JP5491928B2 - Particle detection method and particle detection apparatus - Google Patents

Description

  The present invention relates to a particle detection method and a particle detection apparatus for detecting organic particles adhering to the surface by irradiating the surface of an object to be inspected and receiving scattered light from the surface.

  In the manufacturing process of a semiconductor device, for example, an ultra-LSI (Large Scale Integrated circuit), when a particulate foreign material (hereinafter referred to as “particle”) adheres to the wafer surface, the circuit may be short-circuited and the semiconductor device may not function. , Which was a factor in yield reduction. As a method of detecting particles adhering to the wafer surface, a method of measuring the position and size of particles in the wafer surface by scanning the wafer surface with laser light and detecting scattered light from the particles is generally used. Is.

  In recent years, with the miniaturization of semiconductor devices, detection of finer particles is required. Currently, ITRS (International Technology Roadmap for Semiconductors) requires detection of particles on the order of 20 nm, but the detection sensitivity in the laser scattering method is about 30 to 40 nm, and particles on the order of 20 nm cannot be detected.

  On the other hand, it is generally known that when a wafer to which particles are attached is formed, the scattering intensity of laser light is increased. Patent Document 1 discloses that the detection sensitivity in the laser scattering method is improved by forming a wafer. A technique is disclosed.

JP 2009-206500 A

However, since the wafer is exposed to a high-temperature atmosphere during film formation, particles adhering to the wafer surface may be damaged or lost, and detection may not be possible.
The present invention has been made in view of such circumstances, and an object of the present invention is to perform a film formation process on the surface of an inspection object in a predetermined temperature range in which organic particles are not damaged, and to form the inspection object A particle detection method capable of improving the detection sensitivity of particles in the laser scattering method by irradiating the surface of the light and receiving the scattered light from the surface, regardless of the type of particles attached to the inspection object And providing a particle detector.

The particle detection method according to the present invention is a particle detection method for detecting organic particles adhering to the surface by irradiating the surface of the object to be inspected and receiving scattered light from the surface. A film forming process is performed to form a silicon oxide film on the surface of the inspection object by an atomic layer deposition method within a predetermined temperature range in which particles are not damaged, and a reflection film is further formed on the surface of the formed inspection object. The organic particles are detected by irradiating light on the surface of the object to be inspected and receiving scattered light from the surface.

  The particle detection method according to the present invention is characterized in that a film of 30 nm or more is formed by the film forming process.

  The particle detection method according to the present invention is characterized in that the predetermined temperature range is less than 50 ° C.

The particle detector according to the present invention is a particle detector that detects organic particles adhering to the surface by irradiating light on the surface of the inspection object and receiving scattered light from the surface. A film forming means for performing a film forming process for forming a silicon oxide film on the surface of the inspection object by an atomic layer deposition method within a predetermined temperature range in which particles are not damaged, and further reflecting on the surface of the formed inspection object A reflection film forming section for forming a film; a light irradiation means for irradiating light on the surface of the object to be inspected; a means for detecting organic particles by receiving scattered light from the surface; It is characterized by providing.

In the present invention, the film formation process is performed by the atomic layer deposition method on the surface of the inspection object within a predetermined temperature range in which the organic particles are not damaged. Since the atomic layer deposition method is a room temperature film formation, the film can be formed without damaging the organic particles adhering to the surface of the object to be inspected, and the particle size can be apparently increased. In addition, the atomic layer deposition method is a method in which a single atomic layer is stacked to form a film, and therefore, a coverage can be formed and a conformal and smooth film can be formed. That is, a smooth film can be formed following the surfaces of the test object and the organic particles. Furthermore, the atomic layer deposition method generates very few particles during film formation as compared with other film formation methods such as CVD.
Then, light is irradiated on the surface of the object to be inspected, and organic particles are detected by receiving scattered light from the surface. Since the organic particles apparently have a larger particle size due to the film formation, the scattered light increases and the detection sensitivity of the organic particles increases.
Needless to say, the present invention may be applied to detection of particles that are less likely to be damaged than organic particles, for example, inorganic particles, or particles when organic particles and inorganic particles are mixed. The present invention may be applied to the detection of the above. Therefore, it is possible to detect minute organic particles exceeding the detection limit in the light scattering method.

  In the present invention, a silicon oxide film is formed on the surface of the inspection object by atomic layer deposition. A silicon oxide film formed by an atomic layer deposition method has a better coverage and can form a conformal and smooth film than films formed by other methods and other materials. Therefore, compared to other film forming methods, scattered light from organic particles can be effectively enhanced without increasing noise, and the detection sensitivity of organic particles can be improved.

  In the present invention, the thickness of the formed film is 30 nm or more. It is possible to detect particles having a particle size of 34 nm or less using a particle detector having a detection sensitivity of 40 nm. In particular, when the film thickness is 60 nm or more, it is possible to detect particles having a particle diameter of 22 nm, and when the film thickness is 120 nm or more, it is possible to detect particles having a particle diameter of 14 nm. Become.

  In the present invention, the predetermined temperature range is less than 50 ° C. Therefore, the organic particles are not damaged.

  In the present invention, a reflective film is further formed on the surface of the object to be inspected. Therefore, it is possible to enhance the scattered light from the particles and improve the particle detection sensitivity more effectively.

  According to the present invention, it is possible to improve the detection sensitivity of particles in the laser scattering method regardless of the type of particles attached to the inspection object.

It is the sectional side view which showed the example of 1 structure of the particle | grain detection apparatus which concerns on embodiment of this invention. It is the flowchart which showed an example of the particle | grain detection method which concerns on this Embodiment. It is the flowchart which showed the procedure of the ALD film-forming in a film-forming process part. It is the flowchart which showed the procedure of the particle | grain detection in a particle | grain detection part. It is a cross-sectional SEM photograph of the ALD silicon oxide film formed in the wafer which the silica particle adhered. It is the graph which showed the relationship between the thickness of an ALD silicon oxide film, and the real particle size of the detectable silica particle. It is the graph which showed the relationship between the actual particle size adhering to a wafer, and the particle size of the silica particle detected after the film-forming process. It is the graph which showed the relationship between the effect of film-forming processing, and the kind of film | membrane. It is the graph which showed the relationship between a film thickness and S / N ratio. It is the graph which showed the relationship between a film thickness and a haze level. It is the graph which showed notionally the signal intensity of the scattered light from a wafer. It is the schematic diagram which showed notionally the cross-sectional SEM photograph of the film | membrane formed in the wafer. It is the sectional side view which showed the example of 1 structure of the particle | grain detection apparatus which concerns on a modification. It is the flowchart which showed an example of the particle | grain detection method which concerns on a modification.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
<Particle detection device>
FIG. 1 is a side sectional view showing an example of the configuration of a particle detection apparatus according to an embodiment of the present invention. The particle detection apparatus according to the present embodiment includes a film formation processing unit 1 that performs a film formation process on the surface of a wafer (inspection object) W in a predetermined temperature range in which organic particles (hereinafter referred to as particles P) are not damaged, A particle detection unit 3 that detects particles P on the wafer W by a laser scattering method, and a transfer unit 2 that transfers the wafer W from the film formation processing unit 1 to the particle detection unit 3 are provided.

  The film formation processing unit 1 includes a film formation processing chamber 11 for accommodating the wafer W and performing the film formation process. The film formation processing chamber 11 has, for example, a hollow and substantially cylindrical shape, and is formed of a material having excellent heat resistance and corrosion resistance, for example, quartz. A loading / unloading port 11 a for loading and unloading the wafer W is provided on the side wall of the film forming chamber 11, and the wafer W loaded into the film forming chamber 11 is placed on the bottom of the film forming chamber 11. A stage 12 is provided.

  An exhaust pipe 17 for exhausting the gas in the film formation processing chamber 11 is disposed at an appropriate location on the side wall of the film formation processing chamber 11. The exhaust pipe 17 is formed along the film forming chamber 11 so that the longitudinal direction thereof is the vertical direction, and communicates with the film forming chamber 11 through a hole 17 a provided in the side wall of the film forming chamber 11. doing. The upper end of the exhaust pipe 17 is connected to an exhaust port disposed in the upper part of the film forming process chamber 11. An exhaust pipe 17 is connected to the exhaust port, and an exhaust unit 18 is connected to the exhaust pipe 17 via a valve (not shown). The exhaust unit is configured by a pressure adjustment mechanism such as a vacuum pump, for example.

  In addition, a source gas supply pipe 16 is formed along the vertical direction on the side wall of the film forming chamber 11, on the opposite side of the exhaust unit 18, and a hole 16 a provided on the side wall of the film forming chamber 11 is provided. The film formation processing chamber 11 is communicated with each other. A silicon-containing material supply unit 15 is connected to the source gas supply pipe 16 via a valve (not shown). The silicon-containing material supply unit 15 supplies a silicon-containing material, for example, diisopropylaminosilane, to the wafer W through the source gas supply pipe 16 and adsorbs it.

  Further, an activation processing unit 14 that activates an oxidizing gas and supplies the activated oxidizing gas to the film forming processing chamber 11 through the hole is provided in the source gas supply pipe 16 on the side wall of the film forming processing chamber 11. It is installed side by side. The oxidizing gas is, for example, oxygen, and is a gas for oxidizing the silicon-containing substance adsorbed on the wafer W surface. Inside the activation processing unit 14, an oxidizing gas supply pipe 14a is arranged along the vertical direction. The oxidizing gas supply pipe 14a is connected to the oxidizing gas supply unit 13 through a valve (not shown). The oxidizing gas supply unit 13 includes, for example, an oxygen cylinder, a mass flow controller, a pressure adjustment valve, and the like. The activation processing unit 14 includes a pair of electrodes 14b for activating the oxidizing gas supplied through the oxidizing gas supply pipe 14a. An oxidizing gas is supplied between the pair of electrodes 14b. The pair of electrodes 14b is connected to a high-frequency power source, a matching unit, etc. (not shown). Then, high-frequency power is applied between the pair of electrodes 14b from a high-frequency power source through a matching unit, thereby plasma-exciting (activating) the processing gas supplied between the pair of electrodes 14b, for example, generating oxygen radicals To do. The oxidizing gas thus activated is supplied from the activation processing unit 14 into the film forming process chamber 11.

  Further, a temperature adjusting mechanism (not shown) is provided around the film forming chamber 11. The temperature adjustment mechanism includes a heater, and the inside of the film forming process chamber 11 and the wafer W are held at a predetermined temperature by the heater.

  Furthermore, the film formation processing unit includes a control unit (not shown). The control unit controls the operation of each component of the film formation processing unit, thereby alternately supplying the silicon-containing material and the oxidizing gas to the wafer surface, and a silicon oxide film (hereinafter referred to as ALD silicon oxide) on the wafer W surface. A film L1).

  The transport unit 2 includes a hollow substantially rectangular parallelepiped housing 21 in which carry-in / out ports 21 a and 21 b communicating with the film forming process unit 1 and the particle detection unit 3 are formed. At the bottom of the casing 21, a transfer robot 22 that carries the wafer W into and out of the film formation processing unit 1 and the particle detection unit 3 is provided. Moreover, the conveyance part 2 is provided with the door bodies 23 and 24 which open and close the carrying in / out ports 21a and 21b.

The particle detector 3 includes a hollow, substantially rectangular parallelepiped particle detection chamber 31. A loading / unloading port 31 a for loading and unloading the wafer W is provided on the side wall of the particle detection chamber 31, and a stage 32 on which the wafer W loaded into the particle detection chamber 31 is placed at the bottom of the particle detection chamber 31. Is provided. The stage 32 can be moved in the horizontal direction by the stage driving unit 33. Further, the particle detection chamber 31 is provided with a gas exhaust port 31 b through which gas is discharged from the inside of the particle detection chamber 31. The gas exhaust port 31b is connected to an exhaust unit 34 constituted by a vacuum pump such as a dry pump. The gas exhaust port 31b and the exhaust part 34 are not essential components.
Further, the particle detection unit 3 receives the light irradiation unit 35 that irradiates light on the surface of the wafer W placed on the stage 32 and the scattered light from the surface of the wafer W, and responds to the intensity of the received scattered light. A light receiving unit 36 for outputting a signal. The signal processing unit 37 receives the signal output from the light receiving unit 36, performs various signal processing such as enhancement of the received signal, and outputs the processed signal to the calculation unit 38. Based on the signal output from the signal processing unit 37, the calculation unit 38 performs processing such as detection of particles P and calculation of particle size.

<Operation of Particle Detection Method and Particle Detection Device>
FIG. 2 is a flowchart showing an example of the particle detection method according to the present embodiment. First, a wafer W that is an object to be inspected is carried into the film forming chamber 11 and placed on the stage 12. Then, an ALD silicon oxide film L1 is formed on the surface of the wafer W by the atomic layer deposition method in a predetermined temperature range where the particles P are not damaged (step S11). The predetermined temperature range is a temperature range in which the organic matter is not deformed or disappeared, for example, less than 50 ° C. According to an atomic layer deposition method to be described later, a film forming process in the predetermined temperature range is possible. Then, the formed wafer W is transferred from the film forming processing unit 1 to the particle detecting unit 3 by using the transfer unit 2 (step S12). Next, the organic particles P are detected by irradiating light onto the surface of the wafer W which is transported to the particle detector 3 and placed on the stage 32 and receiving scattered light from the surface of the wafer W (step S13), the process ends.

  FIG. 3 is a flowchart showing the procedure of ALD film formation in the film formation processing unit 1. First, a silicon-containing material is supplied to the film forming chamber 11 (step S31). The silicon-containing material supplied to the film forming chamber 11 is adsorbed on the surface of the wafer W in atomic layer units. Next, an oxidizing gas is supplied to the film forming chamber 11 (step S32). The oxidizing gas supplied to the film forming chamber 11 oxidizes the silicon-containing material adsorbed on the surface of the wafer W, thereby forming an ALD silicon oxide film L1 on the surface of the wafer W. The supply of the silicon-containing material and the oxidizing gas is performed at room temperature. That is, the film formation process of the ALD silicon oxide film L1 can be performed at room temperature. Then, it is determined whether or not a specific number of film formation processes determined according to the target thickness of the ALD silicon oxide film L1 have been executed (step S33). The film thickness of the ALD silicon oxide film L1 is appropriately determined depending on the particle size of the particles P desired to be detected, but is preferably 30 nm or more and 60 nm or less. If it is determined that the specific number of film formation has not been completed (step S33: NO), the process returns to step S31. When it is determined that the specific number of film formation processes have been completed (step S33: YES), the film formation process is ended.

  In this way, a conformal and smooth film with good coverage is formed by alternately repeating the supply of the silicon-containing gas and the oxidizing gas.

  FIG. 4 is a flowchart showing the procedure of particle detection in the particle detector 3. The light irradiation unit 35 irradiates the wafer W, which has been transferred to the particle detection chamber 31 and placed on the stage 32, with laser light (step S51). Then, the stage drive unit 33 starts scanning the surface of the wafer W with laser light by moving the stage 32 in the horizontal direction (step S52).

  Next, the light receiving unit 36 detects the scattered light scattered by the particles P on the surface of the wafer W (step S53). And the calculating part 38 determines whether the particle | grains P were detected based on the signal received from the light-receiving part 36 via the signal processing part 37 (step S54). Specifically, it is determined whether or not the intensity of the scattered light received by the light receiving unit 36 is greater than or equal to a predetermined value.

  When it is determined that the particle P has been detected (step S54: YES), the calculation unit 38, based on the signal received via the signal processing unit 37, the particle P whose apparent particle size has been increased by the film forming process. The particle diameter is calculated (step S55). Next, the calculation unit 38 calculates the particle size before film formation based on the film thickness formed by the film formation process and the particle size calculated in step S55 (step S56). Since the method for calculating the particle size before film formation is a known technique, detailed description thereof is omitted.

  Next, the calculation unit 38 stores the particle size calculated in step S56 (step S57). When the process of step S57 is completed, or when it is determined in step S54 that the particles P are not detected (step S54: NO), it is determined whether or not the entire surface of the wafer W is scanned with a laser by the stage driving unit 33. Determination is made (step S58). When it is determined that the entire surface of the wafer W has not been scanned (step S58: NO), the stage drive unit 33 returns the process to step S53 and continues scanning. When it is determined that the entire surface of the wafer W has been scanned (step S58: YES), the laser irradiation by the light irradiation unit 35 and the scanning by the stage driving unit 33 are stopped (step S59). And the calculating part 38 outputs the detection result of particle | grains P to the exterior (step S60), and complete | finishes a process.

Next, operations and effects of the particle detection method and the particle detection apparatus according to the present embodiment will be described.
<Experimental result 1: cross-sectional SEM photograph>
Silica particles having an average particle diameter of 115 nm were sprayed on the wafer W, and a silicon oxide film having a thickness of 60 nm was formed by atomic layer deposition. Then, a tomographic SEM photograph of silica particles covered with the ALD silicon oxide film was taken.

  FIG. 5 is a cross-sectional SEM photograph of an ALD silicon oxide film formed on a wafer having silica particles attached thereto. In FIG. 5, a circle indicated by a broken line indicates a portion where silica particles having a particle diameter of 115 nm sprayed on the wafer are present, and the lower side of the horizontal line in contact with the lower end of the silica particles is the wafer. As shown in FIG. 5, it can be seen that the ALD silicon oxide film formed by the atomic layer volume method has a very good coverage and is a conformal and smooth film formed so as to follow the surface of the wafer and silica particles. . As will be described later, by forming a conformal and smooth film with good coverage, it is possible to detect fine silica particles exceeding the detection limit of the particle detector 3.

<Experimental result 2: Relationship between thickness of ALD silicon oxide film and measured particle diameter>
Silica particles having an average particle size of 14 nm, 22 nm, 34 nm, 67 nm, 106 nm, and 115 nm are sprayed on different portions of the wafer, respectively, an ALD silicon oxide film is formed by atomic layer deposition, and silica particles are detected by laser scattering. The experiment was conducted. The detection limit of the particle detector 3 used for detecting silica particles is 40 nm. In addition, the same experiment was performed by changing the thickness of the ALD silicon oxide film to 0 nm (no film formation), 30 nm, 60 nm, and 120 nm.

  FIG. 6 is a chart showing the relationship between the thickness of the ALD silicon oxide film and the actual particle size of the detectable silica particles, and FIG. 7 is the actual particle size attached to the wafer and the silica detected after the film formation process. It is the graph which showed the relationship with the particle size of particle | grains. The horizontal axis of the graph shown in FIG. 7 is the particle size of the silica particle size (hereinafter referred to as the actual particle size), and the vertical axis is the scattering intensity from the silica particles whose apparent particle size is increased by the film forming process. The particle diameter calculated based on (hereinafter referred to as measured particle diameter) is shown. In FIG. 6, the hatched items with no numbers indicate that silica particles could not be detected. Also, the numbered items and hatched items indicate the minimum film thickness conditions that make it possible to detect silica particles with a detection limit of less than 40 nm. Items with a cross mark indicate that the experiment was not performed under the corresponding conditions.

  The detection limit of the particle detector 3 is 40 nm. As can be seen from FIGS. 7 and 8, when the film formation process was not performed, silica particles having actual particle sizes of 14 nm, 22 nm, and 34 nm were not detected when the thickness of the ALD silicon oxide film was 10 nm. However, by forming an ALD silicon oxide film having a thickness of about 30 nm, it has become possible to detect silica particles having an actual particle diameter of 34 nm. In addition, by forming an ALD silicon oxide film having a thickness of about 60 nm, silica particles having an actual particle diameter of 22 nm can be detected. Further, by forming an ALD silicon oxide film having a thickness of about 120 nm, it has become possible to detect silica particles having an actual particle diameter of 14 nm. As described above, when the wafer surface and the silica particles are covered with the ALD silicon oxide film, the apparent particle size increases, so that the scattering intensity increases and the detection of minute silica particles exceeding the detection limit becomes possible.

<Experimental result 3: Comparison of film forming method and film forming material>
FIG. 8 is a graph showing the relationship between the effect of the film forming process and the type of film.
In place of the ALD silicon oxide film, a titanium Ti film, an ArF resist film, and an HTO (High Temperature Oxide) film were formed, and an experiment was conducted to detect silica particles. The horizontal axis represents the thickness of the film formed on the wafer surface, and the vertical axis represents the measured particle diameter after film formation. From the viewpoint of enhancing the light scattering intensity, the titanium Ti film is the best, followed by the ALD silicon oxide film, HTO, and ArF resist.

  9 is a graph showing the relationship between the film thickness and the S / N ratio, FIG. 10 is a graph showing the relationship between the film thickness and the haze level, and FIG. 11 is a graph showing the scattered light from the wafer. It is the graph which showed signal strength notionally. 9 and FIG. 10, the horizontal axis indicates the thickness of the film formed on the wafer surface, the vertical axis in FIG. 9 indicates the S / N ratio of the scattering intensity, and the vertical axis in FIG. 10 indicates the haze level. 9 and 10, the ALD silicon oxide film has an extremely high S / N and a low haze level. When the S / N ratio is large and the haze level is small, the particle detection signal can be accurately detected without error as shown in the left diagram of FIG. On the other hand, it can be seen that the titanium Ti film, which was excellent in terms of enhancing the light scattering intensity, has a low S / N ratio and a high haze level. If the S / N ratio is small and the haze level is large, noise may be detected due to the particle detection signal, and the particle detection signal may be overlooked due to noise, so fine silica particles can be accurately detected. It is difficult to detect and measure the particle size.

FIG. 12 is a schematic diagram conceptually showing a cross-sectional SEM photograph of the film formed on the wafer. 12A shows the ALD silicon oxide film formed on the wafer W, FIG. 12B shows the Ti film L11, and FIG. 12C shows the ArF resist film L12. As shown in FIG. 12A, the ALD silicon oxide film is a conformal and smooth film with good coverage. Accordingly, the particle detection signal can be enhanced by accurately reflecting the actual particle size of the particle P, and a particle detection signal having a large S / N ratio and a low haze level can be obtained. Therefore, it is possible to accurately detect the minute particles P.
On the other hand, since the Ti film L11 has poor coverage and smoothness, only a particle detection signal having a low S / N ratio and a high haze level can be obtained. Therefore, the minute particles P cannot be detected accurately.
Further, in the case of the ArF resist film L12, since the conformal property is poor, the scattering intensity is decreased by the film formation. Therefore, the minute particles P cannot be detected.
From the above experimental results, it can be seen that the ALD silicon oxide film is most suitable for particle detection by the laser scattering method.

  In the particle detection method and the particle detection apparatus according to the embodiment, since the room temperature film formation is performed by the atomic layer stacking method, the particles attached to the surface of the wafer W are not deformed. Therefore, even if the particles P attached to the wafer W are organic particles, the detection sensitivity in the laser scattering method can be improved.

  Moreover, since the silicon oxide film is formed by the atomic layer stacking method, the surface of the wafer W and the particles P can be covered with a film having a good coverage, a conformal and smooth. By forming the ALD silicon oxide film L1, the scattered light can be increased with the high S / N ratio and the low haze level, and the detection sensitivity by the laser scattering method can be improved.

  Further, since the silicon oxide film is formed by the atomic layer stacking method, the number of particles P newly generated and deposited on the wafer W is extremely small. Therefore, it is possible to increase the scattering intensity of only the particles P attached to the surface of the wafer W and detect the fine particles P.

(Modification)
Since the particle detection method according to the modification is different only in that a reflection film is further formed on the surface of the formed wafer W and the particles are detected, the difference will be mainly described below.

  FIG. 13 is a side sectional view showing a configuration example of a particle detection apparatus according to a modification. The particle detection apparatus according to the modification includes a reflective film forming unit 4 between the film forming processing unit 1 and the particle detecting unit 3 via the conveying units 2 and 2.

  The reflective film forming unit 4 is, for example, a sputtering apparatus. The reflective film forming unit 4 includes a processing chamber 41 for forming a reflective film. In the processing chamber 41, loading / unloading ports 41a and 41b for loading and unloading the wafer W are formed on the film forming processing unit 1 side and the particle detection unit 3 side, respectively. In the processing chamber 41, an assembly 45 of a magnetron sputtering gun 46, a sputtering gas supply unit 48 for supplying a sputtering gas (for example, argon gas) to the sputtering gun 46, and a stage 42 for supporting the wafer W are provided. And a reaction gas supply unit 44 for supplying a reaction gas (for example, nitrogen gas) into the processing chamber 41.

  Further, the processing chamber 41 is provided with a gas exhaust port 41 c through which gas is exhausted from the inside of the processing chamber 41. The gas exhaust port 41c is connected to an exhaust unit 43 configured by a vacuum pump such as a dry pump. By exhausting the gas in the processing chamber 41 by this vacuum pump, the inside of the processing chamber 41 is maintained at a desired degree of vacuum.

  The sputtering gun 46 incorporated in the assembly 45 includes a target 47 having a recess, and the target 47 is sputtered by the plasma of the sputtering gas supplied from the gas supply unit described above. Thereby, sputtered particles are ejected toward the wafer W, and a reflective film L2 is formed on the ALD silicon oxide film L1.

  FIG. 14 is a flowchart illustrating an example of a particle detection method according to a modification. A silicon oxide film is formed by atomic layer deposition on the surface of the wafer W within a predetermined temperature range in which the organic particles P are not damaged (step S111). Then, the formed wafer W is transferred from the film forming unit 1 to the reflective film forming unit 4 using the transfer unit 2 (step S112). Next, a reflective film L2 is formed on the surface of the wafer W that is transported to the particle detector 3 and placed on the stage 42 (step S113). The reflective film L2 is, for example, titanium Ti, and is formed by sputtering. Since the refractive indexes of the ALD silicon oxide film L1 and the reflective film L2 contribute to the scattering intensity by the fourth power, it is preferable that the difference in refractive index with respect to the vacuum of the ALD silicon oxide film L1 and the reflective film L2 is large. The refractive index of the ALD silicon oxide film L1 is 1.46, whereas the refractive index of titanium Ti is significantly different from 2.52, which is preferable. Further, the thickness of the reflective film L2 is preferably as thin as possible. This is because the coverage, conformality, and smoothness of the ALD silicon oxide film L1 are impaired. However, in order to ensure the reflection intensity at the interface between the ALD silicon oxide film L1 and the reflection film L2, the thickness of the reflection film L2 should be set to be equal to or greater than the penetration length of the irradiated light. Therefore, the thickness of the reflective film L2 is preferably the penetration length of the irradiated light.

  When the process of step S113 is completed, the wafer W on which the reflective film L2 is formed is transported from the reflective film forming unit 4 to the particle detecting unit 3 using the transport unit 2 (step S114). Next, the particle P is detected by irradiating the surface of the wafer W, which is transported to the particle detection unit 3 and placed on the stage 32, and receiving scattered light from the surface of the wafer W (step S115). Finish the process.

  In the modified example, the scattered light from the particles P can be further enhanced, and the fine particles P can be detected more effectively.

  The embodiment disclosed this time is to be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Film-forming process part 2 Conveyance part 3 Particle | grain detection part 4 Reflective film formation part 11 Film-forming process chamber 12 Stage 13 Oxidation gas supply part 14 Activation process part 15 Silicon-containing substance supply part 16 Source gas supply pipe 17 Exhaust pipe 18 Exhaust Unit 31 particle detection chamber 32 stage 33 stage drive unit 34 exhaust unit 35 light irradiation unit 36 light receiving unit 37 signal processing unit 38 arithmetic unit 42 stage 43 exhaust unit 44 reactive gas supply unit 45 assembly 46 sputtering gun 47 target 48 sputtering gas supply Part W Wafer P Particle

Claims (4)

In a particle detection method for detecting organic particles adhering to the surface by irradiating the surface of the inspection object with light and receiving scattered light from the surface,
A film forming process is performed to form a silicon oxide film by atomic layer deposition on the surface of the inspection object within a predetermined temperature range in which the organic particles are not damaged,
A reflective film is further formed on the surface of the object to be inspected,
Irradiate light to the surface of the object to be inspected,
A particle detection method comprising detecting organic particles by receiving scattered light from the surface. The particle detection method according to claim 1, wherein a film of 30 nm or more is formed by the film forming process. The particle detection method according to claim 1 or 2, wherein the predetermined temperature range is less than 50 ° C. In a particle detection device that detects organic particles attached to the surface by irradiating the surface of the object to be inspected and receiving scattered light from the surface,
A film forming means for performing a film forming process for forming a silicon oxide film on the surface of the inspection object by an atomic layer deposition method within a predetermined temperature range in which organic particles are not damaged;
A reflective film forming portion for further forming a reflective film on the surface of the object to be inspected,
A light irradiation means for irradiating light on the surface of the object to be inspected,
And a means for detecting organic particles by receiving scattered light from the surface.