achieving an activation rate equivalent to that achieved with heater heating at 600°C. The low temperature results in impurity diffusion comparable to that achieved with ion implantation. Furthermore, processing at a substrate temperature of 360-470°C achieves good activation in single-mode modification processing. If the substrate temperature is below 360°C, the annealing effect is not achieved, resulting in a reduced film modification effect. Furthermore, if the substrate temperature is above 470°C, the substrate W is overheated, causing the substrate temperature to rise.

[0037] According to this aspect, one or more of the following effects can be obtained.

[0038] (a) The use of a single mode allows for the application of only an electric field or a magnetic field, which makes it possible to obtain a high electric field strength that cannot be obtained with a multimode.

[0039] (b) The use of a single mode enables pulse control of microwaves (pulse irradiation).

[0040] (c) Pulse irradiation can suppress an increase in substrate temperature.

[0041] (d) By applying pulsed irradiation and a high electric field strength, modification processes (for example, impurity activation annealing) can be performed without increasing the temperature of the substrate.

[0042] (e) (d) allows for improved transistor performance, making it possible to implement it in advanced CMOS transistor processes.

[0043] The configuration of a microwave radiating device according to another embodiment will be described with reference to FIGS. 4 and 5. FIG.

[0044] A microwave irradiation device 10 in another aspect includes one oscillator 101, a plurality of resonators 110 arranged in an array, and a thermometer 111. A slug tuner 104, a power monitor 103, a semiconductor amplifier 102, and a phase shifter 105 are connected to each of the plurality of resonators 110. The oscillator 101 is connected to the plurality of phase shifters 105. In this aspect, the solid-state microwave source 100 includes the phase shifter 105.

[0045] The resonator 110 in this embodiment is an antenna resonator. Multiple antenna resonators supply microwaves to the substrate W. The resonator 110 is configured, for example, as a λ / 2 dipole antenna, with a gap between λ / 4 antennas 110a and 110b. The substrate W is placed in the gap. The antenna 110a is placed on the front side of the substrate W, and the antenna 110b is placed on the back side. One end of the antenna 110a is connected to the slug tuner 104, and the other end is open. Both ends of the antenna 110b are open. The antennas 110a and 110b are shielded to suppress interference with other antennas arranged in an array. The resonator 110 may also be configured as a λ / 4 monopole antenna having only the antenna 110a.

[0046] The phase shifter 105 is configured to be able to change the phase of the microwave, and by adjusting the phase, the electric field is adjusted. For example, a phased array antenna is configured, and by adjusting the phase, interference is caused between the arrayed antennas so that an electric field is applied to the surface of the substrate W located between the antennas. This makes it possible to heat the substrate uniformly. It also makes it possible to widen the antenna spacing.

[0047] 5, a rotation mechanism 112 may be provided to rotate the substrate W. Since microwaves are supplied to the substrate W while it is being rotated, it is not necessary to provide resonators 110 so as to correspond to the entire surface of the substrate W, and the number of resonators 110 can be reduced.

[0048] The microwave irradiation device 10 of this embodiment is otherwise configured in the same manner as the microwave irradiation device 10 shown in Figure 1, and elements that are substantially the same as the elements described in Figure 1 are given the same reference numerals, and their description will be omitted.

[0049] In this embodiment, since a plurality of resonators 110 are arranged (for example, in an array), it is also applicable to substrates W having a diameter of 100 mm or more. In addition, this embodiment also has the same effects as the above-mentioned embodiment.

[0050] The above description has been given of impurity activation annealing, which is one of the steps in the pre-processing of semiconductor devices, but it can also be applied to hardening of mold materials in the mounting process.

[0051] It should be noted that the present disclosure is not limited to the above-described embodiments, and various modifications are also included. For example, the above-described embodiments have been described in detail to clearly explain the present disclosure, and the present disclosure is not necessarily limited to those having all of the described configurations.

[0052] 10: Microwave irradiation device (substrate processing device) 101: Oscillator 110: Resonator 111: Thermometer 120: Controller (control unit)

Claims

1. A substrate processing apparatus comprising: a low-mode resonator for placing a substrate perpendicular to an electric field; an oscillator for supplying microwave power in pulses to the resonator; a temperature measurement unit for measuring the temperature of the substrate; and a control unit configured to be able to control the oscillator so that the temperature of the substrate becomes a predetermined temperature.

2. The substrate processing apparatus according to claim 1, wherein the resonator is a cavity resonator.

3. The substrate processing apparatus according to claim 1, wherein the resonator operates in a TM010 mode or a TE101 mode.

4. The substrate processing apparatus according to claim 1, wherein the microwave is pulsed and is ON for a first predetermined time period and OFF for a second predetermined time period.

5. The substrate processing apparatus according to claim 4, wherein the second predetermined time is longer than the first predetermined time.

6. The substrate processing apparatus according to claim 5, wherein the duty ratio of the microwaves is adjustable.

7. The substrate processing apparatus according to claim 6, wherein the duty ratio is in the range of 10 to 15%.

8. A substrate processing method according to claim 4, wherein the first predetermined time is set to be no less than 0.6 microseconds.

9. The substrate processing apparatus according to claim 1, wherein the predetermined temperature is 470° C. or less.

10. The substrate processing apparatus according to claim 1, wherein the resonator is an antenna resonator.

11. The substrate processing apparatus according to claim 10, further comprising a plurality of antennas for supplying the microwaves to the substrate.

12. The substrate processing apparatus according to claim 11, wherein the substrate is disposed between a plurality of antennas disposed on the front surface of the substrate and an antenna disposed on the rear surface of the substrate.

13. The substrate processing apparatus of claim 11, wherein the plurality of antennas are shielded.

14. The substrate processing apparatus according to claim 11, wherein the plurality of antennas are arranged in an array.

15. The substrate processing apparatus according to claim 14, wherein the plurality of antennas are either monopole antennas, dipole antennas or phased array antennas.

16. The substrate processing apparatus according to claim 11, further comprising a rotation mechanism for rotating the substrate.

17. The substrate processing apparatus according to claim 1, wherein the thermometer is a radiation thermometer.

18. A substrate processing method comprising: a substrate processing apparatus having a low-mode resonator for placing a substrate perpendicular to an electric field; an oscillator for supplying pulsed microwave power to the resonator; a thermometer for measuring the temperature of the substrate; and a control unit configured to be able to control the oscillator so that the temperature of the substrate becomes a predetermined temperature, the method comprising: supplying the pulsed microwave to the resonator of the substrate processing apparatus; 19. A method for manufacturing a semiconductor device, comprising the step of processing a substrate by supplying pulsed microwaves to the resonator of a substrate processing apparatus having a low-mode resonator in which the substrate is positioned perpendicular to an electric field, an oscillator that supplies pulsed microwave power to the resonator, a thermometer that measures the temperature of the substrate, and a control unit configured to be able to control the oscillator so that the temperature of the substrate becomes a predetermined temperature.

20. A program for causing a substrate processing apparatus having a low-mode resonator for positioning a substrate perpendicular to an electric field, an oscillator for supplying pulsed microwave power to the resonator, a thermometer for measuring the temperature of the substrate, and a control unit configured to be able to control the oscillator so that the temperature of the substrate becomes a predetermined temperature, to execute a procedure for processing the substrate by supplying the pulsed microwave to the resonator of the substrate processing apparatus using a computer.

Images