JPH09129614A - Manufacture of semiconductor device and semiconductor device manufacturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor device, which reduces a dimensional conversion difference between the lower end of a projected part, which is formed by etching, and a mask and can control the dimensional conversion difference, and a semiconductor device manufacturing device. SOLUTION: A semiconductor wafer 10 with a part to be treated, which is coated with a resist film having a pattern which consists of the remaining part of the resist film and an aperture, is installed in a chamber 21, gas is introduced in the chamber 21 and a dry etching is performed to form respectively a projected part under the lower part of the remaining part of the resist film and a recess part under the lower part of the aperture. The relation between a dimensional conversion difference under a constant gas pressure and a gas flow rate is previously made into a data base to hold stored and the gas flow rate is controlled so that a dimensional conversion difference in a dry etching process becomes equal to a difference between the dimension of the remaining part of the resist film and the finished dimension of the part to be treated. Thereby, an irregularity in the dimension of the resist film is dissolved to make the accuracy of the finished dimension of the part to be etched enhance and an irregularity in the finihsed diemension is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device manufacturing method and a semiconductor device manufacturing apparatus, and more particularly to improvement of a dry etching process.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, dry etching is a processing method mainly used for patterning an object to be processed. A typical patterning process is a photolithography process in which a resist film having a predetermined pattern consisting of a remaining portion and an opening is formed on the object to be processed, and the object below the opening in the resist film is removed. And a dry etching step.

Here, the patterning process of the gate electrode of the MOSFET will be described as an example. As shown in FIG. 18A, a silicon oxide film 7 to be a gate oxide film and a polysilicon film 4 to be a gate electrode are sequentially deposited on a silicon substrate 6, and then a resist is applied thereon to form a resist. The film 5 is formed. Then, a pattern including the remaining portion and the opening is formed on the resist film 5 by a photolithography process. Using the resist film 5 as an etching mask, the polysilicon film 4 is dry-etched.
In FIG. 1A, reference numeral 1 indicates active species, 2 indicates ions, and 3 indicates etching products.

At this time, a concave portion 9 is formed in the polysilicon film below the opening of the resist film 5, and a convex portion 8 is formed in the polysilicon film 4 below the remaining portion of the resist film 5. Also,
The convex portions 8 shown in FIG. 18A include isolated convex portions 8a having a large distance between adjacent convex portions (hereinafter referred to as isolated convex portions) and dense convex portions having a small distance between the convex portions. There is a portion 8b (hereinafter referred to as a dense convex portion), and similarly, each convex portion 8a, 8
There are isolated recesses 9a and dense recesses 9b on both sides of b. Then, by removing all of the polysilicon film 4 below the opening of the resist film 5, each of the protrusions 8a and 8b becomes a gate electrode, whereby the patterning of the gate electrode is completed. Dry etching using a reactive gas as an etchant causes etching products generated by the reaction between the workpiece and the etching gas, the decomposition of the etching gas, or the like on the sidewalls of the protrusions 8a and 8b formed by removing the workpiece. By adhering and blocking the progress of etching in the lateral direction, so-called anisotropic etching can be performed in which only the downward etching action is exerted. By such anisotropic etching, the protrusions 8a and 8b having substantially vertical sidewalls can be formed, and the lateral dimension of the protrusions 8a and 8b substantially matches the lateral dimension of the remaining portion of the resist film 5. Therefore, dry etching is now an indispensable technique in fine processing of semiconductors.

By the way, in recent years, as the miniaturization technology of semiconductor devices has progressed, in the patterning process including the photolithography process and the dry etching process, a dimensional conversion difference (CD gain (CD gain ( Critical Dimension Gain) or CD loss (Critical Dimension Loss)) is a problem. Since the resist film is a workpiece in the photolithography process, the dimension conversion difference is the dimension difference between the reticle pattern and the resist film pattern. The dimensional conversion difference in dry etching is the dimensional difference between the pattern of the resist film and the pattern of the workpiece after dry etching, and specifically, the remaining portion of the resist film and the convex portion formed on the workpiece. Is the lateral dimension difference from the lower end of the. The main factors that cause such a dimensional conversion difference are as follows: 1) Photolithography process: thermal expansion / expansion of the resist material for a pattern during post-baking, and resolution due to a focus shift during exposure. Difference 2) Dry etching step: Side etching progresses due to an increase in the size of the lower end of the convex portion caused by an excessive amount of deposits on the side wall of the convex portion during etching, and an excessive amount of the adhered portion on the side wall of the convex portion. There is a decrease in the size of the lower end of the convex portion caused by the above.

First, the dimensional conversion difference in dry etching will be described. For example, conventional RIE (Reactive
It is known that in the etching of a polysilicon film by Ion Etching), a dimensional conversion difference is likely to occur particularly when HBr gas is used. In particular, in the convex portion 8 shown in FIG. 18A, the isolated convex portion 8a has a larger dimensional conversion difference than the dense convex portion 8b. For example, when patterning a polysilicon film corresponding to a gate length of about 0.5 μm, the isolated protrusion 8a is formed.
Then, as shown in FIG. 18B, the dimension increase amount of the width W2 of the lower end portion of the convex portion 8a with respect to the width W1 of the remaining portion of the resist film is about 0.05 μm, and in the dense convex portion 8b, as shown in FIG.
As shown in FIG. 8 (c), the width W1 of the remaining portion of the resist film 5
The amount of increase in the width W2 of the lower end of the convex portion 8b tends to be about 0.00 μm (that is, 0.005 μm).
smaller than m). Generally, in one semiconductor device, a memory cell array having densely packed transistors and a peripheral circuit having isolated transistors are mixed. Therefore, the size conversion from a mask such as a gate is performed depending on the location of the transistor. The difference will vary. as a result,
For example, since the accuracy of the gate length of the MOSFET in the peripheral circuit is deteriorated, there have been problems in variations in the electrical characteristics of the device and in the yield.

In order to prevent the occurrence of such a large dimensional conversion difference, a process not using HBr is also performed in the dry etching process. For example, a high vacuum etcher (ECR using electron cyclotron resonance, plasma source using helicon wave, etc.) has been introduced, and attempts have been made to reduce the size conversion difference.

On the other hand, in the photolithography technique, as one method of reducing the dimensional conversion difference, there is a shortening of the wavelength of the exposure light source and improvement of the mechanical accuracy of the optical system. At present, the mechanical accuracy has been improved to the extent that processing accuracy equivalent to the wavelength of the exposure light source can be obtained. For example 0.3
For a device with a 5 μm rule, the current standard processing accuracy is about ± 0.04 μm according to i-line exposure.

It is also known that the dimensional conversion difference in the photolithography process also varies depending on the type of pattern. Generally, the dimensional conversion difference in the isolated convex portion is larger than the dimensional conversion difference in the dense convex portion. For the dimension conversion difference that occurs in the photoresist process,
Up to now, the size conversion difference in the photolithography process has been taken into consideration in advance to reduce the size of the reticle pattern for photolithography, thereby eliminating the size conversion difference to some extent.

Furthermore, domestic companies, including the United States, anticipate that the form of future semiconductor manufacturing plants will be the form in which each manufacturing process is controlled by computer management, and attempts are being made to actually realize that form. ing. That is, not only is it necessary to improve the basic characteristics of the work piece in each manufacturing process, but also to manage the individual wafers so as to meet the high-mix low-volume production demanded in the future semiconductor business. Therefore, it is becoming important to reduce the variation in device characteristics by managing the variation in dimensional conversion difference between wafers.
It also controls each process, manages information for each wafer,
Attempts have also been made to manufacture products with uniform performance by suppressing variations in the characteristics of individual products as much as possible.

[0011]

However, the dry etching process and the photolithography process have the following problems.

In the dry etching process, even with a high vacuum etcher or the like, in reality, the dimensional change difference between the isolated convex portions becomes large, and the dimensional conversion difference between the isolated convex portions and the dense convex portions varies. With the current technology, it is difficult to eliminate such variation in dimensional conversion difference. With further miniaturization in the future, it is expected that the variation in the dimensional conversion difference will be one of the main causes of lowering the yield, but as described above, not only in the conventional RIE type etcher but also in the high vacuum etcher. It was very difficult to suppress the variation in dimensional conversion difference.

In order to obtain desired characteristics of the transistor, it is expected that it will be important in the future to freely control the cross-sectional shape of the convex portion formed by etching, such as the gate electrode, but it is formed by dry etching. It was extremely difficult to control the cross-sectional shape of the workpiece.

On the other hand, in the photolithography process, shortening the wavelength of exposure light is approaching its limit, and mechanical precision such as lens precision and component positioning precision is approaching its limit. Therefore, it is currently difficult to significantly improve the processing accuracy. In addition, even if the dimensional conversion difference can be reduced by reducing the reticle pattern or the like as described above, the dimensional conversion difference varies among wafers even in the photolithography process. Although it is recognized that the variation in the dimensional conversion difference occurs, the variation in the dimensional conversion difference between the wafers in the photolithography technology is largely due to mechanical restrictions, and it is difficult to eliminate it fundamentally. Is. On the other hand, with the miniaturization of the device size, the variation in the dimensional conversion difference, which has not been a problem in the past, has become a problem.

Therefore, temporarily, information management is performed at the wafer level, and the dimension conversion difference in the dry etching process is controlled based on the information of the dimension conversion difference for each wafer in the photolithography process to obtain the final dimension as much as possible. If the conversion difference can be made constant between wafers, devices having uniform characteristics can be manufactured. Or,
By reducing the size of the photolithography mask as described above, it is possible to make the finished sizes of the isolated convex parts and the dense convex parts to be about the same.

That is, by keeping the "sum" of the dimension conversion difference in the photolithography process and the dimension conversion difference in the dry etching process constant, the "variation" of the final dimension conversion difference between wafers can be reduced. You can

The present invention has been made in view of the above problems, and an object thereof is a sum of a dimension conversion difference generated in a photolithography process and a dimension conversion difference in a dry etching process, that is, an etching mask forming reticle. The purpose is to control the dimensional conversion difference in the dry etching process so that the dimensional conversion difference between the master pattern and the final pattern of the workpiece is constant.

[0018]

[Means for Solving the Problems]

(Elucidation of Mechanism of Generation of Dimensional Change) First, the mechanism of generation of difference of dimensional conversion clarified in the process of carrying out the invention will be described.

Generally, in the course of dry etching, an etching product is generated due to a reaction between a gas turned into plasma and a decomposed product in the portion to be etched. And
By adhering the etching products to the side portions of the concave portions and appropriately preventing the etching of the side portions from proceeding, proper anisotropic etching is performed. However, in particular, in a portion where the respective convex portions of the etched portion are isolated from each other, the phenomenon that the lower end portion of the convex portion becomes wider than the width of the remaining portion of the etching mask is likely to occur. This is because the distance between each convex portion, that is, the width of the concave portion is large, so that the amount of etching products generated in the concave portions is large, and an excessively large amount of etching products adheres to the side wall, resulting in an excessively disturbing etching effect. Conceivable.
Regarding the mechanism of such variation in the dimensional conversion difference, the points elucidated in the process of the present invention are shown in FIG.
A description will be given with reference to 8 (a) to 8 (c).

As shown in FIG. 18A, generally, in the recess 9, the active species 1 are attached to the polysilicon film 4 which is the portion to be etched, the ions 2 are incident, and the reaction is caused by the kinetic energy. Etching is promoted and progresses. However, the adhesion amount of the etching product 3 generated by etching to the side wall of the convex portion 8 is different between the isolated convex portion 8a and the dense convex portion 8b. That is, since the widths of the isolated concave portions 9a on both sides of the isolated convex portion 8a are large, the area of the region to be etched is also large, and the amount of the etching product 3 attached to the sidewall of the isolated convex portion 8a is large. As a result, the film thickness of the deposit that protects the side wall becomes large, and the effect of disturbing the lateral etching becomes large. Therefore, in the isolated convex portion 8a, as shown in FIG. 18B, the width W2 of the lower end portion of the isolated convex portion 8a is smaller than the size of the remaining portion of the resist film 5, that is, the width W1 of the upper end portion of the isolated convex portion 8a. Also grows. On the other hand, since the width of the dense concave portions 9b between the dense convex portions 8b is narrow, the area of the region to be etched is small, and the amount of etching products attached to the side wall of each dense convex portion 8b is small. as a result,
The effect of disturbing the etching effect in the side wall direction is reduced. Therefore, as shown in FIG. 18 (c), the width W1 of the lower end portion of the dense convex portion 8b is hardly larger than the dimension W1 of the upper end portion. In this way, the isolated convex portion 8a
The dimensional conversion difference is larger than the dimensional conversion difference of the dense convex portions 8b.

It is presumed that the above mechanism causes variations in dimensional conversion difference in devices such as transistors arranged in one chip.

(Means taken by each claim) Focusing on the mechanism of occurrence of the variation in the dimensional change difference, the present invention
By controlling the cross-sectional shape of the convex portion and creating a dimensional conversion difference corresponding to the variation of the etching mask dimension in the photolithography process in the dry etching process, the precision of the finished dimension of the etched portion is improved and the finished dimension is improved. The measures described in claims 1 to 17 are taken in order to eliminate the variation.

According to the method of manufacturing a semiconductor device of the present invention, as described in claim 1, a photolithography step of forming an etching mask on a portion to be etched of a semiconductor wafer and a lateral portion of the remaining portion of the etching mask. A step of measuring the directional dimension, a step of determining the pressure and flow rate of the gas in the reaction chamber based on the measurement result, a step of installing the semiconductor wafer in the reaction chamber, and introducing an etching gas into the reaction chamber. The step of performing dry etching using the gas to form a convex portion below the remaining portion of the etching mask in the etched portion and a concave portion below the opening portion of the etching mask. In the step of performing, the gas pressure and flow rate are set according to the conditions determined in the step of determining the gas pressure and flow rate. By adjusting the discharge ratio of the etching product generated by the dry etching to the outside of the concave portion and the adhesion ratio to the side wall of the convex portion, the lower end of the convex portion and the remaining of the etching mask This is a method of keeping the dimensional conversion difference, which is the lateral dimensional difference between the parts, within a predetermined range.

By controlling the gas pressure and the gas flow rate as in the first aspect, the dimensional conversion difference of the etched portion can be controlled. Although this mechanism has not been clarified, it is presumed to be due to the following actions.

When the pressure of the gas is increased, as shown in FIG.
The mean free path λ of the active species 1 and the etching product 3 shown in (where λ is mainly determined by the etching pressure p).
Is sufficiently smaller than the reaction chamber dimension d (or wafer size) (for example, P = 100 mTorr, d =
20 cm), the flow of gas becomes a region called viscous flow. At this time, the neutral gas acts as a resistance when the etching product tries to adhere to the side wall of the convex portion.
Further, when the gas pressure and the gas flow rate increase, the recess 9
A strong turbulence is generated in the side wall, and the effect of preventing the etching products from adhering to the side wall becomes stronger. When the gas pressure and flow rate increase due to the above two actions, the rate of adhesion of etching products to the sidewalls of the protrusions decreases.

Further, as the gas pressure increases, the weight of the gas per unit volume increases (viscosity increases), so that the transport efficiency of the etching product is increased and the action of discharging the etching product to the upper space is achieved. growing.
That is, the three particles of the etching product, which contribute to the protection of the sidewall of the convex portion, are drawn into the bulk gas flow rate and discharged. In addition, in the reaction chamber, a negative pressure is generated in the space above the bottom of the recess where there is almost no flow and in the static pressure state, and near the side wall, but negative pressure and positive pressure occur when the gas flow rate increases. Since the pressure difference between the two becomes large, discharge of etching products is promoted. That is, when the pressure or flow rate of the gas increases, the discharge ratio of the etching product 3 to the upper space increases due to the above-described effects and the effects due to the generation of strong turbulence.

Further, as a reverse action of the above, the etching product 3 is reduced by reducing the gas pressure or flow rate.
The adhesion ratio of the to the side wall of the convex portion increases.

Therefore, by controlling the pressure and flow rate of the gas, any one of the above-mentioned respective actions is predominant and the respective actions are related to each other, and the discharge ratio of the etching product to the upper space and the side wall. It becomes possible to control the adhesion ratio. Further, it becomes possible to control the dimensional conversion difference in dry etching in consideration of the difference between the dimensions of the etching mask and the final dimension of the etched portion, and the final finish accuracy of the etched portion is improved.

That is, in the photolithography process for forming an etching mask, the difference between the reticle size and the etching mask size, that is, the size conversion difference between wafers includes statistical variations. It generally has a normal distribution. The center value of the normal distribution is
It is an average dimensional conversion difference in the photolithography process generally called. On the other hand, even in the dry etching process, the difference between the resist pattern dimension and the dimension after etching,
That is, the variation in dimensional conversion difference between wafers also includes statistical variation. It is also given with a normal distribution.

Therefore, in the conventional method for manufacturing a semiconductor device in which the photolithography process and the dry etching process are performed without any relation, the average value of the finished dimensions of the etched portion is the dimension conversion of each step. It will deviate from the desired size by the sum of the differences. Further, variations in the finished dimensions of the portions to be etched (variations between wafers) are statistically statistically large variations in which variations in dimensional conversion differences in the photolithography process and the dry etching process are superimposed.

On the other hand, in this method, the dimensional conversion difference in the dry etching process is controlled so as to correct the dimensional conversion difference generated in photolithography, so that the average value of the finished dimensions of the etched portion becomes a desired dimension. Almost match. Further, since the dimensional conversion difference in the dry etching process is controlled so as to eliminate the variation in the dimensions of the etching mask generated in the photolithography process, the variation in the finished dimensions of the etched portion is reduced. The average value of the finished dimensions of the etched portion substantially matches the desired dimension. Further, since the dimensional conversion difference in the dry etching process is controlled so as to eliminate the variation in the dimensions of the etching mask generated in the photolithography process, the variation in the finished dimensions of the etched portion is reduced.

According to a second aspect of the present invention, in the method of manufacturing a semiconductor device according to the first aspect, in the step of performing the dry etching, the pressure of the gas in the reaction chamber is made constant and the gas flow rate is set as an external parameter. As a result, the gas flow rate can be adjusted.

With this method, the flow rate can be controlled more easily and more accurately than the pressure control. Therefore, the gas state in the reaction chamber can be controlled to a state necessary for obtaining the desired finished dimension of the etched portion. It becomes easy to do.

According to a third aspect of the present invention, in the method of manufacturing a semiconductor according to the first or second aspect, the steps of measuring the size of the remaining portion of the etching mask, and determining the pressure and flow rate of the gas. The flow rate of gas in the dry etching step can be controlled for each wafer.

According to this method, it is possible to carry out dry etching in consideration of the history of each wafer while reducing the variation in the finished dimension of the portion to be etched, and it becomes a semiconductor device manufacturing method suitable for high-mix low-volume production.

According to a fourth aspect of the present invention, in the method of manufacturing a semiconductor device according to the second or third aspect, in the step of determining the gas flow rate and the gas pressure, the dimensional conversion difference and the dimensional conversion difference are maintained under a constant gas pressure. The gas flow rate can be approximated by a hyperbolic function to determine the gas flow rate.

According to this method, an appropriate gas flow rate during dry etching can be extremely quickly determined based on the experimental fact that the relationship between the dimensional conversion difference and the gas flow rate can be approximated by a hyperbolic function. Will be smooth. That is, in the process of the present invention, the dimensional conversion difference d and the gas flow rate f are experimentally determined by the following hyperbolic function (d-do) (f-fo) = A (do, fo) under a constant gas pressure. It was experimentally recognized that A and A can be approximated by a constant determined by the gas pressure. Therefore, the size of the remaining portion of the etching mask can be determined by previously grasping the relationship between the material type and gas type of each etched portion and the dimensional conversion difference under a predetermined gas pressure and the gas flow rate by the hyperbolic function. The measurement makes it possible to immediately determine the appropriate gas flow rate in dry etching.

According to a fifth aspect of the present invention, in the method of manufacturing a semiconductor device according to the first aspect, in the step of forming the etching mask, the remaining portion of the etching mask on the isolated convex portion of the portion to be etched is laterally aligned. The etching mask can be formed so that the dimension is smaller than the final finished dimension of the etched portion by a certain value.

According to this method, in the dry etching process, the lateral dimension of the lower end portion of the isolated convex portion of the etched portion is made larger than the lateral dimension of the etching mask by a certain value, so that the finished dimension of the etched portion is increased. Can be placed in the desired dimensions. Therefore, the strict dry etching condition that makes the dimension conversion difference 0 becomes unnecessary,
Management in the manufacturing process of the semiconductor device becomes easy.

According to a sixth aspect of the present invention, in the method of manufacturing a semiconductor device according to the first aspect, the gas pressure in the reaction chamber is 5 mTorr or more and the gas flow rate is 100 sc.
cm or more.

By this method, the viscosity of the gas is increased, and the pressure difference between the side wall of the recess and the upper space and the strength of the turbulence are increased, so that the efficiency of transporting the etching product to the upper space of the recess by the gas is increased. It is enhanced, and the size conversion difference is surely reduced.

According to a seventh aspect of the present invention, in the method of manufacturing a semiconductor device according to the first aspect, at least one of the protrusions in the etched portion has a lateral dimension of a lower end of 0.4 μm or less. Thus, it is possible to form an isolated convex portion in which the lateral dimension of the concave portions on both sides is 1 μm or more.

By this method, the shape of the isolated convex portion having a large dimensional conversion difference is improved.

According to an eighth aspect of the present invention, in the method of manufacturing a semiconductor device according to the first aspect, at least one of the protrusions in the etched portion has a lateral dimension of 1 μm on both sides. As the isolated convex portion as described above, another plurality of the convex portions in the etched portion can be dense convex portions in which the lateral dimension of the concave portions between the convex portions is 1 μm or less.

By this method, the following effects are obtained, and the variation in the dimensional change difference between the isolated convex portions and the dense convex portions in the etched portion is suppressed. That is, when the gas flow velocity is gradually increased, as shown in FIG.
The discharge rate of the etching product 3 shown in 1 also increases, and the residence time of the etching product 3 on the etching surface is shortened. However, the effect of shortening the residence time depends on the etching pattern. In the isolated recesses 9a, the etching products 3 are easily influenced by the flow of gas, and the effect of shortening the stay time is large, whereas in the dense recesses 9b, the recesses 9b have a narrow and recessed shape. In addition, the residence time of the etching product 3 is not easily influenced by the gas flow. For the above reason, the dimension conversion difference of the dense convex portions due to the side wall protection effect of the etching product 3 hardly changes, whereas the isolated convex portions decrease the dimension conversion difference as the gas flow increases. Become. Therefore, variations in dimensional conversion difference are reduced.

According to a ninth aspect of the present invention, in the method of manufacturing a semiconductor device according to the first aspect, the portion to be etched is made of single crystal silicon, polysilicon, Al, Cu, W,
It can be made of a material containing at least one of Ti, Co, Ta, Mo and Ni.

By this method, the shape accuracy of the electrodes and wirings of various devices is improved, and the electrical characteristics are improved.

According to a tenth aspect of the present invention, there is provided a semiconductor device manufacturing apparatus for accommodating a semiconductor wafer in which an etched portion is covered with an etching mask having a pattern of a remaining portion and an opening. And a gas supply means for supplying an etching gas into the reaction chamber,
Plasma generating means for plasma-converting the gas to form a convex portion below the remaining portion of the etching mask of the etched portion while performing dry etching to form a concave portion below the opening portion of the etching mask; A control means for controlling at least one of the pressure and the flow rate of the gas in the reaction chamber so that the dimension conversion difference, which is the lateral dimension difference between the lower end portion and the remaining portion of the etching mask, falls within a predetermined range. ing.

With this configuration, the same operation as that of the above-described claim 1 can be obtained.

As described in claim 11, claim 1
In the semiconductor device manufacturing apparatus of No. 0, the gas supply unit may supply an etching gas having a predetermined pressure into the reaction chamber, and the control unit may change the gas flow rate in the reaction chamber.

With this configuration, it is possible to easily control the dimensional conversion difference, and it is possible to manufacture a semiconductor device in which the finished dimensions of the etched portion are highly accurate.

As described in claim 12, claim 1
In the manufacturing apparatus of a semiconductor device of 0 or 11, the control unit includes an adjusting unit that adjusts at least one of the gas pressure and the gas flow rate, and the same material as that of the portion to be etched in advance before performing dry etching. Storage means for storing a database of the relationship between the dimensional conversion difference measured for already-etched products having the same pattern and the gas pressure and gas flow rate; and the dimensional conversion difference and the gas pressure stored in the storage means. And a gas flow rate calculated by the calculation means for calculating the gas pressure and the gas flow rate for making the dimension of the lower end of the convex portion a desired value by using the relationship between the gas pressure and the gas flow rate. And a transfer means for transferring the gas flow rate condition to the adjusting means.

As described in claim 13, claim 1
In the semiconductor device manufacturing apparatus of No. 2,
The gas flow rate can be determined by approximating the relationship between the dimension conversion difference and the gas flow rate with a hyperbolic function under the condition that the gas pressure is constant.

According to the twelfth or thirteenth aspect, it is possible to quickly determine an appropriate condition of the gas flow rate in the dry etching process, and a semiconductor device with high finished dimension accuracy of the etched portion can be manufactured at low cost. It will be.

As described in claim 14, claim 1
In the semiconductor device manufacturing apparatus of No. 0, the gas supply means may supply a gas containing at least one of a halogen gas and a halide gas.

As described in claim 15, claim 1
In the semiconductor device manufacturing apparatus of No. 4, the halogen gas is any one of hydrogen bromide gas, a mixed gas of hydrogen bromide gas and chlorine gas, and a mixed gas of hydrogen bromide gas and hydrogen chloride gas. be able to.

As described in claim 16, claim 1
In the semiconductor device manufacturing apparatus of No. 0, the etched portion is made of single crystal silicon, polysilicon, Al, Cu,
It can be made of a material containing at least one of W, Ti, Co, Ta, Mo and Ni.

[0058]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Next, a first embodiment of the present invention will be described. FIG. 2 is a sectional view schematically showing the configuration of the medium vacuum region magnetron RIE apparatus according to the first embodiment of the present invention. In FIG. 2, the relationship between the reference numerals and the member names is as follows. Reference numeral 21 is a chamber which is a reaction chamber, 22 is an electromagnetic coil, 10 is a sample such as a semiconductor wafer for LSI, 11 is a high frequency power supply (for example, 13.56 MHz industrial power supply), 12 is a coupling capacitor, 13 is a cathode electrode, and 14 is a An anode electrode, 15 is a turbo molecular pump, 16 is a rotary pump, 17 is a mass flow controller, and 20 is a plasma generation region. The anode electrode 14 is grounded, and the turbo molecular pump 1
5 and the rotary pump 16 exhausts the gas in the chamber 1 from the exhaust port. In addition, the mass flow controller 1
7, the flow rate of gas flowing into the chamber 21 is adjusted.

FIG. 3 is a sectional view of the portion to be etched, in which the polysilicon film 4 which is the portion to be etched is deposited on the silicon substrate 6 via the gate oxide film 7.
The convex portion 8 which is the gate electrode is formed from this polysilicon film. At that time, depending on the location of the transistor,
The isolated convex portion 8a and the dense convex portion 8b are formed.

When performing dry etching, as shown in FIG. 2, the chamber size is set to a chamber radius of about 20.
The gas is filled in the chamber 21 in a viscous region where the pressure is 100 cm and the gas pressure is 100 mTorr. Thereafter, the electric power (215 W) output from the high frequency power supply 11 is transmitted to the cathode electrode 13 via the coupling capacitor 12. Due to the transmitted electric power and the magnetic field generated by the electromagnetic coil 22, the HBr gas, C introduced into the chamber 21
The etching gas consisting of 12 gas is ionized to form the plasma region 20. Then, Br radicals, which are active species dissociated from the HBr gas, and Cl radicals dissociated from Cl2, etch polysilicon under the ion assist. SiB produced by etching
rx (x = 1, 2, 3, 4) adheres to the etching sidewall and prevents side etching.

According to the method of this embodiment, as the total flow rate of the HBr gas and the Cl2 gas increases, the isolated convex portion 8a
The difference in the adhesion amount of the etching product to the side wall between the dense convex portion 8b and the dense convex portion 8b decreases. FIG. 4A shows a gas pressure of 100 mT.
The change of the dimension conversion difference with respect to the total gas flow rate under orr is shown. Under a gas pressure of 100 mTorr,
If the total gas flow rate is 100 sccm or more, the variation in dimensional conversion difference can be reduced to 0.04 μm on average. As a result, compared to the conventional method in which the gas flow rate is about 50 sccm, the variation in dimensional conversion difference can be reduced by half, and the device yield can be improved. FIG. 4 (b)
Shows the change in dimensional conversion difference with respect to the total gas flow rate under a gas pressure of 50 mTorr. Gas pressure is 50
Even under mTorr, it is possible to reduce the variation in the dimensional conversion difference as shown in FIG.

Further, it should be noted that the dimensional conversion difference of the isolated pattern is in a relationship almost inversely proportional to the total gas flow rate. That is, by controlling the gas flow rate, it is possible to control only the dimension conversion difference of the isolated convex portion. If the size of the remaining portion becomes large during patterning of the photoresist film, it is possible to control the gas flow rate and keep the finished size within the standard.

Further, during etching, the cross-sectional shape of each convex portion 8a, 8b can be freely controlled by changing the gas flow rate with time to change the amount of adhesion to the side wall.

In this embodiment, as shown in FIG. 3, only the isolated convex portion 8a has a trapezoidal shape. In this case, the gas flow rate is 75 sccm to 150 sccm during etching.
It has been increased to cm.

(Second Embodiment) Next, a second embodiment will be described.

FIG. 5 is a sectional view schematically showing the structure of an intermediate vacuum RIE apparatus according to the second embodiment of the present invention.
In FIG. 5, the relationship between the reference numerals and the member names is as follows. Reference numeral 21 is a chamber, 22 is a sample such as a semiconductor wafer for LSI, 11 is a high frequency power source (for example, 13.56 MHz industrial power source), 12 is a coupling capacitor, 13 is a cathode electrode, 14 is an anode electrode, 15 is a turbo molecular pump, Reference numeral 16 is a rotary pump, 17 is a mass flow controller, and 20 is a plasma generation region. The anode electrode 14 is grounded, and the turbo molecular pump 15
The gas in the chamber 21 is exhausted from the exhaust port by the rotary pump 16. In addition, the mass flow controller 1
7, the flow rate of gas flowing into the chamber 21 is adjusted. Unlike the medium vacuum region magnetron RIE device according to the first embodiment, the RIE device according to the present embodiment has no electromagnetic coil attached to the side of the chamber 21.

When performing dry etching, as shown in FIG. 5, the chamber size (chamber radius) is about 18 cm,
In the viscous region where the gas pressure region is 180 mTorr,
The chamber 21 is filled with gas. After that, high frequency power 11
The electric power (200 W) output from is transmitted to the cathode electrode 13 via the coupling capacitor 12. Due to the transmitted power, the H introduced in the chamber 21
An etching gas composed of Br gas, HCl gas and O2 gas is ionized to form a plasma region 20. And H
The action of the Br radical, which is an active species dissociated from Br, and the Cl radical, which is dissociated from HCl, to etch polysilicon under the ion assist is basically the same as the action in the first embodiment.

FIG. 6 shows the relationship between the total gas flow rate and the dimensional conversion difference in this embodiment.
It is mTorr. In the present embodiment, as shown in FIG. 6, when the total gas flow rate is 100 sccm or more under a gas pressure of 180 mTorr, the variation in dimensional conversion difference can be reduced to 0.04 μm on average. As a result, it is possible to greatly reduce the variation in the dimensional conversion difference as compared with the conventional method in which the gas flow rate is about 45 sccm.
The device yield can be improved.

Further, as in the case of the first embodiment,
Also in the second embodiment, since the total gas flow rate and the size conversion difference of the isolated convex portion are in a nearly inversely proportional relationship,
By controlling the gas flow rate using this relationship, it is possible to control only the dimension conversion difference of the isolated convex portion.
In addition, the cross-sectional shape of the convex portion can be freely controlled by changing the gas flow rate during etching to change the amount of the etching product attached to the side wall.

(Summary of First and Second Embodiments and Additional Experiment Data) Next, the results of the experiment conducted to obtain data to be added to the data in the first and second embodiments and A summary of the embodiments will be described. The experiment here was performed using the medium vacuum region magnetron RIE apparatus similar to that of the first embodiment.

7 (a) to 7 (c), the gas pressure is constant at 100 mTorr and the gas flow rate is 30, 75, 1.
3 is an SEM photograph showing the cross-sectional shape of an isolated convex portion when changed to 50 sccm. Moreover, FIG.
(C) is an SEM photograph showing the cross-sectional shape of the dense convex portions when the gas pressure is set to a constant value of 100 mTorr and the gas flow rate is set to 30, 75, and 150 sccm. FIG.
As shown in FIGS. 7A to 7C, the gas flow rate is 50
When it is sccm, the size of the lower end portion of the isolated convex portion is larger than the size of the upper end portion, and the dimensional conversion difference is large. On the other hand, when the gas flow rate is 75 sccm, the dimensional conversion difference is considerably small, but it is not zero. And the gas flow rate is 1
At 50 sccm, the size of the lower end of the isolated protrusion is almost equal to the size of the upper end, and the size conversion difference is almost zero.
On the other hand, as shown in FIGS. 8 (a) to 8 (c), the size of the lower end of the dense convex portion is almost equal to the size of the upper end regardless of the gas pressure, and the size conversion difference Is almost 0 regardless of the change in gas flow rate.

9 (a) and 9 (b), the gas flow rate is set to a constant value of 75 sccm, and the gas pressure is set to 20,100.
It is a SEM photograph showing the cross-sectional shape of an isolated convex part when changing to mTorr. As shown in FIGS. 9A and 9B, when the gas pressure is 20 mTorr, the size of the lower end of the isolated convex portion is larger than the size of the upper end, and the size conversion difference is large. On the other hand, the gas pressure is 100 mT
At orrr, the dimensional conversion difference is considerably small.

FIG. 10 is a diagram showing the gas pressure dependence of the dimensional conversion difference of the isolated convex portion under the conditions of the gas flow rate of 75 sccm and the gas flow rate of 150 sccm. As shown in the figure, when the gas flow rate is 75 sccm, by extrapolating this data, the gas pressure is about 13
When it is 0 mTorr or more, the dimensional conversion difference can be suppressed to 0.04 μm or less. When the gas flow rate is 150 sccm, the dimensional conversion difference can be suppressed to 0.04 μm or less when the gas pressure is about 90 mTorr or more.

FIG. 11 is a map showing the relationship between the gas flow rate and the gas pressure in the dry etching method of the present invention and the conventional dry etching method.

The initial dry etching technique has been carried out under the condition of the region Re A shown in the figure, that is, under a relatively low vacuum (high pressure) and under a relatively small gas flow rate. On the other hand, recently, the condition has been shifted to a relatively small gas flow rate under the condition of the region Re B shown in the figure, that is, high vacuum (low pressure). For example, in an ECR type, which is a high vacuum etcher, an attempt has been made to change the exhaust rate to control the amount of active species deposited on the etching side wall (for example, JP-A-5-
259119, 5 ― 267227, 5 ― 267249, 5 ― 275
376). However, although it is considered that the gas flow is not in the viscous region, the size conversion difference in the isolated convex portion has not been eliminated yet, and it is difficult to reduce the variation in the size conversion difference.

On the other hand, in the present invention, the process is performed under the condition of the region Re C shown in the figure, that is, under a relatively low vacuum (high pressure) and under a relatively large gas flow rate. By performing the dry etching under such a condition, it is possible to almost eliminate the dimensional conversion difference even in the isolated convex portion as described above.

From experience, the range of the gas pressure P for reliably producing the effect of the present invention is 5 mTorr or more in the chamber having the diameter d of 30 cm. That is, the pressure P
It is preferable that the product P · d of the chamber diameter d and the chamber diameter d be in the following range.

P · d ≧ 5 (mTorr) × 30 (cm) = 1.5 × 10 ⁻³ (Torr · m) = 1.5 × 10 ⁻³ × 1.33 Pa · m = 1.5 × 10 ^{− 3 × 1.33 (Kg / m)} · sec 2 · m = 0.2Kg / sec 2 the material of the patternable be etched portion according to the present invention, (including doped and undoped) Si, poly-Si, Amorphous Si, GaAs, Ga
N, AlGaAs, InGaAs, AlP, AlAs,
Semiconductor materials such as InP, InAs, InSb, Al, C
u, Cu alloy, Al alloy, W, T, Co, Ta, Mo,
Metallic materials such as Nb, WSix, TiSix, CoSix
Etc. are silicides.

Further, focusing on the gas flow rate dependence of the dimensional conversion difference shown in the data in each of the above-described embodiments, by controlling the gas flow rate, the side wall protection effect of the isolated convex portion is particularly controlled, and the isolated convex portion of the isolated convex portion is controlled. The cross-sectional shape can be controlled freely.

(Third Embodiment) Next, a third embodiment will be described. First, the principle of controlling the dimension conversion difference according to the third embodiment will be described with reference to FIGS. 12 and 13.

FIG. 12 is a diagram for explaining the principle of controlling the dimension conversion difference between the photolithography process and the dry etching process. FIG. 13 shows a member of a semiconductor device on a wafer (eg, polysilicon gate of MOSFET).
9 is a flowchart showing a procedure for forming a gas, showing a procedure for controlling the gas flow rate in the dry etching process by paying attention to the gas flow rate dependency of the dimensional conversion difference shown in each of the above embodiments.

As shown in FIG. 13, first, step ST
1, a photolithography process is performed on each wafer to form a photoresist film (etching mask) having a predetermined pattern. At that time, the dimensional conversion difference (C
In consideration of (D gain), a resist film is formed to be 0.04 μm smaller than the final finished dimension of 0.4 μm (gate length) for the gate electrode to be an isolated convex portion. Note that such a resist film size is obtained by adding the size of the portion corresponding to the isolated convex portion of the reticle pattern to the size conversion difference of 0.04 μm in the dry etching process and the size conversion difference generated in the photolithography process. It can be easily realized by setting the details.

Then, in step ST2, the dimension of the remaining portion of the resist film is measured, and the measurement result is recorded for each wafer. As will be described later, there is a dimensional conversion difference between the reticle pattern and the resist film pattern even in the photolithography process, and further, the dimensional conversion difference varies, so that as shown in FIG. The dimension of the remaining portion of the resist film covering the gate electrode formation region of the MOSFET in the same portion has a predetermined variation.

Next, in step ST3, the measurement data of the resist film dimension is transferred to the control system, and step ST
At 4, the data is made into a database by the computer.

Next, in step ST5, a dry etching process is performed on each wafer. In the dry etching process, the etching condition (gas flow rate) for each wafer is set through the control system based on the dimension measurement result in step ST2. That is, as shown in FIG. 12, when the difference between the size of the remaining portion of the resist film on the isolated convex portion of each wafer and the final gate length of 0.4 μm of the gate electrode is calculated, the difference is calculated in the dry etching process. The desired dimensional conversion difference is obtained. Therefore, by changing the conditions in the dry etching process, specifically, the gas pressure and flow rate for each wafer to control the size conversion difference, the finished size of the polysilicon gate can be more accurately set to the standard value of 0.4 μm. Should be able to fit.

FIG. 14 is a sectional view schematically showing the structure of a magnetron RIE apparatus for performing dry etching. However, in the present embodiment, as in the first embodiment, a photoresist film is applied onto an LSI semiconductor wafer on which polysilicon, which is a gate electrode material, is deposited through element isolation and gate oxidation steps, A processed sample on which an etching mask made of a resist film is formed in the lithography process is used as a processed sample (see FIG. 3). At this time, i-line is used as the light source for exposure.

In FIG. 14, the relationship between reference numerals and member names is as follows. 21 is a chamber which is a reaction chamber, 22
Is an electromagnetic coil, 10 is a semiconductor wafer for LSI, 11 is a high frequency power source (for example, 13.56 MHz industrial power source), 12
Is a coupling capacitor, 13 is a cathode electrode, 14
Is an anode electrode, 15 is a turbo molecular pump, 16 is a rotary pump, 17 is a mass flow controller, and 20 is a plasma generation region. The anode electrode 14 is grounded, and the gas in the chamber 21 is exhausted from the exhaust port by the turbo molecular pump 15 and the rotary pump 16. Further, the mass flow controller 17 adjusts the flow rate of gas flowing into the chamber 21. The configuration up to this point is the same as that of the magnetron RIE device used in the first embodiment.

Here, in the present embodiment, a control computer 18 for changing the gas flow rate by controlling the mass flow controller 17 based on the dimension data in the photolithography process is provided. That is, the control computer 18 causes the data signal Sdata relating to the dimensions of the resist film obtained in the photolithography process.
In response to this, the mass flow controller 17 sends the control signal Scont
Is configured to send.

When dry etching is performed, the gas is filled in the chamber 21 in a viscous region where the gas pressure is 100 mTorr. After that, the power (215 W) output from the high frequency power supply 11 is applied to the coupling capacitor 12
Is transmitted to the cathode electrode 13 via. The transmitted electric power and the magnetic field generated by the electromagnetic coil 22 ionize the etching gas composed of HBr gas and Cl2 gas introduced into the chamber 21 to form the plasma region 20. Then, Br, which is an active species dissociated from the HBr gas,
Radicals and Cl radicals dissociated from Cl2 etch polysilicon under ion assist.

At this time, in this embodiment, the relationship between the dimensional conversion difference and the gas flow rate is approximated by the following hyperbolic function.
FIG. 15 is a diagram of FIG. 4A and FIG. 4B in the first embodiment.
The data of the gas flow rate dependency of the dimensional conversion difference shown in are arranged and shown. As shown in the figure, the dimension conversion difference d
The gas flow rate f can be approximated by a hyperbolic function within a predetermined gas flow rate range. More simply, depending on the gas pressure, it is possible to approximate that the dimension conversion difference d is inversely proportional to the gas flow rate f.

For example, the relationship between the size conversion difference d (μm) and the gas flow rate f (sccm) under a pressure of 100 mTorr can be approximated by d = A / f (A = 4).

By utilizing this relationship, the gas flow rate is controlled so that the final finished size of the polysilicon gate becomes constant between wafers. For example, when the target finish dimension is set to 0.4 μm, in a wafer in which the average dimension of the resist film in the wafer is 0.38 μm, the dimension conversion difference (CD gain) of 0.02 μm in the dry etching process.
The gas flow rate is set so that When the average size of the resist film in the wafer is 0.36 μm, the size conversion difference (CD gain) in the dry etching process is 0.04.
Set to be μm. Below, for each wafer,
By the same procedure as described above, etching is performed by controlling the gas flow rate for each wafer.

16A and 16B show the dimensions of the remaining portion of the resist film on the isolated convex portion in the photolithography process. The figure (a) is the data obtained about the sample which dry-etches by the manufacturing method of this invention, and the figure (b) is the data obtained about the sample processed by the conventional method.

FIGS. 17A and 17B show the dimensions (that is, the finished dimensions of the gate length) of the lower end portion of the finally formed polysilicon gate (isolated convex portion) for each wafer. FIG. 17A shows data when the gas flow rate is controlled by the dry etching method of the present invention, and FIG. 17B shows data when the gas flow rate is controlled by a conventional method.

According to the dry etching method of the present invention,
Since the size conversion difference in the dry etching process is controlled so as to correct the size conversion difference generated in the photolithography, the average value of the finished size of the etched portion (polysilicon gate) substantially matches the desired size. In addition, the dimensional variation in the resist film before dry etching shown in FIG. 16A is 0.00974 μm in terms of standard deviation, and the finished dimension variation of the gate length after dry etching shown in FIG. Is 0.010907 μm in terms of standard deviation. That is, by controlling the gas flow rate, the variation in the finished dimension after dry etching can be reduced to a level that is almost the same as the variation in the photolithography process. That is, since the dimensional conversion difference in the dry etching process is controlled so as to eliminate the variation in the dimensions of the etching mask generated in the photolithography process, the variation in the finished dimensions of the etched portion is reduced.

On the other hand, in the sample prepared by the conventional method, the variation in the dimension of the resist film before dry etching shown in FIG. 16B is converted into a standard deviation of 0.0068.
At 2 μm, the variation of the finished dimension after dry etching shown in FIG. 17B is 0.017 in terms of standard deviation.
29 μm. In other words, as a result of the dimensional variation in the photolithography process being superimposed on the variability in the dry etching process, the dimensional variation of the etched portion is enlarged to about 2.5 times the dimensional variation of the resist film.

On the other hand, by performing the dry etching while controlling the gas flow rate as in this embodiment, the variation in the resist film dimension in the photolithography process is almost eliminated, and the variation in the finished dimension of the etched portion is reduced. Therefore, high processing accuracy can be obtained. Therefore, it is possible to improve the uniformity of device performance and improve the product yield.

It should be noted that no other changes in etching characteristics, changes in etching rate, and charge-up damage due to gas flow rate control were observed.

The gas pressure shown in FIG. 15 is 50 mTo.
Under the condition of rr, the gas flow rate is 75 to 200 sc
In the vicinity of cm, the relationship between the dimension conversion difference d and the gas flow rate f can be approximated by the following hyperbolic functions (d-do) (f-fo) = A. In that case, by substituting the data into the hyperbolic function and using the least squares method or the like, do = 0.0075 (μm) fo = 37.5 (sccm) A = 2.81 is obtained.

In this case, d = do is an asymptote of the hyperbolic function, and therefore at this pressure and at 75 to 200 sccm.
It shows that it is difficult to obtain a dimensional conversion difference of do or less at a gas flow rate in the vicinity. On the other hand, when it is desired to obtain a constant dimensional conversion difference value d1, the residual dimensional conversion difference d can be set even if the gas flow rate is slightly changed by setting the gas pressure so that it is close to d1 and is equal to or less than d1. Does not change, so
A stable dimensional conversion difference can be obtained.

[0101]

According to the first aspect of the present invention, when dry etching is performed in which a convex portion is formed below the remaining portion of the etching mask of the portion to be etched and a concave portion is formed below the opening portion of the etching mask, the etching mask remains. The dimension change of the dry etching process is controlled by adjusting the gas pressure and the flow rate so that the dimension change difference caused in the photolithography can be corrected based on the measurement of the dimension of the portion. It is possible to improve the finished dimensional accuracy of the etched portion and reduce variations.

According to a second aspect, in the dry etching step according to the first aspect, the gas pressure is kept constant,
Since the gas flow rate is controlled, the control can be facilitated.

According to the third aspect of the present invention, in the semiconductor manufacturing method of the first or second aspect, since each step is performed for each wafer, dry etching can be performed in consideration of the history of each wafer. It is possible to provide a semiconductor device manufacturing method suitable for high-mix low-volume production.

According to the fourth aspect, in the second or third aspect, the gas flow rate is determined by approximating the dimensional conversion difference and the gas flow rate with a hyperbolic function under a constant gas pressure. The appropriate gas flow rate during etching can be determined extremely quickly, and thus the progress of the manufacturing process can be facilitated.

According to a fifth aspect, in the first aspect, the lateral dimension of the remaining portion of the etching mask on the isolated convex portion of the etched portion is made smaller than the final finished dimension of the etched portion by a certain value. Since the etching mask is formed, the finished size of the etched portion can be easily set to a desired size.

According to the sixth aspect, in the first aspect, the gas pressure in the reaction chamber is set to 5 mTorr or more and the gas flow rate is set to 100 sccm or more. It is possible to improve, and thus it is possible to surely reduce the dimensional conversion difference.

According to the seventh aspect, in the first aspect, at least one of the protrusions in the etched portion is an isolated protrusion, so that the shape of the isolated protrusion having a large dimensional conversion difference is improved. become.

According to the eighth aspect, in the first aspect, at least one of the convex portions in the etched portion is an isolated convex portion and the other plural portions are dense convex portions. Therefore, the isolated convex portion in the etched portion is formed. It is possible to suppress variation in the dimensional change difference between the portion and the dense convex portion.

According to a ninth aspect, in the first aspect, the portion to be etched is made of single crystal silicon, polysilicon or A.
Since it is made of a material containing at least one of l, Cu, W, Ti, Co, Ta, Mo, and Ni, it is possible to improve the shape accuracy of electrodes and wirings of various devices to improve the electrical characteristics. Can be improved.

According to the tenth aspect, in a semiconductor device manufacturing apparatus for performing dry etching to form a pattern of convex portions and concave portions on a portion to be etched, the dimensional conversion difference is set within a predetermined range. Since the control means for controlling at least one of the pressure and the flow rate of the gas in the reaction chamber is provided, the same effect as that of claim 1 can be exhibited.

According to the eleventh aspect, in the tenth aspect, the gas pressure is kept constant in the reaction chamber, and the gas flow rate is controlled by the control means. Therefore, the control of the dimensional conversion difference is facilitated, and the etching target is etched. It is possible to manufacture a semiconductor device with a high finished dimension accuracy.

According to claim 12 or 13, claim 10
In the above, in the control means, the adjusting means for adjusting the gas flow rate, the storing means for storing the relationship between the pre-measured dimensional conversion difference, the gas pressure and the gas flow rate in a database, and the stored contents are used to properly control. Since it is composed of the calculating means for calculating the gas pressure and the gas flow rate and the transferring means for transferring the calculated condition to the adjusting means, it becomes possible to quickly determine the proper condition of the gas flow rate. Therefore, the manufacturing process can be facilitated.

According to claim 14 or 15, claim 10
In the above, since the gas supply means is configured to supply a gas containing at least one of halogen gas and halide gas, it is possible to obtain high dimensional accuracy while exhibiting a high etching function.

According to a sixteenth aspect, in the tenth aspect, the portion to be etched is made of single crystal silicon, polysilicon, Al, Cu, W, Ti, Co, Ta, Mo and Ni.
Since it is made of a material containing at least one of the above, the same effect as in claim 9 can be exhibited.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a cross-sectional shape of a silicon substrate, an isolated convex portion, and a dense convex portion when performing etching by a dry etching method of the present invention.

FIG. 2 is a cross-sectional view schematically showing the structure of the dry etching apparatus in the first embodiment.

FIG. 3 is a cross-sectional view of a portion to be etched in the first embodiment.

FIG. 4 is a diagram showing data of gas flow rate dependence of a dimensional conversion difference obtained according to the first embodiment.

FIG. 5 is a sectional view schematically showing the structure of a dry etching apparatus according to a second embodiment.

FIG. 6 is a diagram showing data of gas flow rate dependence of a dimensional conversion difference obtained according to the second embodiment.

FIG. 7: Gas pressure of 100 mTorr with additional experiments,
It is a SEM photograph figure which shows the cross-sectional shape of an isolated convex part at the time of gas flow of 30,75,150 sccm, respectively.

FIG. 8: Gas pressure of 100 mTorr with additional experiments,
It is a SEM photograph figure which shows the cross-sectional shape of a dense convex part, respectively when gas flow rates are 30, 75, and 150 sccm.

FIG. 9: Gas pressure of 20,100 mTo according to additional experiment
It is a SEM photograph figure which shows the cross-sectional shape of an isolated convex part at the time of rr and a gas flow rate of 75 sccm, respectively.

FIG. 10 is a diagram showing data on the gas pressure dependence of the dimensional conversion difference obtained by an additional experiment.

FIG. 11 is a map diagram showing the difference in gas pressure and flow rate regions between the dry etching of the present invention and the conventional dry etching.

FIG. 12 is a diagram illustrating a relationship between a dimensional change difference in a photolithography process and a dimensional conversion difference in a dry etching process in the third embodiment.

FIG. 13 is a flowchart showing a procedure of a photolithography process and a dry etching process according to the third embodiment.

FIG. 14 is a cross-sectional view schematically showing the configuration of a dry etching apparatus according to a third embodiment.

FIG. 15 is a characteristic diagram showing a functional relationship between a dimensional conversion difference and a gas flow rate for controlling the gas flow rate according to the third embodiment.

FIG. 16 is data of dimensions of a resist film on each semiconductor wafer sample for performing dry etching according to the third embodiment and dimensions of a resist film on a semiconductor wafer sample for performing dry etching by a conventional method. FIG.

FIG. 17 is a diagram showing data on the finished dimensions of a polysilicon gate obtained by dry etching according to the third embodiment and the finished dimensions of a polysilicon gate obtained by dry etching by a conventional method.

FIG. 18 is a cross-sectional view showing a cross-sectional shape of a silicon substrate, an isolated convex portion, and a dense convex portion when performing etching by a conventional dry etching method.

[Explanation of symbols]

 1 active species 2 ions 3 etching product 4 polysilicon film 5 resist film (etching mask) 6 silicon substrate 7 silicon oxide film 8 convex portion 8a isolated convex portion 8b dense convex portion 9 concave portion 9a isolated concave portion 9b dense concave portion 10 sample 11 high frequency Power supply 12 Coupling capacitor 13 Cathode electrode 14 Anode electrode 15 Turbo molecular pump 16 Rotary pump 17 Mass flow controller 20 Plasma region 21 Chamber (reaction chamber) 22 Electromagnetic coil

Claims (16)

[Claims] 1. A photolithography step of forming an etching mask on a portion to be etched of a semiconductor wafer, a step of measuring a lateral dimension of a remaining portion of the etching mask, and a gas in the reaction chamber based on the measurement result. The step of determining the pressure and the flow rate of the semiconductor wafer, the step of installing the semiconductor wafer in the reaction chamber and introducing an etching gas into the reaction chamber, and the dry etching using the gas to perform the etching in the etched portion. And a step of forming a convex portion below the remaining portion of the mask and a concave portion below the opening portion of the etching mask. In the step of performing the dry etching, it is determined in the step of determining the pressure and flow rate of the gas. By adjusting the gas pressure and flow rate according to the specified conditions, the energy generated by the dry etching is A lateral dimension difference between the lower end of the protrusion and the remaining portion of the etching mask is controlled by controlling the discharge ratio of the etching product to the outside of the recess and the adhesion ratio to the sidewall of the protrusion. A method of manufacturing a semiconductor device, characterized in that a dimensional conversion difference is kept within a predetermined range. 2. The method for manufacturing a semiconductor device according to claim 1, wherein in the step of performing the dry etching, the pressure of the gas in the reaction chamber is made constant, and the gas flow rate is adjusted using the gas flow rate as an external parameter. A method of manufacturing a semiconductor device, comprising: 3. The method of manufacturing a semiconductor according to claim 1, further comprising: a step of measuring a dimension of a remaining portion of the etching mask, a step of determining a pressure and a flow rate of the gas, and a step of the dry etching. A method of manufacturing a semiconductor device, wherein the gas flow rate is controlled for each semiconductor wafer. 4. The method of manufacturing a semiconductor device according to claim 2, wherein in the step of determining the gas flow rate and the gas pressure, the dimensional conversion difference and the gas flow rate are expressed by a hyperbolic function under a constant gas pressure. A method for manufacturing a semiconductor device, wherein the gas flow rate is determined by approximation. 5. The method of manufacturing a semiconductor device according to claim 1, wherein, in the step of forming the etching mask, the lateral dimension of the remaining portion of the etching mask on the isolated convex portion of the etching target portion is set to the final dimension of the etching target portion. A method for manufacturing a semiconductor device, comprising forming an etching mask so as to be smaller than a finished dimension by a constant value. 6. The dry etching method according to claim 1, wherein the gas pressure in the reaction chamber is 5 mTorr or more and the gas flow rate is 100 sccm or more. 7. The dry etching method according to claim 1, wherein at least one of the protrusions in the object to be etched has a lower end portion having a lateral dimension of 0.4 μm or less and lateral portions having concave portions on both sides. Is an isolated convex part having a size of 1 μm or more. 8. The dry etching method according to claim 1, wherein at least one of the projections in the object to be etched is an isolated projection in which the lateral dimension of the recesses on both sides is 1 μm or more. The other plurality of the protrusions in the object to be etched are dense protrusions in which the lateral dimension of the recesses between the protrusions is 1 μm or less. 9. The method of manufacturing a semiconductor device according to claim 1, wherein the portion to be etched is single crystal silicon, polysilicon, Al, Cu, W, Ti, Co, Ta, Mo and Ni.
A method of manufacturing a semiconductor device, comprising a material containing at least one of the above. 10. A dry etching apparatus for forming a pattern of convex portions and concave portions on an object to be etched by using an etching mask having a pattern consisting of a remaining portion and an opening, and storing the object to be etched. And a gas supply means for supplying an etching gas into the reaction chamber, a plasma is generated from the gas to form a convex portion below the remaining portion of the etching mask of the object to be etched. A plasma generating means for performing dry etching so as to form a concave portion below the opening, and a dimension conversion difference which is a lateral dimension difference between the lower end portion of the convex portion and the remaining portion of the etching mask are set within a predetermined range. And a control means for controlling at least one of the pressure and the flow rate of the gas in the reaction chamber. Dry etching apparatus. 11. The semiconductor device manufacturing apparatus according to claim 10, wherein the gas supply unit supplies an etching gas having a predetermined pressure into the reaction chamber, and the control unit includes a gas flow rate in the reaction chamber. An apparatus for manufacturing a semiconductor device, which is characterized in that: 12. The semiconductor device manufacturing apparatus according to claim 10, wherein the control means adjusts at least one of the gas pressure and the gas flow rate, and the dry etching is performed before the dry etching. Storage means for storing the relationship between the dimension conversion difference measured for the already-etched material having the same material and the same pattern as the etched portion and the gas pressure and the gas flow rate in a database, and storing the storage means in the storage means. Calculating means for calculating the gas pressure and the gas flow rate for making the dimension of the lower end of the convex portion a desired value using the relationship between the dimension conversion difference and the gas pressure and the gas flow rate; and the calculating means. And a transfer means for transferring the conditions of the gas pressure and the gas flow rate calculated by the above to the adjusting means. Forming apparatus. 13. The semiconductor device manufacturing apparatus according to claim 12, wherein the arithmetic means approximates the relationship between the dimensional conversion difference and the gas flow rate with a hyperbolic function under the condition that the gas pressure is constant, and calculates the gas flow rate. An apparatus for manufacturing a semiconductor device, characterized in that. 14. The semiconductor device manufacturing apparatus according to claim 10, wherein the gas supply means supplies a gas containing at least one of a halogen gas and a halide gas. Semiconductor device manufacturing equipment. 15. The semiconductor device manufacturing apparatus according to claim 14, wherein the halogen gas is hydrogen bromide gas, a mixed gas of hydrogen bromide gas and chlorine gas, or a mixed gas of hydrogen bromide gas and hydrogen chloride gas. An apparatus for manufacturing a semiconductor device, wherein the manufacturing apparatus is a semiconductor device. 16. The apparatus for manufacturing a semiconductor device according to claim 10, wherein the portion to be etched is single crystal silicon, polysilicon, Al, Cu, W, Ti, Co, Ta, Mo and Ni.
A semiconductor device manufacturing apparatus comprising a material containing at least one of the above.