JP2001201442A - Surface contaminant recovery apparatus, surface analyzing apparatus and method for manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent lowering of the quantitative and qualitative analyzing accuracy of impurities, when the impurities on the surface of a semiconductor wafer are analyzed quantitatively and qualitatively by total reflection fluorescent X-rays or the like. SOLUTION: A negative pressure pipe 4, constituted of a material high in chemical solution resistance like PFA or PTFE, is arranged so that the other end of a through- hole 4A thereof connected to an external negative pressure control part at one end thereof is positioned directly above the liquid drop 2 on the surface 1S of a semiconductor wafer. Accordingly, the negative pressure pipe 4 brings the region above the liquid drop 2 to a negative pressure state, so as to suck the air in the periphery of the liquid drop 2 from the through-hole 4A to control the flow of air streams 3. With this constitution, the drying of the liquid drop 2 advances from the periphery of the liquid drop 2 to the center thereof by the friction of the air streams 3 with the liquid drop 2, and a force is applied to the liquid drop 2 from the lateral direction thereof to the center thereof by the air streams 3, and as a result, the area of the drying mark of the liquid drop 2 can be reduced to the contact area of the liquid drop 2 at dripping time with the semiconductor wafer 1 or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface contamination collecting apparatus for a surface analyzer, and more particularly to a technique for improving the accuracy of analyzing impurities present on the surface of a semiconductor wafer.

[0002]

2. Description of the Related Art As a surface analysis method for analyzing the type and amount of impurities in a thin film formed on the surface of a semiconductor wafer, a step of vapor-phase decomposition of a thin film on the surface of the wafer is provided.
A method is used which includes a step of collecting the surface contaminants decomposed in the step and a step of analyzing the degree of surface contamination from the collected material. That is, for example,
A thin film on the surface of a semiconductor wafer is decomposed by a hydrogen fluoride gas or the like using a semiconductor thin film decomposing device described in JP-A-6-9531 or a semiconductor thin film decomposing device described in JP-A-1-98944. Thereafter, for example, Japanese Patent Application Laid-Open No.
No. 43, JP-A-7-176580 and JP-A-8-176.
The surface of the semiconductor wafer was decomposed by the thin film decomposition step by scanning the surface of the semiconductor wafer with a solution such as hydrofluoric acid for measuring impurities using the surface contamination recovery device described in JP-A-233709. The decomposition products of the thin film scattered on the upper surface are taken into the solution, and surface contaminants, which are impurities in the thin film, are collected in the solution.
At that time, the dissolved liquid after recovery becomes droplets. Here, the scanning of the solution is performed by first bringing the solution close to a position where the solution is attached to the surface of the semiconductor wafer placed on the stage while holding the solution with a holding jig, and then rotating the stage. This is achieved by sliding the holding jig laterally. Further, as described in JP-A-7-176580, droplets of the solution obtained after collecting the surface contaminants are irradiated with infrared rays emitted from a lamp to dry the surface of the semiconductor wafer. After that, the area (drying marks) where the droplets were dried on the surface of the semiconductor wafer was analyzed by an analyzer such as total reflection X-ray fluorescence, so that the type and amount of impurities present on the surface of the semiconductor wafer were within the allowable range. Is analyzed and determined whether or not

[0003]

However, in the surface contamination recovery apparatus used in the above-mentioned process, as described in the prior art described in Japanese Patent Application Laid-Open No. 7-176580 described above, the surface contamination is not irradiated on the surface of the semiconductor wafer by infrared irradiation. When the droplets are dried, there are the following problems. That is, since the analysis area of the total reflection X-ray fluorescence is generally about 1 cm ^2, it is necessary in the above-described process to set the dried area of the collected droplets within the range in which the analysis is possible. However, when the droplet (chemical solution) is dried on the surface of the semiconductor wafer as described above, the droplet reacts with a semiconductor wafer having a hydrophobic surface, for example, a silicon wafer to form a silicon oxide film, and the surface of the semiconductor wafer becomes Becomes hydrophilic. When the surface of the semiconductor wafer becomes hydrophilic as described above, the surface tension of the droplet is reduced, and the droplet spreads in the horizontal direction, and the drying mark of the droplet becomes large. As a result, if the dry region is beyond the range that can be analyzed by total reflection X-ray fluorescence, part of the collected impurities cannot be analyzed, and the accuracy of the quantitative value will be lost, and the total amount of impurities will decrease. Therefore, there arises a problem that the precision of quantitative and qualitative analysis of impurities on the semiconductor wafer surface is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it has been found that when performing quantitative and qualitative analysis of impurities on the surface of a semiconductor wafer by total reflection X-ray fluorescence or the like, the accuracy of impurity analysis is improved. The purpose is to prevent a decrease in In other words, an object of the present invention is to improve the droplet drying step of the above-mentioned steps or the steps or the droplet drying section of the surface contamination recovery apparatus.

[0005]

According to a first aspect of the present invention, there is provided a surface contamination recovery apparatus comprising: dropping a droplet of a solution for measuring impurities on a surface of a semiconductor wafer after a thin film is decomposed; A surface contamination recovery device for drying the droplet after scanning the surface of the semiconductor wafer with the droplet, the device having a through-hole connected at one end to an external negative pressure control unit via a pipe, wherein the through-hole Is arranged so that the other end thereof is located above the droplet after the scanning, and is provided with a negative pressure tube capable of setting a negative pressure state above the droplet.

According to a second aspect of the present invention, there is provided the surface contamination recovery apparatus according to the first aspect, wherein the atmosphere around the semiconductor wafer is filled with an inert gas, and A heating device that is installed in a passage of a gas flow sucked into the through-hole of the negative pressure tube from above the droplet through the upper side of the droplet, and heats the inert gas forming the air flow to a predetermined temperature. Wherein the predetermined temperature suppresses diffusion of the impurities from the surface of the semiconductor wafer to the inside of the semiconductor wafer based on a diffusion coefficient of an impurity to be analyzed contained in the droplet. It is characterized in that it corresponds to the temperature to be obtained.

According to a third aspect of the present invention, there is provided a surface contamination recovery apparatus according to the first or second aspect, wherein a negative pressure plate having a through hole formed in a central portion instead of the negative pressure pipe. While being disposed parallel to the surface of the semiconductor wafer, one end of the through-hole is connected to an external negative pressure control unit via a pipe, and the other end of the through-hole is disposed above the droplet. It is characterized by being.

According to a fourth aspect of the present invention, there is provided a surface contamination recovery apparatus according to the third aspect, wherein a height of a surface of the negative pressure plate facing the semiconductor wafer surface is higher than the semiconductor wafer surface. The height is substantially equal to the height of the droplet.

According to a fifth aspect of the present invention, there is provided a surface contamination recovery apparatus according to the third or fourth aspect, wherein the negative pressure plate has a surface opposite to the surface of the semiconductor wafer. A notch is formed toward the center of the pressure plate.

According to a sixth aspect of the present invention, in the surface contamination recovery apparatus, a chemical solution serving as a solution for measuring impurities is dropped on the surface of the semiconductor wafer having the decomposition product of the thin film, and the surface of the semiconductor wafer is treated with the chemical solution. A surface contamination collection device that collects and collects the chemical solution after scanning over the surface, and then dries the collected chemical solution onto the semiconductor wafer surface and then dries on the semiconductor wafer surface. A chemical solution is placed on the semiconductor wafer surface, and the semiconductor solution surface can be moved up and down so that the semiconductor solution surface can come into contact with the semiconductor solution surface. A sample support for mounting a wafer, and a drying device for drying the chemical in a state where the surface of the semiconductor wafer and the droplets are in contact with each other by raising the chemical support. Characterized in that it comprises.

According to a seventh aspect of the present invention, there is provided a surface analysis apparatus including the surface contamination recovery apparatus according to any one of the first to sixth aspects.

According to a eighth aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of: (a) preparing a dummy semiconductor wafer having a predetermined semiconductor thin film formed on its surface under certain conditions; Analyzing the impurities contained in the predetermined semiconductor thin film using the surface analyzer according to claim 7 for the dummy semiconductor wafer;
(C) forming the predetermined semiconductor thin film on the original semiconductor wafer under the certain conditions when the analysis result obtained in the step (b) is within an allowable range. I do.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) A surface analyzer according to the present embodiment is roughly divided into a semiconductor thin film decomposing device, a surface contamination recovery device, and a total reflection X-ray fluorescence spectrometer. In particular, the above-described device has different features from the conventional device described above. In addition, the characteristic part of the present surface contamination recovery apparatus is a drying section for drying the droplets of the solution obtained by collecting the impurities after scanning on the semiconductor wafer surface in the conventional surface contamination recovery apparatus described above. In the configuration. Therefore, also in the present embodiment, the step of performing the surface analysis of the semiconductor wafer corresponds to each of the above-described apparatuses or the like, and a predetermined semiconductor thin film (hereinafter, simply referred to as a thin film) on the wafer surface is subjected to gas phase decomposition. A first step of causing the thin film to decompose the thin film in the first step, and disperse the contaminants on the surface of the thin film containing impurities in the thin film with a solution or a chemical solution for measuring impurities. A second step of collecting the droplets by scanning over the same solution and drying the collected droplets, and performing total reflection X-ray fluorescence analysis on the dried traces of the droplets And a third step of performing quantitative and qualitative analysis on the type and amount of impurities. In the first to third steps, the steps up to the first half of the first step and the second step of the impurity recovery step are the same as those in the conventional technique described above. That is, for example, a thin film on the surface of a semiconductor wafer is converted into a chemical such as hydrogen fluoride gas by a semiconductor thin film decomposition apparatus corresponding to that described in JP-A-60-69531 or JP-A-1-98944. Decompose by Thereafter, for example, JP-A-3-239343, JP-A-7-176580 and JP-A-8-2337.
The surface of the semiconductor wafer was decomposed by the thin film decomposition step by scanning the surface of the semiconductor wafer with a solution for measuring impurities using a collection unit of a surface contamination collection device corresponding to that described in JP-A-09-0909. By dissolving the decomposition product of the thin film scattered on and taking it into the solution,
All surface contaminants, which are impurities in the thin film, are recovered in the solution. At that time, the solution after the completion of scanning becomes droplets. At this time, the chemical solution used as a solution or droplets is generally a mixture of chemical solutions such as hydrofluoric acid, nitric acid, hydrochloric acid, and hydrogen peroxide at an arbitrary ratio. However, the solution is determined individually according to the type of impurities to be recovered.

The scanning of the solution is performed as follows. First, the solution is held by the holding jig, and then the holding jig is moved to bring the solution close to a position where the solution adheres to the surface of the semiconductor wafer mounted on the stage. Thus, the solution is dropped on the surface of the semiconductor wafer as droplets in a range of about 25 μl to 200 μl.
Then, the solution is scanned over the surface of the semiconductor wafer by sliding the holding jig laterally while rotating the stage.

Next, with reference to the drawings, the configuration or drying step of a droplet drying unit which is a characteristic part of the surface contamination recovery apparatus according to the present embodiment will be specifically described.

FIG. 1 is a view showing a drying section 14 of a surface contamination recovery apparatus according to the present embodiment in a vertical sectional view and a block diagram. The drying section 14 is disposed in a chamber 20 and is sealed. Have been. FIG. 2 is an enlarged perspective view schematically showing a configuration of a core portion of the main drying unit 14. 1 and 2, reference numeral 1 denotes a semiconductor wafer, 1 S denotes a hydrophobic surface of the semiconductor wafer 1, 2 denotes a droplet of a solution after the scanning is completed (the maximum area is about 1 cm ² when viewed from the top), 4 Is a vacuum tube, 4A is a through hole formed in the vacuum tube 4, 4AE1
Denotes a first end (corresponding to the other end) of the through hole 4A,
A is connected to the other end of the chamber 20 (corresponding to one end).
Is connected via a pipe 21 to a suction port of a negative pressure control unit (including a vacuum pump (not shown)) 13 disposed outside the unit. The inner diameter of the pipe 21 is equal to or slightly larger than the diameter of the through-hole 4A. Reference numeral 16 denotes a stage for mounting the semiconductor wafer 1, and reference numeral 18 denotes a stage control unit for rotating the stage 16. Further, 15 is a gas introduction pipe. The gas introduction pipe 15 for introducing the inert gas into the chamber 20 is an optional component.

The present embodiment is characterized in that a negative pressure tube 4 is provided in order to solve the above-mentioned problems. That is,
The negative pressure tube 4 is arranged such that the droplet 2 after scanning is located directly below the first end 4AE1 of the through hole 4A with a certain gap or space therebetween, in other words, the first end 4AE1 is located above the droplet 2. It is arranged above the semiconductor wafer surface 1S so as to be located. Here, the inner diameter of the negative pressure tube 4, that is, the diameter of the through-hole 4A is within a range of several mm to several cm. In order to prevent the occurrence of new contamination by disposing the negative pressure tube 4 in the chamber 20, a material having high chemical resistance is used.
That is, even if the material is in contact with the chemical, the material is unlikely to dissolve and cause contamination, and the negative pressure tube 4
It is preferable to configure For example, a fluororesin such as PFA (tetrafluoroethylene) or PTFE (polytetrafluoroethylene) is used as the material of the negative pressure tube 4.

When the negative pressure control unit 13 shown in FIG. 1 is operated, the first end 4AE1 of the through-hole 4A of the negative pressure tube 4
The negative pressure pipe 4 puts the space above the droplet 2 between the first end 4AE1 and the droplet 2 into a negative pressure state. Here, the negative pressure above the droplet 2 is adjusted so that the droplet 2 does not move. With this configuration, the shape of the droplet 2 is changed by the airflow 3 sucked from the periphery of the droplet 2 through the space above the droplet 2 from the first end 4AE1 of the through hole 4A, and the center of the droplet 2 is formed. Maintained to be caught in the part. In addition, the drying of the droplet 2 proceeds from the periphery of the droplet 2 due to friction at the contact portion between the airflow 3 and the droplet 2, and finally the central portion of the droplet 2 dries. As described above, the drying of the droplet 2 proceeds from the periphery of the droplet 2, and the force from the lateral direction of the droplet 2 toward the center thereof is continuously applied to the droplet 2 by the air current 3 during the drying. The droplet 2 can be dried with an area equal to or smaller than the contact area between the droplet 2 and the semiconductor wafer 1 at that time.

Thereafter, the drying traces formed after the droplets 2 are dried on the semiconductor wafer surface 1S as described above are analyzed by an analyzer such as a total reflection fluorescent X-ray, so that the drying traces are present on the semiconductor wafer surface. It is possible to accurately and highly sensitively analyze and determine whether the type and amount of the impurities are within the allowable range.

(Modification 1 of Embodiment 1) In this modification, in the drying unit 14 (FIG. 1) of the surface contamination recovery apparatus according to Embodiment 1, the atmosphere around the droplet is changed to a stable inert gas. Filling with gas and installing a heating device in the path of the air stream shortens the drying time, while optimizing the temperature of the hot air that collides with the droplets, and enables the analysis of semiconductors in the droplets that are impurities to be analyzed. Improvements have been made to suppress the reaction on the surface of the semiconductor wafer by not accelerating the diffusion into the inside of the wafer. Hereinafter, a specific configuration example of the drying unit of the surface contamination recovery apparatus according to the present modification will be described with reference to the drawings.

FIG. 3 is an enlarged perspective view schematically showing a core portion of the drying section 14 of the surface contamination recovery apparatus according to this modification. In FIG. 3, by introducing the inert gas 11 into the chamber 20 shown in FIG. 1 from the gas introduction pipe 15, the atmosphere around the droplet 2 is filled with the inert gas 11 (for example, nitrogen or arcon gas). I have. In addition, the path of the airflow in the chamber 20 that causes the airflow 3 to be sucked into the through-hole 4A from above the droplet 2 from around the droplet 2,
A heating device 10 is provided. The heating device 10 is connected to a temperature controller 17 outside the chamber 20 as shown in FIG. 4 described later, and the temperature of the heating device 10 is set by the temperature controller 17.

With the above configuration, in this modification, the droplet 2
Is placed in a negative pressure state by a negative pressure tube 4 and an inert gas 11 around the droplet 2 is heated by a heating device 10 to a predetermined temperature described later. Since the hot air of the heated inert gas 11 flowing upward collides with the droplet 2 to dry the droplet 2, FIG.
The drying time can be shorter than in the case of (1).

Further, here, the heating temperature of the inert gas 11 is determined based on the diffusion coefficient of the impurity to be analyzed contained in the droplet 2, and the impurity is heated to the surface 1 of the semiconductor wafer.
The predetermined temperature is set such that diffusion from S to the inside of the semiconductor wafer 1 can be sufficiently suppressed. For example, when the impurities to be analyzed are iron or copper, the heating temperature of the inert gas 11 is set so that the droplets 2 can be dried at a low diffusion temperature in consideration of their diffusion coefficients. Is set. More specifically, when the impurity to be analyzed is copper, the diffusion coefficient of copper is generally very large, and it is considered that copper can diffuse inside the semiconductor wafer 1 even at room temperature.
At this time, the predetermined temperature of the inert gas 11 is set to a temperature that is slightly higher than the normal temperature and that is about several tens of minutes for the droplet 2 to dry. In addition, if the diffusion coefficient of various other impurities to be analyzed is taken into consideration, the predetermined temperature when heating the inert gas 11 may be several degrees Celsius in some cases. Therefore, according to this modification,
Diffusion of impurities to be analyzed from the semiconductor wafer surface 1S into the semiconductor wafer 1 can be sufficiently suppressed,
The droplet 2 can be dried and left in the drying mark while all the impurities to be analyzed collected in the droplet 2 by scanning are taken into the droplet 2 as they are. Further, the extent to which the semiconductor wafer surface 1S is contaminated by external impurities can be minimized. In addition, as a result of the hot air of the inert gas 11 whose temperature has been appropriately adjusted colliding with the droplet 2 from right beside, the drying time is sufficiently reduced, so that the spread in the horizontal direction can be further suppressed.
A droplet having a smaller dry area can be obtained.

(Modification 2 of Embodiment 1)
The present embodiment is characterized in that a negative pressure plate having a through hole in the center is arranged in parallel to the semiconductor wafer surface instead of the negative pressure tube 4 (FIG. 2) of the surface contamination recovery apparatus according to the first embodiment.

FIG. 4 is a diagram showing the configuration of the drying unit 14 of the surface contamination recovery apparatus according to the present modification using a sectional view and a block diagram. FIG. 5 is a perspective view schematically showing the negative pressure plate 5 shown in FIG. 4 and its peripheral portion, that is, the core portion of the present modified example.

The difference between FIG. 4 and FIG. 1 lies in the negative pressure plate 5. As shown in FIGS. 4 and 5, the negative pressure plate 5, which is an alternative to the negative pressure tube 4 in FIG. 2, is provided in parallel above the semiconductor wafer surface 1 </ b> S, and is sufficient for the size of the droplet 2. It has a large size. For example, the droplet 2 is 1c
In the case of about m ² , the diameter of the cylindrical negative pressure plate 5 is 10 c
m. In addition, a through-hole 9 is formed in the center of the negative pressure plate 5, and the first end (corresponding to the other end) 9E1 of the through-hole 9 is positioned above the droplet 2 so that the negative pressure plate 5 Is installed. Moreover, the other second end (corresponding to one end) 9E2 of the through-hole 9 is the second end 4A of the negative pressure tube 4 in FIG.
Similarly to E2, it is connected via a pipe 21 to the suction port of a negative pressure control unit 13 provided outside the chamber 20. The diameter of the through-hole 9 is in a range of several mm to several cm.

With the above configuration, when the negative pressure control unit 13 is operated, the negative pressure plate 5 sucks the gas in the space above the droplet 2 from the through-hole 9 to bring the upper space into a negative pressure state.
Thereby, the gas around the negative pressure plate 5 is drawn into the gap between the surface 5S of the negative pressure plate 5 facing the semiconductor wafer surface 1S and the semiconductor wafer surface 1S, and the negative pressure plate surface 5S
Then, an air flow 3 flowing toward the through-hole 9 is generated.
Moreover, in the present modification, the airflow 3 can be controlled by the shape of the negative pressure plate 5. In the present modification, the negative pressure plate 5 is provided so that the flat surface 5S faces in parallel to the semiconductor wafer surface 1S. With such a shape and arrangement of the negative pressure plate 5, the same effects as those of the first embodiment described above can be obtained.

Further, while maintaining the above-mentioned shape, the negative pressure plate 5 is adjusted so that the height of the surface 5S of the negative pressure plate 5 from the semiconductor wafer surface 1S is substantially equal to the height of the droplet 2 from the semiconductor wafer surface 1S. May be set. When the air flow 3 is arranged in this manner, the air flow 3 is parallel to the semiconductor wafer surface 1S, and the air flow 3 collides with the droplet 2 from the sideways direction of the droplet 2 and escapes to the through-hole 9; The area can be controlled to be smaller than in the first embodiment. That is, a force directed from the lateral direction to the center of the droplet 2 can be efficiently applied to the droplet 2 during drying, and the area of the drying mark can be reduced by the droplet 2 and the semiconductor wafer 1 at the time of dripping. Can be controlled to be smaller than the contact area.

Further, when the gas flows in a natural state, a slight distortion of the jig at that time disturbs the air flow and generates an air flow in an unintended direction. As a result, the droplet 2 may move. . To prevent this, it is necessary to control the position at which the gas flows and the direction (angle) at which the gas hits the droplet 2. More preferably, the symmetry of the direction and force when the air stream collides with the droplet 2 should be better maintained. Therefore, as shown in FIG. 6 which is a plan view of the negative pressure plate surface 5S when the negative pressure plate 5 is viewed from below, a cut 12 may be made in the surface 5S of the negative pressure plate 5 facing the semiconductor wafer 1. good. At this time, the cut 12 is formed toward the center of the negative pressure plate 5. Thereby, the air flow 3 is guided to the cut 12 and surely flows toward the center of the negative pressure plate 5, and the air flow 3
Flow can be smoothed. Especially in FIG.
The number of cuts 12 is set to four. This is because when the number of cuts 12 is even, the symmetry of the airflow 3 (the direction and force with which the airflow 3 collides with the droplet 2) is better than when the number of the slits 12 is odd, and the droplet 2 is moved in the horizontal direction. This is because it is effective to surely prevent the liquid picker 2 from spreading to the outside and to keep the shape of the liquid picker 2 smaller. Moreover, in FIG.
A slit 12 is spirally formed. Accordingly, the air flow 3 advances while swirling toward the center of the negative pressure plate 5, so that the flow of the air flow 3 can be further smoothed. Drop 2
The symmetry can be maintained in a well-balanced manner by controlling the direction (angle) corresponding to. Therefore, it is possible to prevent the airflow 3 from flowing from an unintended direction as much as possible due to the disturbance of the airflow 3 due to a slight distortion of a jig or the like, and to efficiently apply the airflow 3 to the droplet 2. Can be.

As described above, according to the present modification, it is possible to realize a dry trace of the droplet 2 having an even smaller area than the contact area between the droplet 2 and the semiconductor wafer 1 at the time of dropping. it can.

The above-described modification (1) can be applied to this modification. The interior of the chamber 20 is filled with an inert gas, and the heating device 10 as shown in FIG. And a temperature controller 17 may be provided.

(Embodiment 2) As described above, in the drying section of the prior art, as described in Japanese Patent Application Laid-Open No. 7-176580, for example, droplets of the dissolved liquid after collecting the surface contaminants Is dried on the surface of the semiconductor wafer by irradiating infrared rays from a lamp. This embodiment is characterized in that the drying section is improved. That is, a chemical solution (droplet) serving as a solution for measuring impurities is dropped on the surface of a semiconductor wafer having a decomposition product of a thin film, and the chemical solution after scanning the surface of the semiconductor wafer with the chemical solution is used as a dropper or the like. It collects and collects using a collecting device that can be adsorbed under a negative pressure. Then, a chemical solution from which impurities have been collected is dropped onto the surface of the semiconductor wafer. In this case, PTFE or PF is placed in the drying section of the surface contamination collection device.
A liquid chemical support made of fluororesin having chemical resistance such as A, on which a recovered chemical can be placed and at least vertically movable so that the placed chemical can be brought into contact with the surface of the semiconductor wafer. And a sample support or stage for placing the semiconductor wafer downward so that the surface of the semiconductor wafer faces the chemical support.
Further, in the present embodiment, after a certain amount of droplets are dried on the chemical support beforehand, the chemical support is raised to bring the chemical placed on the chemical support into contact with the surface of the semiconductor wafer. By doing so, the collected chemical solution is dropped again on the semiconductor wafer, thereby reducing the dry area of the chemical solution. Hereinafter, a specific configuration example of the drying unit of the surface contamination recovery apparatus according to the present embodiment will be described with reference to the drawings.

FIG. 7 is a view showing the drying section 14 of the surface contamination recovery apparatus according to the present embodiment in a vertical sectional view and a block diagram, and the drying section 14 is disposed in the chamber 20 and sealed. Have been. FIG. 8 is an enlarged perspective view schematically showing the configuration of the core portion of the main drying unit 14. 7 and 8, reference numeral 6 denotes a chemical support, reference numeral 7 denotes a chemical solution (droplets) collected and collected after scanning, and reference numeral 19 denotes a chemical support controller for moving the chemical support 6. , 22
Indicates that the semiconductor wafer surface 1S has the mounting portion 6A of the chemical support 6
This is a sample support table on which the semiconductor wafer 1 can be placed in a downward state so as to face the mounting surface. Here, the chemical support 6
Arm 6B and shaft 19A of chemical liquid support stand control unit 19 are in a fitted state. The chemical support control unit 19 rotates the chemical support 6 around the axis 19A to dispose the chemical 7 below the semiconductor wafer 1 and moves the shaft 19A up and down to move the chemical 7 and the semiconductor wafer surface 1S. And the distance can be adjusted. The gas introduction pipe 15 for introducing the inert gas into the chamber 20 is an optional component.

First, as shown in FIGS. 7 and 8, the recovered chemical 7 is mounted on the mounting portion 6A of the chemical support 6. Further, the semiconductor wafer 1 is supported by the sample support table 22 shown in FIG. 7 so that the semiconductor wafer surface 1S faces down. Next, by driving the chemical liquid support base control unit 19, the chemical liquid support base 6 is rotated about the axis 19A, and the mounting part 6A and the chemical liquid 7 are arranged below the semiconductor wafer surface 1S. Further, by raising the shaft 19A by the drive control of the chemical solution support controller 19, the chemical solution 7 placed on the mounting portion 6A is brought into contact with the semiconductor wafer surface 1S in that state. In some cases, the semiconductor wafer 1 may be replaced with a new one before the chemical solution 7 comes into contact with the semiconductor wafer surface 1S. This is because the semiconductor wafer 1 after decomposing the film on the semiconductor wafer surface 1S to collect impurities has poor surface homology, and therefore, when analyzed by total reflection X-ray fluorescence, X-rays are scattered on the semiconductor wafer surface 1S. As a result, the analysis sensitivity may be reduced.

In this manner, the mounting portion 6A of the chemical support 6 is brought close to the semiconductor wafer 1 to a position where the chemical solution 7 comes into contact with the semiconductor wafer surface 1S, and then, at low humidity, not shown. The drying of the chemical 7 by a drying device (such as an infrared lamp) is started. At this time, the chemical solution 7 reacts with silicon, which is a material forming the semiconductor wafer 1, and a hydrophilic silicon oxide film is formed only on the portion of the semiconductor wafer surface 1S that is in contact with the chemical solution 7. . When dried in this state, the chemical solution 7 is attracted to the semiconductor wafer 1 and exists so as to hang on the surface 1S of the semiconductor wafer as a droplet 8 shown in FIG. In addition, a force is applied to the droplet 8 by gravity in a downward direction, that is, in a direction away from the semiconductor wafer surface 1S. Therefore, the force that adheres to the semiconductor wafer surface 1S due to the hydrophilicity and the force that tries to move downward from the semiconductor wafer surface 1S by its own weight act on the droplet 8, thereby reducing the lateral force of the droplet 8. The drying of the droplet 8 can be continued. In addition, by increasing the time for holding the chemical solution 7 on the chemical support 6 and partially drying the chemical 7 on the chemical support 6 and reducing the volume of the chemical 7 by evaporating the solvent, the surface of the semiconductor wafer is reduced. It is also possible to reduce the contact area between the chemical solution 7 and the semiconductor wafer surface 1S when drying on 1S.

As described above, according to the present invention, the area of the finally formed dry mark on the semiconductor wafer surface 1S can be made sufficiently smaller than that of the dry mark formed in the case of the prior art. In the analysis step using the total reflection X-ray fluorescence, the quantitative and qualitative analysis of impurities can be performed accurately.

(Semiconductor Device Manufacturing Method) Any one of the surface analyzers having the surface contamination recovery apparatus described in the first embodiment and its modifications (1) and (2) and the second embodiment can be replaced with a predetermined semiconductor. The present invention can be applied to a manufacturing method for forming a thin film on a semiconductor wafer surface. For example, a surface analyzer can be applied as follows.

First, after preparing a dummy semiconductor wafer, a predetermined semiconductor thin film is formed on the surface of the dummy semiconductor wafer under certain conditions.

Next, the dummy semiconductor wafer is placed on a stage in any of the above-mentioned surface analyzers, and the amount of impurities to be analyzed contained in the predetermined semiconductor thin film by the surface analyzer is determined. Analyze etc.

Next, it is determined whether or not the amount of impurities to be analyzed given by the analysis result is within an allowable range. If the value is not within the allowable range, the above condition is changed, the predetermined semiconductor thin film is newly formed on the surface of a new dummy semiconductor wafer under a new condition, and the analysis / determination is performed. repeat. On the other hand, when it is determined that the semiconductor thin film is within the allowable range, the predetermined semiconductor thin film is formed on the surface of the original semiconductor wafer under the certain condition.

The above-described manufacturing method may be performed individually or individually for the original semiconductor wafer, may be performed for each lot, or may be performed for each predetermined number of lots.

By this application, it is possible to provide a semiconductor device having a good semiconductor thin film having much less surface contaminants.

[0043]

According to the surface contamination recovery apparatus according to the first aspect of the present invention, a gas flow is generated in which the gas around the droplet flows along the surface of the droplet and is then sucked into the through hole. With such an air flow, the droplet is maintained in the form of being wound toward the center, and the drying of the droplet is directed from the periphery to the center immediately below the through hole. Can progress. Moreover,
During the progress of such drying, it is possible to continue to apply a force to the droplet from the lateral direction toward the center by colliding with the air flow, so that the area of the drying mark of the droplet after drying is reduced. The area may be equal to or smaller than the contact area between the droplet and the semiconductor wafer surface. As a result, according to the present invention, it is possible to analyze all of the collected impurities in the subsequent analysis step using total reflection X-ray fluorescence, and to perform accurate quantitative analysis and the like, The effect of not causing the problem of sensitivity reduction due to the decrease in the total amount is obtained.

According to the surface contamination recovery apparatus of the second aspect of the present invention, the inert gas heated to a predetermined temperature becomes a gas stream that collides with the liquid droplets from the lateral direction, thereby suppressing the surface reaction of the semiconductor wafer. Droplets can be dried with all of the impurities to be analyzed incorporated in the droplets without causing diffusion of the impurities into the semiconductor wafer, and the drying time of the droplets is significantly reduced. Can be shortened.

According to the surface contamination recovery apparatus according to the third aspect of the present invention, an air flow can be generated from the periphery of the droplet toward the through-hole of the negative pressure plate.
The same effect as that of the invention can be obtained.

According to the surface contamination recovery apparatus according to the fourth aspect of the present invention, it is possible to create a flow of airflow parallel to the surface of the semiconductor wafer. Therefore, the airflow can collide with the droplet from just beside the droplet and pass through the through-hole of the negative pressure plate, and exert a force on the droplet from the lateral direction to the center of the droplet. Can work efficiently,
The area of the dry mark can be controlled to be smaller than the contact area between the droplet and the semiconductor wafer at the time of dropping.

According to the surface contamination recovery apparatus according to the fifth aspect of the present invention, the flow of the airflow is smoothly controlled so that the airflow flows from the periphery to the center of the through-hole of the negative pressure plate along the cut. As a result, it is possible to prevent the air flow from flowing from an unintended direction as much as possible due to the disturbance of the air flow due to slight distortion of the jig etc., and to efficiently apply the air flow to the droplets Can be. Therefore, according to the present invention, the droplet can be dried more stably so that the size of the drying mark is smaller than the contact area between the droplet and the semiconductor wafer at the time of dropping.

According to the surface contamination recovery apparatus of the present invention, when the chemical solution is brought into contact with the semiconductor wafer surface by the chemical solution support, the semiconductor wafer surface at the contact portion can be made hydrophilic. In this state, the drying device dries the chemical, and the chemical is drawn to the surface of the semiconductor wafer, and the chemical that hangs down on the surface of the semiconductor wafer is attached to the surface of the semiconductor wafer by hydrophilic force and weight. As a result, a force for moving the droplet downward from the surface of the semiconductor wafer acts, so that the droplet can be dried while reducing the lateral force of the droplet as the chemical liquid. Therefore, according to the present invention, the area of the finally formed dry mark on the surface of the semiconductor wafer can be made sufficiently smaller than that of the dry mark formed in the prior art, and the total reflection fluorescent X In the analysis process using a line, it is possible to accurately perform quantitative and qualitative analysis of impurities.

According to the invention of claim 7, according to claim 1,
There is an effect that it is possible to provide a surface analysis device having the effect of having the surface contamination recovery device according to any one of (6) to (6).

According to the method of manufacturing a semiconductor device according to the eighth aspect of the present invention, a semiconductor device having a good quality semiconductor thin film in which the type and amount of impurities contained in the semiconductor device are within an allowable range, This has the effect that a semiconductor device having a high-quality semiconductor thin film with a sufficiently low degree of surface contamination can be reliably manufactured.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a drying unit of a surface contamination recovery apparatus according to a first embodiment.

FIG. 2 is a perspective view showing a core part of a drying unit of the surface contamination recovery device according to the first embodiment.

FIG. 3 is a perspective view showing a core part of a drying unit of the surface contamination recovery apparatus according to a first modification of the first embodiment.

FIG. 4 is a diagram illustrating a drying unit of a surface contamination recovery apparatus according to a second modification of the first embodiment.

FIG. 5 is a diagram showing a core part of a drying unit of the surface contamination recovery device according to the second modification of the first embodiment.

FIG. 6 is a plan view showing the surface of a negative pressure plate of the surface contamination recovery device according to Modification 2 of Embodiment 1.

FIG. 7 is a diagram illustrating a drying unit of the surface contamination recovery device according to the second embodiment.

FIG. 8 is a perspective view showing a core part of a drying unit of the surface contamination recovery device according to the second embodiment.

[Explanation of symbols]

1 semiconductor wafer, 1S semiconductor wafer surface, 2
Droplet, 3 air flow, 4 negative pressure tube, 4A through hole, 5 negative pressure plate, 5S negative pressure plate surface, 6 chemical support, 7 chemical liquid, 8
Droplets, 9 through holes, 10 heating devices, 11 inert gas, 12 cuts.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01N 1/28 Z

Claims (8)

[Claims] 1. A surface on which a droplet of a solution for impurity measurement is dropped on the surface of a semiconductor wafer after a thin film is decomposed, and the droplet is dried on the surface of the semiconductor wafer and then dried. A pollution recovery device, wherein one end has a through-hole connected to an external negative pressure control unit via a pipe, and the other end of the through-hole is positioned above the droplet after the scanning. An apparatus for collecting surface contamination, comprising a negative pressure tube arranged and capable of bringing a negative pressure above the droplet. 2. The surface contamination recovery apparatus according to claim 1, wherein an atmosphere around the semiconductor wafer is filled with an inert gas, and the atmosphere around the droplet is above the droplet and above the droplet. The apparatus further includes a heating device that is installed in a passage of the flow of the gas sucked into the through-hole of the negative pressure tube and that heats the inert gas forming the air flow to a predetermined temperature. Based on a diffusion coefficient of an impurity to be analyzed contained in the droplet, the surface corresponds to a temperature capable of suppressing the diffusion of the impurity from the semiconductor wafer surface to the inside of the semiconductor wafer, Pollution recovery equipment. 3. The surface contamination collecting apparatus according to claim 1, wherein a negative pressure plate having a through hole formed in a central portion is arranged in parallel with the semiconductor wafer surface instead of the negative pressure tube. An end of the through-hole is connected to an external negative pressure control unit via a pipe, and the other end of the through-hole is disposed above the droplet. 4. The surface contamination recovery apparatus according to claim 3, wherein a height of the surface of the negative pressure plate facing the semiconductor wafer surface from the semiconductor wafer surface is equal to a height of the droplet. The surface contamination recovery device. 5. The surface contamination collecting apparatus according to claim 3, wherein a cut is formed on the surface of the negative pressure plate facing the semiconductor wafer surface, toward the center of the negative pressure plate. A surface contamination recovery device, characterized in that: 6. A chemical solution serving as a solution for measuring impurities is dropped on a surface of a semiconductor wafer having a decomposition product of a thin film, and the chemical solution after scanning the surface of the semiconductor wafer with the chemical solution is collected and collected. A surface contamination recovery device for dropping the collected chemical on the surface of the semiconductor wafer and then drying it on the surface of the semiconductor wafer, wherein the recovered chemical is placed, and the chemical and the semiconductor A chemical support that can be moved up and down so that the wafer surface can be contacted; a sample support on which a semiconductor wafer is placed so that the semiconductor wafer surface faces downward and faces the direction of the chemical support; A drying device for drying the chemical solution in a state where the surface of the semiconductor wafer and the droplets are in contact with each other by raising a support base, wherein a surface contamination recovery device is provided. . 7. A surface analyzer comprising the surface contamination recovery device according to claim 1. Description: 8. A step of: (a) preparing a dummy semiconductor wafer on a surface of which a predetermined semiconductor thin film is formed under certain conditions; and (b) providing a dummy semiconductor wafer with respect to the dummy semiconductor wafer.
Analyzing the impurities contained in the predetermined semiconductor thin film using the surface analyzer described in (c); and (c) when the analysis result obtained in the step (b) is within an allowable range, Forming the predetermined semiconductor thin film on the wafer under the certain conditions.