JP3303751B2 - Processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a processing apparatus,
Particularly, it is suitably used in a semiconductor wafer processing step of a semiconductor device manufacturing line, and simultaneously and automatically detects and evaluates dissolved species and / or dissolved chemical species of an object to be processed contained in a processing liquid such as a cleaning liquid during processing. The present invention relates to a processing device that performs

[0002]

2. Description of the Related Art In recent years, in a manufacturing process of a semiconductor device (semiconductor device), a new material has been used, so that a Si wafer with a new material is immersed in a cleaning liquid stored in a cleaning tank for cleaning. At this time, there is a phenomenon that the metal derived from the new material dissolves in the cleaning solution. There is a concern that metal ions dissolved in the cleaning solution may cause cross-contamination in the cleaning premises by adhering to the surface of the Si wafer again.

FIG. 7 is a schematic configuration diagram showing a conventional cleaning liquid evaluation system in a Si wafer cleaning step.
A diluting liquid 5 obtained by diluting a sampling liquid 4 obtained by directly collecting a cleaning liquid 3 in a cleaning tank 2 in which an i-wafer 1 is immersed.
A small amount of a mixed solution of hydrofluoric acid and nitric acid 6 obtained by scanning the surface of the Si wafer 1 immersed in the cleaning liquid 3 is analyzed for inorganic ions using a high-performance liquid ion chromatography 7 as an ion analyzer. In addition, metal ions are analyzed using an inductively coupled plasma mass spectrometer (ICP-MS) 8 or an atomic absorption spectrophotometer 9.

On the other hand, from the viewpoint of reduction of manufacturing cost and space saving, not only a cleaning tank dedicated to a new material is not provided, but also a Si wafer with a new material and the same cleaning structure are used.
It is conceivable to clean various types of Si wafers using other materials. Therefore, metal ions in the cleaning solution,
It is extremely useful to attach a device for simultaneously detecting inorganic ions, organic substances, and the like during the cleaning process to the cleaning device in order to control the degree of cleaning of the surface of the Si wafer and the cleaning liquid. It is also very useful to detect and quantify the species dissolved when the material of each object to be washed is dissolved in the washing solution, and to feed back the result to the determination of whether or not the washing process is possible.

In view of the above, there has been proposed a wet processing apparatus having a mechanism for checking the degree of contamination of contaminants in a cleaning liquid in a cleaning apparatus on-line (for example, Japanese Patent Laid-Open No. 3-1074).
No. 77). This wet processing apparatus uses a particle counter as a means for measuring the concentration of contaminants in a processing liquid, and controls the flow rate of circulating filtration. The wet processing apparatus communicates with an immersion tank for immersing and processing a semiconductor material and the immersion tank. Measuring means for measuring the concentration of the components contained in the processing liquid, measuring means for measuring the temperature of the processing liquid, and / or measuring means for measuring the concentration of contaminants in the processing liquid. A means for replenishing the components contained in the treatment liquid, a means for heating and cooling the treatment liquid, and / or a means for controlling the amount of circulation and filtration of the treatment liquid are provided according to the measurement values obtained by the measurement means. .

[0006]

In the conventional cleaning liquid evaluation system, although a small amount of inorganic ions or metal ions can be quantified, the operation from the time when the cleaning liquid 3 is collected to the time when the diluting liquid 5 is obtained is reduced. Since the operation until obtaining the hydrofluoric acid-nitric acid mixture 6 having scanned the surface of the Si wafer and the subsequent analysis operation using the analyzer are performed manually, it takes a long time to obtain an analysis result after collecting a sample. There is a problem that it takes time and it is difficult to analyze the cleaning solution in real time during the cleaning process.

[0007] In the conventional wet processing apparatus, the dissolved species of the new material in the cleaning liquid is not always particles.
Further, since particles are detected by measuring scattered light, there is a problem that particles that do not cause light scattering cannot be detected.

[0008] Further, the cleaning liquid is often a concentrated chemical liquid, and it is difficult to directly analyze the cleaning liquid due to the necessity of complicated pretreatment, and the size of the cleaning apparatus tends to be reduced. For this reason, when a large analyzer is installed in the cleaning device, the outer shape becomes too large, and there is a problem that it is not possible to cope with downsizing of the cleaning device.

As described above, in various conventional processing apparatuses,
Particles other than particles that cause light scattering cannot be detected by the particle counter, and it is difficult to install an analyzer that can detect dissolved species of the material to be cleaned in real time in the cleaning device. There was a problem.

[0010] The present invention has been made in view of the above circumstances, and simultaneously and automatically detects and evaluates dissolved species and / or dissolved chemical species of an object contained in a processing solution during processing. It is an object of the present invention to provide a processing device that can perform the processing.

[0011]

In order to solve the above problems, the present invention provides the following processing apparatus. That is,
A treatment tank for immersing the object in the treatment liquid to perform a predetermined treatment; and a detection tank provided in the treatment tank for detecting and evaluating dissolved species and / or dissolved chemical species of the object in the treatment liquid. Processing liquid evaluation means for performing, the processing liquid evaluation means ,
Pretreatment for pretreating a sample collected from the treatment liquid
Section and an elution suitable for the sample pretreated by the pretreatment section
Eluent mixing section for selecting and mixing liquids, and
Dissolved species and / or dissolved
A detection unit for detecting a chemical species, and an output from the detection unit
A control unit that determines whether or not processing is possible based on the detected value and notifies the controller.
It is provided.

[0012]

Further, the pre-processing section may be configured to perform a high-frequency treatment and / or a heat treatment on a sample collected from the treatment liquid. Further, the detection unit may be a capillary electrophoresis device having one or more capillaries. Also, the control unit stores a detection target substance and a type of the processing liquid in the processing liquid, an eluent corresponding thereto, and a limit concentration capable of performing the next processing on the detection target substance. And a determination unit that compares a detection value output from the detection unit with data in the storage unit to determine whether or not processing is possible.

In the processing apparatus according to the present invention, the detection of dissolved species and / or dissolved chemical species of the processing target in the processing liquid is performed in a processing tank in which the processing target is immersed in the processing liquid to perform predetermined processing. The provision of the processing liquid evaluation means for performing the evaluation makes it possible to simultaneously detect and evaluate the dissolved species and / or dissolved chemical species of the object in the processing liquid during the processing. This makes it possible to quickly determine whether or not the next processing should be performed by quickly knowing the degree of contamination of the processing liquid, thereby improving the operation rate of the processing apparatus and reducing the manufacturing cost of the processing process. Decrease.

Here, the reason why the present inventors have reached the present invention will be described. For example, in the Si wafer cleaning process, it is necessary to remove the influence of hydrogen peroxide, which is often contained in the cleaning liquid, in order to enable simultaneous detection of dissolved species in the cleaning liquid during the cleaning process. There is. This is because, for example, when optical detection is performed using the capillary electrophoresis method, bubbles derived from hydrogen peroxide are generated, which lowers the detection sensitivity of the target substance or overlaps with the peak position of the target substance. This is because hydrogen peroxide often hinders the detection and analysis of the substance to be measured.

Therefore, for the purpose of removing the influence of hydrogen peroxide, a pretreatment unit is provided for subjecting a sample collected from the cleaning liquid to high-frequency treatment or heating treatment to measure the weight before and after cleaning. By the heat treatment, the sample can be concentrated, and the sensitivity of the quantitative analysis can be improved.

Further, in the capillary electrophoresis method for detecting and analyzing various kinds of metal ions, inorganic ions, organic ions, molecules and particles in a washing solution, it is important to select an eluent necessary for separating a substance to be measured. is there. This is because the type and sensitivity of ions and molecules that can be separated and analyzed are determined by the type of eluent, the mixing ratio of the eluent when mixing multiple eluents, and the pH after mixing. It is. Therefore, in order to select and mix the eluent suitable for the type of the washing liquid and the substance to be measured, at the same time during the cleaning process, the substance to be measured contained in the washing liquid is automatically detected and the eluent suitable for it And an eluent mixing section for mixing was provided.

In addition, a database is prepared in advance which contains the type of the substance to be detected and the cleaning liquid, the corresponding eluent used in the capillary electrophoresis, and the limit concentration at which the next substance to be detected can be cleaned by the next Si wafer. In advance,
A control unit is provided for feeding back the result of the cleaning solution analysis by capillary electrophoresis or the like to the next Si wafer cleaning process determination.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a processing apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram illustrating a cleaning apparatus (processing apparatus) according to an embodiment of the present invention. The cleaning apparatus includes a cleaning tank (processing tank) 12 in which a cleaning liquid (processing liquid) 11 is stored, and a cleaning liquid 11. A pre-processing unit 13 for performing pre-processing on the sample collected from the sample, a capillary electrophoresis apparatus 14 for analyzing the pre-processed sample, an eluent mixing unit 15 for mixing the eluent, and a cleaning processing availability control unit 16. It is configured.

The pre-processing unit 13 includes a pipe 21 with an open / close valve.
Is connected to the cleaning tank 11. In addition, the capillary electrophoresis apparatus 14 includes a sample vial 31, a buffer vial (+) 32, a buffer vial (-) 33,
It comprises a high voltage power supply 34, an electrode 35, a capillary 36, and an optical detector 37 for ultraviolet (UV) absorption and the like.

The eluent mixing section 15 is provided in the capillary electrophoresis apparatus 14 and includes a material to be washed (object to be processed) type input section 41, a selection section 42 for selecting a buffer solution and a mixing ratio, and an elution section. The supply unit 43 supplies the liquid (mixed buffer liquid) to the buffer vial (+) 32 and the buffer vial (-) 33. Then, in the material to be cleaned input section 41,
When the material to be cleaned is cleaned, the type of the cleaning liquid and the substance to be measured are input corresponding to each cleaning liquid 11.

The cleaning processing availability control section 16 determines whether or not the next cleaning processing is possible based on the measurement results of ions and molecules in the cleaning liquid 11 output from the capillary electrophoresis apparatus 14. Storage means for storing the type of the measurement target substance and the washing liquid 11, the corresponding eluent, the limit concentration at which the next measurement processing can be performed on the measurement target substance, and the like, which are output from the capillary electrophoresis apparatus 14. Determining means for comparing the detected value with the data in the storage means to determine whether or not processing is possible;

Next, the pre-processing unit 13 will be described with reference to FIG. The cleaning liquid 11 in the cleaning tank 12 is directly applied to the cleaning tank 1.
It is sent to the pretreatment unit 13 through a thin pipe 21 with an on-off valve drawn from 2. In the pre-processing unit 13, the cleaning liquid 11 that has passed through the pipe 21 with the open / close valve is sent to a sample collecting unit 51 for quantifying the volume, and is quantified to a fixed volume to collect a small amount (several μl) of the sample.

This sample is transferred to a weight measuring section (A) 52 and weighed. Next, high-frequency processing is performed in the high-frequency processing section 53, and heat processing is performed in the heat processing section 54, so that hydrogen peroxide in the sample is degassed. In the case of a sample containing no hydrogen peroxide, the high frequency treatment and the heat treatment may be omitted as long as no volatile components are contained. Further, even when these treatments are inappropriate for the substance to be measured, one or both of the high-frequency treatment and the heat treatment may be omitted.

It is also possible to perform a heat treatment for the purpose of concentrating the sample. The sample after degassing the hydrogen peroxide is subjected to volume measurement and weight measurement in the weight / volume measuring section (B) 55. The sample whose volume and weight have been measured in the weight / volume measuring section (B) 55 is injected into the sample vial 31.

Next, the eluent mixing section 15 will be described with reference to FIG. The eluent mixing section 15 automatically mixes the eluent, and the turntables 61 and 62 include:
Dozens of vials can be prepared for each. The mixing type of the measurement target substance and the eluent corresponding to the cleaning liquid as the solvent is previously made into a database, and when the measurement target substance and the cleaning liquid are inputted in the material type input unit 41, the vial 61a on the turntable 61 Is injected into the vial 63a on the mixing turntable 63 through the suction tube 64a.

Similarly, the vial 62a on the turntable 62 is injected into the vial 63a on the mixing turntable 63 through the suction tube 64b. Here, the suction tubes 64a and 64b have a fixed amount. For example, when measuring tungstate ions in an ammonia-hydrogen peroxide mixture (APM), sodium sulfate and citric acid are mixed.

Vial 63 on mixing turntable 63
The vial (+) 67a on the vial (+) turntable 67 and the vial (-) 68 on the vial (-) turntable 68 through the suction tube 65 from a.
a The eluent is injected into each of them. Then, both ends of the capillary 36 are connected to the vial (+) 67a and the vial (-).
The capillary 36 is filled with an eluent by immersing the capillary 36a.

Next, as shown in FIG.
6 into a buffer vial (+) 32 and a buffer vial (-) 33 respectively,
When the anion such as tungstate ion is measured after the inside is filled with the eluent, the end on the anode side of the capillary 36 is withdrawn from the buffer vial (+) 32, and the sample is placed in the sample vial 31 and the sample is collected. Inject into 36.

Thereafter, the end of the capillary 36 on the anode side is pulled out of the sample vial 31 to remove the buffer vial (+).
Put in 32. Here, buffer vial (+) 3
2 and the buffer vial (−) 33 are connected by an electrode 35, which is provided with a high-voltage power supply 34.
6, a high voltage can be applied from both ends.

When a high voltage is applied, the substance to be measured, for example, a tungstate ion moves in the eluent in the capillary 36 and is detected by the optical detector 37 in the capillary 36 on the cathode side by ultraviolet absorption or the like. Here, the result of analyzing the tungstate ion (WO ₄ ^2- ) in the APM will be described.

[0032] FIG. 4 is a diagram showing an example of measuring the dissolved species of the semiconductor material of the concentrated chemical solution, AP was dissolved WSi _x
The figure which shows the result of having measured the M liquid with the capillary electrophoresis apparatus 14, and FIG. 5 is a figure which shows the result of identification amount. As shown in these figures, WO ₄ ^{2 -} it can be quantified concentration using the height of the peak corresponding to the peak. The obtained quantitative result is fed back to the determination of the next cleaning process availability, and if the concentration is higher than the allowable concentration, the process is not performed.

As described above, the substance to be measured is detected within a few minutes from the start of the separation, and can be quantified using the peak intensity or the peak area. In addition, the measurement target in the washing liquid 11 quantitatively analyzed by the capillary electrophoresis apparatus 14 based on the measurement results of the sample collection unit 51 and the weight measurement unit (A) 52 and the measurement results of the volume and weight measurement unit (B) 55. The concentration of the substance can be calculated.

The calculated concentration is determined by the cleaning process control unit 16.
To determine if the next wafer cleaning process is possible by comparing it with the limit concentration of the contaminants contained in the database, and if it exceeds the allowable concentration, warn not to perform the next process . In addition, by installing a plurality of capillaries 36 and using them together with the eluent mixing section 15, it is possible to analyze a plurality of substances to be measured at the same time. For example, a plurality of ions, molecules, and particles in the cleaning solution 11 containing hydrogen peroxide and the cleaning solution that is a concentrated chemical solution can be automatically and simultaneously quantified during the cleaning process.

FIG. 6 shows the effect of tungsten (W) contamination on the reliability of the gate oxide film.
It can be seen that when the concentration is 1 × 10 ¹² atoms / cm ² , the initial breakdown voltage of the gate oxide film is reduced to 80%. Therefore,
The cleaning tank 1 is controlled by controlling the W concentration in the cleaning liquid 11.
2 can prevent cross contamination accidents.

According to the cleaning apparatus of this embodiment, the cleaning liquid 1
1 is stored, a pretreatment unit 13 for pretreating a sample collected from the washing liquid 11, a capillary electrophoresis apparatus 14 for analyzing the pretreated sample, and an eluent mixing for mixing the eluent Unit 15 and cleaning processing availability control unit 16
, The inorganic ions, metal ions, organic ions, organic molecules, and particles in the cleaning solution 11 are simultaneously detected during the cleaning process without being affected by hydrogen peroxide often mixed in the cleaning solution 11, The cross-contamination in the cleaning tank 12 can be prevented by feeding back the detection result to the determination of whether the next wafer cleaning is possible or not.

Since the sample can be concentrated by the heat treatment section 54 of the pretreatment section 13, the sensitivity of the quantitative analysis of ions, molecules, and particles in the cleaning liquid 11 can be improved. In addition, by using the eluent mixing unit 15, not only the species to be cleaned in the cleaning liquid 11, but also the halogen ions in the cleaning liquid 11, the dissolved chemical species of the cleaning liquid 11, and the organic ions are detected during the cleaning process. be able to.

Further, by using the eluent mixture section 15 and a plurality of capillaries 36, a plurality of ions, molecules and particles in the cleaning solution 11 containing hydrogen peroxide and the cleaning solution which is a concentrated chemical solution are cleaned. Quantification can be performed automatically at the same time during processing, and cross-contamination accidents in the cleaning solution 11 due to these substances to be measured can be prevented beforehand.
It is also expected to be effective in elucidating the problem of abnormal occurrence in the semiconductor manufacturing process.

Furthermore, in a trial of a new material department in a semiconductor manufacturing prototype line, after a basic dissolution evaluation was performed, a wafer with a new material was made the same as another wafer without providing a cleaning tank dedicated to the new material. The cleaning process can be performed using the cleaning tank described above, and the development and production of semiconductor devices (semiconductor devices) can be smoothly performed. Further, since there is no need to provide a dedicated washing tank for new materials, it is possible to reduce equipment costs and save space occupied in a clean room.

[0040]

As described above, according to the processing apparatus of the present invention, a processing tank for immersing an object to be processed in a processing liquid to perform a predetermined processing and the processing liquid provided in the processing tank. Detection of dissolved species and / or dissolved chemical species of the object to be treated
Means for evaluating the processing solution,
The means performs pretreatment on a sample collected from the treatment liquid.
Pretreatment unit and a sample pretreated by the pretreatment unit.
An eluent mixing section for selecting and mixing the eluent,
Dissolved species of the object to be treated in the mixed solution from the mixing section and / or
Or, a detector for detecting dissolved species, and an output from the detector.
System that determines whether or not processing is possible based on the detected value
Control unit, so that the dissolved species and / or dissolved chemical species of the object to be treated in the treatment liquid can be simultaneously detected and processed during the treatment.
It is possible to evaluate, and by knowing the degree of contamination of the processing solution quickly, it is possible to prevent cross contamination accidents beforehand,
It is possible to quickly determine whether or not to perform the next process. Therefore, the operation rate of the processing apparatus can be improved, and the cost of the processing step can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a cleaning apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a pretreatment unit of the cleaning device according to the embodiment of the present invention.

FIG. 3 is a schematic configuration diagram showing an eluent mixing section of the cleaning device according to one embodiment of the present invention.

FIG. 4 is a diagram showing the results of measurement of tungstate ions by capillary electrophoresis.

FIG. 5 is a diagram showing the results of measuring the concentration of tungstate ions by capillary electrophoresis.

FIG. 6 is a diagram showing the effect of tungsten contamination on gate oxide film reliability.

FIG. 7 is a schematic configuration diagram showing a conventional cleaning liquid evaluation system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Si wafer 2 Cleaning tank 3 Cleaning liquid 4 Collecting liquid 5 Diluent 6 Hydrofluoric acid-nitric acid mixed liquid 7 High-performance liquid ion chromatography 8 Inductively coupled plasma mass spectrometer (ICP-MS) 9 Atomic absorption spectrophotometer 11 Cleaning liquid (processing liquid) 12) Cleaning tank (processing tank) 13 Pretreatment section 14 Capillary electrophoresis apparatus 15 Eluent mixing section 16 Cleaning processing availability control section 21 Pipe with open / close valve 31 Sample vial 32 Buffer vial (+) 33 Buffer vial (-) 34 High voltage power supply 35 Electrode 36 Capillary 37 Optical detector 41 Material to be cleaned (object to be processed) seed input unit 42 Selection unit 43 Supply unit 51 Sampling unit 52 Weight measuring unit (A) 53 High frequency processing unit 54 Heat processing unit 55 Weight・ Volume measuring unit (B) 61, 62 Turntable 61a, 62a Vial 63 mixed Combination turntable 63a Vial 64a, 64b Suction tube 65 Suction tube 67 Turntable for vial (+) 67a Vial (+) 68 Turntable for vial (-) 68a Vial (-)

Continuation of the front page (51) Int.Cl. ⁷ identification code FI H01L 21/306 G01N 27/26 331E 21/66 H01L 21/306 J (58) Investigated field (Int.Cl. ⁷ , DB name) H01L 21 / 304,21 / 306,21 / 66 B05C 3/02 C23G 3/00 G01N 1 / 28,27 / 447

Claims (4)

(57) [Claims] 1. A processing tank for immersing an object in a processing liquid to perform a predetermined processing, and a dissolved species and / or a dissolved chemical species of the object in the processing liquid provided in the processing tank. Processing solution evaluation means for detecting / evaluating the processing solution , wherein the processing solution evaluation means
A pre-processing unit for performing pre-processing;
Eluent mixing section to select and mix eluents suitable for the sample
And the dissolution of the object to be treated in the mixture from the eluent mixture section.
A detection unit for detecting disassembled and / or dissolved chemical species;
Determines whether or not processing is possible based on the detection value output from the detector
And a control unit for giving notification . 2. The method according to claim 1, wherein the pre-processing section is configured to collect a sample from the processing solution.
Subject to high frequency and / or heat treatment
The processing apparatus according to claim 1, wherein: 3. The apparatus according to claim 2, wherein the detecting unit includes one or more capillaries.
Characterized by being a capillary electrophoresis device having
The processing device according to claim 1. 4. The method according to claim 1, wherein the control unit detects and measures the processing liquid.
Target substance and the type of the processing solution, and corresponding elution
Solution and the target concentration for the next process
Storage means for storing the degree, and a detection output from the detection unit.
The output value is compared with the data in the storage means to determine whether or not processing is possible.
2. The apparatus according to claim 1, further comprising: a determination unit configured to perform the determination.
Processing equipment.