Substrate processing device, substrate processing method, factor estimation device, factor estimation method, and storage medium

Abstract

This invention provides a substrate processing apparatus that can effectively and rapidly adjust the removal width of a coating film formed on a substrate. The substrate processing apparatus of this invention includes: a peripheral removal unit for removing the peripheral portion of a coating film formed on the surface of a substrate; a variation curve acquisition unit for acquiring a removal width variation curve representing the relationship between "the circumferential position of the substrate" and "the width of the portion of the substrate where the coating film has been removed"; and a cause estimation unit for outputting cause information representing the cause of width error based on the removal width variation curve.

Description

[Technical Field]

[0001] This invention relates to a substrate processing apparatus, a substrate processing method, and a recording medium. [Previous Technology]

[0002] Patent Document 1 discloses a method for removing a coating film, comprising the following steps: a coating film removal step in which solvent is supplied from a solvent nozzle to the periphery of the coating film on the surface of the substrate while rotating a circular substrate around its orthogonal axis, and the coating film is removed circumferentially with a predetermined width; a transport step in which the substrate is transported to an inspection module for inspecting the state of the coating film by photographing the entire surface of the substrate; a detection step in which the area where the coating film has been removed is detected based on image data obtained by the inspection module; and a correction step in which the subsequent transfer position of the substrate is corrected based on the detection results. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2014-91105 [Summary of the Invention]

[0004] [Problem to be Solved by the Invention] The present invention provides a substrate processing apparatus that can effectively and rapidly adjust the removal width of a coating formed on a substrate. [Technical Means for Solving the Problem]

[0005] A substrate processing apparatus according to one aspect of the present invention includes: a peripheral removal unit for removing a peripheral portion of a coating film formed on the surface of a substrate; a profile acquisition unit for acquiring a removal width profile indicating the relationship between "the circumferential position of the substrate" and "the width of the portion of the substrate where the coating film has been removed"; and a cause estimation unit for outputting cause information indicating the cause of width error based on the removal width profile. [Effects of the Invention]

[0006] According to the present invention, a substrate processing apparatus is provided, which can effectively and rapidly adjust the removal width of the coating formed on the substrate.

Implementation Method

[0008] Hereinafter, the embodiments will be described in detail with reference to the drawings. In the description, the same symbols are assigned to the same elements or elements with the same function, and repeated descriptions are omitted.

[0009] [Substrate Processing System] The substrate processing system 1 is a system for forming a photosensitive coating on a substrate, exposing the photosensitive coating, and developing the photosensitive coating. Examples of substrates that can be processed include: semiconductor wafers, glass substrates, mask substrates, or FPDs (Flat Panel Displays). Substrates also include semiconductor wafers, etc., on which coatings have been formed in previous processing stages.

[0010] As shown in FIG. 1, the substrate processing system 1 includes a coating and developing apparatus 2 and an exposure apparatus 3. The exposure apparatus 3 performs an exposure process on a photoresist film (photosensitive coating) formed on a substrate W. The substrate W is, for example, circular, and has position indicators (e.g., cuts) at its periphery as a position reference in the circumferential direction. Specifically, the exposure apparatus 3 irradiates the exposed portion of the photoresist film with energy lines by methods such as immersion exposure. The coating and developing apparatus 2 performs a process to form the photoresist film on the surface of the substrate W before the exposure process performed by the exposure apparatus 3, and performs a development process on the photoresist film after the exposure process.

[0011] [Substrate Processing Apparatus] Hereinafter, the configuration of a coating and developing apparatus 2, which is an example of a substrate processing apparatus, will be described. The coating and developing apparatus 2 includes: a carrier block 4, a processing block 5, an interface block 6, and a control unit 100.

[0012] The carrier block 4 is used to introduce the substrate W into the coating and developing apparatus 2 and to remove the substrate W from the coating and developing apparatus 2. For example, the carrier block 4 can support multiple carriers C (storage sections) for the substrate W and has a built-in transfer arm A1. The carrier C, for example, stores multiple circular substrates W. The transfer arm A1 can remove the substrate W from the carrier C and transfer it to the processing block 5, and receive the substrate W from the processing block 5 and send it back to the carrier C.

[0013] Processing block 5 includes multiple processing modules 11, 12, 13, and 14. Processing module 11 has multiple coating units U1, multiple heat treatment units U2, and a transport arm A3 for transporting the substrate W to these units.

[0014] The processing module 11 forms a lower layer film on the surface of the substrate W by means of a coating unit U1 and a heat treatment unit U2. The coating unit U1 coats the substrate W with a processing solution for forming the lower layer film. The heat treatment unit U2 performs various heat treatments accompanying the formation of the lower layer film. The heat treatment unit U2, for example, has a built-in hot plate and a cooling plate, and heats the substrate W by means of the hot plate and then cools the heated substrate W by means of the cooling plate to perform heat treatment.

[0015] The processing module 12 (film formation processing unit) includes multiple coating units U1, multiple heat treatment units U2, multiple inspection units U3, and a transport arm A3 for transporting the substrate W to these units. The processing module 12 forms a photoresist film on a lower layer film using the coating units U1 and the heat treatment units U2. The coating unit U1 forms a coating film on the surface of the substrate W by coating a processing solution for photoresist film formation onto the lower layer film. Hereinafter, this coating film is referred to as the "photoresist film before baking". The heat treatment unit U2 performs various heat treatments accompanying the formation of the photoresist film. Thereby, the photoresist film before baking becomes a photoresist film.

[0016] The coating unit U1 may also remove at least a portion of the photoresist film. Removing at least a portion of the photoresist film includes removing a portion of the photoresist film before baking before the heat treatment performed by the heat treatment unit U2. For example, after forming the photoresist film before baking on the surface of the substrate W, the coating unit U1 removes the peripheral portion of the photoresist film before baking by supplying a removal liquid to the periphery of the substrate W.

[0017] The inspection unit U3 performs a process for inspecting the state of the surface Wa of the substrate W. For example, the inspection unit U3 obtains information indicating the state of the surface Wa of the substrate W. The information indicating the state of the surface Wa includes information on the width of the portion of the substrate W where the photoresist film has been removed (e.g., the radial width of the substrate W).

[0018] The processing module 13 includes a plurality of coating units U1, a plurality of heat treatment units U2, and a transport arm A3 for transporting the substrate W to these units. The processing module 13 forms an upper layer film on the photoresist film using the coating units U1 and the heat treatment units U2. The coating unit U1 of the processing module 13 coats the liquid for forming the upper layer film onto the photoresist film. The heat treatment unit U2 of the processing module 13 performs various heat treatments accompanying the formation of the upper layer film.

[0019] The processing module 14 includes multiple developing units U4, multiple heat treatment units U5, and a transport arm A3 for transporting the substrate W to these units. The processing module 14 performs the developing process of the photoresist film after exposure using the developing units U4 and the heat treatment units U5. The developing unit U4 applies the developing solution to the surface of the exposed substrate W and then rinses off the developing solution with a rinsing solution to perform the developing process of the photoresist film. The heat treatment unit U5 performs various heat treatments accompanying the developing process. Specific examples of heat treatments include: heat treatment before developing (PEB: Post Exposure Bake), heat treatment after developing (PB: Post Bake), etc.

[0020] A shelving unit U10 is provided on the side of the carrier block 4 within the processing block 5. The shelving unit U10 is divided into a plurality of unit cells arranged side by side in the vertical direction. A lifting arm A7 is provided near the shelving unit U10. The lifting arm A7 is positioned between the unit cells of the shelving unit U10 to raise and lower the substrate W.

[0021] A shelving unit U11 is provided on the side of the interface block 6 within the processing block 5. The shelving unit U11 is divided into a plurality of unit cells arranged side by side in the vertical direction.

[0022] Interface block 6 is used to transfer substrate W between itself and exposure apparatus 3. For example, interface block 6 has a transfer arm A8 built in it and is connected to exposure apparatus 3. Transfer arm A8 transfers substrate W disposed in booth unit U11 to exposure apparatus 3 and receives substrate W from exposure apparatus 3 and returns it to booth unit U11.

[0023] The control unit 100 controls each element included in the coating and developing apparatus 2. Hereinafter, a series of control steps performed by the control unit 100 on a substrate W are illustrated. For example, the control unit 100 first controls the transfer arm A1 to transport the substrate W in the carrier C to the rack unit U10, and controls the lifting arm A7 to place the substrate W in the unit cell used by the processing module 11.

[0024] Next, the control unit 100 controls the transport arm A3 to transport the substrate W of the shelf unit U10 to the coating unit U1 and heat treatment unit U2 in the processing module 11. The control unit 100 also controls the coating unit U1 and heat treatment unit U2 to form a lower layer film on the surface of the substrate W. Afterwards, the control unit 100 controls the transport arm A3 to return the substrate W with the lower layer film formed to the shelf unit U10, and controls the lifting arm A7 to place the substrate W in a unit cell for the processing module 12.

[0025] Next, the control unit 100 controls the transport arm A3 to transport the substrate W of the shed unit U10 to the coating unit U1 and heat treatment unit U2 within the processing module 12. The control unit 100 also controls the coating unit U1 and heat treatment unit U2 to form a photoresist film on the lower layer film of the substrate W. For example, the control unit 100 controls the coating unit U1 to form the aforementioned pre-baking photoresist film on the lower layer film of the substrate W, removes the peripheral portion of the pre-baking photoresist film, and then controls the heat treatment unit U2 to apply heat treatment to the substrate W to transform the pre-baking photoresist film into a photoresist film.

[0026] Furthermore, the control unit 100 controls the transport arm A3 to transport the substrate W to the inspection unit U3 and obtains information from the inspection unit U3 indicating the surface condition of the substrate W. Subsequently, the control unit 100 controls the transport arm A3 to send the substrate W back to the shelf unit U10 and controls the lifting arm A7 to place the substrate W in the unit cell used by the processing module 13.

[0027] Next, the control unit 100 controls the transport arm A3 to transport the substrate W of the shed unit U10 to each unit in the processing module 13, and controls the coating unit U1 and the heat treatment unit U2 to form an upper film on the photoresist film of the substrate W. Thereafter, the control unit 100 controls the transport arm A3 to transport the substrate W to the shed unit U11.

[0028] Next, the control unit 100 controls the transfer arm A8 to send the substrate W of the booth unit U11 to the exposure apparatus 3. Thereafter, the control unit 100 controls the transfer arm A8 to receive the substrate W that has been exposed from the exposure apparatus 3 and place it in the unit cell of the processing module 14 in the booth unit U11.

[0029] Next, the control unit 100 controls the transport arm A3 to transport the substrate W from the rack unit U11 to the developing unit U4 and the heat treatment unit U5 within the processing module 14, and controls the developing unit U4 and the heat treatment unit U5 to perform developing treatment on the photoresist film of the substrate W. Afterwards, the control unit 100 controls the transport arm A3 to return the substrate W to the rack unit U10, and controls the lifting arm A7 and the transfer arm A1 to return the substrate W to the carrier C. The above completes a series of control steps for one substrate W.

[0030] [Coating Unit] Next, an example of the configuration of the coating unit U1 in the processing module 12 will be described in detail. As described above, the coating unit U1 supplies a processing liquid for forming a photoresist film to the surface Wa of the substrate W to form the aforementioned photoresist film before baking. Furthermore, after the photoresist film before baking is formed on the surface Wa of the substrate W, the coating unit U1 (peripheral removal section) supplies a removal liquid to the periphery of the substrate W, thereby removing the peripheral portion of the photoresist film before baking.

[0031] As shown in FIG. 2, the coating unit U1 includes: a rotation holding part 20, a processing liquid supply part 30, and a removal liquid supply part 40. The rotation holding part 20 holds the substrate W and rotates it. For example, the rotation holding part 20 includes a holding part 21 and a rotation drive part 22. The holding part 21 supports the substrate W, which is horizontally arranged with its surface Wa facing upward, and holds the substrate W by adsorption (e.g., vacuum adsorption). The rotation drive part 22 uses an electric motor as a power source, for example, to rotate the holding part 21 about a vertical rotation center CL. In this way, the substrate W rotates.

[0032] The processing liquid supply unit 30 supplies the processing liquid for photoresist film formation to the surface Wa of the substrate W. For example, the processing liquid supply unit 30 includes: a nozzle 31, a liquid source 32, a liquid delivery unit 33, and a nozzle moving unit 34. The nozzle 31 sprays the processing liquid onto the surface Wa of the substrate W. The liquid source 32 stores the processing liquid and pumps it to the nozzle 31. The liquid delivery unit 33 guides the processing liquid from the liquid source 32 to the nozzle 31. For example, the liquid delivery unit 33 includes a liquid delivery line L1 and a valve V1. The liquid delivery line L1 connects the liquid source 32 to the nozzle 31. The valve V1 is, for example, a pneumatic valve, which opens and closes the flow path in the liquid delivery line L1. The nozzle moving unit 34 moves the nozzle 31 between the rotation center CL and the area outside the substrate W by means of a power source such as an electric motor.

[0033] The removal liquid supply unit 40 supplies removal liquid to the surface Wa of the substrate W. The removal liquid is a solvent that can remove (dissolve) the photoresist film formed by the processing liquid supplied from the processing liquid supply unit 30 before baking. Specific examples of removal liquids include organic solvents such as diluents. For example, the removal liquid supply unit 40 includes: a nozzle 41, a liquid source 42, a liquid delivery unit 43, a flow sensor 45, and a nozzle moving unit 44.

[0034] Nozzle 41 sprays a cleaning liquid onto the periphery of the substrate W, which is held and rotated by the rotating holding part 20. Nozzle 41 sprays the cleaning liquid onto the surface Wa of the substrate W, which is rotating by the rotating holding part 20. Liquid source 42 stores the cleaning liquid and supplies it to nozzle 41. Liquid delivery part 43 guides the cleaning liquid from liquid source 42 to nozzle 41. For example, liquid delivery part 43 includes liquid delivery line L2 and valve V2. Liquid delivery line L2 connects liquid source 42 to nozzle 41. Valve V2 is, for example, a pneumatic valve, and opens and closes the flow path in liquid delivery line L2. Flow sensor 45 detects the flow rate (flow rate per unit time) of the cleaning liquid in liquid delivery line L2. Nozzle moving part 44 moves nozzle 41 between the periphery of substrate W and the area outside substrate W by means of a power source such as an electric motor.

[0035] [Inspection Unit] Next, an example of the configuration of the inspection unit U3 will be described in detail. The inspection unit U3 obtains image data as surface information indicating the state of the surface Wa by photographing the surface Wa of the substrate W. As shown in FIG3, the inspection unit U3 includes: a holding part 51, a rotation drive part 52, a position index detection part 53, and a photographing part 57.

[0036] The holding part 51 supports the substrate W, which is horizontally arranged with its surface Wa facing upward, and holds the substrate W by adsorption (e.g., vacuum adsorption). The rotation drive part 52 rotates the holding part 51 about a vertical rotation center by a power source such as an electric motor. In this way, the substrate W is rotated.

[0037] The position indicator detection unit 53 detects the cut on the substrate W. For example, the position indicator detection unit 53 includes a light-emitting unit 55 and a light-receiving unit 56. The light-emitting unit 55 emits light towards the periphery of the rotating substrate W. For example, the light-emitting unit 55 is disposed above the periphery of the substrate W and emits light downwards. The light-receiving unit 56 receives the light emitted by the light-emitting unit 55. For example, the light-receiving unit 56 is disposed below the periphery of the substrate W, facing the light-emitting unit 55.

[0038] The imaging unit 57 is a camera that at least images the peripheral portion of the surface Wa of the substrate W. For example, the imaging unit 57 images the peripheral portion of the surface Wa of the substrate W where no photoresist film is formed (the photoresist film is removed before baking). For example, the imaging unit 57 is disposed above the peripheral portion of the substrate W held by the holding unit 51 and faces downward.

[0039] [Control Unit] The coating unit U1 and inspection unit U3 described above are controlled by the control unit 100. The control steps of the coating unit U1 and inspection unit U3 executed by the control unit 100 include the following steps: the coating unit U1 removes the peripheral portion of the photoresist film formed on the surface Wa of the substrate W; the inspection unit U3 obtains a removal width variation curve showing the relationship between the "circumferential position of the substrate W" and the "width of the portion of the substrate W where the photoresist film has been removed (hereinafter referred to as "removal width")"; based on the removal width variation curve, the control unit outputs factor information indicating the cause of the error in the removal width. Error refers to deviation from a predetermined target value.

[0040] In the removal width, errors may occur due to various factors, but it takes time to identify which factor caused the error based solely on the error assessment results. In contrast, the removal width variation curve, which shows the relationship between the "circumferential position of the substrate W" and the "removal width," tends to display different characteristics depending on the error factor. Therefore, accurate factor information can be output based on the removal width variation curve.

[0041] Hereinafter, referring to FIG4, the configuration of the control unit 100 for controlling the coating unit U1 and the inspection unit U3 will be specifically illustrated. As shown in FIG4, the control unit 100 includes the following functional components (hereinafter referred to as "functional blocks"): transport control unit 111, film formation control unit 112, peripheral removal control unit 113, program storage unit 114, change curve acquisition unit 115, feature quantity calculation unit 116, factor selection object storage unit 123, device status acquisition unit 117, record generation unit 118, and data storage unit 119.

[0042] The transport control unit 111 controls the transport arm A3 to transport the substrate W based on the motion program stored in the program storage unit 114. The motion program of the transport arm A3 includes commands in a time sequence defined by at least one control parameter. Specific examples of the at least one control parameter include the target position of the substrate W and the speed at which it moves to the target position.

[0043] The film formation control unit 112 controls the coating unit U1 to form a photoresist film on the surface of the substrate W based on the operation program stored in the program storage unit 114. The peripheral removal control unit 113 controls the coating unit U1 to remove the peripheral portion of the photoresist film before baking based on the operation program stored in the program storage unit 114.

[0044] The operating program of the coating unit U1 includes commands for a time sequence defined by at least one control parameter. Specific examples of at least one control parameter include: the amount of processing liquid sprayed from nozzle 31 for forming the photoresist film (spray amount per unit time), the position of nozzle 41 when spraying the removal liquid (e.g., the distance from the rotation center CL to the center of nozzle 41), and the amount of removal liquid sprayed from nozzle 41 (spray amount per unit time). The opening degree of valve V1 can also be set to replace the amount of processing liquid sprayed from nozzle 31, and the opening degree of valve V2 can also be set to replace the amount of removal liquid sprayed from nozzle 41.

[0045] The variation curve acquisition unit 115 acquires the aforementioned removal width variation curve from the inspection unit U3. This removal width variation curve represents the relationship between the "circumferential position of the substrate W" and the "width of the portion of the substrate W where the photoresist film has been removed (the aforementioned removal width)". The circumferential position of the substrate W is a position based on a position index detected by the position index detection unit 53, for example, expressed as an angle around the center of the substrate W. The width of the portion where the photoresist film has been removed is, for example, the radial width of the substrate W. The removal width variation curve can also be sequential data that discretely represents the relationship between the circumferential position of the substrate W and the removal width, or it can be functional data that continuously represents the relationship between the circumferential position of the substrate W and the removal width.

[0046] The feature quantity calculation unit 116 calculates a complex number of feature quantities corresponding to at least one error factor based on the removal width variation curve. The complex number of feature quantities includes: an evaluation value of the removal width, an evaluation value of the eccentricity of the photoresist film periphery relative to the periphery of the substrate W, an evaluation value of the roundness of the photoresist film periphery, and an evaluation value of the roughness of the photoresist film periphery. The evaluation value of the removal width is, for example, a value representing the overall trend of the removal width variation curve. Examples of such evaluation values ​​include the average value, the median, etc.

[0047] The feature quantity calculation unit 116 calculates an approximate function of the shape of the photoresist film with the center of the substrate W as the origin based on the width variation curve, and calculates the above-mentioned evaluation values ​​of eccentricity, roundness, and roughness based on the function.

[0048] The feature quantities of the complex types calculated by the feature quantity calculation unit 116 each correspond to at least one error factor in the factor selection object storage unit 123. The feature quantities of the complex types may also include composite feature quantities that correspond to the error factors of the complex types.

[0049] In one example, the width assessment value corresponds at least to the positional offset of the nozzle 41 and the change in the amount of removal liquid ejected from the nozzle 41 in the factor selection object storage unit 123. The change here refers to a long-term change over a longer period compared to the processing period for a substrate W.

[0050] The eccentricity evaluation value corresponds at least to the positional offset of the substrate W in the rotating holding part 20 within the factor selection object storage unit 123; the roundness evaluation value corresponds at least to the twisting of the substrate W and the twisting of the rotating holding part 20; and the roughness evaluation value corresponds at least to the liquid splashing of the removal liquid and the variation in the amount of removal liquid sprayed from the nozzle 41. Here, variation refers to variation during the processing of a substrate W. The width evaluation value, roundness evaluation value, and roughness evaluation value, which correspond at least to two error factors, are equivalent to the aforementioned composite characteristic quantities.

[0051] The device status acquisition unit 117 acquires information indicating the operating status of devices such as the transport arm A3 and the coating unit U1, which are at least related to the formation of the photoresist film. For example, the device status acquisition unit 117 acquires the arrangement position of the substrate W transported to the coating unit U1 by the transport arm A3 (the position of the substrate W in the rotation holding unit 20), the arrangement position of the nozzle 41 when removing the photoresist film before baking, and the amount of removal liquid sprayed from the nozzle 41 when removing the photoresist film before baking (e.g., the flow rate detected by the flow sensor 45).

[0052] The recording generation unit 118 generates a record containing "the calculation result of a feature quantity" and "the state of the coating unit U1 corresponding to the feature quantity", and stores it in the data storage unit 119. Here, "corresponding" means corresponding to the same substrate W. The state of the coating unit U1 corresponding to the feature quantity means the state of the coating unit U1 when the substrate W to which the feature quantity is calculated is being treated to remove the photoresist before baking.

[0053] The state of the coating unit U1 includes at least: the position of the substrate W in the rotating holding section 20 (the position of the center of the substrate W relative to the rotation center CL of the holding section 21), the position of the nozzle 41 when spraying the removal liquid, the spray volume of the removal liquid from the nozzle 41, and the variation width of the spray volume of the removal liquid from the nozzle 41. Here, the variation width refers to the variation width during the processing of one substrate W. The data storage unit 119 stores the records generated by the record generation unit 118.

[0054] The control unit 100 further includes an evaluation unit 121, an impact evaluation unit 122, and a cause estimation unit 124. The evaluation unit 121 evaluates the removal width based on the removal width variation curve. The evaluation result of the removal width obtained by the evaluation unit 121 may also include multiple types of evaluation values. For example, the evaluation result of the removal width obtained by the evaluation unit 121 may also include the maximum and minimum values ​​of the removal width in the removal width variation curve, and may also include the maximum, average, and minimum values ​​of the removal width in the removal width variation curve.

[0055] The influence assessment unit 122 assesses the influence of the characteristic quantities of complex numbers on the error based on the calculation results of the characteristic quantities of complex number types. The influence degree is a value that represents the degree of influence on the error. The influence degree is calculated using conventional statistical methods.

[0056] The cause estimation unit 124 outputs cause information indicating the cause of the error in removing the width based on the width variation curve. The output includes displaying it on the display element 196 described later and transmitting the cause information to other devices. The output also includes a function block that outputs the cause information to a parameter adjustment unit 125 described later, which performs further processing based on the cause information.

[0057] The cause estimation unit 124 may also output cause information based on the calculation results of a plurality of characteristic quantities. The cause estimation unit 124 may also output cause information based on the degree of influence of a plurality of characteristic quantities on the error. The cause estimation unit 124 may also output cause information based on at least one error cause corresponding to the characteristic quantity with the highest degree of influence among the plurality of error causes. For example, the cause estimation unit 124 outputs cause information indicating that at least one error cause corresponding to the characteristic quantity with the highest degree of influence is attached.

[0058] The cause estimation unit 124 can also output cause information representing the degree of influence and the corresponding at least one error cause for each of the multiple types of feature quantities. Based on this cause information, in addition to displaying the error cause corresponding to the feature quantity with the highest degree of influence, it can also display how much higher the degree of influence of the error cause is compared to the degree of influence of other error causes.

[0059] Furthermore, the cause estimation unit 124 can also output information about which of the multiple types of feature quantities has the highest influence. For the user, when it is known which error factor each of the multiple types of feature quantities corresponds to, displaying which of the multiple types of feature quantities has the highest influence can also be regarded as displaying the error factor.

[0060] The factor estimation unit 124 can also output factor information representing the degree of influence for each of the multiple types of feature quantities. Based on this factor information, in addition to displaying the feature quantity with the highest degree of influence, it can also display how much higher the degree of influence of that feature quantity is compared to the degree of influence of other feature quantities.

[0061] When the feature quantity with the highest influence is a composite feature quantity, the cause estimation unit 124 can also output cause information based on the multiple types of error causes corresponding to the composite feature quantity and the state of the coating unit U1. The state of the coating unit U1 here refers to the state of the coating unit U1 corresponding to the composite feature quantity. The term "corresponding" means corresponding to the same substrate W. The term "state of the coating unit U1 corresponding to the composite feature quantity" refers to the state of the coating unit U1 when the substrate W to which the composite feature quantity is being calculated is being treated to remove the photoresist before baking.

[0062] For example, when the feature quantity with the highest influence is a composite feature quantity, the cause estimation unit 124 can also evaluate the correlation level of each of the multiple types of error factors with the composite feature quantity based on the records stored in the data storage unit 119, and output cause information based on the evaluation results of the correlation level.

[0063] The cause estimation unit 124 can also evaluate the correlation level of each of the multiple types of error factors with the composite feature quantity based on a predetermined number of records, including the latest records, stored in the data storage unit 119. For example, the cause estimation unit 124 outputs cause information indicating the error factor with a relatively high correlation level for the composite feature quantity.

[0064] In one example, when the feature quantity with the highest influence is the width assessment value, the estimation unit 124 evaluates the "correlation level between the position of nozzle 41 and the width assessment value (hereinafter referred to as the "first correlation level")" and the "correlation level between the amount of desorbed liquid sprayed from nozzle 41 and the width assessment value (hereinafter referred to as the "second correlation level")" based on a predetermined number of records. For example, the first correlation level represents the correlation level between the positional offset of nozzle 41 and the width assessment value. For example, the second correlation level represents the correlation level between the change in the amount of desorbed liquid sprayed from nozzle 41 and the width assessment value.

[0065] When the first correlation level is higher than the second correlation level, the cause estimation unit 124 outputs cause information indicating the positional deviation of the nozzle 41 as the most likely error cause. When the second correlation level is higher than the first correlation level, the cause estimation unit 124 outputs cause information indicating the change in the spray volume of the removal liquid from the nozzle 41 as the most likely error cause.

[0066] When the feature quantity with the highest influence is the roughness evaluation value, the cause estimation unit 124 evaluates the correlation level (hereinafter referred to as the "third correlation level") between the "variation width of the amount of removal liquid sprayed from the nozzle 41" and the "roughness evaluation value" based on a predetermined number of records. If the third correlation level exceeds the predetermined level, the cause estimation unit 124 outputs cause information indicating the variation of the removal liquid sprayed volume as the most likely error cause. If the third correlation level does not reach the predetermined level, the cause estimation unit 124 outputs cause information indicating the liquid splash of the removal liquid as the most likely error cause.

[0067] The cause estimation unit 124 may output cause information if the evaluation result of the removal width obtained by the evaluation unit 121 falls outside the predetermined range, and omit the output of cause information if the evaluation result of the removal width obtained by the evaluation unit 121 falls within the predetermined range. For example, the cause estimation unit 124 may output cause information if the maximum value of the removal width exceeds the upper limit of the predetermined range, or if the minimum value of the removal width is lower than the lower limit of the predetermined range, and omit the output of cause information if both the maximum and minimum values ​​of the removal width fall within the predetermined range.

[0068] Correspondingly, the impact assessment unit 122 can also calculate the impact degree if the assessment result of the removal width obtained by the assessment unit 121 falls outside the predetermined range, and omit the calculation of the impact degree if the assessment result of the removal width obtained by the assessment unit 121 falls within the aforementioned predetermined range. For example, the impact assessment unit 122 can also calculate the impact degree if the maximum value of the removal width exceeds the upper limit of the predetermined range, or if the minimum value of the removal width is lower than the lower limit of the predetermined range, and omit the calculation of the impact degree if both the maximum and minimum values ​​of the removal width fall within the predetermined range.

[0069] The control unit 100 may further include a parameter adjustment unit 125. The parameter adjustment unit 125 adjusts at least one control parameter in the operation program stored in the program storage unit 114 based on the cause information. For example, the parameter adjustment unit 125 changes at least one control parameter to mitigate the error cause indicated by the cause information.

[0070] In one example, when the positional deviation of the nozzle 41 is identified as the most likely cause of error, the parameter adjustment unit 125 changes the position of the nozzle 41 when spraying the removal liquid. When the change in the amount of removal liquid sprayed from the nozzle 41 is identified as the most likely cause of error, the parameter adjustment unit 125 changes the amount of removal liquid sprayed from the nozzle 41. When the positional deviation of the substrate W in the rotating holding unit 20 is identified as the most likely cause of error, the parameter adjustment unit 125 changes the arrangement position of the substrate W transported to the coating unit U1 by the transport arm A3.

[0071] Figure 5 is a block diagram illustrating the hardware configuration of the control unit 100. The control unit 100 is composed of one or more control computers. As shown in Figure 5, the control unit 100 includes a circuit 190. The circuit 190 includes: at least one processor 191, memory 192, storage device 193, input / output port 194, input element 195, and display element 196. The storage device 193 includes, for example, a computer-readable recording medium such as a hard disk. The storage device 193 stores a program for causing the control unit 100 to perform the following steps: causing the coating unit U1 to remove the peripheral portion of the photoresist film formed on the surface Wa of the substrate W; obtaining a removal width variation curve from the inspection unit U3 indicating the relationship between the "circumferential position of the substrate W" and the "removal width"; and outputting factor information indicating the cause of the removal width error based on the removal width variation curve. For example, the storage device 193 stores a program for causing the control unit 100 to construct the above-mentioned functional blocks.

[0072] Memory 192 temporarily stores the program loaded from the recording medium of storage device 193 and the calculation results obtained by processor 191. Processor 191 works in conjunction with memory 192 to execute the above program, thereby forming the above functional modules. Input / output port 194 connects the transport arm A3, coating unit U1 and inspection unit U3 for input and output of electrical signals according to instructions from processor 191. Input element 195 and display element 196 function as the user interface of control unit 100. Input element 195 is, for example, a keyboard, and obtains input information input by the user. Display element 196 includes, for example, a liquid crystal display, for displaying information to the user. Display element 196 is used, for example, to display the above-mentioned factor information. Input element 195 and display element 196 can also be integrated into a so-called touch panel.

[0073] [Control Steps] Hereinafter, with regard to one example of a substrate processing method, the control steps of the coating and developing apparatus 2 performed by the control unit 100 will be illustrated. The overall steps are as described in the section on [Substrate Processing Apparatus]. The control steps of the coating and developing apparatus 2 performed by the control unit 100, in addition to the overall steps described above, also include: a film formation control step, a removal variation curve acquisition step, and a cause information output step.

[0074] The film formation control step involves the control unit 100 controlling the coating unit U1 to perform the formation of the photoresist film before baking and the removal of the peripheral portion of the photoresist film before baking. The removal variation curve acquisition step involves the control unit 100 measuring the removal width at at least two positions in the circumferential direction of the substrate W using the inspection unit U3, thereby acquiring the removal variation curve. The cause information output step involves the control unit 100 outputting cause information indicating the cause of the error in the removal width based on the removal variation curve. Hereinafter, the film formation control step, the removal variation curve acquisition step, and the cause information output step will be described in detail.

[0075] (Film Formation Control Steps) As shown in FIG6, the control unit 100 sequentially executes steps S01, S02, S03, S04, S05, S06, and S07. In step S01, the transport control unit 111 controls the transport arm A3 to place the substrate W in the coating unit U1 based on the operation program stored in the program storage unit 114. At this time, the device status acquisition unit 117 acquires information on the placement position of the substrate W obtained by the transport arm A3. In step S02, the film formation control unit 112 uses the transport arm A3 to hold the substrate W placed in the coating unit U1 in the holding part 21. In step S03, the film formation control unit 112 uses the rotation drive unit 22 to start rotating the holding part 21 and the substrate W.

[0076] In step S04, the film formation control unit 112 controls the coating unit U1 based on the operation program stored in the program storage unit 114 to form a pre-baking photoresist film on the surface Wa of the substrate W. For example, the film formation control unit 112 controls the nozzle moving unit 34 to position the nozzle 31 on the rotation center CL of the substrate W, and controls the liquid delivery unit 33 to spray the processing liquid from the nozzle 31 for a predetermined period. Thereby, a liquid film of the processing liquid is formed on the surface Wa. Thereafter, the film formation control unit 112 controls the liquid delivery unit 33 to stop the spraying of the processing liquid from the nozzle 31, and uses the nozzle moving unit 34 to retract the nozzle 31 from above the substrate W. After the spraying of the processing liquid stops, the film formation control unit 112 controls the rotation drive unit 22 to continue the rotation of the substrate W for a predetermined period. Thereby, the liquid film is dried, and a pre-baking photoresist film is formed.

[0077] In step S05, the peripheral removal control unit 113 controls the coating unit U1 based on the operation program stored in the program storage unit 114 to remove the peripheral portion of the photoresist film before baking. For example, the peripheral removal control unit 113 controls the nozzle moving unit 44 to position the nozzle 41 on the peripheral portion of the substrate W, and controls the liquid delivery unit 43 to continuously spray the removal liquid from the nozzle 41 for a predetermined period. This removes the peripheral portion of the photoresist film before baking.

[0078] When removing the photoresist film before baking, the device status acquisition unit 117 acquires information on the configuration position of the nozzle 41 obtained by the nozzle movement unit 44, and the amount of removal liquid sprayed from the nozzle 41 (for example, the detection value obtained by the flow sensor 45). Thereafter, the peripheral removal control unit 113 controls the liquid delivery unit 43 to stop the spraying of removal liquid from the nozzle 41, and uses the nozzle movement unit 44 to retract the nozzle 41 from above the substrate W.

[0079] In step S06, the peripheral removal control unit 113 stops the rotation of the holding part 21 and the substrate W by means of the rotation drive unit 22. In step S07, the peripheral removal control unit 113 releases the substrate W from the holding part 21, and the transport control unit 111 controls the transport arm A3 to move the substrate W out of the coating unit U1. The film formation control steps are then completed.

[0080] (Step for obtaining the change curve) As shown in FIG7, the control unit 100 first executes steps S11, S12, S13, S14, S15, S16, and S17. In step S11, the transport control unit 111 controls the transport arm A3 based on the operation program stored in the program storage unit 114 to place the substrate W in the inspection unit U3. In step S12, the change curve acquisition unit 115 uses the transport arm A3 to hold the substrate W placed in the inspection unit U3 in the holding part 51. In step S13, the change curve acquisition unit 115 uses the rotation drive unit 52 to start rotating the holding part 51 and the substrate W.

[0081] In step S14, the change curve acquisition unit 115 waits for the position indicator (e.g., a cut) to be detected by the position indicator detection unit 53. In step S15, the change curve acquisition unit 115 waits for the rotation angle after the cut detection to reach a predetermined measurement angle. In step S16, the change curve acquisition unit 115 causes the imaging unit 57 to capture images of the periphery of the substrate W, calculates the removal width based on the captured image, and stores it in conjunction with the current measurement angle. In step S17, the change curve acquisition unit 115 covers the entire circumference of the substrate W to confirm whether the acquisition of the removal width has been completed. For example, the change curve acquisition unit 115 checks whether the acquisition of the removal width has been completed along the periphery of the substrate W for all preset measurement positions.

[0082] If, in step S17, it is determined that a portion of the removal width acquisition is not yet complete and still remains on the periphery of the substrate W, the control unit 100 returns the process to step S15. Thereafter, the removal width corresponding to the predetermined measurement angle is repeatedly acquired until the removal width acquisition covers the entire circumference.

[0083] If, in step S17, it is determined that the width removal has been completed by covering the entire circumference of the substrate W, the control unit 100 executes steps S18 and S19. In step S18, the change curve acquisition unit 115 stops the rotation of the holding part 51 and the substrate W by means of the rotation drive unit 52. In step S19, the change curve acquisition unit 115 releases the substrate W from the holding part 51, and the transport control unit 111 controls the transport arm A3 to remove the substrate W from the inspection unit U3. The step of obtaining the removal change curve is thus completed.

[0084] (Output Steps for Root Cause Information) As shown in FIG8, the control unit 100 first executes steps S21, S22, S23, S24, and S25. In step S21, the feature quantity calculation unit 116 waits for the completion of the removal of the variation curve by the variation curve acquisition unit 115. In step S22, the feature quantity calculation unit 116 calculates the aforementioned multiple types of feature quantities based on the removal of the width variation curve. In step S23, the record generation unit 118 generates a record containing the calculation result of the feature quantity and the state of the coating unit U1 corresponding to the feature quantity, and stores it in the data storage unit 119. The record generation unit 118 obtains information indicating the state of the coating unit U1 corresponding to the feature quantity from the device state acquisition unit 117.

[0085] In step S24, the evaluation unit 121 evaluates the removal width based on the removal width variation curve. For example, the evaluation unit 121 evaluates the maximum and minimum values ​​of the removal width in the removal width variation curve. In step S25, the influence evaluation unit 122 confirms whether the evaluation result of the removal width obtained by the evaluation unit 121 falls outside the predetermined range. For example, if the maximum value of the removal width exceeds the upper limit of the predetermined range, the influence evaluation unit 122 determines that the evaluation result of the removal width falls outside the predetermined range; similarly, if the minimum value of the removal width is lower than the lower limit of the predetermined range, the evaluation result of the removal width also falls outside the predetermined range.

[0086] In step S25, if it is determined that the evaluation result of removing the width falls outside the predetermined range, the control unit 100 executes steps S26, S27, and S28. In step S26, the influence evaluation unit 122 evaluates the influence of the multiple types of feature quantities on the error based on the calculation results of the multiple types of feature quantities. In step S27, the cause estimation unit 124 derives the error cause corresponding to the feature quantity with the highest influence based on the cause selection object storage unit 123. In step S28, the cause estimation unit 124 confirms whether the feature quantity with the highest influence is the aforementioned composite feature quantity.

[0087] In step S28, if it is determined that the feature quantity with the highest influence is a composite feature quantity, the control unit 100 executes steps S31, S32, and S33. In step S31, the cause estimation unit 124 evaluates the correlation level of each of the multiple error factors with the composite feature quantity based on "the records stored in the data storage unit 119 when the feature quantity with the highest influence is a composite feature quantity". In step S32, the cause estimation unit 124 selects the error factor with the highest correlation level with the composite feature quantity from the multiple error factors corresponding to the composite feature quantity. In step S33, the cause estimation unit 124 outputs "cause information representing the error factor selected in step S32".

[0088] In step S28, if it is determined that the feature quantity with the highest influence is not a composite feature quantity, the control unit 100 executes step S33 without executing steps S31 and S32. In this case, the cause estimation unit 124 outputs the cause information representing the error cause derived in step S27.

[0089] Next, the control unit 100 executes step S34. In step S34, the parameter adjustment unit 125 adjusts at least one control parameter in the operation program stored in the program storage unit 114 based on the factor information.

[0090] In step S25, if it is determined that the evaluation result of the width removal falls within a predetermined range, the influence evaluation unit 122 omits the calculation of the influence, the cause estimation unit 124 omits the output of cause information, and the parameter adjustment unit 125 omits the adjustment of control parameters. The cause information output step is then completed.

[0091] [Effects of this embodiment] As explained above, the coating and developing apparatus 2 (substrate processing apparatus) includes: a coating unit U1 (peripheral removal unit) that removes the peripheral portion of the coating film formed on the surface Wa of the substrate W; a variation curve acquisition unit 115 that acquires a removal width variation curve that shows the relationship between "the position of the substrate W in the circumferential direction" and "the width of the portion of the substrate W where the coating film has been removed"; and a cause estimation unit 124 that outputs cause information indicating the cause of the width error based on the removal width variation curve.

[0092] Errors may occur in the removal width due to various factors, but it takes time to identify the specific factor causing the error based solely on the error assessment results. In contrast, the removal width variation curve, which shows the relationship between the circumferential position of the substrate W and the removal width, tends to display different characteristics depending on the error factor. Therefore, accurate factor information can be output based on the removal width variation curve. Based on accurate factor information, the cause of the error can be quickly identified and adjusted. Thus, the coating and developing apparatus 2 can effectively and rapidly adjust the removal width.

[0093] The coating and developing apparatus 2 further includes: an evaluation unit 121 that evaluates the width based on the width variation curve, and a cause estimation unit 124 that can output cause information if the width evaluation result falls outside a predetermined range. In this case, by limiting the output processing of cause information to be performed only when the error evaluation result exceeds a predetermined level, the information processing burden in the coating and developing apparatus 2 can be reduced.

[0094] The coating and developing apparatus 2 further includes: a feature quantity calculation unit 116, which calculates a plurality of feature quantities corresponding to at least one error factor based on the removal width variation curve; and a factor estimation unit 124, which can also output factor information based on the calculation results of the plurality of feature quantities. In this case, it is easier to output factor information.

[0095] The multiple types of characteristic quantities may include: an evaluation value for the width, an evaluation value for the eccentricity of the coating periphery relative to the substrate periphery, an evaluation value for the roundness of the coating periphery, and an evaluation value for the roughness of the coating periphery. In this case, more helpful factor information can be output.

[0096] The coating unit U1 includes: a rotating holding part 20 that holds and rotates a substrate W; and a nozzle 41 that sprays a removal liquid for removing the coated film toward the periphery of the substrate W held and rotated by the rotating holding part 20. The width evaluation value can also correspond at least to the positional offset of the nozzle 41 and the change in the spray volume of the removal liquid from the nozzle 41; the eccentricity evaluation value can also correspond at least to the positional offset of the substrate W in the rotating holding part 20; the roundness evaluation value can also correspond at least to the twisting of the substrate W and the twisting of the rotating holding part 20; and the roughness evaluation value can also correspond at least to the liquid splashing of the removal liquid and the change in the spray volume of the removal liquid from the nozzle 41. In this case, more helpful factor information can be output.

[0097] The coating and developing apparatus 2 further includes: an influence evaluation unit 122, which evaluates the influence of multiple types of characteristic quantities on the error based on the calculation results of multiple types of characteristic quantities; and a cause estimation unit 124, which can also output cause information based on the influence of multiple types of characteristic quantities on the error. In this case, more accurate cause information can be output more easily.

[0098] The cause estimation unit 124 may also output cause information based on at least one error factor corresponding to the feature quantity with the highest influence among the multiple types of error causes. In this case, cause information that is easier to understand can be output.

[0099] The feature quantities of the multiple types include composite feature quantities corresponding to the error factors of the multiple types. When the feature quantity with the highest influence is a composite feature quantity, the factor estimation unit 124 can also output factor information based on the error factors of the multiple types corresponding to the composite feature quantity and the state of the coating unit U1. In this case, more accurate factor information can be output.

[0100] The embodiments have been described above, but the present invention is not necessarily limited to the above embodiments. Various modifications can be made within the scope of its main idea. [Simplified Explanation of the Diagram]

[0007] Figure 1 is a schematic diagram illustrating the general structure of a substrate processing system. Figure 2 is a schematic diagram illustrating the general structure of a coating unit. Figure 3 is a schematic diagram illustrating the general structure of an inspection unit. Figure 4 is a schematic diagram illustrating the functional structure of a control unit. Figure 5 is a schematic diagram illustrating the hardware structure of the control unit. Figure 6 is a flowchart illustrating the film formation control steps. Figure 7 is a flowchart illustrating the steps for obtaining the removal variation curve. Figure 8 is a flowchart illustrating the steps for outputting cause information.

Claims

1. A substrate processing apparatus, comprising: a peripheral removal unit for removing a peripheral portion of a coating film formed on the surface of a substrate; a variation curve acquisition unit for acquiring a removal width variation curve representing the relationship between the circumferential position of the substrate and the width of the portion of the substrate where the coating film has been removed; a feature quantity calculation unit for calculating, based on the removal width variation curve, a plurality of feature quantities corresponding to at least one factor contributing to the error of the width; and a factor estimation unit for outputting factor information representing the factor contributing to the error based on the calculation results of the plurality of feature quantities; wherein the plurality of feature quantities includes: an evaluation value of the width, an evaluation value of the eccentricity of the periphery of the coating film relative to the periphery of the substrate, an evaluation value of the roundness of the periphery of the coating film, and an evaluation value of the roughness of the periphery of the coating film.

2. The substrate processing apparatus as described in claim 1, wherein, The factor estimation unit outputs factor information when the assessed value of the width falls outside a predetermined range.

3. The substrate processing apparatus as described in claim 1 or 2, wherein, The peripheral removal section includes: a rotating holding section for holding and rotating the substrate; and a nozzle for spraying a removal liquid for removing the coating film toward the peripheral portion of the substrate held and rotated by the rotating holding section; the width evaluation value corresponds at least in addition to the positional offset of the nozzle and the variation in the spray volume of the removal liquid from the nozzle; the eccentricity evaluation value corresponds at least in addition to the positional offset of the substrate in the rotating holding section; the roundness evaluation value corresponds at least in addition to the twist of the substrate and the twist of the rotating holding section; and the roughness evaluation value corresponds at least in addition to the liquid splash of the removal liquid and the variation in the spray volume of the removal liquid from the nozzle.

4. The substrate processing apparatus as described in claim 1 or 2 further includes: an influence assessment unit that assesses the influence of the multiple types of feature quantities on the error based on the calculation results of the multiple types of feature quantities; and a cause estimation unit that outputs cause information based on the influence of the multiple types of feature quantities on the error.

5. The substrate processing apparatus as described in claim 4, wherein, The factor estimation unit outputs factor information based on at least one factor of the error corresponding to the feature quantity with the highest influence among the factors of the error of the multiple types.

6. The substrate processing apparatus as described in claim 1 or 2, wherein, The feature quantity of the complex type includes a composite feature quantity corresponding to the cause of the error of the complex type; when the feature quantity with the highest influence is the composite feature quantity, the cause estimation unit outputs the cause information based on the cause of the error of the complex type corresponding to the composite feature quantity and the state of the peripheral removal unit.

7. A substrate processing method comprising the following steps: removing a peripheral portion of a coating film formed on the surface of a substrate by means of a peripheral removal portion; obtaining a removal width variation curve representing the relationship between the circumferential position of the substrate and the width of the portion of the substrate from which the coating film has been removed; calculating, based on the removal width variation curve, a plurality of characteristic quantities corresponding to at least one factor of error in the width; and outputting factor information representing the factor of the error based on the calculation results of the plurality of characteristic quantities; the plurality of characteristic quantities including: an evaluation value of the width, an evaluation value of the eccentricity of the periphery of the coating film relative to the periphery of the substrate, an evaluation value of the roundness of the periphery of the coating film, and an evaluation value of the roughness of the periphery of the coating film.

8. The substrate processing method as described in claim 7, wherein, If the evaluated value of this width falls outside the predetermined range, the factor information is output.

9. The substrate processing method as described in claim 7 or 8, wherein, The peripheral removal section includes: a rotating holding section for holding and rotating the substrate; and a nozzle for spraying a removal liquid for removing the coating film toward the peripheral portion of the substrate held and rotated by the rotating holding section; the width evaluation value corresponds at least in addition to the positional offset of the nozzle and the variation in the spray volume of the removal liquid from the nozzle; the eccentricity evaluation value corresponds at least in addition to the positional offset of the substrate in the rotating holding section; the roundness evaluation value corresponds at least in addition to the twist of the substrate and the twist of the rotating holding section; and the roughness evaluation value corresponds at least in addition to the liquid splash of the removal liquid and the variation in the spray volume of the removal liquid from the nozzle.

10. The substrate processing method as described in claim 7 or 8 further includes the following step: evaluating the influence of the complex type of feature quantities on the error based on the calculation results of the feature quantities of the complex type; wherein, Based on the influence of the characteristic quantity of the complex number type on the error, the factor information is output.

11. The substrate processing method as described in claim 10, wherein, Based on the factors of the error of the complex type, at least one factor of the error is attached to the feature quantity with the highest influence, and the factor information is output.

12. The substrate processing method as described in claim 7 or 8, wherein, The feature quantity of the complex type includes a composite feature quantity corresponding to the factor of the error of the complex type; when the feature quantity with the highest influence is the composite feature quantity, the factor information is output based on the factor of the error of the complex type corresponding to the composite feature quantity and the state of the peripheral removal portion of the peripheral portion of the coating.

13. A computer-readable recording medium storing a program for causing a device to perform a substrate processing method as described in any one of claims 7 to 12.

14. A cause estimation apparatus, comprising: a change curve acquisition unit, acquiring a width change curve representing the relationship between the circumferential position of a substrate on which a coating film is formed on its surface and the width of the portion of the substrate from which the coating film has been removed by a peripheral removal unit; a feature quantity calculation unit, calculating a plurality of feature quantities corresponding to at least one cause of the error in width based on the width change curve; and a cause estimation unit, outputting cause information representing the cause of the error based on the calculation results of the plurality of feature quantities; wherein the plurality of feature quantities include: an evaluation value of the width, an evaluation value of the eccentricity of the periphery of the coating film relative to the periphery of the substrate, and an evaluation value of the roundness of the periphery of the coating film.

15. The cause estimation apparatus as described in claim 14, wherein, The peripheral removal section includes: a rotating holding section for holding and rotating the substrate; and a nozzle for spraying a removal liquid for removing the coating film toward the peripheral portion of the substrate held and rotated by the rotating holding section; the width evaluation value corresponds at least in addition to the positional offset of the nozzle and the variation in the spray volume of the removal liquid from the nozzle; the eccentricity evaluation value corresponds at least in addition to the positional offset of the substrate in the rotating holding section; and the roundness evaluation value corresponds at least in addition to the twist of the substrate and the twist of the rotating holding section.

16. A cause estimation apparatus, comprising: a change curve acquisition unit, acquiring a width change curve representing the relationship between the circumferential position of a substrate on which a coating film is formed on its surface and the width of the portion of the substrate on which the coating film has been removed by a peripheral removal unit; a feature quantity calculation unit, calculating a plurality of feature quantities corresponding to at least one cause of the error in width based on the removal width change curve; and a cause estimation unit, outputting cause information representing the cause of the error based on the calculation results of the plurality of feature quantities; wherein the plurality of feature quantities include: an evaluation value of the width, an evaluation value of the eccentricity of the periphery of the coating film relative to the periphery of the substrate, and an evaluation value of the roughness of the periphery of the coating film.

17. The cause estimation apparatus as described in claim 16, wherein, The peripheral removal section includes: a rotating holding section for holding and rotating the substrate; and a nozzle for spraying a removal liquid for removing the coating film toward the peripheral portion of the substrate held and rotated by the rotating holding section; the width evaluation value corresponds at least in addition to the positional offset of the nozzle and the variation in the spray volume of the removal liquid from the nozzle; the eccentricity evaluation value corresponds at least in addition to the positional offset of the substrate in the rotating holding section; and the roughness evaluation value corresponds at least in addition to the liquid splash of the removal liquid and the variation in the spray volume of the removal liquid from the nozzle.

18. A cause estimation apparatus as described in any one of claims 14-17, wherein, The factor estimation unit outputs factor information when the assessed value of the width falls outside a predetermined range.

19. The cause estimation apparatus as described in any one of claims 14 to 17 further comprises: an influence assessment unit that assesses the influence of the feature quantities of the complex types on the error based on the calculation results of the feature quantities of the complex types; and the cause estimation unit outputs the cause information based on the influence of the feature quantities of the complex types on the error.

20. The cause estimation apparatus as described in claim 19, wherein, The factor estimation unit outputs factor information based on at least one factor of the error corresponding to the feature quantity with the highest influence among the factors of the error of the multiple types.

21. A cause estimation apparatus as described in any one of claims 14-17, wherein, The feature quantity of the complex type includes a composite feature quantity corresponding to the cause of the error of the complex type; when the feature quantity with the highest influence is the composite feature quantity, the cause estimation unit outputs the cause information based on the cause of the error of the complex type corresponding to the composite feature quantity and the state of the peripheral removal unit.

22. A cause estimation method, comprising the steps of: obtaining a width variation curve representing the relationship between the circumferential position of a substrate on which a coating film is formed on its surface and the width of the portion of the substrate on which the coating film has been removed by a peripheral removal portion, and the width of the portion of the substrate on which the coating film has been removed; calculating, based on the width variation curve, a plurality of characteristic quantities corresponding to a cause of error in at least one width; and outputting cause information representing a cause of error based on the calculation results of the plurality of characteristic quantities; wherein the plurality of characteristic quantities include: an evaluation value of the width, an evaluation value of the eccentricity of the periphery of the coating film relative to the periphery of the substrate, and an evaluation value of the roundness of the periphery of the coating film.

23. The cause-of-fact estimation method as described in claim 22, wherein, The peripheral removal section includes: a rotating holding section for holding and rotating the substrate; and a nozzle for spraying a removal liquid for removing the coating film toward the peripheral portion of the substrate held and rotated by the rotating holding section; the width evaluation value corresponds at least in addition to the positional offset of the nozzle and the variation in the spray volume of the removal liquid from the nozzle; the eccentricity evaluation value corresponds at least in addition to the positional offset of the substrate in the rotating holding section; and the roundness evaluation value corresponds at least in addition to the twist of the substrate and the twist of the rotating holding section.

24. A cause estimation method, comprising the steps of: obtaining a width variation curve representing the relationship between the circumferential position of a substrate on which a coating film is formed on its surface and the width of the portion of the substrate on which the coating film has been removed by a peripheral removal portion, and the width of the portion of the substrate on which the coating film has been removed; calculating, based on the width variation curve, a plurality of characteristic quantities corresponding to a cause of error in at least one width; and outputting cause information representing a cause of error based on the calculation results of the plurality of characteristic quantities; wherein the plurality of characteristic quantities include: an evaluation value of the width, an evaluation value of the eccentricity of the periphery of the coating film relative to the periphery of the substrate, and an evaluation value of the roughness of the periphery of the coating film.

25. The cause-of-fact estimation method as described in claim 24, wherein, The peripheral removal section includes: a rotating holding section for holding and rotating the substrate; and a nozzle for spraying a removal liquid for removing the coating film toward the peripheral portion of the substrate held and rotated by the rotating holding section; the width evaluation value corresponds at least in addition to the positional offset of the nozzle and the variation in the spray volume of the removal liquid from the nozzle; the eccentricity evaluation value corresponds at least in addition to the positional offset of the substrate in the rotating holding section; and the roughness evaluation value corresponds at least in addition to the liquid splash of the removal liquid and the variation in the spray volume of the removal liquid from the nozzle.

26. The cause-of-fact estimation method as described in any of claims 22-25, wherein, If the evaluated value of this width falls outside the predetermined range, the factor information is output.

27. The factor estimation method as described in any one of claims 22-25 further comprises the following steps: evaluating the influence of the characteristic quantity of the complex number type on the error based on the calculation results of the characteristic quantity of that complex number type; wherein, Based on the influence of the characteristic quantity of the complex number type on the error, the factor information is output.

28. The cause-of-fact estimation method as described in claim 27, wherein, Based on the factors of the error of the complex type, at least one factor of the error is attached to the feature quantity with the highest influence, and the factor information is output.

29. The cause-of-fact estimation method as described in any of claims 22-25, wherein, The feature quantity of the complex type includes a composite feature quantity corresponding to the factor of the error of the complex type; when the feature quantity with the highest influence is the composite feature quantity, the factor information is output based on the factor of the error of the complex type corresponding to the composite feature quantity and the state of the peripheral removal part.

30. A computer-readable recording medium storing a program for causing a device to perform a cause estimation method as described in any one of claims 22 to 29.

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