JP2007115790A - Resist film processing apparatus and resist pattern formation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resist film processing apparatus which can sufficiently reflect the status of a latest apparatus and reduce the variation of dimension enough. <P>SOLUTION: In the lithography step of semiconductor manufacture, when the quantity of exposure is determined to start working of the following substrate; a finish size estimation processing (step S109) is to estimate the pattern size of a substrate to be worked next on the basis of a PEB process parameter and an exposure process parameter in use, and to calculate a difference between a target value of the pattern size and an estimated value in the step S109 through a error calculation processing (step S10), and a next exposure quantity setting processing (step S11) is to change the setting of the exposure quantity of a substrate to be worked next. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a feedback technique in a semiconductor device manufacturing process, and more particularly to a feedback technique in a lithography process.

  In recent years, with the miniaturization of semiconductor devices, requirements for processing accuracy required for gate electrode formation, wiring processing, and the like have become very strict. In particular, it is well known that there is a linear correlation between the gate electrode processing dimension and the transistor threshold voltage Vt. In order to satisfy the required specification of the threshold voltage Vt, the gate electrode processing dimension It is required to finish with high accuracy.

  Currently, in the manufacture of semiconductor devices, resist patterns by lithography processes are widely used as masks for element region formation, gate electrode formation, wiring processing, and the like. Therefore, in order to improve the processing dimension accuracy of the gate electrode, it is necessary to reduce the variation in the resist finish dimension as much as possible. Until now, as one of the means, there has been a method of processing the remaining substrates by performing prior processing of the substrates and confirming the finished dimensions in advance, and then adjusting the exposure energy again based on the results. At this time, the preceding substrate is once regenerated and processed again. However, this method has a problem of significantly reducing the productivity of the lithography process.

  On the other hand, for the purpose of abolishing the preceding process, a feedback system that determines exposure energy using finished dimension data of several processed lots has been adopted. For example, a feedback system typified by IBM's PHALCON is one example.

However, feedback systems such as PHALCON are not suitable for small-lot, high-variety production lines where one lot flows in a few days or weeks, so it is based on in-process process data for several lots that have already been processed. Thus, there has been proposed a method (for example, see Patent Document 1) for determining lot processing conditions by a weighted average.
Japanese Patent Laid-Open No. 11-16805

  In such a conventional feedback system, exposure conditions are determined using resist finished dimension data of several processed lots, but after the lithography processing, after development, macro inspection, overlay measurement, resist finished dimension measurement, Since it passes through a plurality of processes, it takes a relatively long time of about several hours until the exposure amount can be set using the dimension measurement data. Accordingly, the lithographic apparatus continues to process the substrate during the time difference, and the apparatus state may change.

  In addition, since past data is used even during processing after the apparatus state has changed after maintenance, there has been a problem that the exposure conditions cannot follow the change in the apparatus state. For example, when a KrF stepper using a KrF excimer laser (wavelength: 248 nm) as an exposure light source and a chemically amplified resist is used as a resist material, a heat treatment process called PEB (Post Exposure Bake) is performed after the exposure process. Needed. PEB is performed using a bake unit to diffuse the acid generated in the exposure process, but the exhaust pipe from the bake unit is clogged by sublimated resist, and the exhaust flow rate changes over time. Come on.

  Since the resist evaporation material is exhausted to the exhaust pipe of the bake unit, regular connection and monitoring of a flow meter using an orifice cannot be performed due to concerns about clogging. There was a case where a gauge was attached and rough monitoring was performed so as not to affect particle generation, but no example of active management was found for dimensional control.

  In the above conventional feedback system, the exposure energy is changed in units of lots based on the resist finish dimension data after the lithography process. However, due to the above reasons, it takes several hours until the resist finish dimension data can be obtained and utilized after lithography. Particularly, when focusing on one lithography apparatus, a mass production factory can process several lots. It is likely that it has already progressed.

  Therefore, since feedback is performed based on the processing state several lots ago, the latest apparatus state cannot be sufficiently reflected, and as a result, there is a problem that variations in resist finish dimensions cannot be sufficiently reduced. In addition, since the information source for feedback uses only the finished dimensions of the resist, follow-up is delayed with respect to changes in the state of the apparatus, and the influence on the change in process parameters can be canceled in the next substrate or lot. There is a problem that cannot be done. Further, for example, when the prior process is performed only after the maintenance of the apparatus with the conventional feedback system, the lithography apparatus cannot be operated until the result of the prior process is obtained, resulting in a problem that the productivity is lowered.

  For example, there is a bake unit that performs PEB as a unit for monitoring the equipment state. In many cases where a chemically amplified resist is used, the substrate is heated by a bake unit after exposure to diffuse the acid generated in the resist by exposure. Since this acid decomposes the resin (positive type) or crosslinks (negative type), the substrate heating temperature in the bake unit is an important parameter affecting the finished dimensions of lithography.

FIG. 17 is a block diagram of a conventional bake unit. Hereinafter, a conventional PEB processing method will be described with reference to FIG.
In the conventional PEB processing method, the heater 2 installed in the bake unit is heated at a constant temperature, the substrate 1 is transferred onto the substrate support base 8, and the distance between the substrate 1 and the heater 2 is kept constant. Then, the substrate is heated. At this time, a constant flow rate of N ₂ gas or clean air 5 is supplied into the bake unit through the supply pipe 4, and is exhausted from the exhaust pipe 7 through the periphery of the substrate 1 and the rectifying plate 10. The heating of the substrate 1 is indirectly performed under the condition where the distance from the heater 2 is separated from the heater 2 by the substrate support 8 and monitoring of the substrate surface temperature is not performed. For this reason, there is a possibility that the substrate surface temperature changes due to the positional relationship between the rectifying plate 10 and the substrate 1 being slightly shifted depending on the assembly state of the bake unit for each maintenance.

  On the other hand, with the number of processed substrates, resist sublimates gradually accumulate around the air holes in the rectifying plate 10 and the exhaust supply portion of the exhaust pipe 7, and the exhaust flow rate in the exhaust pipe decreases. Even if it is within the management standards of the apparatus, if the exhaust flow rate decreases, the flow of the clean air 5 in the unit becomes worse, and the substrate surface temperature tends to increase due to the influence. As a result, there is a problem that the acid generated in the chemically amplified resist is accelerated in diffusion and works in a direction of further decomposition (positive type), and the wiring width tends to be narrowed under the same exposure energy.

  The present invention has been made in order to solve the above-mentioned problems, and the first object is to delay in time using past processing data, that is, resist finish size data of a lot processed in the past. By using the information to feed back the exposure energy, the finished dimensions after lithography will vary. By measuring the process parameters of the substrate currently being processed by the lithographic apparatus, the resist finished dimensions can be predicted immediately. A resist film processing apparatus and a resist pattern forming method capable of reducing variations in resist finish dimensions by detecting a difference between a target value and a predicted value based on this difference and reflecting the difference in the exposure energy condition of the next substrate based on the difference. It is to provide.

  A second object of the present invention is to provide a resist film processing apparatus and a resist pattern forming method capable of reducing the fact that resist sublimates evaporated from a substrate to be processed are clogged in an exhaust pipe in a baking unit. It is to provide.

  A third object of the present invention is based on the process parameters of the substrate currently being processed by the lithographic apparatus, compared to a conventional exposure energy feedback system using resist finish dimension data of previously processed lots. An object of the present invention is to provide a resist film processing apparatus and a resist pattern forming method capable of reducing variations in resist finish dimensions by sequentially correcting the exposure energy conditions of the next substrate.

  In order to solve the above problems, a resist film processing apparatus according to a first aspect of the present invention performs a current process in a lithography process of a semiconductor device manufacturing process without using a resist finish dimension of a substrate that has already been processed. The resist finish size is predicted based on the state of the apparatus process parameters, and the exposure energy of the substrate to be processed is determined from the difference between the target value and the predicted value.

  Thus, based on the result of measuring the substrate surface temperature currently processed by the bake unit that performs PEB processing or the result of estimating the substrate surface temperature, the finished dimension of the substrate to be processed is predicted, and the target of the finished dimension In order to determine the processing conditions from the difference between the measured value and the predicted value, the influence of fluctuations in the exhaust flow rate caused by deposition of sublimates generated in the baking unit that performs PEB processing, for example, on the dimension variation factors given by the process parameters of the apparatus Thus, it is possible to prevent variations in the finished dimensions caused by fluctuations in the substrate surface temperature.

Therefore, the dimensional accuracy can be improved as compared with the existing feedback system that changes the exposure amount based only on the data of the finished dimension after the lithography process.
In the resist film processing apparatus according to the second aspect of the present invention, in the bake unit that performs the PEB processing, a supply pipe is branched, and a resist decomposition gas such as O ₃ gas can be supplied from one supply pipe. It is characterized by that. In this case, it is desirable to apply an oxidation-resistant member such as PFA or quartz heater as the constituent member of the bake unit.

  Thereby, the control valve for supplying the resist decomposition gas is closed during the baking process of the substrate, and clean air is supplied to the supply pipe. When the substrate processing is completed and there is no substrate in the unit, the control unit for clean air supply and the resist decomposition gas supply control valve are automatically switched to supply the resist decomposition gas to the bake unit. It is possible to decompose resist sublimate deposited on the inside, the current plate, the exhaust pipe, etc., to make the exhaust flow rate of the bake unit constant, and to keep the surface temperature of the substrate constant regardless of the number of processed sheets.

As described above, the dimension variation factor given by the process parameters of the apparatus can be prevented, and the dimensional accuracy of the lithography process can be improved.
Also, a resist film processing apparatus according to a third aspect of the present invention uses a resist finish dimension of a substrate that has already been processed in a lithography process of a semiconductor device manufacturing process to reduce exposure energy in order to solve the above problems. A feedback method for adjustment is utilized, and in addition to this, the exposure energy of the substrate to be started is corrected based on the state of the apparatus process parameter currently being processed.

  As a result, the result of measuring the substrate surface temperature currently being processed by the bake unit performing the PEB process or the result of estimating the substrate surface temperature can be reflected on the substrate for the next process. It is possible to reduce variations in finished dimensions caused by fluctuations in the substrate surface temperature due to the influence of fluctuations in the exhaust flow rate caused by the accumulation of sublimates generated in the baking unit to be performed in the unit.

  Therefore, the dimensional accuracy can be improved as compared with the existing feedback system that changes the exposure energy based only on the data of the finished dimensions after the lithography process.

  As described above, according to the present invention, by incorporating the process parameters of the apparatus, which is a dimensional fluctuation factor of lithography, into the feedback system, the latest apparatus state is sufficiently reflected, and the dimensional fluctuation due to the tracking delay with respect to the apparatus state change can be reduced. Can be suppressed.

  As a result, the dimensional accuracy of lithography can be improved, which greatly contributes to the manufacture of highly integrated circuit devices.

Hereinafter, a resist film processing apparatus and a resist pattern forming method according to an embodiment of the present invention will be specifically described with reference to the drawings. In the following description, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description will be given only when necessary.
(Embodiment 1)
FIG. 1 shows a basic conceptual diagram of this method. In this embodiment, prior to lot injection, “resist film formation” (step S1), “heating before exposure” (step S2), “cooling” (step S3), “exposure” (step S4), “Heating after exposure” (step S5), “cooling” (step S6), “development” (step S7) are performed, and “inspection” (step S8) performs macro inspection, overlay measurement, resist pattern Measure the dimensions of

  At this time, in the “finished dimension prediction” (step S109), the PEB process parameter and the exposure process parameter currently being processed, specifically, the exhaust pressure P (n) and the exposure amount X (n) of the bake unit are set. Based on this, the finished dimension of the current processing substrate is predicted, and the difference between the target value of the finished dimension and the predicted value predicted in step S109 is calculated in “error calculation” (step S10), and “next processing exposure amount setting” ( In step S11), the exposure amount of the substrate to be started next is changed.

  The algorithm of the “finished dimension prediction” (step S109) can be expressed as the following equation (1).

（１）式の係数ａ_０、ａ_１、ａ_２は、予め従来の方法で、リソグラフィの処理を行いながら取得した、仕上がり寸法データと排気圧力、露光量のデータセットから重回帰分析を用いて求めている。

The coefficients a ₀ , a ₁ , and a _{2 in the} formula (1) are obtained by using multiple regression analysis from the finished dimension data, the exhaust pressure, and the exposure dose data set that are obtained in advance by performing the lithography process using a conventional method. Looking for.

  Next, the algorithm of the “error calculation” (step S10) is as shown in equation (2).

次に、「次処理露光量設定」（ステップＳ１１）のアルゴリズムは（３）式のように表せる。

Next, the algorithm of “next process exposure amount setting” (step S11) can be expressed as shown in equation (3).

このように、本発明による実施の形態１では、排気圧力Ｐ（ｎ）と露光量Ｘ（ｎ）の２つの装置プロセスパラメータを用いることで、従来のフィードバックシステムでは必須であった寸法測定を実施することなく、次処理基板の露光量を予測し、フィードバックすることが可能になる。

As described above, in the first embodiment according to the present invention, by using the two apparatus process parameters of the exhaust pressure P (n) and the exposure amount X (n), the dimension measurement that is essential in the conventional feedback system is performed. Without this, the exposure amount of the next processing substrate can be predicted and fed back.

  Next, FIG. 2 shows an example of a bake unit structure that can measure the exhaust pressure of the bake unit. This is characterized in that a pressure gauge 21 is provided in the exhaust pipe 7 with respect to the conventional bake unit structure of FIG. With this structure, the exhaust pressure in the bake unit can be measured.

  The bake unit that performs the PEB process is closed by the top plate 9 and the housing 3. A heater 2 divided into a plurality of parts and a hot plate 11 having a sensor for monitoring the heater temperature are provided on the bottom surface of the housing 3. A resist film after exposure and before development is provided on the upper surface of the hot plate 11. A substrate support base 8 that supports the substrate 1 is provided.

The substrate 1 is heated by the heater 2 and covered with a rectifying plate 10 having one or more holes above it, and N ₂ gas or clean air 5 is supplied into the bake unit through the supply pipe 4, The exhaust pipe 7 exhausts 6 through 10 holes.

  As an example, the present feedback system when the exhaust pressure P (n) and the exposure amount X (n) are used as process parameters, and the conventional feedback system based on the exposure amount and resist finish dimensions of several already processed lots. The comparison results are shown in FIG.

  FIG. 3 is a histogram of resist dimensions, in which the X-axis indicates the resist dimension data section, and the Y-axis indicates the frequency in each data section. The resist pattern used for the dimension measurement is an L / S (Line and Space) pattern, and the target value of the resist finished dimension is 129 nm. FIG. 3 shows that the conventional feedback system has a peak of 127 nm, which is 127 nm narrower than the target dimension, whereas the present feedback system has a target value of 129 nm. Further, the process capability index Cpk is 0.77 of the conventional system, and 1.17 of the present feedback system, and the variation is also improved.

  FIG. 4 shows the relationship between the exhaust pressure of the bake unit and the exposure amount when the comparison is made in FIG. The X axis shows time, the left Y axis shows the exposure amount, and the right Y axis shows the exhaust pressure of the bake unit. Black lines in the figure indicate the timing at which periodic maintenance of the apparatus, for example, resist film thickness confirmation, particle confirmation, baking unit cleaning, and the like are performed. FIG. 4 shows that the exhaust pressure of the bake unit decreases with time between maintenance. This is because when the substrate 1 on which the resist film is formed is baked, sublimates generated from the resist are deposited on the current plate 10 and the exhaust pipe 7 in the bake unit.

  On the other hand, when the bake unit is cleaned, the accumulated sublimate is removed, so that the exhaust pressure immediately after maintenance returns to a constant value, in this case, about -1.1 kPa. Thereafter, as the number of processed sheets increases, the exhaust pressure decreases again. At this time, in the present feedback system, a strong correlation is observed between the exhaust pressure and the exposure amount, but the correlation between the exposure amount and the exhaust pressure of the conventional method is weak and the followability immediately after maintenance is poor.

  FIG. 5 shows the relationship between the exhaust pressure and the exhaust flow rate. In the bake unit structure of FIG. 2, a flow meter was connected in series with the exhaust pipe 7 to obtain the relationship between the exhaust pressure and the exhaust flow rate of the bake unit. . From this, it can be seen that when the exhaust pressure decreases, the exhaust flow rate also decreases linearly.

  FIG. 6 shows the relationship between the substrate surface temperature and the exhaust flow rate as a parameter in the bake unit structure of FIG. The measurement of the substrate surface temperature was carried out using a wireless temperature measurement wafer manufactured by OnWafer, USA. From this, it can be seen that the substrate surface temperature increases as the exhaust flow rate decreases. What should be noted here is that the heater 2 for heating the substrate 1 always maintains the set temperature even if the exhaust gas flow rate fluctuates. That is, the conventional bake unit does not take into consideration any change in the substrate surface temperature due to the fluctuation of the exhaust flow rate.

  FIG. 7 shows the relationship between the substrate surface temperature and the finished dimensions of the L / S pattern. The parameters used here are only the substrate surface temperature, and parameters such as exposure amount, focus, baking time, development temperature, development time, etc. are fixed. From this, it can be seen that when the substrate surface temperature rises, the finished dimension becomes thinner in the case of a positive resist.

  As described above, according to the first embodiment of the present invention, based on the relationship between FIG. 5, FIG. 6, and FIG. 7, the two apparatus process parameters of the exhaust pressure P (n) and the exposure amount X (n) are used. In this feedback system, the exposure amount of the next processing substrate can be predicted and fed back without performing the dimension measurement which is essential in the feedback system.

Therefore, the latest apparatus state is sufficiently reflected, and it becomes possible to suppress the dimensional variation due to the tracking delay with respect to the apparatus state change.
In the unlikely event that equipment conditions other than the assumed process parameters have changed significantly due to the effects of equipment overhaul, etc., and the estimated final dimensions of the resist deviate greatly from the actual final dimensions, for example, Of formula (2)

の値に制限を設けておく事により、これを検出し、もう一度、係数ａ_０、ａ_１、ａ_２の再設定からはじめると良い。
（実施の形態２）
図８に本手法の基本概念図を示した。本実施の形態では、ロットの投入に先立ち、「レジスト膜の形成」（ステップＳ１）、「露光前の加熱」（ステップＳ２）、「冷却」（ステップＳ３）、「露光」（ステップＳ４）、「露光後の加熱」（ステップＳ５）、「冷却」（ステップＳ６）、「現像」（ステップＳ７）を行い、「検査」（ステップＳ８）でパターン形成後のマクロ検査、重ね合せ測定、レジストパターンの寸法測定等を実施する。

This is detected by setting a limit on the value of, and it is good to start again by resetting the coefficients a ₀ , a ₁ , a ₂ .
(Embodiment 2)
FIG. 8 shows a basic conceptual diagram of this method. In this embodiment, prior to lot injection, “resist film formation” (step S1), “heating before exposure” (step S2), “cooling” (step S3), “exposure” (step S4), “Heating after exposure” (step S5), “cooling” (step S6), “development” (step S7) are performed, and “inspection” (step S8) performs macro inspection, overlay measurement, resist pattern Measure the dimensions of

  At this time, in “finished dimension prediction” (step S809), the PEB process parameters and exposure process parameters currently being processed, specifically, the exhaust flow rate L (n) and the exposure amount X ( n), the finished dimension of the substrate to be processed is predicted, and the difference between the target value of the finished dimension and the predicted value predicted in step S809 is calculated in “error calculation” (step S10). In the “setting” (step S11), the exposure amount of the substrate to be started next is changed.

  The algorithm of the “finished dimension prediction” (step S809) can be expressed as the following equation (4).

（４）式の係数ｂ_０、ｂ_１、ｂ_２は、予め従来の方法で、リソグラフィの処理を行いながら取得した、仕上がり寸法データと排気流量、露光量のデータセットから重回帰分析を用いて求めている。

The coefficients b ₀ , b ₁ , and b _{2 in the} equation (4) are obtained by using multiple regression analysis from the finished dimension data, the exhaust flow rate, and the exposure dose data set obtained in advance by performing lithography processing by a conventional method. Looking for.

  Next, the algorithm of the “error calculation” (step S10) is as shown in equation (5).

次に、「次処理露光量設定」（ステップＳ１１）のアルゴリズムは（６）式のように表せる。

Next, the algorithm of “next processing exposure amount setting” (step S11) can be expressed as in equation (6).

前記図６、図７の関係に基づいて、本発明の実施の形態２では、排気流量Ｌ（ｎ）と露光量Ｘ（ｎ）の２つの装置プロセスパラメータを用いることで、従来のフィードバックシステムでは必須であった寸法測定を実施することなく、次処理基板の露光量を予測し、フィードバックすることが可能になる。

Based on the relationship between FIG. 6 and FIG. 7, in the second embodiment of the present invention, two apparatus process parameters of the exhaust flow rate L (n) and the exposure amount X (n) are used. The exposure amount of the next processing substrate can be predicted and fed back without carrying out the dimension measurement that was essential.

Therefore, the latest apparatus state is sufficiently reflected, and it becomes possible to suppress the dimensional variation due to the tracking delay with respect to the apparatus state change.
Next, an example of a unit configuration capable of measuring the exhaust flow rate of the bake unit is shown in FIG. The exhaust pipe 7 branches off from the exhaust pipe 37 upstream of the control valve 34, and the exhaust pipe 37 has a control valve 35 and a flow meter 36 downstream thereof. When the substrate 1 is baked, exhaust is performed at the time of baking by piping to which the flow meter 36 is not connected. When the baking process is finished, the control valve 34 and 35 are automatically switched, whereby the exhaust flow rate is adjusted by the flow meter 36. It becomes possible to measure.

In the bake unit, if the supply pipe is branched, the resist decomposition gas 31 such as O ₃ gas can be supplied from the supply pipe 38. In this case, it is desirable to apply an oxidation-resistant member such as PFA or a quartz heater as a constituent member of the bake unit. During the baking process of the substrate 1, the control valve 32 is closed, and the supply pipe 4 is supplied with N ₂ gas or clean air 5. When the processing of the substrate 1 is completed and there is no substrate in the unit, the control valves 33 and 32 are automatically switched, and the resist decomposition gas 31 is supplied to the baking unit. It is possible to decompose the resist sublimate deposited at 7 etc., make the exhaust flow rate of the bake unit constant, and keep the surface temperature of the substrate 1 constant irrespective of the number of processed sheets.

  In the unlikely event that equipment conditions other than the assumed process parameters have changed significantly due to the effects of equipment overhaul, etc., and the estimated final dimensions of the resist deviate greatly from the actual final dimensions, for example, Of formula (5)

の値に制限を設けておく事により、これを検出し、もう一度、係数ｂ_０、ｂ_１、ｂ_２の再設定からはじめると良い。
（実施の形態３）
図１０に本手法の基本概念図を示した。本実施の形態では、ロットの投入に先立ち、「レジスト膜の形成」（ステップＳ１）、「露光前の加熱」（ステップＳ２）、「冷却」（ステップＳ３）、「露光」（ステップＳ４）、「露光後の加熱」（ステップＳ５）、「冷却」（ステップＳ６）、「現像」（ステップＳ７）を行い、「検査」（ステップＳ８）でパターン形成後のマクロ検査、重ね合せ測定、レジストパターンの寸法測定等を実施する。

This is detected by setting a limit on the value of, and it is preferable to start again by resetting the coefficients b ₀ , b ₁ , and b ₂ .
(Embodiment 3)
FIG. 10 shows a basic conceptual diagram of this method. In this embodiment, prior to lot injection, “resist film formation” (step S1), “heating before exposure” (step S2), “cooling” (step S3), “exposure” (step S4), “Heating after exposure” (step S5), “cooling” (step S6), “development” (step S7) are performed, and “inspection” (step S8) performs macro inspection, overlay measurement, resist pattern Measure the dimensions of

  At this time, in “finished dimension prediction” (step S1009), the PEB process parameter and the exposure process parameter that are currently processed, specifically, the substrate surface temperature T (n) during the baking process in the baking unit that performs the PEB process. And the amount of exposure X (n), the finished dimension of the substrate currently being processed is predicted, and the difference between the target value of the finished dimension and the predicted value predicted in step S1009 is calculated by “error calculation” (step S10). Based on this, the exposure amount of the substrate to be started next is changed in “next processing exposure amount setting” (step S11).

  The algorithm of the “finished dimension prediction” (step S1009) can be expressed as the following equation (7).

（７）式の係数ｃ_０、ｃ_１、ｃ_２は、予め従来の方法で、リソグラフィの処理を行いながら取得した、仕上がり寸法データとＰＥＢ処理時の基板表面温度、露光量のデータセットから重回帰分析を用いて求めている。

The coefficients c ₀ , c ₁ , and c _{2 in} equation (7) are obtained from the final dimension data, the substrate surface temperature during PEB processing, and the exposure dose data set, which are obtained in advance by performing lithography processing using a conventional method. Calculated using regression analysis.

  Next, the algorithm of the above “error calculation” (step S10) is as shown in equation (8).

次に、「次処理露光量設定」（ステップＳ１１）のアルゴリズムは（９）式のように表せる。

Next, the algorithm of “next process exposure amount setting” (step S11) can be expressed as in equation (9).

前記図７の関係に基づいて、本発明の実施の形態３では、基板表面温度Ｔ（ｎ）と露光量Ｘ（ｎ）の２つの装置プロセスパラメータを用いることで、従来のフィードバックシステムでは必須であった寸法測定を実施することなく、次処理基板の露光量を予測し、フィードバックすることが可能になる。

Based on the relationship shown in FIG. 7, in the third embodiment of the present invention, two apparatus process parameters of the substrate surface temperature T (n) and the exposure amount X (n) are used, which is indispensable in the conventional feedback system. The exposure amount of the next processing substrate can be predicted and fed back without performing the dimension measurement.

Therefore, the latest apparatus state is sufficiently reflected, and it becomes possible to suppress the dimensional variation due to the tracking delay with respect to the apparatus state change.
Next, FIG. 11 shows an example of a unit configuration that enables measurement of the substrate surface temperature during substrate baking of the baking unit. The bake unit is configured to supply N ₂ gas or clean air 5 from above and exhaust from the exhaust pipe 44 from below the housing 3, and for example, an infrared radiation thermometer that measures near 100 ° C. such as made of calcium fluoride. In order to measure the surface temperature of the substrate 1 above the rectifying plate 43, using a glass material through which the infrared rays are transmitted and disposing the rectifying plate 43 having one or more holes on the heating portion of the substrate 1. The infrared radiation thermometer 42 is arranged.

  With this configuration, the substrate surface temperature during baking can be measured with the radiation thermometer 42. At this time, the portion of the glass material used for the rectifying plate 43 only needs to be large enough to perform temperature measurement.

In the bake unit, if the supply pipe is branched, the resist decomposition gas 31 such as O ₃ gas can be supplied from the supply pipe 48. In this case, it is desirable to apply an oxidation-resistant member such as PFA or quartz heater as the constituent member of the bake unit.

During the baking process of the substrate 1, the control valve 47 is closed, and N ₂ gas or clean air 5 is supplied to the supply pipe 41. When the processing of the substrate 1 is completed and there is no substrate in the unit, the control valves 46 and 47 are automatically switched and the resist decomposition gas 31 is supplied to the baking unit, so that the inside of the baking unit, the current plate 43, the exhaust pipe The resist sublimate deposited on 44 etc. can be decomposed, and the exhaust flow rate of the bake unit can be kept constant.

  Furthermore, by providing a variable flow rate control valve 45 and a pressure gauge 49 in the exhaust pipe 44, the exhaust pressure in the bake unit can be monitored and controlled. As a result, the exhaust flow rate can be kept constant, and the substrate 1 It is possible to keep the surface temperature constant regardless of the number of processed sheets.

  In the unlikely event that equipment conditions other than the assumed process parameters have changed significantly due to the effects of equipment overhaul, etc., and the estimated final dimensions of the resist deviate greatly from the actual final dimensions, for example, Of formula (8)

の値に制限を設けておく事により、これを検出し、もう一度、係数ｃ_０、ｃ_１、ｃ_２の再設定からはじめると良い。
（実施の形態４）
図１２に本手法の基本概念図を示した。本実施の形態では、ロットの投入に先立ち、「レジスト膜の形成」（ステップＳ１）、「露光前の加熱」（ステップＳ２）、「冷却」（ステップＳ３）、「露光」（ステップＳ４）、「露光後の加熱」（ステップＳ５）、「冷却」（ステップＳ６）、「現像」（ステップＳ７）を行い、「検査」（ステップＳ８）でパターン形成後のマクロ検査、重ね合せ測定、レジストパターンの寸法測定等を実施する。

This is detected by setting a limit on the value of, and it is preferable to start again by resetting the coefficients c ₀ , c ₁ , and c ₂ .
(Embodiment 4)
FIG. 12 shows a basic conceptual diagram of this method. In this embodiment, prior to lot injection, “resist film formation” (step S1), “heating before exposure” (step S2), “cooling” (step S3), “exposure” (step S4), “Heating after exposure” (step S5), “cooling” (step S6), “development” (step S7) are performed, and “inspection” (step S8) performs macro inspection, overlay measurement, resist pattern Measure the dimensions of

  At this time, in the “first next processing exposure amount setting” (step S1209), based on the exposure amount Xi of one or more substrates in each lot of already processed lots and the dimension measurement value Si of the resist pattern. Then, the exposure amount of the lot to be started is set. With respect to the set value, in the “second next processing exposure dose setting” (step S1210), the PEB process parameters for the substrate currently being processed and the previous substrate, specifically, the baking unit The exposure value set value is further corrected based on the exhaust pressure P (n).

  The “first next processing exposure dose setting” (step S1209) is a feedback system that has been used conventionally, and the algorithm can be expressed as shown in equation (10).

次に、「第２の次処理露光量設定」（ステップＳ１２１０）のアルゴリズムは（１１）式のように表せる。

Next, the algorithm of “second next processing exposure amount setting” (step S1210) can be expressed as the following equation (11).

まず初めに、あらかじめ使用する校正曲線（図５、図６、図７、図１３）を求めた。図１３は前記Ｌ／Ｓパターンの露光量と仕上がり寸法の関係を示したものであり、露光量が増えると仕上がり寸法が細くなることが分かる。（１１）式中の係数、ｊ，ｋ，ｌ，ｍは各々、校正曲線、図５、図６、図７、図１３の傾きである。

First, calibration curves (FIGS. 5, 6, 7, and 13) used in advance were obtained. FIG. 13 shows the relationship between the exposure amount of the L / S pattern and the finished size, and it can be seen that the finished size becomes thinner as the exposure amount increases. Coefficients j, k, l, and m in the equation (11) are calibration curves, and slopes of FIGS. 5, 6, 7, and 13, respectively.

  As described above, according to the fourth embodiment of the present invention, the latest apparatus state is sufficiently reflected, and it is possible to suppress the dimensional variation due to the tracking delay with respect to the apparatus state change. As an example, a comparison result between the feedback system according to the fourth embodiment in the case where the exhaust pressure P (n) is used as a process parameter and the conventional feedback system based on the exposure amount of several lots already processed and the resist finished size is shown. As shown in FIG.

FIG. 14 is a histogram of resist dimensions, where the X-axis represents the resist dimension data section, and the Y-axis represents the frequency in each data section. The resist pattern used for the dimension measurement is an L / S pattern, and the target value of the resist finished dimension is 129 nm. As shown in FIG. 14, in the conventional feedback system, the peak is 127 nm, which is 2 nm narrower than the target dimension, whereas in this feedback system, the target value is 129 nm. Further, the process capability Cpk is 0.82 in the present feedback system compared to 0.77 in the conventional system, and the variation is also improved.
(Embodiment 5)
FIG. 15 shows a basic conceptual diagram of this method. In this embodiment, prior to lot injection, “resist film formation” (step S1), “heating before exposure” (step S2), “cooling” (step S3), “exposure” (step S4), “Heating after exposure” (step S5), “cooling” (step S6), “development” (step S7) are performed, and “inspection” (step S8) performs macro inspection, overlay measurement, resist pattern Measure the dimensions of

  At this time, in "first next processing exposure dose setting" (step S1509), based on the exposure dose Xi of one or more substrates in each lot of already processed lots and the dimension measurement value Si of the resist pattern. Then, the exposure amount of the lot to be started is set. With respect to the set value, in “second next processing exposure amount setting” (step S1510), PEB process parameters for the substrate currently being processed and the previous substrate, specifically, the exhaust of the bake unit. Based on the flow rate L (n), the exposure value setting value is further corrected.

The “first next processing exposure dose setting” (step S1509) is a feedback system that has been used in the past, and is given by the equation (10).
Next, the algorithm of “second next processing exposure amount setting” (step S1510) can be expressed as the following equation (12).

まず初めに、あらかじめ使用する校正曲線（図６、図７、図１３）を求めた。図１３は前記Ｌ／Ｓパターンの露光量と仕上がり寸法の関係を示したものである。（１２）式中の係数、ｋ，ｌ，ｍは各々、校正曲線、図６、図７、図１３の傾きである。

First, calibration curves (FIGS. 6, 7, and 13) to be used in advance were obtained. FIG. 13 shows the relationship between the exposure amount of the L / S pattern and the finished dimensions. The coefficients, k, l, and m in the equation (12) are calibration curves, and the slopes of FIGS. 6, 7, and 13, respectively.

As described above, according to the fifth embodiment of the present invention, the latest apparatus state is sufficiently reflected, and it becomes possible to suppress the dimensional variation due to the tracking delay with respect to the apparatus state change.
(Embodiment 6)
FIG. 16 shows a basic conceptual diagram of this method. In this embodiment, prior to lot injection, “resist film formation” (step S1), “heating before exposure” (step S2), “cooling” (step S3), “exposure” (step S4), “Heating after exposure” (step S5), “cooling” (step S6), “development” (step S7) are performed, and “inspection” (step S8) performs macro inspection, overlay measurement, resist pattern Measure the dimensions of

  At this time, in “first next processing exposure dose setting” (step S1609), based on the exposure dose Xi of one or more substrates in each lot of already processed lots and the dimension measurement value Si of the resist pattern. Then, the exposure amount of the lot to be started is set. With respect to the set value, in the “second next processing exposure dose setting” (step S1610), PEB process parameters for the substrate currently being processed and the previous substrate, specifically, the baking is performed by the baking unit. Based on the substrate surface temperature T (n) during processing, the exposure amount setting value is further corrected.

The “first next processing exposure dose setting” (step S1609) is a feedback system that has been used in the past, and is expressed by equation (10).
Next, the algorithm of “second next processing exposure amount setting” (step S1610) can be expressed as the following equation (13).

まず初めに、あらかじめ使用する校正曲線（図７、図１３）を求めた。図１３は前記Ｌ／Ｓパターンの露光量と仕上がり寸法の関係を示したものである。（１３）式中の係数、ｌ，ｍは各々、校正曲線、図７、図１３の傾きである。

First, calibration curves (FIGS. 7 and 13) to be used in advance were obtained. FIG. 13 shows the relationship between the exposure amount of the L / S pattern and the finished dimensions. In the equation (13), coefficients l and m are the calibration curve and the slopes of FIGS. 7 and 13, respectively.

As described above, according to the sixth embodiment of the present invention, the latest apparatus state is sufficiently reflected, and it is possible to suppress the dimensional variation due to the tracking delay with respect to the apparatus state change.
In the first to sixth embodiments, the exposure amount is changed and feedback is applied to the next processing substrate. However, the PEB temperature, the PEB time, the developer temperature, and the development time are changed. The same effect can be obtained by feeding back to either. The scope of application of the present invention is not limited to chemically amplified resists, but can be applied to conventional novolak resists, and similar effects can be obtained.

  In the resist film processing apparatus and resist pattern forming method of the present invention, the latest apparatus state is sufficiently reflected, dimensional fluctuation due to a delay in tracking the apparatus state change can be suppressed, and the dimensional accuracy of the fine pattern is improved. Therefore, the present invention can be applied to a feedback technique of a semiconductor device manufacturing process.

The flowchart which shows the basic concept of this method concerning Embodiment 1 of this invention Schematic diagram showing a substrate processing apparatus and a substrate processing method according to the first embodiment The figure which shows the result of having compared the dimensional dispersion in Embodiment 1 and the conventional system The figure which showed the relationship between the exhaust pressure of the bake unit which concerns on the same Embodiment 1, and time The figure which showed the relationship (calibration curve) of the exhaust pressure and exhaust flow volume of the bake unit which concerns on the same Embodiment 1. The figure which showed the relationship (calibration curve) of the exhaust_gas | exhaustion flow rate of the bake unit which concerns on the same Embodiment 1, and substrate surface temperature The figure which showed the relationship (calibration curve) of the substrate surface temperature and finishing dimension based on Embodiment 1 The flowchart which shows the basic concept of this method concerning Embodiment 2 of this invention Schematic diagram showing a substrate processing apparatus and a substrate processing method according to the second embodiment The flowchart which shows the basic concept of this method which concerns on Embodiment 3 of this invention. Schematic diagram showing a substrate processing apparatus and a substrate processing method according to the third embodiment The flowchart which shows the basic concept of this method which concerns on Embodiment 4 of this invention. The figure which showed the relationship (calibration curve) of the exposure amount and finishing dimension which concern on the same Embodiment 4. The figure which shows the result of having compared the dimensional dispersion in Embodiment 4 and the conventional system The flowchart which shows the basic concept of this method which concerns on Embodiment 5 of this invention. The flowchart which shows the basic concept of this method concerning Embodiment 6 of this invention Schematic diagram showing a conventional substrate processing apparatus

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Heater 3 Housing | casing 4 Supply piping 5 Clean air 6 Exhaust 7 Exhaust pipe 8 Board support stand 9 Top plate 10 Rectification plate 11 Hot plate 21 Pressure gauge 35 Control valve 36 Flow meter 42 Radiation thermometer 43 Rectification plate 45 Variable flow rate Control valve 49 Pressure gauge

Claims (25)

  In a resist pattern forming method including at least a photosensitive resin coating step, an exposure step, and a development step, a step of acquiring at least two process parameters, and another acquisition process based on the acquisition process parameter 1 And calculating a predicted value of the resist finish dimension of the substrate to be processed according to the parameter 2. In the predicted value calculating step, the predicted value is determined by the relationship between the process parameter 1 and the process parameter 2 measured in advance. A method of forming a resist pattern, characterized by being calculated.   In a resist pattern forming method comprising at least a photosensitive resin coating step, an exposure step, and a development step, acquiring at least one process parameter other than the exposure amount in the exposure step, and based on the acquisition process parameter And calculating a predicted value of the resist finish dimension of the substrate subjected to the exposure process. In the predicted value calculating step, the predicted value is calculated based on the relationship between the process parameter measured in advance and the exposure amount. A resist pattern forming method.   In a resist pattern forming method comprising at least a photosensitive resin coating step, an exposure step, and a development step, acquiring at least one process parameter other than the exposure amount in the exposure step, and based on the acquisition process parameter A step of calculating a predicted value of a resist finished dimension of a substrate subjected to exposure processing, and a step of resetting an exposure amount in a substrate exposure step from a difference between the predicted value and a preset target value, In the predicted value calculation step, the predicted value is calculated based on a relationship between the process parameter measured in advance and an exposure amount.   At least one process parameter is a process parameter of the bake unit, and is one or more of a bake unit exhaust pressure, a bake unit exhaust flow rate, and a substrate surface temperature during substrate heating in the bake unit. The resist pattern forming method according to claim 1, wherein:   A step of measuring a pressure gauge installed in the exhaust pipe of the bake unit, a step of calculating an exhaust flow rate from the pressure of the pressure gauge, a step of calculating a substrate surface temperature during baking using the calculated value of the exhaust flow rate, and A method for measuring a substrate surface temperature, comprising:   The exhaust pipe of the bake unit is branched into two or more, a control valve is provided to at least one of the pipes, a pipe 1 connected with a flow meter and a pipe 2 not connected with a flow meter are provided, and the flow rate when baking the substrate A step of exhausting through the pipe 2 not connected to the meter, a step of switching the control valve when the substrate baking process is completed, and a step of measuring the exhaust flow rate by the pipe 1 connected to the flow meter by the step of switching the control valve; A method for measuring a substrate surface temperature, comprising:   In the bake unit, a rectifying plate using a glass material made of calcium fluoride is disposed above the substrate heat treatment position, a radiation thermometer is disposed above the rectifying plate, and the heat treatment is performed with the radiation thermometer. In a resist pattern forming method comprising a step of measuring the temperature of a substrate, a step of supplying a clean gas at a constant flow rate from a supply pipe installed above the substrate processing position, and an exhaust port provided below the substrate processing position. A step of exhausting and a step of supplying a clean gas for decomposing the resist sublimate from a supply pipe installed above the substrate processing position between the processing of the substrate by the bake unit and the start of the next substrate processing A method of forming a resist pattern, comprising:   8. The resist pattern formation according to claim 7, wherein the clean gas for decomposing the resist sublimate is a gas containing ozone as a main component, and includes at least one step of a water vapor supply step or an ultraviolet light emission step. Method.   In the resist pattern forming method including at least a photosensitive resin coating step, an exposure step, and a development step, the exposure amount of the substrate 2 to be processed next is set from the exposure amount of the substrate 1 already processed and the resist finished dimensions. A step of acquiring at least one process parameter other than the exposure amount in the exposure step, and a step of resetting the exposure amount of the substrate 2 to be processed next in the exposure step of the substrate based on the acquired process parameter In the exposure amount resetting step, the exposure amount to be reset is calculated from the relationship between the process parameter and the resist finish dimension measured in advance and the relationship between the exposure amount and the resist dimension. Resist pattern forming method.   At least one process parameter other than the exposure amount is a process parameter of the bake unit, and any one of the exhaust pressure of the bake unit, the exhaust flow rate of the bake unit, and the substrate surface temperature when the substrate is heated in the bake unit The resist pattern forming method according to claim 9, which is as described above.   In a resist film processing apparatus comprising at least one of a photosensitive resin coating unit, an exposure unit, and a developing unit, a unit that acquires at least two process parameters, and the other based on the acquisition process parameter 1 Means for calculating a predicted value of the resist finish dimension of the substrate to be processed according to the obtained process parameter 2. In the predicted value calculation means, the predicted values are the process parameter 1 and the process parameter 2 measured in advance. The resist film processing apparatus is calculated by the relationship of   In a resist film processing apparatus comprising at least one of a photosensitive resin coating unit, an exposure unit, and a development unit, a unit that acquires at least one process parameter other than an exposure amount in the exposure unit, and the acquisition process Means for calculating a predicted value of the resist finish dimension of the substrate to be subjected to exposure processing based on the parameter. In the predicted value calculation means, the predicted value depends on the relationship between the process parameter measured in advance and the exposure amount. A resist film processing apparatus characterized by being calculated.   In a resist film processing apparatus comprising at least one of a photosensitive resin coating unit, an exposure unit, and a development unit, a unit that acquires at least one process parameter other than an exposure amount in the exposure unit, and the acquisition process Means for calculating a predicted value of the resist finish dimension of the substrate to be exposed based on the parameters, and means for resetting the exposure amount in the substrate exposure means from the difference between the predicted value and a preset target value Thus, in the predicted value calculation means, the predicted value is calculated based on a relationship between the process parameter measured in advance and an exposure amount.   At least one process parameter other than the exposure amount is a process parameter of the bake unit, and any one of the exhaust pressure of the bake unit, the exhaust flow rate of the bake unit, and the substrate surface temperature when the substrate is heated in the bake unit The resist film processing apparatus according to claim 11, which is as described above.   Means for measuring a pressure gauge installed in the exhaust pipe of the bake unit; means for calculating the exhaust flow rate from the pressure of the pressure gauge; and means for calculating the substrate surface temperature during baking using the calculated value of the exhaust flow rate; An apparatus for processing a resist film, comprising:   The exhaust pipe of the bake unit is branched into two or more, a control valve is provided to at least one of the pipes, a pipe 1 connected with a flow meter and a pipe 2 not connected with a flow meter are provided, and the flow rate when baking the substrate Means for exhausting through the pipe 2 not connected to the meter, means for switching the control valve when the substrate baking process is completed, means for measuring the exhaust flow rate by the pipe 1 connected to the flow meter by means of switching the control valve; An apparatus for processing a resist film, comprising:   In the bake unit, substrate temperature measuring means, means for supplying clean gas at a constant flow rate from a supply pipe installed above the substrate processing position, and means for exhausting by installing an exhaust port below the substrate processing position And a resist film processing apparatus.   The substrate temperature measuring means comprises a radiation thermometer, and the rectifying plate installed between the substrate temperature measuring means and the processing substrate uses a glass material made of calcium fluoride, and after processing the substrate with a bake unit, 18. The resist film according to claim 17, further comprising means for supplying a clean gas for decomposing the resist sublimate from a supply pipe installed above the substrate processing position before starting the substrate processing. Processing equipment.   19. The resist film processing apparatus according to claim 18, wherein the clean gas for decomposing the resist sublimate is a gas containing ozone as a main component, and includes at least one of water vapor supply means and ultraviolet light radiation means. .   In a resist film processing apparatus comprising at least one of a photosensitive resin coating means, an exposure means, and a development means, the exposure amount of the substrate 2 to be processed next from the exposure amount of the substrate 1 already processed and the finished resist dimensions. , A means for acquiring at least one process parameter other than the exposure amount in the exposure means, and an exposure amount of the substrate 2 to be processed next in the substrate exposure means based on the acquired process parameters. The exposure amount resetting means calculates the exposure amount to be reset based on the relationship between the process parameter and the resist finish dimension measured in advance and the relationship between the exposure amount and the resist dimension. A resist film processing apparatus.   At least one process parameter other than the exposure amount is a process parameter of the bake unit, and any one of the exhaust pressure of the bake unit, the exhaust flow rate of the bake unit, and the substrate surface temperature when the substrate is heated in the bake unit 21. The resist film processing apparatus according to claim 20, wherein:   In a resist pattern forming method comprising at least a photosensitive resin coating step, an exposure step, and a development step, a step of acquiring at least two or more process parameters, and another acquisition process based on the acquisition process parameter 1 And calculating a predicted value of a resist finish dimension of the substrate to be processed according to parameter 2. In the predicted value calculating step, the predicted value is determined according to a relationship between the process parameter 1 and the process parameter 2 measured in advance. A computer program characterized by being calculated.   Obtaining at least two or more process parameters; and calculating a predicted value of a resist finish dimension of a substrate to be processed by another acquisition process parameter 2 based on the acquisition process parameter 1; In the predicted value calculating step, the predicted value stores a computer program calculated based on the relationship between the process parameter 1 and the process parameter 2 measured in advance.   At least in the program used for the resist pattern forming method including the photosensitive resin coating process, the exposure process, and the development process, the substrate 2 to be processed next from the exposure amount and the resist finished dimension of the substrate 1 already processed. A step of setting an exposure amount, a step of acquiring at least one process parameter other than the exposure amount in the exposure step, and an exposure amount of the substrate 2 to be processed next in the exposure step of the substrate based on the acquired process parameter In the exposure amount resetting step, the exposure amount to be reset is calculated from the relationship between the process parameter measured in advance and the resist finish dimension, and the relationship between the exposure amount and the resist dimension. A computer program characterized by the above.   The step of setting the exposure amount of the substrate 2 to be processed next from the exposure amount of the already processed substrate 1 and the resist finished dimensions, the step of obtaining at least one process parameter other than the exposure amount in the exposure step, A step of resetting the exposure amount of the substrate 2 to be processed next in the exposure process of the substrate based on the acquisition process parameter. In the exposure amount resetting step, the exposure amount to be reset is measured in advance. A computer program storage medium storing a computer program calculated from the relationship between the process parameter and the resist finish size and the relationship between the exposure amount and the resist size.

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