JP2007266211A - Semiconductor manufacturing apparatus and semiconductor manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor manufacturing apparatus and a semiconductor manufacturing method capable of treating a wafer with a chemical liquid in an appropriate state efficiently, by detecting whether a filter has been torn by circulating chemical liquid treatment. <P>SOLUTION: The semiconductor manufacturing apparatus comprises: a wafer treatment chamber 11 for treating a wafer by a circulating chemical liquid; a circulation line 12 of the circulating chemical liquid; a first filter 13 that is installed in the circulation line 12 and captures particles in the circulating chemical liquid discharged from the wafer treatment chamber 11; a particle counter 14 that is installed at the primary or secondary side of the first filter 13, and measures the number of particles in the circulating chemical liquid; and an arithmetic processing means 18 for calculating the time differential value of the number of measured particles. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a semiconductor manufacturing apparatus and a semiconductor manufacturing method for performing a circulating chemical solution process such as a cleaning process for a semiconductor wafer.

  In general, in the manufacturing process of a semiconductor device, a cleaning process using a chemical solution is performed in order to remove deposits attached to a wafer, a surface oxide film, and the like. As one of them, a circulating chemical solution process is used in which a chemical solution is circulated while filtering and a cleaning process is performed with the circulating chemical solution.

  In such a circulating chemical solution treatment, the pressure loss before and after the filter gradually increases due to the regularly captured particles, the circulation flow rate decreases, and the circulation stops. Further, the continuous use deteriorates the filter function and increases the number of particles passing through the filter. Although such a state is called a filter breakage, there is a problem that due to the filter breakage, a sufficient cleaning process cannot be performed and defects occur on the wafer.

  In order to avoid such problems, the filter is regularly replaced periodically. The filter life until the filter breaks depends on the initial state of the wafer, the number of processed wafers, processing steps, processing ratio, etc. It depends on the situation and varies depending on various other factors. If there is a sufficient margin for such fluctuations, it is necessary to replace the filter in a short period of time, resulting in a problem that costs increase and apparatus downtime increases.

In general, a method of detecting the replacement time of a chemical solution and the end point of cleaning by monitoring particles in the circulating chemical solution is used (see, for example, Patent Documents 1 and 2). However, the state of the filter is not detected, and there is a problem that it is difficult to efficiently avoid the filter breakage.
Japanese Patent Laid-Open No. 4-192524 (FIG. 1 etc.) JP 2004-356356 A ([0014] to [0022], FIG. 1 etc.)

  It is an object of the present invention to provide a semiconductor manufacturing apparatus and a semiconductor manufacturing method capable of detecting whether a filter is broken in a circulating chemical processing and performing chemical processing on a wafer efficiently in a good state. .

  According to one aspect of the present invention, a wafer processing chamber for processing a wafer with a circulating chemical solution, a circulating line for the circulating chemical solution, and particles in the circulating chemical solution that are installed in the circulating line and discharged from the wafer processing chamber are captured. A first counter for performing the measurement, a particle counter for measuring the number of particles in the circulating chemical solution installed on the primary side or the secondary side of the first filter, and a time differential value of the measured number of particles. There is provided a semiconductor manufacturing apparatus comprising an arithmetic processing means for calculating.

  Moreover, according to one aspect of the present invention, a process of processing a wafer with a circulating chemical solution, a step of capturing particles in the circulating chemical solution with a filter, a step of measuring the number of particles in the circulating chemical solution, and a measured particle There is provided a semiconductor manufacturing method comprising a step of calculating a time differential value of a number and a step of diagnosing whether the filter is broken based on the calculated time differential value of the number of particles.

  According to one embodiment of the present invention, it is possible to detect whether the filter is broken in the circulating chemical solution processing, and to efficiently perform chemical treatment on the wafer in a good state.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 shows the configuration of the semiconductor manufacturing apparatus of this embodiment. As shown in the figure, a wafer processing chamber 11 for processing a wafer with a circulating chemical solution and a circulation line 12 for circulating the chemical solution collected from the wafer processing chamber 11 and supplying the chemical solution to the wafer processing chamber 11 are installed. The circulation line 12 has a filter 13 for capturing particles in the circulating chemical solution, a particle counter 14 installed on the primary side of the filter 13 for measuring the number of particles in the circulating chemical solution, and a circulating chemical solution in the circulation line 12. A pump 15 for applying circulation pressure to circulate, a valve 16 for controlling circulation, and a flow meter 17 for checking the controlled flow rate are installed.

  The particle counter 14 is connected to arithmetic processing means 18 that calculates a time differential value from the number of particles input from the particle counter 14. Detection means 19 for detecting whether the filter 13 is broken or not is connected to the arithmetic processing means 18 from the time differential value of the number of particles, and a warning is given to the detection means 19 when the break of the filter 13 is detected. Warning means 20 is connected.

  In such a semiconductor manufacturing apparatus, the wafer is treated with a circulating chemical solution as follows. First, a chemical solution used for processing is newly introduced from the collection side 12a of the circulation line 12 to perform temperature-controlled circulation. After confirming that the number of particles in the circulating chemical measured by the particle counter 14 is below the preset upper limit by being captured by the filter 13, wafer processing is started in the wafer processing chamber 11.

  A circulating chemical solution is supplied to the wafer processing chamber 11 from a side (hereinafter referred to as a supply side) 12 b of the circulation line 12 that supplies the wafer processing chamber 11. At this time, the circulating chemical solution is supplied onto the wafer by being discharged onto the wafer, for example, in the wafer processing chamber 11, and the wafer is cleaned. Then, the circulating chemical solution used for cleaning is recovered, for example, in a recovery tank (not shown) serving as a buffer tank under normal pressure, and the recovered circulating chemical solution (hereinafter referred to as a recovery solution) It is introduced into the circulation line 12 from the collection side 12a and merges with the circulating chemical solution. At this time, since the circulating pressure is applied to the circulating chemical liquid by the pump 15, the recovered liquid is pressurized by a pump or the like so as to exceed the circulating pressure. In many cases, desorbed dust from the wafer is included in the collected liquid, so that the number of particles in the circulating chemical solution that has joined increases, but is trapped by passing through the filter 13 and the number of particles in the circulating chemical solution. Is reduced. At this time, the number of particles in the circulating fluid is measured by a particle counter 14 provided on the primary side of the filter 13.

  The capture rate by the filter 13 gradually deteriorates as the filter 13 is used. That is, as shown in the conceptual diagrams of FIGS. 2A and 2B, the filter 13b having a longer use period has a lower capture rate than the new filter 13a immediately after replacement. Therefore, the circulating chemical solution decreases the number of particles by passing through the filter, and the number of particles attenuates with time. However, a filter having a long use period has a low capture rate and a slowing rate of the number of particles.

  FIG. 3 shows the relationship between the processing time and the number of particles. As shown in the figure, the number of particles increases between the start of wafer processing and the completion of processing, and after the processing is completed, there is no recovered liquid containing new particles, so the number of particles attenuates (attenuation curve). ). At this time, when the new filter is used, the capture rate is high, so the slope of the particle attenuation curve is steep, but when the filter with a long period of use is used, the slope is small. That is, a decrease in the capture rate can be determined by a change in the slope of the attenuation curve.

  Therefore, the arithmetic processing means 18 calculates the slope of the tangent line of the attenuation curve (hereinafter referred to as a time differential value) when a predetermined time has elapsed from the completion of the processing, based on the number of particles input from the particle counter 14. Then, in the detection means 19, this time differential value is compared with the filter breakage obtained in advance or the time differential value (set value) in the immediately preceding state, and by detecting the time point when this set value is reached, the filter breakage is detected. Is detected. When the filter breakage is detected, a warning is issued by the warning means 20 based on the detection information.

  In this way, it is possible to accurately detect whether the filter breaks in advance regardless of the initial state of the wafer and the process status. This makes it possible to perform filter replacement efficiently. As a result, defects of the wafer and the semiconductor device formed from the wafer can be suppressed, and an increase in cost due to an increase in the frequency of filter replacement can be suppressed.

(Embodiment 2)
FIG. 4 shows the configuration of the semiconductor manufacturing apparatus of this embodiment. The present embodiment has the same configuration as that of the first embodiment, but differs in that a subline is provided in the circulation line and a spare filter is provided in the subline.

  As shown in the figure, as in the first embodiment, a wafer processing chamber 21 for processing a wafer with a circulating chemical solution, and a circulation line 22 for circulating the chemical solution collected from the wafer processing chamber 21 and supplying it to the wafer processing chamber 21 are provided. is set up. The circulation line 22 has a filter 23 for capturing particles in the circulating chemical solution, a particle counter 24 installed on the primary side of the filter 23 for measuring the number of particles in the circulating chemical solution, and a circulating chemical solution in the circulation line 22. A pump 25 for applying circulation pressure to circulate, a valve 26a for controlling the circulation, a flow meter 27 for confirming the controlled flow rate, and a valve 26b for switching the circulation are installed. The circulation line 22 is further provided with a sub-line 32, and a spare filter 33 and a valve 36b for switching circulation are installed.

  The particle counter 24 is connected to arithmetic processing means 28 for calculating the time differential value from the number of particles input from the particle counter 24. Detection means 29 for detecting whether the filter 23 is broken or not is connected to the arithmetic processing means 28 from the time differential value of the number of particles. The detection means 29 is connected to valves 26b and 36b and valve control means for controlling them. 30 is connected.

  In such a semiconductor manufacturing apparatus, as in the first embodiment, the wafer is subjected to the circulating chemical treatment as follows. First, a chemical solution used for processing is newly introduced from the collection side 22a of the circulation line 22 to perform temperature-controlled circulation. After confirming that the number of particles in the circulating chemical measured by the particle counter 24 is captured by the filter 23 and falls below a preset upper limit, wafer processing is started in the wafer processing chamber 21.

  Similarly, a circulating chemical solution is supplied to the wafer processing chamber 11 from a side (hereinafter referred to as a supply side) 22 b of the circulation line 22 that supplies the wafer processing chamber 21. The recovered liquid collected and used for wafer cleaning is introduced into the circulation line 22 from the recovery side 22a, and merges with the circulating chemical liquid. At this time, since the circulating pressure is applied to the circulating chemical liquid by the pump 25, the recovered liquid is pressurized by a pump or the like so as to exceed the circulating pressure. In many cases, desorbed dust from the wafer is included in the recovered liquid, so that the number of particles in the circulating chemical solution that has joined increases, but it is captured by passing through the filter 23 and the number of particles in the circulating chemical solution is increased. Is reduced. At this time, the number of particles in the circulating fluid is measured by a particle counter 24 provided on the primary side of the filter 23.

  The measured number of particles is input to the arithmetic processing means 28, and a time differential value is calculated at the time when a predetermined time has elapsed since the completion of the processing. Then, in the detection means 29, this time differential value is compared with a set value obtained in advance, and it is detected whether the filter has been broken by detecting the time point when the set value is reached.

  When filter breakage is detected, based on the detected information, the valve control means 30 turns off the valve 26b and turns on the valve 36b, thereby switching the circulation line 22 to the subline 32. Then, the filter 23 that has been turned off is replaced, and the process waits until it is detected that the filter 33 is broken.

  In this way, regardless of the initial state of the wafer and the process status, it is possible to accurately detect whether the filter is broken in advance and switch the circulation line. It is possible to perform the circulating chemical solution treatment, and it is possible to reduce downtime associated with filter replacement. As a result, defects of the wafer and the semiconductor device formed from the wafer can be suppressed, lead time can be shortened, and an increase in cost can be suppressed.

  In this embodiment, when the filter breakage is detected, the filter 23 is switched to the subline 32 and the filter 23 is replaced. However, as shown in FIG. A valve 26c for discharging to a not shown), a pure water for cleaning the filter 33 is introduced, and a valve 36c for discharging to an automatic chemical liquid drain (not shown) is provided. An automatic cleaning function for cleaning the circulation line may be provided by controlling the valve 26c or the valve 36c after switching between 23 and 33, respectively. By having such an automatic cleaning function, it is possible to replace the filter in the circulation line that has been washed with water, so that it is possible to significantly reduce the work time associated with the filter replacement.

  In these embodiments, the time differential value at the time when a predetermined time has elapsed from the completion of the processing is calculated by the arithmetic processing means from the number of particles input from the particle counter. Since the total number of circulating chemical solutions decreases due to a decrease in the recovery rate of the circulating chemical solution after the cleaning process, the number of particles in the unit volume may increase accordingly. In addition, if the amount of dust brought in by the wafer is large, the capture rate by the first filter is considered to be high. In order to cope with such a case, it is preferable to perform normalization with a value when the number of observed particles becomes maximum. In this way, by comparing the time differential value at the time when a predetermined time has elapsed from the completion of the processing obtained from the normalized attenuation curve with the set value, it is possible to detect filter breakage more accurately.

  In addition, it is desirable that the particle counter used in these embodiments is resistant to circulating chemicals and has a particle detection capability of about 0.1 μm. In these embodiments, the particle counter is installed on the primary side of the filter, but by setting the set value to a value obtained in advance based on the number of particles measured on the secondary side, It is also possible to set to.

  Further, in these embodiments, a single wafer cleaning device that cleans a wafer by discharging a circulating chemical solution onto the wafer is taken as an example, but it can also be applied to a batch cleaning device. is there.

  In addition, this invention is not limited to embodiment mentioned above. Various other modifications can be made without departing from the scope of the invention.

FIG. 6 illustrates a structure of a semiconductor manufacturing apparatus of one embodiment of the present invention. The conceptual diagram of the capture state of the particle | grains by the filter use state in 1 aspect of this invention. FIG. 6 shows a relationship between processing time and the number of particles in one embodiment of the present invention. FIG. 6 illustrates a structure of a semiconductor manufacturing apparatus of one embodiment of the present invention. FIG. 6 illustrates a structure of a semiconductor manufacturing apparatus of one embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11, 21 ... Wafer processing chamber, 12, 22 ... Circulation line, 13, 23 ... Filter, 14, 24 ... Particle counter, 15, 25 ... Pump, 16, 26a, 26b, 36b ... Valve, 17, 27 ... Flow meter, 18, 29 ... Arithmetic processing means, 19, 29 ... Detection means, 20 ... Warning means, 30 ... Valve control means, 32 ... ..Subline, 33 ... Spare filter

Claims (5)

A wafer processing chamber for processing wafers with circulating chemicals;
A circulation line of the circulating chemical solution;
A first filter installed in the circulation line for capturing particles in the circulating chemical solution discharged from the wafer processing chamber;
A particle counter installed on the primary or secondary side of the first filter for measuring the number of particles in the circulating chemical solution;
A semiconductor manufacturing apparatus comprising: arithmetic processing means for calculating a time differential value of the measured number of particles. Based on the calculated time derivative of the number of particles, detection means for detecting whether the filter is broken,
2. The semiconductor manufacturing apparatus according to claim 1, further comprising warning means for giving a warning when it is detected that the filter is broken. A second filter for capturing particles in the circulating chemical solution discharged from the wafer processing chamber;
The semiconductor manufacturing apparatus according to claim 1, further comprising a filter switching unit configured to switch from the first filter to the second filter. Processing the wafer with circulating chemicals;
Capturing particles in the circulating chemical solution by a filter;
Measuring the number of particles in the circulating chemical over time;
A semiconductor manufacturing method comprising: calculating a time differential value of the measured number of particles and diagnosing whether the filter is broken based on the time differential value of the number of particles. In the step of diagnosing whether the filter is broken,
In the decay curve of the measured number of particles with respect to time, normalize with the maximum value,
Calculate a time differential value of the number of particles after a predetermined time has elapsed from the time when the maximum value is reached,
The semiconductor manufacturing method according to claim 4, wherein the time differential value of the number of particles is compared with a reference value obtained in advance.

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