JP2021021712A - Thermo camera - Google Patents

Abstract

To provide a thermo camera which can be installed within a processing chamber to acquire thermal images of a processing liquid on substrates during single-wafer processing of the substrates.SOLUTION: A thermo camera 20 is provided, comprising a thermal image sensor 21 for visualizing temperature of a processing liquid on a substrate, a housing 23 accommodating the thermal image sensor therein, and a protective unit 50 provided on the housing on a side of a light receiving surface of the thermal image sensor and configured to transmit infrared rays.SELECTED DRAWING: Figure 1

Description

The present invention relates to a thermo camera for acquiring a thermal image of a processing liquid on a substrate in a single-wafer processing of a substrate.

A single-wafer type substrate processing apparatus is known. In such a processing apparatus, the substrate is held horizontally in the processing chamber, rotated in a horizontal plane about the center of the substrate, and the processing liquid is supplied onto the substrate to perform etching, cleaning, rinsing, etc. of the substrate surface. Processing is done.

Japanese Unexamined Patent Publication No. 2017-183498 Japanese Unexamined Patent Publication No. 2018-054429 International Publication No. WO2012 / 081586

The temperature of the processing liquid is adjusted and supplied onto the substrate, but since it is difficult to put a measuring instrument in the processing chamber, it is confirmed on the spot whether the temperature of the processing liquid on the substrate being processed is as expected. That was difficult.

Regarding the installation of a camera in the processing chamber of a single-wafer processing apparatus, Patent Document 1 provides a side reflection image by a mirror provided directly above the peripheral edge in order to image the peripheral edge of a rotating wafer. It is described that the image is taken by the image pickup device.

Patent Document 2 describes that an image is taken with a camera with the entire substrate in the field of view for the purpose of detecting the presence or absence of liquid falling on the substrate from the liquid supply nozzle. However, although the camera may be installed in the chamber, it is desirable that the camera is installed outside the chamber from the viewpoint of preventing the processing liquid from adhering to the chamber, and the camera is installed in the chamber. The specific configuration when it is provided is also not explained.

Neither patent document discloses that a thermo camera is installed in the processing chamber to measure the temperature of the processing liquid on the substrate. In addition, general optical glass used in visible light cameras cannot be used because it absorbs most of the light in the wavelength range required for measuring temperature. As described above, it is difficult to apply the conventional visible light camera technology as it is because the required optical conditions, installation conditions, internal structure, etc. are different between the camera that captures visible light and the thermo camera that measures the temperature.

The present invention has been made in consideration of the above, and provides a thermo camera that can be installed in a processing chamber and can take a thermal image of a processing liquid on the substrate on the spot in a single-wafer processing of a substrate. With the goal.

The thermo camera of the present invention is provided on the thermal image sensor that visualizes the temperature of the processing liquid on the substrate, the housing that houses the thermal image sensor inside, and the light receiving surface side of the thermal image sensor of the housing. It has a protective unit that transmits infrared rays.

According to the thermo camera of the present invention, since the inside of the housing can be protected from the droplets and steam of the treatment liquid by the protective unit, it can be installed in the treatment room and the thermal image of the treatment liquid on the substrate can be acquired on the spot. It will be possible.

It is a figure which shows the structure of the thermo camera of one Embodiment. It is sectional drawing of the thermo camera of one Embodiment. It is a figure which shows the structure of the shutter mechanism of the thermo camera of one Embodiment, and is the partially enlarged view of FIG. It is a figure for demonstrating the opening and closing operation of the shutter of one Embodiment. A: Open operation, B: Close operation. It is sectional drawing which shows the structure of A: protection part and B: a part of a housing of one Embodiment. It is a figure for demonstrating the air flow in the housing of one Embodiment. It is a figure which shows the arrangement of the cable, the gas supply pipe, and the cable cover of one Embodiment. It is a thermal image taken by the thermo camera of an embodiment. It is a figure for demonstrating that the thermo camera of one Embodiment is installed in a substrate processing room.

As an embodiment of the thermo camera of the present invention, a case where a disk-shaped semiconductor substrate is installed in a processing chamber of a single-wafer processing apparatus will be described with reference to the drawings. In the following, the direction taken by the thermo camera is referred to as "forward", and the opposite direction is referred to as "rear". Further, when referring to the figure, it may be referred to as "upper" or "lower" instead of "forward" or "rear" according to the positional relationship in the figure.

With reference to FIG. 9, the semiconductor substrate (hereinafter, simply referred to as “substrate”) W is held on the holding table 11 in the processing chamber 10. The substrate W, together with the holding base 11, is rotated in a horizontal plane about a rotating shaft 12 by a motor (not shown). The processing liquid L is discharged from the nozzle 13 onto the substrate W, and spreads on the surface of the substrate W by the rotation of the substrate W. A cover member 14 that blocks droplets of the treatment liquid L covers the substrate W and the holding table 11 from the side to the bottom. In addition, a plurality of nozzles 13 are often installed for different types of treatment liquids. In addition, a gas nozzle for injecting a drying gas may be installed.

The thermo camera 20 of the present embodiment is installed above the processing chamber 10 and away from directly above the substrate W, and photographs the entire upper surface of the substrate W from diagonally above. The thermo camera 20 is connected to the gas supply source 62 by the gas supply pipes 72 and 73 by the power supply 61 and the controller 60 and the cables 71 and 71 outside the processing chamber 10. Generally, a single-wafer type substrate processing apparatus includes a plurality of processing chambers 10, and various power supplies and control devices are grouped in a control block separated from the processing chamber 10. The distance between the processing chamber 10 and the control block is typically 4 to 5 m. The cables 71, 71 and the gas supply pipes 72, 73 have at least a portion inside the treatment chamber 10 housed in the cable cover 70 and are protected from being corroded by the treatment liquid L.

The type of substrate is not particularly limited. The substrate may be a wafer of silicon or other various semiconductors. Further, although a semiconductor substrate will be described as an example in this embodiment, the substrate may be a glass substrate for various displays, magneto-optical disks, photomasks, or the like. Further, the surface of the substrate may be processed or a film may be formed.

The type of the treatment liquid L is not particularly limited, and may be various etching liquids, cleaning liquids, pure water for rinsing, photoresists, developing liquids, and the like.

FIG. 1 shows the configuration of the thermo camera 20. Inside the housing 23, a container 22 containing the thermal image sensor 21 and the control circuit of the thermal image sensor is housed. A shutter mechanism 40 is provided on the light receiving surface side (front) of the thermal image sensor 21 of the housing 23. Further in front of the shutter mechanism 40, a protective portion 50 is attached to the front end portion of the housing 23 so as to close the opening of the housing 23.

Further, referring to FIG. 2, the housing 23 is formed with two gas supply paths penetrating the inside of the wall from the rear to the front. FIG. 2 shows one of them (28). Details of the gas supply path will be described later.

Since the housing 23 is exposed to droplets and steam of the treatment liquid L, it is manufactured using a material having heat resistance and chemical resistance. The housing 23 is preferably made of a fluororesin such as polytetrafluoroethylene (PTFE) or an aromatic polyetherketone (PAEK). This is because all of them have heat resistance and chemical resistance that can be installed in a semiconductor processing chamber. The housing 23 is more preferably made of PAEK. This is because PAEK has better machinability than fluororesin. Here, PAEK may be a resin substantially made of PAEK, and may contain other resins or various additives as long as the required heat resistance and chemical resistance can be maintained. The ratio of PAEK to the total resin components is preferably 90% by mass or more, more preferably 100% by mass. The blending ratio of the various additives is preferably 10 parts by mass or less with respect to 100 parts by mass of the resin component.

The housing 23 is particularly preferably substantially made of polyetheretherketone (PEEK). This is because PEEK has a good balance of heat resistance, chemical resistance, and strength among PAEK. The preferable range of the ratios of the other resins and additives to be blended in PEEK is the same as in the case of PAEK.

The thermal image sensor 21 is a sensor in which elements for detecting infrared radiant energy are arranged in a plane, and captures a thermal image of the processing liquid L of the substrate W. As the thermal image sensor 21, various known ones can be used, and many types are commercially available. The wavelength of infrared rays to be measured differs depending on the sensor, but most of them measure infrared radiant energy over a wavelength range of about 8 to 14 μm. The control circuit of the thermal image sensor performs shooting and transfer of a thermal image, flat field correction, etc., which will be described later, in response to a signal received from the controller 60.

FIG. 3 is a partially enlarged view of FIG. In the shutter mechanism 40, the shutter 46 including the shutter drive element 41, the drive element cover 43, and the two blades 46A and 46B is mounted in this order from the side closest to the thermal image sensor 21. The shutter 46 opens and closes with gas.

The shutter driver 41 has a C-shaped shape in a plan view, and is also a C-shaped groove (hereinafter referred to as “C-shaped groove”) 25 formed on the front end surface 24 of the housing 23 so as to surround the opening 24A. It is fitted to. The driver cover 43 presses the shutter drive 41 from above (front) in FIG. 1 so that the shutter drive 41 does not separate from the C-shaped groove 25. The blades 46A and 46B are arranged on the upper surface of the driver cover 43 by inserting the fulcrum pins 47A and 47B protruding downward into the fulcrum holes 44A and 44B of the driver cover 43, respectively. The drive pins 42A and 42B protruding from the upper surface of the shutter driver 41 penetrate the elongated holes 45A and 45B of the drive element cover 43 and are inserted into the drive pin receivers 48A and 48B of the shutter 46.

Both ends 26 and 27 of the C-shaped groove 25 are provided with openings for gas supply paths formed inside the wall of the housing 23. The two gas supply paths are a first supply path 28 for supplying an open drive gas for opening the shutter 46 and a second supply path 29 for supplying a closed drive gas for closing the shutter 46, respectively. In the following, the open drive gas and the closed drive gas are collectively referred to as a drive gas.

The opening / closing operation of the shutter 46 will be described with reference to FIG. FIG. 4 is a plan view of the shutter 46 as viewed from the front (upper side of FIG. 3). In FIG. 4, only the front end surface 24 of the housing 23, the shutter drive element 41, and the shutter 46 are drawn, and the driver cover 43 interposed between the shutter drive element 41 and the shutter 46 is omitted.

With reference to FIG. 4A, in a state where the open driving gas is supplied from the first supply path 28 to one end 26 of the C-shaped groove 25, a force that causes the shutter driver 41 to rotate the inside of the C-shaped groove 25 clockwise. Works. As a result, when the drive pin 42A pushes the drive pin receiver 48A downward in the figure, a force that rotates the blade 46A counterclockwise around the fulcrum pin 47A acts on the blade 46A. Similarly, when the drive pin 42B pushes the drive pin receiver 48B upward in the figure, a force that rotates the blade 46B counterclockwise around the fulcrum pin 47B acts on the blade 46B. As a result, the shutter 46 is opened or kept open.

With reference to FIG. 4B, in a state where the closing drive gas is supplied from the second supply path 29 to the other end 27 of the C-shaped groove 25, the shutter driver 41 rotates counterclockwise in the C-shaped groove 25. The force to make it works. As a result, when the drive pin 42A pushes the drive pin receiver 48A upward in the figure, a force that rotates the blade 46A clockwise around the fulcrum pin 47A acts on the blade 46A. Similarly, when the drive pin 42B pushes the drive pin receiver 48B downward in the figure, a force that rotates the blade 46B clockwise around the fulcrum pin 47B acts on the blade 46B. As a result, the shutter 46 is closed or maintained in the closed state.

The side where the two blades 46A and 46B come into contact is chamfered at the upper corner of FIG. 3 of the blade 46A and the lower corner of FIG. 3 of the blade 46B, and both are formed in a wedge shape. As a result, the two blades 46A and 46B come into contact with each other on a wedge-shaped inclined surface (FIG. 4B).

The open drive gas and the closed drive gas are not supplied at the same time. Further, either the open drive gas or the closed drive gas is always supplied. The driving gas is preferably adjusted to a constant temperature.

As the driving gas, a non-corrosive gas is used. Air can be used as the driving gas, but an inert gas is preferably used. Further, since the processing chamber for processing the semiconductor substrate is often controlled to have a nitrogen atmosphere, in that case, it is preferable to use nitrogen gas as the driving gas.

Each member of the shutter mechanism 40 can be made of the same material as the housing 23. Since each member of the shutter mechanism 40 is required to have particularly high processing accuracy, PEEK having excellent machinability is preferably used. Further, more preferably, a resin in which carbon black is mixed with PEEK is used. This is because the coefficient of friction is small and it can slide smoothly. Further, each member of the shutter mechanism 40 (particularly, the shutter blades 46A and 46B) is preferably black. This is because the emissivity is as high as 0.9 or more and does not adversely affect the temperature measurement.

The effect of driving the shutter 46 with gas is to suppress the temperature change due to opening and closing. In the temperature measurement by the thermal image sensor 21, the thermal image sensor 21 receives not only the heat radiated from the object to be measured but also the heat radiated from various places in the housing 23. Therefore, flat field correction (FFC) is frequently performed in order to correct the amount of heat received from other than the object to be measured. For example, in the present embodiment, the FFC is performed every time one substrate W is processed. Specifically, the shutter 46 is closed to perform measurement, and the result at the time of actual temperature measurement is corrected based on the result. At this time, even if there is a slight temperature change in the shutter mechanism 40 during FFC, the accuracy of the subsequent temperature measurement is greatly impaired.

In a general thermal image sensor, a shutter mechanism is provided immediately before the sensor, and the shutter is electromagnetically driven by a solenoid or the like. However, the inventors have found through experiments that when the shutter is electromagnetically driven, the temperature of the shutter mechanism rises when the shutter is opened and closed, and proper correction cannot be performed even if FFC is performed. According to the experiment, the temperature of the shutter increased by about 20 ° C. from the ambient temperature during the shutter operation, which caused the temperature of the thermal image sensor to increase by about 0.3 ° C. and the temperature of the housing by about 0.8 ° C. The measured values of the standard sample, which kept the temperature constant, changed by about 1.3 ° C before and after the FFC. In the chemical treatment of a semiconductor substrate, the temperature of the treatment liquid to be measured is often in the range of about 180 ° C. from room temperature, and considering that high temperature measurement accuracy is required, this influence cannot be ignored. When the shutter is driven by gas, there is no temperature effect due to the opening and closing of the shutter, and the relative error of the measured value of the standard sample is within 0.4 ° C.

In the present embodiment, since the opening and closing of the shutter 46 is driven by gas, the temperature of the shutter mechanism 40 does not rise, and the temperature can be measured with higher accuracy. In the present embodiment, since the shutter 46 is provided apart from the thermal image sensor 21, heat is not easily transferred from the shutter 46 to the thermal image sensor 21. The distance between the thermal image sensor 21 and the shutter 46 is preferably 2 to 9 mm.

Further, since the driving gas flows forward from the C-shaped groove 25 through the shutter mechanism 40, the shutter mechanism 40 is cooled. Further, when the temperature of the driving gas is adjusted to be constant, the temperature inside the housing 23 including the shutter mechanism 40 becomes stable.

With reference to FIG. 5A, the protective section 50 has a cap 51, an infrared transmissive member 56, and a fixed frame 59. A window 55 is formed in the cap 51 at a central portion located in front of the thermal image sensor 21. The window 55 includes an infrared transmitting member 56. A contact surface 52 for contacting the infrared transmitting member 56 is formed on the inner surface of the front end of the cap 51. The infrared transmitting member 56 is a window by applying packing (not shown) on both sides of the peripheral edge portion and screwing the fixing frame 59 having a threaded outer periphery onto the first female threaded portion 53 on the inner surface of the cap 51 with a necessary and sufficient torque. It is fixed so as to block 55. As a result, the cap 51, the infrared ray transmitting member 56, and the fixed frame 59 constituting the protective portion 50 are integrated.

With reference to FIG. 5B, a male screw portion 31 is formed on the outer periphery of the housing 23 near the front end surface 24, and an O-ring 33 is mounted in the O-ring groove 32 behind the male screw portion 31. Then, the assembly of the thermo camera 20 is completed by screwing the second screw portion 54 on the inner surface of the cap 51 shown in FIG. 5A into the male screw portion 31 of the housing 23. By interposing the O-ring 33 on the joint surface between the cap 51 and the housing 23, the protective portion 50 airtightly closes the opening 24A of the front end surface 24 of the housing 23. The driver cover 43 and the shutter 46 of the shutter mechanism 40 are housed between the front end surface 24 of the housing 23 and the fixed frame 59.

The cap 51 and the fixing frame 59 are made of a material having heat resistance and chemical resistance, preferably made of a fluororesin such as PTFE or PAEK, more preferably made of PAEK, and particularly preferably substantially made of PEEK. The reason is the same as in the case of the housing 23. As the packing, one made of fluororesin such as PTFE can be used.

The infrared transmitting member 56 is required to transmit infrared rays having a wavelength used by the thermal image sensor 21. Many thermal image sensors use infrared rays having a wavelength of 8 to 14 μm. From this, the infrared transmitting member 56 has an average infrared transmittance of preferably 20% or more, more preferably 40% or more in the wavelength range of 8 to 14 μm.

The form of the infrared transmitting member 56 is not particularly limited, and for example, a glass plate having a composition having a high infrared transmittance, a semiconductor plate such as silicon or germanium, or the like can be used.

As the infrared transmitting member 56, a resin film or sheet that transmits infrared rays is preferably used (hereinafter, the film and the sheet are collectively referred to as "film or the like"). The material of the film or the like used as the infrared transmitting member 56 is preferably a polyolefin resin. This is because it has high infrared transmittance and sufficient chemical resistance. As the polyolefin resin, those described in Patent Document 3 can be used. The material of the film or the like is more preferably polyethylene resin (PE). This is because PE has few functional groups that absorb infrared rays, so that the amount of infrared rays transmitted is large. The thickness of the film or the like is 10 μm to 800 μm, preferably 100 μm to 700 μm, and more preferably 150 to 600 μm. This is because if the film or the like is too thin, handling when assembling the protective portion 50 becomes difficult. On the other hand, if the film or the like is too thick, the infrared transmittance will decrease.

When the infrared transmitting member 56 closes the window 55, the opening 24A of the front end surface 24 of the housing 23 is closed. As a result, when the thermo camera 20 is installed in the processing chamber 10 of the substrate W, the droplets of the processing liquid L do not enter the inside of the thermo camera, and the thermal image sensor 21 and its control circuit can be protected. Further, even if particles are generated in the housing 23 due to sliding of the shutter 46 or the like, the particles do not leak to the outside of the thermo camera 20 and contaminate the processing chamber 10.

Preferably, the protective portion 50 airtightly closes the opening 24A of the front end surface 24 of the housing 23. Specifically, for example, as shown in FIG. 5, the protective portion 50 airtightly closes the opening 24A of the front end surface 24 of the housing 23 by interposing the O-ring 33 at the joint surface between the cap 51 and the housing 23. Can be closed to. As a result, even when the thermo camera 20 is installed in the processing chamber 10 of the substrate W, the vapor of the processing liquid L does not enter the inside of the thermo camera and corrode the thermal image sensor 21 and its control circuit.

With reference to FIG. 6, the protective portion 50 closes the opening 24A of the front end surface 24 of the housing 23, so that the driving gas of the shutter 46 is supplied from the first supply path 28 or the second supply path 29 to the C-shaped groove 25. , It hits the inner surface of the infrared transmitting member 56 via the periphery of the shutter 46, and flows backward through the opening 24A of the front end surface 24 of the housing 23 in the housing 23 (arrows in FIG. 6). This air flow cools the protective portion 50, which may be exposed to high temperatures, particularly the infrared transmitting member 56. Further, the thermal image sensor 21 is cooled by the air flow from the opening 24A of the front end surface 24 of the housing 23 to the rear of the housing 23. When the driving gas is adjusted to a constant temperature, the driving gas circulates in the housing 23 to stabilize the temperature in the housing 23.

Returning to FIG. 5A, the protective portion 50 is formed by integrating the constituent members into a single component, and is fixed to the housing 23 without using another fixing component such as a screw. As a result, the protective portion 50 can be easily attached to and detached from the housing 23. In the protective portion 50, the infrared transmitting member 56 is inevitably contaminated by the treatment liquid L and deteriorates with long-term use. However, due to this structure, the infrared transmitting member 56 and the like are contaminated by the processing liquid. In that case, the protective unit 50 can be easily replaced.

With reference to FIG. 7, from the rear end of the thermo camera 20, the first supply pipe 72 that supplies the open drive gas to the first supply path 28 and the second supply tube 29 that supplies the closed drive gas to the second supply path 29. The supply pipe 73 and the cable 71 are housed in the cable cover 70 and led out. The first supply pipe 72 and the second supply pipe 73 are connected to the gas supply source 62 shown in FIG. There are a plurality of cables 71, which are connected to the controller 60 and the power supply 61 shown in FIG. The controller 60 includes an input terminal, and various input settings are transmitted to the thermo camera 20 through the cable 71. The thermal image taken by the thermo camera 20 is transmitted to the controller 60 through the cable 71 and displayed on the output terminal included in the controller 60. The electric power required for operating the thermo camera 20 is supplied from the power supply 61 through the cable 71.

The cable cover 70 is airtightly connected to the rear end of the thermo camera 20. The cable cover 70 accommodates at least the portion of the cable 71 and the gas supply pipes 72 and 73 in the processing chamber 10 and protects them from droplets and steam of the processing liquid L.

The exhaust from the thermo camera 20 and the particles generated in the housing 23 are discharged through the inside of the cable cover 70. By using the cable cover 70, which has a significantly larger cross-sectional area than the first supply pipe 72 and the second supply pipe 73, as an exhaust passage, exhaust from the housing 23 and discharge of particles can be performed more efficiently. .. Further, since the internal pressure of the housing 23 does not increase due to the large cross-sectional area of the exhaust passage, it is possible to prevent gas and the like from leaking from the housing 23 into the processing chamber 10. Further, since the cable cover 70 also serves as an exhaust path, the size of the connection structure between the thermo camera 20 and the controller 60 and the like can be made compact as compared with the case where an exhaust path having a large cross-sectional area is separately provided. The flow of driving gas and exhaust gas in the cable cover 70 is indicated by arrows in FIG.

The cable cover 70 is preferably a bellows tube that is easy to route. Since the cable cover 70 is exposed to droplets and vapor of the treatment liquid L in the treatment chamber 10, it preferably has chemical resistance to the treatment liquid L. The cable cover 70 is preferably made of a fluororesin such as PTFE.

The cable cover 70 of the present embodiment is used for protecting the cable connected to the device and exhausting the device from the device when various devices used by supplying gas from the outside are installed in the processing chamber of the substrate. Can be done.

A thermo camera was manufactured as an example of the above embodiment. A PE film having a thickness of 500 μm was used for the infrared transmitting member 56 of the protective portion 50 of the thermo camera. The average infrared transmittance of the film in the wavelength range of 8 to 14 μm was about 50%. FIG. 8 shows a thermal image taken by the thermo camera of the embodiment. FIG. 8 was taken by supplying a chemical solution at about 50 degrees to the central portion while rotating the silicon substrate.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the technical idea.

10 Processing chamber 11 Holding table 12 Rotating shaft 13 Nozzle 14 Cover member W Substrate L Processing liquid 20 Thermocamera 21 Thermal image sensor 22 Thermal image sensor control circuit container 23 Housing 24 Front end face of housing 24A Front end face of housing Aperture 25 C-shaped groove 26 One end of C-shaped groove 27 The other end of C-shaped groove 28 First supply path 29 Second supply path 31 Male thread 32 O-ring groove 33 O-ring 40 Shutter mechanism 41 Shutter drive Child 42A, 42B Drive pin 43 Shutter drive child cover 44A, 44B Abutment hole 45A, 45B Long hole 46A, 46B Shutter 47A, 47B Abutment pin 48A, 48B Drive pin receiver 50 Protective part 51 Cap 52 Contact surface 53 First female screw part 54 2nd female thread 55 Window 56 Infrared transmission member 59 Fixed frame 60 Controller 61 Power supply 62 Gas supply source 70 Cable cover 71 Cable 72 1st supply pipe 73 2nd supply pipe

Claims (5)

A thermal image sensor that visualizes the temperature of the processing liquid on the substrate,
A housing that houses the thermal image sensor and
A protective unit provided on the light receiving surface side of the thermal image sensor of the housing and transmitting infrared rays,
Thermo camera with. The protective portion airtightly closes the opening of the housing, and a cooling gas is supplied to the inner surface of the protective portion.
The thermo camera according to claim 1. The protective portion is connected to the housing without using a separate fixing component such as a screw, and is detachable from the housing as a single component.
The thermo camera according to claim 1 or 2. The protective unit includes an infrared transmissive member made of polyolefin in a window located in front of the thermal image sensor.
The thermo camera according to any one of claims 1 to 3. The housing is substantially composed of aromatic polyetherketone.
The thermo camera according to any one of claims 1 to 4.