JP2019062003A - Film thickness measuring apparatus, film thickness measuring method, program and manufacturing method of semiconductor device - Google Patents

Abstract

An object of the present invention is to correct an apparent film thickness and measure an accurate film thickness. A film thickness measurement apparatus includes a film thickness measurement unit that measures the film thickness of a film formed on the surface of a substrate, a humidity measurement unit that measures the humidity around the film thickness measurement unit, humidity, and a film The first correction amount for correcting the measured value of the film thickness is calculated from the storage unit for storing the information on the correlation of thickness, the humidity measured by the humidity measurement unit, and the information stored in the storage unit. And a correction unit that corrects the measured value of the film thickness measured by the film thickness measurement unit by the calculated first correction amount, and a control that controls the film thickness measurement unit, the humidity measurement unit, and the correction unit. Have a part. [Selected figure] Figure 4

Description

  The present invention relates to a film thickness measurement apparatus, a film thickness measurement method, a program, and a method of manufacturing a semiconductor device.

  As one step of a manufacturing process of a semiconductor device (device), a substrate is placed on a substrate holder and accommodated in a reaction furnace, and various substrate processing such as film formation and annealing is performed. In a substrate processing apparatus that performs these steps, film thickness measurement is performed on a substrate after film formation processing of a conductor film, a semiconductor film, an insulating film, and the like.

  In the film thickness measurement described above, for example, the measurement results may differ depending on the time of exposure to the atmosphere and the environment where the measurement device is installed, such as humidity around the measurement device, so that it is impossible to accurately measure the film thickness. There was a problem (see, for example, Patent Document 1 and Patent Document 2).

JP 2001-217233 A JP 2001-093954

  An object of the present invention is to provide a technology that makes it possible to correct an apparent film thickness and measure an accurate film thickness.

  According to one aspect of the present invention, a film thickness measurement unit that measures the film thickness of a film formed on the surface of a substrate, a humidity measurement unit that measures the humidity around the film thickness measurement unit, humidity and film thickness Calculating a first correction amount for correcting the measured value of the film thickness from the storage unit for storing information on the correlation of the film thickness, the humidity measured by the humidity measurement unit and the information stored in the storage unit; A correction unit that corrects the measured value of the film thickness measured by the film thickness measurement unit by the calculated first correction amount; and a control unit that controls the film thickness measurement unit, the humidity measurement unit, and the correction unit And a technique is provided.

  According to the present invention, the apparent film thickness can be corrected to accurately measure the film thickness.

It is a block diagram showing the semiconductor manufacturing system concerning the embodiment of the present invention. It is a schematic block diagram of the film-forming apparatus which concerns on embodiment of this invention. It is side surface sectional drawing which shows the film-forming apparatus which concerns on embodiment of this invention. It is a block diagram showing control composition of a film thickness measuring device concerning an embodiment of the present invention. It is a figure which shows the relationship between the air | atmosphere exposure time at the time of film thickness measurement, and the increase amount of TiN film thickness. It is a figure which shows the relationship between the air | atmosphere exposure time at the time of film thickness measurement for every pre-atmosphere exposure time, and the increase amount of TiN film thickness. It is a figure which shows an example of the information stored in the storage part of the film thickness measurement apparatus which concerns on embodiment of this invention, Comprising: It is a figure which shows the film thickness measurement value increase rate according to prior air | atmosphere exposure time. It is the figure which graphed and showed FIG. It is a figure which shows an example of the information stored in the storage part of the film thickness measurement apparatus which concerns on embodiment of this invention, Comprising: It is a figure which shows the correlation of humidity and film thickness. It is the flowchart which showed the film thickness measurement process of the film thickness measurement apparatus which concerns on embodiment of this invention. It is a figure explaining the measurement order at the time of measuring a film thickness using a film thickness measuring device. It is a figure showing the example using the film thickness measuring device concerning the embodiment of the present invention. (A) is a figure showing fluctuation of film thickness (measurement value) to the number of executions before performing correction processing, and (B) is a film thickness (true value) to the number of executions after performing correction processing Is a diagram showing the variation of.

  Next, an embodiment of the present invention will be described based on the drawings.

  The semiconductor manufacturing system in the present embodiment has a host device 10, a film forming device (substrate processing device) 100, a post-processing device 12, and a film thickness measuring device 14, as shown in FIG. In the semiconductor manufacturing system according to the present embodiment, a film is formed on the substrate in the film forming apparatus 100, the film formed on the back surface of the substrate is removed in the post-processing device 12, and the film is formed on the surface of the substrate in the film thickness measuring device 14. It is configured to measure the film thickness of the film. The film forming apparatus 100, the post-processing apparatus 12, and the film thickness measuring apparatus 14 are connected to a host apparatus 10 which is a computer.

  The host apparatus 10 transmits a processing recipe, lot information, and the like to the film forming apparatus 100 before the film forming process by the film forming apparatus 100 is started. Further, after the film forming process is completed, the host apparatus 10 acquires information such as a process start time, a process end time, a process content, and a process result after the film forming process is completed. In addition, the host apparatus 10 transmits a processing recipe, lot information, and the like to the post-processing apparatus 12 before the processing of the post-processing apparatus 12 is started. Further, after the post-processing is completed, the host device 10 acquires information such as processing start time, processing end time, processing content, processing result and the like after the post processing is completed. Further, the film thickness measurement device 14 acquires, from the host device 10, information such as the process start time, the process end time, the process content, and the process result in the film forming apparatus 100 and the post-processing apparatus 12. Then, after the film thickness measurement processing is completed, the film thickness measurement device 14 transmits or outputs information such as the processing result to the host device 10.

Next, the film forming apparatus 100 will be described based on FIGS. 2 and 3.
As shown in FIGS. 2 and 3, the film forming apparatus 100 includes a housing 111 used as a film forming apparatus main body. In the housing 111, a predetermined number of wafers 200 as substrates made of silicon or the like are accommodated, and hoops (also referred to as FOUP or POD, hereinafter referred to as pods) 110 are used as wafer carriers used as accommodation containers. . In FIG. 2, the maintenance door 104 side to be described later is defined as the apparatus front, and the standby unit 126 side is defined as the apparatus rear.

  A front maintenance port 103 as an opening provided for maintenance is opened in a front front portion of a front wall 111a of the housing 111, and a front maintenance door 104 for opening and closing the front maintenance port 103 is constructed respectively. ing. A pod loading / unloading port 112 is opened on the front wall 111 a of the housing 111 so as to connect the inside and outside of the housing 111, and the pod loading / unloading port 112 is opened and closed by the front shutter 113. A load port 114 used as a loading / unloading unit is installed on the front front side of the pod loading / unloading port 112, and the load port 114 is configured such that the pod 110 is placed and aligned. The pod 110 is carried in and out of the load port 114 by an in-process transfer device (not shown) such as OHT (Overhead Hoist Transport).

  A pod shelf (accommodating shelf) 105 is installed at an upper portion of a substantially central portion in the front-rear direction in the housing 111. The pod shelf 105 has a support portion 116 erected vertically, and a plurality of stages of mount portions 117 held so as to be independently movable in the vertical direction, for example, at upper, middle, and lower positions with respect to the support portion 116. The pod shelf 105 is configured to hold a plurality of pods 110 placed on the plurality of stages of the placement units 117. That is, the pod shelf 105, for example, arranges two pods 110 in the same direction and in the same direction, and accommodates the plurality of pods 110 in a plurality of stages in the vertical direction.

  A pod transfer device (storage container transfer mechanism) 118 is installed between the load port 114 and the pod shelf 105 in the housing 111. The pod transfer device 118 includes a pod elevator 118a as an axial portion capable of moving up and down in the vertical direction while holding the pod 110, and a pod transfer portion 118b as a transfer portion for horizontally transferring the pod 110 placed thereon. The pod transport device 118 is configured to transport the pod 110 between the load port 114, the pod shelf 105, and the pod opener 121 by the continuous operation of the pod elevator 118a and the pod transport unit 118b.

  At a lower portion of the housing 111 in a substantially central portion in the front-rear direction, a sub housing 119 is constructed across the rear end. Wafer loading / unloading ports 120 for loading / unloading the wafer 200 into / from the sub-casing 119 are opened in the front wall 119a of the sub-casing 119, for example, vertically aligned in two stages, A pair of pod openers 121 are installed at the lower wafer loading / unloading port 120, respectively. The pod opener 121 includes a mounting table 122 on which the pod 110 is mounted, and a cap attaching / detaching mechanism 123 for attaching / detaching a cap of the pod 110 used as a sealing member. The pod opener 121 is configured to open and close the wafer loading / unloading port of the pod 110 by attaching / detaching the cap of the pod 110 placed on the mounting table 122 by the cap attaching / detaching mechanism 123.

  The sub case 119 constitutes a transfer chamber 124 fluidly isolated from the installation space of the pod transfer device 118 and the pod shelf 105. A wafer transfer mechanism (substrate transfer mechanism) 125 is installed in the front area of the transfer chamber 124. The wafer transfer mechanism 125 is a wafer transfer device capable of rotating or linearly moving the wafer 200 in the horizontal direction. A substrate transfer device 125a and a wafer transfer device elevator 125b for raising and lowering the wafer transfer device 125a. As schematically shown in FIG. 2, the wafer transfer device elevator 125 b is installed on the right side surface of the transfer chamber 124 of the sub case 119. By continuous operation of the wafer transfer device elevator 125 b and the wafer transfer device 125 a, the substrate holder is used as the tweezers 125 c as a substrate holder (substrate transfer device) of the wafer transfer device 125 a as a mounting portion of the wafer 200. The wafer 200 is configured to be charged (charged) and unloaded (discharged) with respect to the boat 217.

  In the rear area of the transfer chamber 124, a stand-by unit 126 which accommodates the boat 217 and stands by is configured. Above the standby unit 126, a processing furnace 202 used as a processing chamber is provided. The lower end portion of the processing furnace 202 is configured to be opened and closed by a furnace port shutter 147. Also, if necessary to lower the oxygen concentration according to wafer processing conditions etc., a preliminary chamber (load lock chamber) not shown is provided to surround the standby portion 126 directly below the processing furnace 202 to lower the oxygen concentration in advance. Alternatively, cooling of a wafer subjected to substrate processing may be performed.

  As schematically shown in FIG. 2, a boat elevator 115 for raising and lowering the boat 217 is installed on the right side surface of the standby unit 126. A seal cap 219 as a lid is horizontally mounted on an arm 128 serving as a connecting member connected to the elevator of the boat elevator 115, and the seal cap 219 supports the boat 217 vertically, and the lower end of the processing furnace 202 It is configured to be able to close the part. The boat 217 is provided with a boat pillar 217a as a plurality of substrate holding pillars, and in a state where the plurality of (for example, about 25 to 200) wafers 200 are vertically aligned and aligned in multiple stages with their centers aligned. Each is configured to be held horizontally.

  As schematically shown in FIG. 2, on the left side opposite to the wafer transfer device elevator 125 b side of the transfer chamber 124 and the boat elevator 115 side, clean is a clean atmosphere or inert gas. A clean unit 134 configured with a supply fan and a dustproof filter is provided to supply air 133. After the clean air 133 blown out from the clean unit 134 is circulated to the wafer transfer device 125a and the boat 217 in the standby unit 126, it is sucked by a duct (not shown) and is exhausted outside the housing 111 Alternatively, it is configured to be circulated to the supply side (left side) which is the suction side of the clean unit 134 and to be blown out into the transfer chamber 124 by the clean unit 134 again.

Next, the operation of the film forming apparatus 100 using the above-described configuration will be described.
In the following description, the operation of each part constituting the film forming apparatus 100 is controlled by the controller 240.

  As shown in FIGS. 2 and 3, when the pod 110 is supplied to the load port 114, the pod loading / unloading port 112 is opened by the front shutter 113, and the pod 110 above the load port 114 is the pod transport device. The pod 118 is carried into the inside of the housing 111 from the pod loading / unloading port 112. The pod 110 carried in is automatically transported and delivered by the pod transport device 118 to the designated loading unit 117 of the pod shelf 105 and temporarily stored, and then one pod opener 121 from the pod shelf 105. And is transferred to the mounting table 122 or directly transferred to the pod opener 121 and transferred to the mounting table 122. At this time, the wafer loading / unloading port 120 of the pod opener 121 is closed by the cap attaching / detaching mechanism 123, and the clean air 133 is circulated and filled in the transfer chamber. For example, when the transfer chamber 124 is filled with nitrogen gas as the clean air 133, the oxygen concentration is lower than a certain value (for example, 20 ppm), which is much lower than the oxygen concentration inside the housing 111 (atmospheric atmosphere). It is set.

The opening side end face of the pod 110 placed on the mounting table 122 is pressed against the opening edge of the wafer loading / unloading port 120 in the front wall 119a of the sub housing 119, and the cap closing the opening of the pod 110 Are removed by the cap attaching / detaching mechanism 123 to open the pod 110.
When the pod 110 is opened by the pod opener 121, the wafers 200 are discharged from the pod 110 by the tweezers 125c of the wafer transfer device 125a and loaded in the boat 217 waiting in the standby unit 126 behind the transfer chamber 124. Be done. The wafer transfer device 125a which has delivered a predetermined number of wafers 200 to the boat 217 returns to the pod 110, and loads the next wafer 200 into the boat 217.

  At this time, another pod 110 is transported from the pod shelf 105 by the pod transport device 118 and transferred onto the other (lower or upper) pod opener 121, and the opening operation of the pod 110 by the pod opener 121 is performed simultaneously.

  When a predetermined number of wafers 200 have been loaded into the boat 217 (charging), the lower end portion of the processing furnace 202 closed by the furnace port shutter 147 is opened by the furnace port shutter 147. Subsequently, the boat 217 holding the group of wafers 200 is carried into the processing furnace 202 (boat loading) by raising the seal cap 219 by the boat elevator 115.

After loading, a film forming process (substrate process) is performed on the wafer 200 in the process furnace 202.
After processing, the boat 217 is unloaded from the processing furnace 202 (boat unloading), and the wafer 200 is unloaded from the boat 217 to the pod (discharging) in the reverse procedure described above, and the wafer 200 and the pod 110 are housed Carried out of the Thereafter, another pod 110 containing the unprocessed wafer 200 is transported, and the above-described process is performed.

  Next, the film thickness measuring device 14 will be described.

  The film thickness measuring device 14 measures the film thickness of the film formed on the wafer 200. For example, an ellipsometer can be used as the film thickness measurement device 14. An ellipsometer, which emits light to measure the change in polarization of incident and reflected light, is used to measure surface properties such as film thickness and refractive index of a single layer or multiple layers on the wafer 200. . The film thickness measurement result of the film thickness measuring device 14 is output to, for example, a display unit of the film thickness measuring device 14 or transmitted to the host device 10.

FIG. 4 is a block diagram showing a control configuration of the film thickness measuring device 14.
The film thickness measurement device 14 mainly includes a film thickness measurement unit 16, a humidity measurement unit 18, a storage unit 20, a storage unit 21, a correction unit 22, a calculation unit 24, a control unit 26, and an output unit. 28 and a communication unit 29.

  The control unit 26 acquires information such as the process start time, the process end time, the process content, and the process result of the film forming apparatus 100 and the post-processing apparatus 12 from the host apparatus 10 via the communication unit 29.

  The film thickness measurement unit 16 measures the film thickness of the film formed on the surface of the wafer 200. The apparent values measured here are hereinafter referred to as measured values.

  The humidity measuring unit 18 measures the humidity around the film thickness measuring unit 16 (film thickness measuring device 14).

  The storage unit 20 stores information on the correlation between humidity and film thickness. In addition, the storage unit 20 stores information indicating the relationship between the air exposure time at the time of film thickness measurement, the prior air exposure time, and the increase amount of the film thickness.

  The storage unit 21 stores information such as the process start time, the process end time, the process content, and the process result of the film forming apparatus 100, the post-processing apparatus 12, and the like. The storage unit 21 also stores information such as the process start time of the film thickness measurement device 14, the measurement start time for each wafer for measuring the film thickness, the process end time, the process content, and the process result.

  The calculation unit 24 calculates an air exposure time which is a time when the wafer 200 after film formation is exposed to the air.

  The correction unit 22 is a correction amount as a first correction amount for correcting the measurement value of the film thickness from the humidity measured by the humidity measurement unit 18 and the information stored in the storage unit 20 (humidity-based correction amount Calculate). Then, the measured value of the film thickness measured by the film thickness measurement unit 16 is corrected by the calculated correction amount.

  Further, the correction unit 22 calculates the correction amount (the air exposure time-derived correction amount) as a second correction amount using the air exposure time calculated by the calculation unit 24 together with the humidity measured by the humidity measurement unit 18 The measured value of the film thickness measured by the film thickness measurement unit 16 is corrected by the calculated correction amount.

  The output unit 28 outputs the correction value whose measurement value has been corrected by the correction unit 22 as the film thickness measurement result.

  Then, the control unit 26 transmits the correction value whose measurement value is corrected by the correction unit 22 to the host device 10 as the film thickness measurement result via the communication unit 29.

  That is, the control unit 26 controls the film thickness measurement unit 16, the humidity measurement unit 18, the storage unit 21, the correction unit 22, the calculation unit 24, the output unit 28, the communication unit 29, and the like.

  Next, the correction process of the film thickness measuring device 14 will be described.

Here, when the cap of the pod 110 is opened after the film forming process, the wafer 200 is exposed to the air, and the film thickness measurement value is increased. This is because the wafer 200 in the pod 110 is exposed to the atmosphere by opening the cap of the pod 110 replaced with a high concentration N ₂ atmosphere, and the film is oxidized, moisture, organic matter, etc. on the surface of the film. It is considered to be for adhesion. Further, immediately after the pod 110 is opened, the rate of increase of the film thickness measurement value is large, and as time passes, the rate of increase of the film thickness measurement value gradually decreases. Further, depending on the order of measuring the film thickness, the time during which the wafer 200 is exposed to the air until the time of film thickness measurement differs. That is, in order to obtain the true value of the film thickness, it is necessary to perform a correction process according to the air exposure time on the measured value.

  FIG. 5 shows the relationship between the increase in film thickness of titanium nitride (TiN) and the air exposure time at the time of film thickness measurement. As shown in FIG. 5, the relationship between the air exposure time at the time of film thickness measurement and the increase in film thickness is the increase time curve of change in the increase in film thickness represented by a curve (FIG. 5 Shown by dashed lines). Here, the air exposure time at the time of film thickness measurement is the air exposure time which occurs due to the difference in measurement start time of film thickness measurement based on the elapsed time by the film thickness measurement device 14. The difference is calculated by the difference between the film thickness measurement start time of the wafer at which measurement is first started and the film thickness measurement start time of the wafer to be measured.

  And in this embodiment, in order to approximate an increase amount time-lapse curve, the air exposure time at the time of film thickness measurement is divided into three fields. And, when the film thickness measurement air exposure time is 0 to 10 minutes, the increase rate is 0.021 Å / min. When the film thickness measurement air exposure time is 10 to 25 minutes, the increase rate is 0.010 Å / In the case where the exposure time for film thickness measurement is 25 minutes or more, the film thickness measurement value is corrected using 0.006 Å / min as the increase rate.

  Note that after the film forming process by the film forming apparatus 100, before performing the film thickness measurement by the film thickness measuring apparatus 14, the step of removing the film formed on the back surface of the wafer 200 or the foreign matter attached to the surface of the wafer 200 is measured. There are cases where post-processing steps such as the step of Even in such a case, it may take time until the film thickness measurement after the wafer 200 is exposed to the atmosphere.

  FIG. 6 is a diagram showing the influence of the advance air exposure time on the increase amount time curve. Here, the prior air exposure time is the air exposure time from the end of the film forming process to the release of the pod 110 to the start of the measurement by the film thickness measuring device 14. It is calculated by the difference from the film thickness measurement start time by the thickness measuring device 14. FIG. 6 shows the increasing amount time curves of the pre-air exposure time after 5 minutes, after 60 minutes and after 120 minutes.

  That is, in the case where the preliminary air exposure time is 5 minutes after, when the air thickness measurement time is 0 to 10 minutes, the increase rate is 0.021 Å / min and the air thickness measurement time is 10 to 10 minutes. In the case of 25 minutes, the film thickness measurement value is corrected using 0.010 Å / min as the increase rate, and 0.006 Å / min as the increase rate when the air exposure time after film thickness measurement is 25 minutes or more.

  Also, if the pre-air exposure time is 60 minutes after, if the air exposure time during film thickness measurement is 0 to 10 minutes, the increase rate is 0.018 Å / min, and the air exposure time during film thickness measurement is 10 to 10 In the case of 25 minutes, the film thickness measurement value is corrected using an increase rate of 0.009 Å / min, and when the film thickness measurement air exposure time is 25 minutes or more, the increase rate is 0.005 Å / min.

  In addition, if the pre-air exposure time is 120 minutes after, if the air exposure time at film thickness measurement time is 0 to 10 minutes, the increase rate is 0.016 Å / min, and the air thickness exposure time for film thickness measurement is 10 to 10 In the case of 25 minutes, the film thickness measurement value is corrected using 0.006 Å / min as an increase rate, and when the air exposure time at film thickness measurement is 25 minutes or more, 0.004 Å / min as an increase rate.

  That is, as shown in FIG. 6, it can be seen that the increase rate of the film thickness measurement value is lower as the preliminary air exposure time is longer. This is because the wafer 200 is exposed to the atmosphere before the film thickness measurement process by the film thickness measurement apparatus 14, so oxidation of the TiN film, adhesion of moisture, organic matter, etc. to the film surface is a film by the film thickness measurement apparatus 14. This is because it occurs before the thickness measurement process, and at the start of the film thickness measurement, the rate of increase of the film thickness measurement value is low.

  FIG. 7 shows the film thickness measurement atmosphere exposure time 0-10 minutes, the film thickness measurement air exposure time 10-25 minutes, and the film thickness measurement air exposure time 25 minutes approximating the above-mentioned increase amount time-lapse curve The film thickness measurement rate increase rate according to the subsequent pre-air exposure time is shown. FIG. 8 is a graph of FIG. According to FIG. 8, the film thickness measurement value increase rate in the three regions according to the prior air exposure time can be calculated by the following approximate expression. Note that y in the following approximate expression is the preliminary air exposure time (minute).

The increase rate a when the air exposure time is 0 to 10 minutes at the time of film thickness measurement is represented by the following equation.
(1)
Increase rate a = -4 x 10 ^-5 x y + 0.0208

Moreover, the increase rate a in the case of 10 to 25 minutes of air | atmosphere exposure time at the time of film thickness measurement is shown by the following Formula.
(2)
Increase rate a = -3 x 10 ^-5 x y + 0.0103

Further, the increase rate a in the case where the air exposure time at film thickness measurement time is 25 minutes or more is expressed by the following equation.
(Number 3)
Increase rate a =-2 x ^10-5 x y + 0.0063

  That is, the film thickness measurement value increase rate is calculated, and the film thickness measurement value is corrected using the calculated increase rate and the calculated air exposure time.

  That is, the film thickness measurement device 14 of the present embodiment shows the relationship between the air exposure time and the film thickness increase amount at the time of film thickness measurement according to the advance air exposure time shown in FIGS. Information and the like are stored, and the film thickness measurement value is corrected using a linear approximation formula obtained from the increasing amount time-lapse curve. That is, the air exposure time when the wafer 200 is exposed to the air is calculated, and the film thickness measurement value is corrected using the calculated air exposure time and the information stored in the storage unit 20.

  As described above, since the film thickness has a close relationship with the exposure time to the atmosphere, the time from the end of the film forming process to the start of film thickness measurement and the elapsed time by the film thickness measuring device 14 are fed back and corrected The true value of the film thickness can be calculated by

  Next, the details of the correction processing according to the humidity around the film thickness measuring device 14 will be described.

FIG. 9 is a diagram showing the correlation between humidity and film thickness. As shown in FIG. 9, when the humidity around the film thickness measuring device 14 is high, it can be seen that the film thickness measurement value of the TiN film is large. The film thickness measurement device 14 of the present embodiment stores the information on the correlation between the humidity and the film thickness as shown in FIG. 9 in the storage unit 20, and uses the following linear approximation formula obtained from this plot. Correct the thickness measurement value. In addition, x in the following approximate expression has shown humidity (%).
(Number 4)
Film thickness Y (Å) = 0.0369 × x + 10.504

  That is, the control unit 26 calculates the increase amount of the film thickness from the humidity measured by the humidity measurement unit 18 and corrects the measured value of the film thickness measured by the film thickness measurement unit 16.

  Next, the film thickness measurement process of the film thickness measurement device 14 will be described. Here, after a film is formed on the wafer 200 by the film forming apparatus 100 described above (after the film forming process), the film is subjected to a post-processing step of removing the film formed on the back surface of the wafer 200 by the post-processing apparatus 12. The case of measuring the film thickness of the film formed on the surface of the wafer 200 using the thickness measuring device 14 will be described with reference to FIGS. 10 and 11.

  First, the control unit 26 opens the cap of the pod 110, and acquires the measured value (measured value) of the film thickness formed on the wafer 200 and the measurement time by the film thickness measurement unit 16 (step S10). Specifically, as shown in FIG. 11, a plurality of wafers 200 are accommodated substantially horizontally in the vertical direction in the pod 110. The film thickness measuring apparatus 14 obtains the measurement value and the measurement time of the film thickness formed on the wafer 200 in the order of the lower wafer 200, the middle wafer 200, and the upper wafer 200 in this order. Do. Next, the control unit 26 acquires the time and processing content from the end of the film forming process to the start of the post-processing from the host apparatus 10 via the communication unit 29 (step S11). Next, the time from the end of the post processing to the start of film thickness measurement and the processing content are acquired (step S12). Then, the pre-air exposure time is calculated by the calculation unit 24 based on the time from the end of the film forming process to the start of post-processing, the time from the end of post-processing to the start of film thickness measurement, and the processing content (step S13). Next, the control unit 26 calculates the atmospheric exposure time during film thickness measurement based on the film thickness measurement start time by the film thickness measurement device 14 and the film thickness measurement start time of the wafer 200 to be measured (step S14). . Specifically, the difference between the film thickness measurement time of the lower wafer 200 and the film thickness measurement start time is the exposure time during film thickness measurement of the lower wafer 200, and the film thickness measurement time of the middle wafer 200 and the film The difference from the thickness measurement start time is the exposure time during film thickness measurement of the middle wafer 200, and the difference between the film thickness measurement time of the upper wafer 200 and the film thickness measurement start time is the film thickness measurement of the upper wafer 200. When it is air exposure time.

  Next, the humidity around the film thickness measuring device 14 is acquired by the humidity measuring unit 18 (step S15). Then, the correction unit 22 calculates the air exposure time at the time of film thickness measurement and the prior air exposure time calculated by the calculation unit 24 described above, the humidity around the film thickness measurement device 14 acquired by the humidity measurement unit 18, and the storage unit 20 The correction amount is calculated on the basis of the information stored in and the measurement value measured in step S10 is corrected on the basis of the calculated correction amount (step S16).

  Then, the corrected film thickness value (true value) calculated in step 16 is output by the output unit 28 (step S17).

  That is, in the present embodiment, the standby time in the pod 110 in a state in which the cap of the pod 110 is closed and sealed, and the pod in a state in which the cap of the pod 110 is open during post-processing and film thickness measurement. The correction amount is calculated in consideration of the in-110 standby time.

Next, an embodiment will be described based on FIG. 12 and FIG.
In the present embodiment, using the film thickness measurement device 14, the TiN film on three wafers 200 at the upper position (Top), middle position (Center), and lower position (Bottom) position in the pod 110 per measurement process is used. The film thickness was measured in order, and 10 times worth of data were acquired.

  In the present embodiment, the values shown in columns A to C shown in FIG. 12 are film thickness measurement at the upper stage (hereinafter referred to as Top), the middle stage (hereinafter referred to as Center), and the lower stage (hereinafter referred to as Bottom). It is a value acquired as a value, and the value shown in the D column is its average film thickness. In the first process, the film thickness of the wafer at the Top position is 11.4068 Å, the film thickness of the wafer at the Center position is 11.3493 Å, and the film thickness of the wafer at the Bottom position is 11.3278 Å. The average of the measured values of the film thickness of the wafer was 11.36 Å. Similarly, as a result of acquiring data for 10 times, the variation 3σ of the average value of the measured values of the film thickness for 1 to 10 times before the correction process was performed was 0.56 Å.

Column E indicates the start time of the post-processing process. The F to H columns indicate the film thickness measurement start times at the Top, Center, and Bottom positions, respectively. That is, column H indicates the film thickness measurement start time of the Bottom position measured first of the three sheets for which film thickness measurement is performed, and the film thickness measurement is performed in the order of Bottom position, Center position, and Top position. It is done. And prior air exposure time of row I in the first measurement process is calculated by the following equation.
(Number 5)
Column I (advanced air exposure time)
= H row (film thickness measurement start time of Bottom position)-E row (start time of post-processing process)
= 5 minutes

In addition, columns J to L are air exposure times at the time of film thickness measurement for the Top position, Center position, and Bottom position, and are calculated by the following equation.
(Number 6)
L column (atmosphere exposure time at bottom position film thickness measurement)
= H row (film thickness measurement start time at bottom position)-H row (film thickness measurement start time)
= 0 minutes (equation 7)
Column K (Atmospheric exposure time at film thickness measurement at Center position)
= G row (film thickness measurement start time at center position)-H row (film thickness measurement start time)
= 3.8 minutes (equation 8)
Column J (Atmospheric exposure time at film thickness measurement at Top position)
= F row (film thickness measurement start time at top position)-H row (film thickness measurement start time)
= 8.5 minutes

  In addition, N to P columns are inclination a for performing the air exposure time correction, and are extracted based on the advance air exposure time of the I column and the information stored in the storage unit 20. Specifically, since the prior air exposure time of row I is 5 minutes, using the above number 1 to number 3, when the exposure time at the time of film thickness measurement of row N is 0 to 10 minutes, it is 0. 021, 0.010 is extracted as the inclination a when the exposure time at the time of film thickness measurement of O row is 10 to 25 minutes, and 0.006 is extracted as the inclination a when the exposure time at the time of film thickness measurement of P row is 25 minutes or later Be done.

  In addition, the Q to S columns indicate the film thickness increase amount (air exposure time correction amount) at the Top, Center, and Bottom positions due to the influence of the air exposure time, and the inclination extracted in the N to P lines; It calculates using the air exposure time at the time of the film thickness measurement calculated by L row.

Here, the film thickness increase amount in the case where the air exposure time at film thickness measurement time is 10 minutes or less is calculated by the following equation.
(Number 9)
Thickness increase (Å)
= J to K column (atmospheric exposure time during film thickness measurement) x N column (slope of 0 to 10 minutes region)

Further, the film thickness increase amount in the case where the air exposure time at the time of film thickness measurement is longer than 10 minutes and not longer than 25 minutes is calculated by the following equation.
(Number 10)
Thickness increase (Å)
= [J to K column (atmospheric exposure time at the time of film thickness measurement)-10] x O column (inclination of 10 to 25 minutes region) + N column x 10

Further, the amount of increase in film thickness when the air exposure time at film thickness measurement time is longer than 25 minutes is calculated by the following equation.
(Equation 11)
Thickness increase (Å)
= [J to K column (air exposure time at film thickness measurement)-25] x P column (inclination of area after 25 minutes) + N column x 10 + O column x 15

That is, in the first measurement process of the present embodiment, since the air exposure time at the time of film thickness measurement is all 10 minutes or less, the film thickness increase for the wafer 200 at each of Top, Center, and Bottom positions using Equation 9 described above The amount is calculated as an air exposure time correction amount.
(12)
Q column (air exposure time correction amount of wafer at Top position (Å))
= J row (Atmospheric exposure time when measuring the film thickness of the wafer at the Top position) x N row (Slope of 0 to 10 minutes area)
= 8.5 x 0.021
= 0.18
(Equation 13)
R column (air exposure time correction amount of wafer at Center position (Å))
= K column (air exposure time when measuring the film thickness of the wafer at the Center position) x N column (slope of 0 to 10 minutes area)
= 3.8 x 0.021
= 0.08
(Equation 14)
S row (Atmospheric exposure time correction amount of wafer at Bottom position (Å))
= L row (atmosphere exposure time when measuring the film thickness of the wafer at the Bottom position) × N row (inclination of 0 to 10 minutes area)
= 0 x 0.021
= 0

Further, in columns T to V, the film thickness increase amount (humidity correction amount) due to the influence of the humidity around the film thickness measurement device 14 is calculated using the above-mentioned equation (4). Here, for example, based on a humidity of 30%, the amount of increase in film thickness is calculated using the difference from the humidity at the time of film thickness measurement. Column M is the humidity around the film thickness measuring device 14 at the time of film thickness measurement.
(Equation 15)
T to V (Humidity correction amount (Å))
= 0.0369 × | M column (humidity at the time of film thickness measurement)-30 (reference humidity) |
= 0.0369 x | 17.8-30 |
= 0.45

  The W to Y columns are corrected film thicknesses excluding the measurement environment disturbances such as the air exposure time and humidity of the wafer at the Top, Center, and Bottom positions, which are true values.

Specifically, the film thickness correction value of the wafer at the Top position of the W column is calculated by the following equation.
(Equation 16)
W column (wafer film thickness correction value at top position)
= A row (film thickness measurement value)-Q row (atmospheric exposure time correction amount)-T row (humidity correction amount)
= 11. 4068-0.18-(-0.45)
= 1.68 (Å)

Similarly, the film thickness correction value of the wafer at the center position of row X is calculated by the following equation.
(17)
Column X (film thickness correction value of wafer at Center position)
= B row (film thickness measurement value)-R row (atmospheric exposure time correction amount)-U row (humidity correction amount)
= 11.3493-0.08-(-0.45)
= 1.72 (Å)

Similarly, the film thickness correction value of the wafer at the bottom position of the Y column is calculated by the following equation.
(Number 18)
Y column (wafer thickness correction value at bottom position)
= C column (film thickness measurement value)-S column (atmospheric exposure time correction amount)-V column (humidity correction amount)
= 11.3278-0- (-0.45)
= 1.78 (Å)

  The Z column is the average value of W column to Y column. That is, after correction, the film thickness of the wafer at the Top position is 11.68 Å, the film thickness of the wafer at the Center position is 11.72 Å, and the film thickness of the wafer at the Bottom position is 11.78 Å. The average of the measured values of the film thickness of the wafer measured by the above was 11.73 Å. Similarly, as a result of acquiring data for 10 times, the variation 3σ of the average value of the correction value of the film thickness for 1 to 10 times after the correction process was performed was 0.13 Å.

  FIG. 13A shows the average value (column D) of the film thickness (measurement value) at the Top, Center, and Bottom positions with respect to the number of executions for each of 1 to 10 times before performing the correction process in the measurement data of FIG. It shows the change. FIG. 13B shows the average value (Z column) of the film thickness (true value) at the Top, Center, and Bottom positions for each execution of 1 to 10 times after performing the correction process in the measurement data of FIG. Indicates the fluctuation of

  As shown in FIGS. 13A and 13B, while the dispersion 3σ of the measured value of the film thickness of the TiN film before the correction processing is performed in the film thickness measuring device 14 is 0.56 Å, The variation 3σ in the correction value of the TiN film thickness after the correction processing in the film thickness measurement device 14 was 0.13 Å. Here, σ is a standard deviation. That is, it can be seen that the variation 3σ is smaller in the correction value than in the measurement value.

  That is, in the film thickness measuring device 14 according to the present embodiment, the standby time in the pod 110 in the state where the cap of the pod 110 is closed and sealed, or the cap of the pod 110 at the time of post processing or film thickness measurement is opened. By taking into account the waiting time in the pod 110 in the closed state, calculate the air exposure time in advance and the air exposure time at the time of film thickness measurement, and correct the measured value according to the ambient humidity of the device. It becomes possible to eliminate the influence, the variation in the film forming performance can be reduced, and the measurement accuracy of the true value can be enhanced.

  In the embodiment described above, although the example of the TiN film is described using the air exposure time and the humidity as the film thickness influential factor, the correlation diagram is also applied to other film types and other film thickness influential factors. The same effect can be obtained by storing and performing correction processing.

  In the embodiment described above, the configuration in which the film thickness measuring device 14 is provided outside the casing 111 of the film forming apparatus 100 has been described, but the present invention is not limited to such an aspect. The present invention can also be applied to a configuration in which the film thickness measuring device 14 is provided.

  In the embodiment described above, an example in which the control unit 26 of the film thickness measuring device 14 performs the correction process of the measurement value has been described, but the present invention is not limited to such an aspect. May be performed.

DESCRIPTION OF SYMBOLS 10 host apparatus 12 post-processing apparatus 14 film thickness measurement apparatus 16 film thickness measurement part 18 humidity measurement part 20 storage part 22 correction part 24 calculation part 26 control part 28 output part 100 film formation apparatus 200 wafer (substrate)
240 controller

Claims (5)

A film thickness measurement unit that measures the film thickness of a film formed on the surface of the substrate;
A humidity measuring unit that measures the humidity around the film thickness measuring unit;
A storage unit for storing information on the correlation between humidity and film thickness;
A first correction amount for correcting the measured value of the film thickness is calculated from the humidity measured by the humidity measuring unit and the information stored in the storage unit, and the film is calculated according to the calculated first correction amount. A correction unit that corrects the measured value of the film thickness measured by the thickness measurement unit;
A control unit that controls the film thickness measurement unit, the humidity measurement unit, and the correction unit;
A film thickness measuring device having a. The system further includes a calculation unit that calculates an air exposure time, which is a time when the substrate is exposed to the atmosphere after the film is formed on the surface of the substrate,
The storage unit stores information indicating the relationship between the air exposure time and the increase in film thickness,
The film thickness measurement device according to claim 1, wherein the correction unit calculates a second correction amount using the air exposure time calculated by the calculation unit together with the humidity measured by the humidity measurement unit. Measuring the film thickness of the film formed on the surface of the substrate by the film thickness measurement unit;
Measuring humidity around the film thickness measurement unit;
A first correction amount for correcting the measured value of the film thickness is calculated and calculated from the humidity around the film thickness measurement unit and the information on the correlation between the humidity and the film thickness stored in the storage unit. Correcting the measured value of the film thickness measured by the first correction amount;
The film thickness measurement method having. Measuring the film thickness of the film formed on the surface of the substrate by the film thickness measurement unit;
Measuring the humidity around the film thickness measurement unit;
A first correction amount for correcting the measured value of the film thickness is calculated and calculated from the humidity around the film thickness measurement unit and the information on the correlation between the humidity and the film thickness stored in the storage unit. Correcting the measured value of the film thickness measured by the first correction amount;
A program that causes the film thickness measurement unit to execute the procedure of performing Forming a film on the substrate;
Removing the film formed on the back surface of the substrate;
Measuring the film thickness of the film formed on the surface of the substrate by the film thickness measuring unit; measuring the humidity around the film thickness measuring unit; and humidity around the film thickness measuring unit. The first correction amount for correcting the measured value of the film thickness is calculated from the information on the correlation between the humidity and the film thickness stored in the storage unit, and the film measured by the calculated first correction amount Correcting the thickness measurement;
And manufacturing a semiconductor device.

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