JP4952338B2 - Semiconductor device manufacturing method, etching apparatus, and storage medium - Google Patents

Description

    The present invention provides a method for manufacturing a semiconductor device for etching a film to be etched using an etching gas on a substrate having a photoresist mask laminated on the film to be etched, an etching apparatus for performing the method, and the method. The present invention relates to a storage medium including a computer program for performing the above.

Semiconductor devices tend to be highly integrated year by year, and resist materials and exposure techniques have improved to meet the miniaturization of patterns formed on wafers, and the opening size of resist masks has become considerably smaller. On the other hand, as pattern miniaturization progresses, stricter accuracy is required for the finished dimensions of the hole (contact hole and via hole) diameter and the trench (wiring groove) width.
For this reason, as described in Patent Document 1, for example, the relationship between the type and supply amount of the reaction gas and the etching rate is obtained in advance, and the supply amount is controlled according to the etching depth, for example. Has been devised.

  By the way, in photolithography, the finish of a development pattern is determined by a number of conditions such as resist coating conditions, post-coating heat treatment conditions, exposure conditions, post-exposure heating conditions, and development processing conditions. In practice, it is impossible to make the opening size constant, and variations in the opening size are inevitable. For this reason, the finished dimension after etching the film to be etched varies due to this variation.

  For example, if the finished dimensions of the recesses after etching deviate from the design value, the device characteristics cannot be obtained as designed, and if it exceeds the design value, adjacent via holes and contact holes may be close to each other. There is also a concern of short-circuiting between holes. Recently, a multilayer resist structure has been developed, but there is a problem that the film collapses when the holes of the organic film in the lowermost layer of the multilayer resist come close to each other.

Therefore, even if the etching process conditions according to the target etching finish are pursued, there is a problem that it is affected by variations in processing in the mask pattern forming process, which is the previous process, and the pattern miniaturization is prevented. It is one of the factors.
JP 2003-282536 A (Claims 1 and 7)

  The present invention has been made in order to solve such a problem, and an object of the present invention is to form an etching film when etching the film to be etched on a substrate in which a photoresist mask is laminated on the film to be etched. It is another object of the present invention to provide a technique capable of suppressing variations in the finished dimensions of the recessed portions.

A method of manufacturing a semiconductor device of the present invention is a method of carrying a substrate in which a photoresist mask is stacked on an etching target film into a processing container and etching the etching target film with an etching gas.
With respect to the first substrate, and the flow ratio of a plurality of etching gas for performing etching, Ru obtains the correlation between the opening dimension of the concave portion of the film to be etched which is formed by the parameter value and an etching process,
Measuring the opening size of the photoresist mask before etching for the second substrate to be etched ;
The difference between the opening size of the photoresist mask measured in the step and the opening size of the photoresist mask on the first substrate before etching when the correlation is obtained, and the target of the opening size of the recess of the film to be etched Determining a flow ratio value of a plurality of etching gases based on the value and the correlation, wherein the opening size of the recess of the etching target film of the second substrate is a target value;
For the flow rate ratio of the plurality of etching gases, a step of etching the etching target film of the second substrate using the value determined in the step;
It is characterized by including.
According to another aspect of the present invention, there is provided a semiconductor device manufacturing method comprising: a substrate; a film to be etched formed on the substrate; and a photoresist mask having an opening formed on the film. A method of manufacturing a semiconductor device by performing an etching process on the film to form a recess in the film,
For one process parameter for the etching process, a first correlation between the parameter value and the opening size of the recess when the etching process is performed using a mask having the opening having a reference opening size The process of seeking
Obtaining a second correlation between the opening dimension change amount of the mask and the opening dimension change amount of the recess;
Measuring the actual opening size of the mask in the object to be processed, the etching process;
Based on the difference between the actual opening size of the mask and the reference opening size, the target opening size of the recess to be formed, and the first and second correlations, the target opening size of the recess is obtained. Determining a target parameter value for the process parameter;
Performing an etching process on the object to be processed such that the process parameter becomes the target parameter value,
The etching process is performed using at least two kinds of etching gas, and the process parameter is a flow rate ratio of the etching gas.
Here, the opening size of the concave portion refers to the diameter of a hole such as a contact hole or a via hole or the width of a groove.

The etching apparatus of the present invention is an etching apparatus for carrying a substrate having a photoresist mask laminated on an etching target film into a processing container and etching the etching target film with an etching gas.
For the flow rate ratio of a plurality of etching gases for performing etching, the correlation between the value of the flow ratio of the plurality of etching gases and the opening size of the recess of the film to be etched formed by etching the first substrate is stored. Storage unit,
The measured value of the opening dimension of the photoresist mask measured before the etching on the second substrate to be etched and the opening of the photoresist mask before the etching of the first substrate when the correlation is obtained. and dimensions, the correlation in the storage unit, and a target value of the opening dimension of the concave portion of the film to be etched, on the basis of the opening size of the recess of the film to be etched of said second substrate of said plurality comprising a target value Means for determining the value of the flow ratio of the etching gas ;
Means for performing etching on the second substrate using a value determined by the means for the flow ratio of the plurality of etching gases and using a preset parameter value for the other process parameters. It is characterized by that.

The flow rate ratio of the plurality of etching gases is, for example, a flow rate ratio between an etching gas for narrowing the opening size of the recess and an etching gas for widening the opening size of the recess, and the etching target film and the photoresist mask An antireflection film containing silicon, oxygen and nitrogen is provided between them, and the plurality of etching gases may be CF4 and C4F8 for etching the antireflection film.

  The storage medium of the present invention is a computer that operates on a computer and is used in a method of manufacturing a semiconductor device using an etching gas by carrying a substrate in which a photoresist mask is laminated on an etching target film into a processing container. A storage medium storing a program, wherein the computer program includes steps for carrying out the semiconductor device manufacturing method described above.

  According to the present invention, even if the opening size of the recess of the photoresist mask varies in the pre-process of the etching process, the parameter value of one process parameter for performing etching and the film to be etched formed by etching are obtained. The one process parameter is controlled so that the opening size of the recessed portion of the film to be etched becomes a target value for each substrate based on the correlation with the opening size of the recessed portion of the photoresist mask and the opening size of the recessed portion of the photoresist mask. Since the etching is performed, the variation in the opening size of the recess of the film to be etched can be suppressed, and as a result, the reduction in yield can be suppressed.

  First, an outline of this embodiment will be described. In this embodiment, a laminated structure in which a photoresist film (hereinafter referred to as a resist film) that is a photoresist mask including an oval pattern is laminated on an etching target film that is an interlayer insulating film. The processing of a wafer which is a substrate provided with a surface portion thereof is an object. Then, the control unit receives the information on the opening size of the pattern from the pre-etching process, and the resist is controlled so that the opening size of the hole formed by etching the etching target film along the resist pattern becomes the target value. The process parameter of the etching process, for example, the flow ratio of two kinds of etching gases is to be controlled based on the opening size of the pattern.

  Next, the structure of the surface of the wafer and the etching process performed on the wafer will be briefly described with reference to FIG. As shown in FIG. 1A, on the surface of the wafer W are an SiO2 (silicon oxide) film 12, an inorganic film 13, an SiO2 film 14, an amorphous carbon (AC) film 15, and an antireflection film on the Si film 11. A SiON (silicon oxynitride) film 16 and a resist film 17 are laminated in this order, and each film thickness of the SiO 2 film 12, the inorganic film 13, the SiO 2 film 14, the AC film 15, the SiON film 16, and the resist film 17 is, for example, These are 500 nm, 90 nm, 100 nm, 500 nm, 65 nm, and 250 nm, respectively. In the figure, reference numeral 18 denotes a resist pattern which is an opening formed in the resist film 17, and is opened in an elliptical shape when viewed from above. In this example, the SiO2 film 12 is formed using TEOS (tetraethoxysilane) as a film forming raw material, and contains B (boron) and P (phosphorus). The inorganic film 13 is a silicon nitride film (SiN film). In this example, the inorganic film 13 contains a larger amount of Si than the content determined by the stoichiometric ratio.

  As an etching process of this embodiment, first, in step 1, the SiON film 16 is etched along the resist pattern 18 to form holes, and in step 2, the AC film is formed along the shape of the holes using the SiON film 16 as a mask. 15 is etched (FIG. 1B). At this time, the resist film 17 is also removed.

  Subsequently, in step 3, the SiO2 film 14 and the SiN film 13 are etched along the hole shape, and then in step 4, the SiO2 film 12 is etched along the hole shape (FIG. 1C). When the etching in step 3 and step 4 is performed, the SiON film 16 is removed. Thereafter, in step 5, the remaining AC film 15 is removed by ashing (FIG. 1D). By performing a series of steps in this manner, a hole 19 that is a recess is formed so as to penetrate the SiO 2 film 14, the SiN film 13, and the SiO 2 film 12 that are to be etched.

  Next, an overall configuration example of an etching apparatus that performs the above-described series of etching processes so as to control the opening dimension (CD) of the hole 19 will be described with reference to FIG. The etching apparatus 2 includes a processing chamber 21 that forms a processing container, and a mounting table 22 for a wafer W is provided in the processing chamber 21. In the figure, reference numeral 23 denotes a gas shower head, which supplies each processing gas supplied from each gas supply source, which will be described later, toward the wafer W on the mounting table 22 in a shower shape. The gas shower head 23 also serves as an upper electrode to which a high-frequency power is applied for plasmaizing (activating) the processing gas. The mounting table 22 includes a lower electrode to which high-frequency power is applied. The lower electrode generates a bias potential in the wafer W and draws ionic species toward the wafer W, thereby improving the perpendicularity of the etching shape. Have a role.

In the figure, reference numeral 31 denotes a gas introduction pipe having one end connected to the gas shower head 23. The other end of the gas introduction pipe 31 is branched into a large number when it goes upstream to constitute branch pipes 32A to 32F. 32A~32F end are each treatment chamber is fed into the 21 treated gas reservoir was C4F8 gas source 35A, CF4 gas supply source 35B, CO gas source 35C, _{O 2} (oxygen) gas supply source 35D, The CHF3 gas supply source 35E and the Ar gas 35F supply source are connected to each other.

  In the branch pipes 32A to 32F, valves 33A to 33F and flow rate control units 34A to 34F are sequentially provided upstream. Each valve and each flow rate control unit constitute a gas supply system 36. The gas supply system 36 is connected to the control unit 4, and controls supply / disconnection and flow rate of each processing gas from each gas supply source 35 </ b> A to 35 </ b> F by a control signal from the control unit 4.

  Next, the configuration of the control unit 4 will be described. The control unit 4 is configured by a computer, for example, and includes an input screen for arbitrarily setting, for example, a target value of the opening size of the hole 19 and other processing parameters when performing etching. In the figure, reference numeral 41 denotes a bus. Connected to the bus 41 are a program storage unit 42 (hereinafter, for convenience, a code “42” is assigned to the stored program), a CPU 43 for performing various operations, and a storage unit 51. Is input information about the opening size of the bottom of the resist pattern 18 of the resist film 17 collected in the previous step of the etching process. The program 42 has a set of steps so that the above-described series of etching processes can be performed, and a control signal is sent to each part of the etching apparatus 2 based on these steps. Further, in the etching process, the program 42 analyzes the opening dimension of the resist pattern 18 from the input information of the resist pattern 18 and, as will be described later, based on the analysis result and the information in the storage unit 51, a series of After the etching process, the flow rate ratio of the processing gas used in step 1 is calculated so that the opening dimension of the hole 19 becomes the set target value.

  The program 42 is stored in a storage medium constituted by, for example, a flexible disk, a compact disk, an MO (magneto-optical disk), etc., and is installed in the control unit 4.

  The graph shown in FIG. 3A is stored in the storage unit 51. In this graph, Step 1 of the above-described series of etching processes is performed on the wafer W using CF4 gas and C4F8 gas, and subsequently. Steps 2 to 5 show the relationship between the flow rates of the CF4 gas and C4F8 gas and the opening size (CD) of the hole 19 when the hole 19 is formed. FIG. 3 (b) shows specific numerical values of the respective plots from which the graph is created. The resist pattern 18 of the resist film 17 before being etched with respect to the wafer W has an elliptical shape, and the minor axis and major axis at the bottom of the pattern are 140 nm and 220 nm, respectively. On the other hand, the hole 19 formed in the SiO2 film 14 is also elliptical, and the short diameter and long diameter at the top thereof are assigned as A and B, respectively, and the dimensions (finished dimensions) are described for each flow rate of CF4 gas. The horizontal axis of the graph represents the flow rate of CF4 gas when the total flow rate of CF4 gas and C4F8 gas is 200 sccm, but the etching finish depends on the flow rate ratio of both gases, not the total flow rate value. Therefore, it can be said that the flow rate ratio of CF4 gas to CF4 gas and C4F8 gas is expressed.

  Approximation lines X and Y are created by connecting the plots in each of A and B. When the minor axis (major axis) of the bottom of the resist pattern 18 is 140 nm (220 nm), the flow rate of CF4 gas and the C4F8 gas When the flow rate, that is, the flow rate ratio between the two is changed along the horizontal axis of the graph, the minor axis (major axis) of the hole 19 changes according to the approximate line X (approximate line Y). Note that the correlation coefficients of the approximate straight lines X and Y are each 0.99 or more. Then, when the hole 19 having a short diameter (finished dimension) of α nm is to be formed when the short diameter of the resist pattern 18 taken in by the control unit 4 is β nm, the flow rates of CF 4 gas and C 4 F 8 gas necessary for that purpose are formed. The value deviates from the flow rate value required when the minor axis is 140 nm by an amount corresponding to the difference between 140 nm and β nm. Therefore, the flow rate value of the CF4 gas necessary for obtaining the target value αnm of the minor axis of the hole 19 takes the value obtained by the arithmetic expression αnm + (140 nm−βnm) on the vertical axis of the graph, The horizontal axis value corresponds to the value.

  Next, the configuration of the above-described etching apparatus 2 will be described in detail with reference to FIG. The surface of the processing chamber 21 is anodized, and for example, the inside of the processing chamber 21 is a sealed space. The mounting table 22 is provided at the center of the bottom surface in the processing chamber 21, and the upper electrode (gas shower head) 23 is provided above the mounting table 22 so as to face the mounting table 22.

  The processing chamber 21 is electrically grounded, and an exhaust device 63 is connected to an exhaust port 62 on the bottom surface of the processing chamber 21 via a pipe 64. The exhaust device 63 includes a pressure adjusting unit (not shown). When the pressure adjusting unit receives a control signal from the control unit 4, the exhaust device 63 evacuates the processing chamber 21 in accordance with the signal. Thus, the inside of the processing chamber 21 is configured to be maintained at a desired degree of vacuum. In FIG. 5, reference numeral 65 denotes a wafer W transfer port formed on the side wall of the processing chamber 21, and this transfer port 65 is configured to be opened and closed by a gate valve 66.

  The mounting table 22 includes a lower electrode 71 and a support body 72 that supports the lower electrode 71 from below, and is disposed on the bottom surface of the processing chamber 21 via an insulating member 73. An electrostatic chuck 74 is provided on the mounting table 22, and the wafer W is mounted on the mounting table 22 via the electrostatic chuck 74. The electrostatic chuck 74 is made of an insulating material, and an electrode plate 76 connected to a high voltage DC power source 75 is provided inside the electrostatic chuck 74. The electrostatic chuck 74 is provided with a through hole 74 a for releasing a backside gas, which will be described later, to the upper portion of the electrostatic chuck 74.

  A refrigerant flow path 77 through which a predetermined refrigerant (for example, a conventionally known fluorine-based fluid, water, etc.) passes is formed in the mounting table 22, and the mounting table 22 is cooled by the refrigerant flowing through the refrigerant flow path 77. The wafer W mounted on the mounting table 22 is cooled to a desired temperature via the mounting table 22. A temperature sensor (not shown) is mounted on the lower electrode 71, and the temperature of the wafer W on the lower electrode 71 is constantly monitored via the temperature sensor.

  Further, a gas flow path 78 for supplying a heat conductive gas such as He (helium) gas as a backside gas is formed inside the mounting table 22, and the gas flow path 78 is provided at a plurality of locations on the upper surface of the mounting table 22. It is open at. These openings communicate with the through hole 74a provided in the electrostatic chuck 74. When a backside gas is supplied to the gas flow path 78, the backside gas passes through the through hole 74a. To the top of The backside gas is evenly diffused over the entire gap between the electrostatic chuck 74 and the wafer W placed on the electrostatic chuck 74, so that the thermal conductivity in the gap is increased.

  The lower electrode 71 is grounded via a high pass filter (HPF) 7a, and a high frequency power source 71a of 13.56 MHz, for example, is connected to the lower electrode 71 via a matching unit 71b. A focus ring 79 is disposed on the outer peripheral edge of the lower electrode 71 so as to surround the electrostatic chuck 74, and the plasma is focused on the wafer W on the mounting table 22 through the focus ring 79 when the plasma is generated. Has been.

  The upper electrode (gas shower head) 23 is formed in a hollow shape, and a plurality of holes 81 for distributing and supplying the processing gas into the processing chamber 21 are formed on the lower surface thereof, for example, so as to be evenly distributed. A gas introduction pipe 31 is formed at the center of the upper surface of the upper electrode 23, and the gas introduction pipe 31 penetrates the center of the upper surface of the processing chamber 21 through an insulating member 67.

  The upper electrode 23 is grounded via a low pass filter (LPF) 87, and a high frequency power source 8a having a frequency higher than that of the high frequency power source 71a, for example, 60 MHz, is connected to the upper electrode 23 via a matching unit 8b. ing. Although not shown, the high frequency power supplies 8a and 71a are connected to the control unit 4, and the power supplied from each high frequency power supply to each electrode is controlled in accordance with a control signal sent from the control unit 4. The upper electrode 23, the lower electrode 71, and the high-frequency power sources 71a and 8a correspond to means for generating plasma by converting the processing gas into plasma.

  In such a plasma processing apparatus 2, the processing chamber 21 is evacuated by the exhaust device 63 and a predetermined processing gas is supplied from the processing gas supply sources 35 </ b> A to 35 </ b> F into the processing chamber 21 at a predetermined flow rate. When high frequency power is applied to the upper electrode 23 and the lower electrode 71, the processing gas is turned into plasma (activated) in the processing chamber 21 by the high frequency power applied to the upper electrode 23 and applied to the lower electrode 71. A bias potential is generated in the wafer W by the high-frequency power, and a predetermined etching process is performed on the wafer W placed on the mounting table 22 so as to enhance the perpendicularity of the etching shape by drawing ion species to the wafer W side. It is configured to be applied.

Subsequently, an example of gas types and process parameters for performing each step of the etching process described above using the etching apparatus 2 will be described.
(Step 1: Etching of SiON film 16)
Pressure in the processing chamber 21: 100 mT (0.13 × 10 ² Pa)
Power supplied to the upper electrode (gas shower head) 23: 1000 W
Power supplied to the lower electrode 71: 400W
Processing time: 90s

  In Step 1, CF4 gas and C4F8 gas are used as described above, and the total flow rate of these CF4 gas and C4F8 gas is set to 200 sccm. As the flow rate ratio of CF4 gas increases, the perpendicularity of the etching shape of the SiON film 16 increases, and the aperture diameter of the SiON film 16 increases. As a result, the SiON film 16 is formed as a mask in a later step. The opening size of the hole 19 is increased. When the C4F8 gas is contained in the CF4 gas, the etching of the SiON film 16 progresses because the CF4 gas proceeds while the polymer component due to the active species of the C4F8 gas is deposited on the surface of the SiON film 16. The verticality of the is reduced. Therefore, the larger the flow rate ratio of C4F8 gas to the flow rate ratio of CF4 gas, the smaller the diameter of the opening of the SiON film 16, and as a result, the opening size of the hole 19 becomes smaller. The flow rates of these CF4 gas and C4F8 gas are determined by the graph stored in the storage unit 51 and the opening size of the resist pattern 18 as described above.

(Step 2: etching of AC film 15)
Pressure in the processing chamber 21: 10 mT (0.13 × 10 Pa)
CO gas flow rate: 39sccm
O2 gas flow rate: 25sccm
Power supplied to the upper electrode 23: 1000 W
Power supplied to the lower electrode 71: 400W
Processing time: 60s

(Step 3: Etching of SiO2 film 14 and SiN film 15)
Pressure in the processing chamber 21: 30 mT (0.39 × 10 Pa)
CF4 gas flow rate: 30sccm
CHF3 gas flow rate: 70sccm
Ar gas flow rate: 1200sccm
O2 gas flow rate: 20 sccm
Power supplied to the upper electrode 23: 500W
Power supplied to the lower electrode 71: 2000 W
Processing time: 90s

(Step 4: Etching of SiO2 film 12)
Pressure in the processing chamber 21: 30 mT (0.39 × 10 Pa)
C4F8 gas flow rate: 30sccm
Ar gas flow rate: 1200sccm
O2 gas flow rate: 20 sccm
Power supplied to the upper electrode 23: 1500 W
Power supplied to the lower electrode 71: 2000 W
Processing time: 90s

(Step 5: Ashing of AC film 15)
Pressure in the processing chamber 21: 60 mT (0.79 × 10 Pa)
O2 gas flow rate: 500sccm
Power supplied to the upper electrode 23: 1000 W
Power supplied to the lower electrode 71: 400W
Processing time: 60s

  Next, how the flow rates of CF4 gas and C4F8 gas are determined in step 1 will be described. First, for example, before being carried into the etching apparatus 2, information on the opening size of the resist pattern 18 of the wafer W is taken into the control unit 4, and the control unit 4 determines the size of the minor axis of the bottom of the resist pattern 18 from the taken-in information. Β (nm) is analyzed, and an arithmetic expression αnm + (140 nm−βnm) is executed from the value of β and the target value α (nm) of the minor axis of the hole 19 input in advance to the control unit 4. Find the computed value. Then, in the graph of the storage unit 51, the value on the horizontal axis corresponding to the calculated value is obtained on the vertical axis, and this value is determined as the flow rate of the CF4 gas.

  For example, it is assumed that the minor axis β of the resist pattern 18 of the wafer W before the etching process is 145 nm and the target value α of the minor axis of the hole 19 of the SiO 2 film 12 is set to 135 nm. In FIG. 6, when the flow rate of the CF4 gas is read out for the plot P1 corresponding to the target value 135 nm of the finished dimension, it is about 181 sccm. However, since this graph is created when the minor axis of the resist pattern 18 is 140 nm, if this flow rate value is used, the finished dimension becomes larger than the target value. Therefore, P1 is shifted along the graph by 145 nm-140 nm = 5 mm and moved to P2, and the flow rate value of CF4 gas at P2 is read. Thereby, the flow rate value becomes 178 nm. This mathematical operation is the same as executing the calculation formula 135 nm + (140 nm-145 nm), plotting the calculated value of 130 nm on the vertical axis, and reading the corresponding value.

By the way, in determining the flow rate of CF ₄ gas in the above embodiment, the opening size of the hole 19 changes according to the opening size of the resist pattern 18, the amount of change in the opening size of the hole 19, and the opening size of the resist pattern 18. , And the control unit 4 performs the above calculation on the premise that there is a proportional relationship Δα = Δβ of the proportional constant 1, and determines the flow rate of the CF ₄ gas in step 1. Yes.

If the proportional relationship of proportionality constant 1 does not hold between Δβ and Δα, and the correlation of Δα = kΔβ holds, for example, the above-described proportional relationship Δα = kΔβ is stored in the storage unit 51 of the control unit 4. In this case, in determining the flow rate of the CF ₄ gas, first, the opening dimension β of the resist pattern 18 and the dimension (140 nm) of the resist pattern 18 serving as a reference when the graph of the control unit 4 is created. Δβ = 140−β is calculated and the above proportional relationship Δα = kΔβ is applied to this to calculate Δα = k (140−β). Subsequently, the target value α of the minor axis of the hole 19 is calculated. Δα is added and an arithmetic expression α + Δα = α + k (140−β) (nm) is executed to determine the calculated value, and in the graph of the storage unit 51, the vertical axis indicates the horizontal axis value corresponding to the calculated value. The calculated value is the flow rate of CF ₄ gas. May be determined.

  According to the above-described embodiment, even if the opening size of the resist pattern 18 varies for each wafer W in the previous process of the etching process, the flow rate ratio between the CF 4 gas and the C 4 F 8 gas stored in the storage unit 51 and the hole 19 Using the correlation with the opening size, the flow rate ratio of CF4 gas and C4F8 gas corresponding to the opening size of the resist pattern 18 on the wafer W is determined, and thereby the finished size (opening size) of the hole 19 is set to the target value. can do. Accordingly, it is possible to suppress a reduction in yield due to variations in the opening size of the resist pattern 18.

  In the above-described embodiment, the opening size of the hole 19 is controlled by changing the flow rates of CF4 gas and C4F8 gas. However, instead of the gas flow rate, process pressure, process temperature, and power supplied to the upper electrode 23 are controlled. Similarly, the relationship between the parameter value of one process condition selected from the above and the opening size of the hole 19 may be obtained in the same manner, and the parameter value may be determined according to the opening size of the resist pattern 18.

  The antireflection film is not limited to the SiON film 16 and may be a film made of, for example, SiN (silicon nitride).

  As described above, the method of taking the opening dimension of the resist pattern 18 of the wafer W into the control unit 4 may be taken in, for example, online from the previous process, or the wafer W may be carried into the inspection apparatus before performing the etching process. Here, the opening dimension may be measured, and the measured value may be taken into the control unit 4.

  7 (a) and 7 (b) show the results of measuring the short diameter opening dimension of the resist pattern 18 and the short diameter opening dimension of the hole 19 by changing the gas flow rate in the same manner as in FIG. Here, the results are shown for the case where the short diameter opening dimension of the resist pattern 18 is 120 nm and the case where the short diameter opening dimension of the resist pattern 18 shown in FIG. 3 is 140 nm. In the table of FIG. 7A, the difference Δβ in the minor axis opening dimension of each resist pattern 18 and the change Δα in the minor axis opening dimension α of the hole 19 when the gas flow rate values are the same are described. ing. In the graph of FIG. 7B, the straight line X described above and the approximate straight line X2 when β = 120 nm are shown. From the above table, Δα is substantially constant when each gas flow rate is the same, Δα = Δβ, and the correlation coefficient of the approximate straight line X2 is 0.99 or more. From the results shown in FIG. 3 and FIG. 7, at least when the measured value of the resist pattern 18 is in the range of about 120 nm to 140 nm and the opening size of the hole 19 is in the range of about 100 to 135 nm, the proportionality constant is approximately 1 as described above. It can be seen that it is appropriate to assume that the relationship Δα = Δβ exists.

It is explanatory drawing of the etching process which concerns on this invention. 1 is an overall configuration diagram of an etching apparatus for carrying out the present invention. It is the graph which showed the relationship between the opening dimension of the hole taken in by the control part, and gas flow rate. It is the top view which showed the shape of the said hole. It is a vertical side view which shows an example of the said etching apparatus. It is explanatory drawing which showed the procedure which calculates | requires the magnitude | size of the aperture of a hole with the said graph from the magnitude | size of the opening part of a resist pattern. It is the table | surface and graph which showed the relationship between the opening dimension of a resist pattern and a hole, and gas flow rate.

Explanation of symbols

16 SiON film 17 Resist film 18 Resist pattern 19 Hole 2 Etching device 36 Gas supply system 4 Control unit 42 Program 51 Storage unit

Claims (7)

In a method of carrying a substrate in which a photoresist mask is laminated on a film to be etched into a processing container and etching the film to be etched with an etching gas,
With respect to the first substrate, and the flow ratio of a plurality of etching gas for performing etching, Ru obtains the correlation between the opening dimension of the concave portion of the film to be etched which is formed by the parameter value and an etching process,
Measuring the opening size of the photoresist mask before etching for the second substrate to be etched ;
The difference between the opening size of the photoresist mask measured in the step and the opening size of the photoresist mask on the first substrate before etching when the correlation is obtained, and the target of the opening size of the recess of the film to be etched Determining a flow ratio value of a plurality of etching gases based on the value and the correlation, wherein the opening size of the recess of the etching target film of the second substrate is a target value;
For the flow rate ratio of the plurality of etching gases, a step of etching the etching target film of the second substrate using the value determined in the step;
A method for manufacturing a semiconductor device, comprising:   An etching process is performed on an object to be processed that includes a substrate, a film to be etched formed on the substrate, and a photoresist mask having an opening formed on the film, and a recess is formed in the film. A method of manufacturing a semiconductor device to be formed,
  For one process parameter for the etching process, a first correlation between a parameter value and an opening dimension of the recess when the etching process is performed using a mask having the opening having a reference opening dimension The process of seeking relationships;
  Obtaining a second correlation between the opening dimension change amount of the mask and the opening dimension change amount of the recess;
  Measuring the actual opening size of the mask in the object to be processed, the etching process;
  Based on the difference between the actual opening size of the mask and the reference opening size, the target opening size of the recess to be formed, and the first and second correlations, the target opening size of the recess is obtained. Determining a target parameter value for the process parameter;
  Performing an etching process on the object to be processed such that the process parameter becomes the target parameter value,
  A method of manufacturing a semiconductor device, wherein the etching process is performed using at least two kinds of etching gases, and the process parameter is a flow rate ratio of the etching gases.   The flow rate ratio of the plurality of etching gases is a flow rate ratio of an etching gas for narrowing the opening size of the recess and an etching gas for widening the opening size of the recess. The manufacturing method of the semiconductor device of description. Claims between the film to be etched and the photoresist mask silicon, provided antireflection film containing oxygen and nitrogen, the plurality of etching gas, which is a CF4 and C4F8 for etching the anti-reflection film A method for manufacturing a semiconductor device according to any one of 1 to 3 . In an etching apparatus for carrying a substrate in which a photoresist mask is laminated on a film to be etched into a processing container and etching the film to be etched with an etching gas,
For the flow rate ratio of a plurality of etching gases for performing etching, the correlation between the value of the flow ratio of the plurality of etching gases and the opening size of the recess of the film to be etched formed by etching the first substrate is stored. Storage unit,
The measured value of the opening dimension of the photoresist mask measured before the etching on the second substrate to be etched and the opening of the photoresist mask before the etching of the first substrate when the correlation is obtained. and dimensions, the correlation in the storage unit, and a target value of the opening dimension of the concave portion of the film to be etched, on the basis of the opening size of the recess of the film to be etched of said second substrate of said plurality comprising a target value Means for determining the value of the flow ratio of the etching gas ;
Means for performing etching on the second substrate using a value determined by the means for the flow ratio of the plurality of etching gases and using a preset parameter value for the other process parameters. An etching apparatus characterized by that. Claims between the film to be etched and the photoresist mask silicon, provided antireflection film containing oxygen and nitrogen, the plurality of etching gas, which is a CF4 and C4F8 for etching the anti-reflection film A method for manufacturing a semiconductor device according to any one of 1 to 3 . A storage medium storing a computer program that runs on a computer and is used in a method of manufacturing a semiconductor device using an etching gas by carrying a substrate in which a photoresist mask is laminated on a film to be etched into a processing container. There,
5. A storage medium characterized in that the computer program includes steps so as to implement the method for manufacturing a semiconductor device according to any one of claims 1 to 4 .

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