JP2003324092A - Method and device for processing semiconductor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide semiconductor processing method and device capable of performing optimum etching without installing a monitoring device in an etching device. <P>SOLUTION: The semiconductor processing method which comprises forming a thin film on the surface of a semiconductor substrate, applying resist to the formed thin film, exposing and developing the resist, and etching the thin film by using the exposed/developed resist is provided with; a process (1) for measuring the film thickness distribution of the thin film; a process (5) for calculating the etching rate uniformity of each of a plurality of etching processors for etching the semiconductor substrate on which the thin film is formed; and a process (2) for selecting the etching device having the etching rate uniformity suited to the film thickness distribution on the basis of the measured film thickness distribution and the calculated etching rate uniformity. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor processing method and a processing apparatus, and more particularly to a semiconductor processing method and a processing apparatus capable of uniformly processing the entire surface of a wafer.

[0002]

2. Description of the Related Art In recent years, semiconductor devices have been highly integrated,
Along with this, circuit patterns are becoming finer, and the required processing dimensional accuracy is becoming more and more severe.

On the other hand, in a semiconductor processing apparatus, residual products are accumulated inside the apparatus as the wafer is processed, and troubles such as chipping occur in internal parts of the apparatus. If residual products accumulate inside the apparatus and if internal parts of the apparatus are damaged such as chipping, the process performance shifts and the wafer processing result deviates. For example, even in the same etching apparatus, the etching rate uniformity (the variation in etching rate is small) and the etching rate change with the lapse of time. Further, these values (etching rate uniformity and etching rate) have different tendencies for each of the plurality of semiconductor processing devices when the devices are equipped.

That is, as the circuit pattern becomes finer and the processing accuracy becomes stricter, the processing result will vary if only the processing conditions (for example, etching conditions) of the semiconductor processing apparatus are centrally managed. The performance variation of the semiconductor element becomes large and the product yield deteriorates.

In Japanese Patent Laid-Open No. 2001-127036,
A residual film monitor for measuring the film thickness is provided at the edge rinse portion of the peripheral portion of the semiconductor wafer arranged in the semiconductor processing apparatus, and an etching gas is provided so that a predetermined etching rate can be obtained based on the output signal of the residual film monitor. It has been shown to adjust the flow rate of, or adjust the etching time.

Further, Japanese Patent Laid-Open No. 5-190505 discloses that the etching rate uniformity within the wafer surface is measured and the etching amount is controlled based on this measured value.

[0007]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
According to the semiconductor processing device disclosed in Japanese Patent No. 27036,
The etching amount can be corrected in real time in the area where the residual film monitor is installed.

By the way, the etching rate in the etching apparatus is usually high in the central portion of the wafer and lower in the peripheral portion of the wafer. Therefore, when the residual film monitor is arranged on the peripheral portion of the wafer as shown in the above publication, the measured etching rate is lower than the actual value. Therefore, if the etching conditions are corrected based on the monitor value of the residual film monitor installed in the peripheral portion of the wafer, the central portion of the wafer will be excessively etched.

Further, if a residual film monitor is installed on the peripheral portion of the wafer, the flow of the etching gas is disturbed by the monitor, which may further reduce the etching rate of the peripheral portion. Further, this apparatus requires an installation cost of an etching gas flow rate control device or a residual film monitor, etc., which increases equipment cost.

In the etching apparatus disclosed in Japanese Patent Laid-Open No. 5-190505, it is possible to measure the etching rate uniformity within the wafer surface, and the etching amount can be controlled based on this measured value. Becomes However, the emission intensity measuring sensor used as the end point sensor is arranged outside the processing chamber (atmosphere side), and information about the inside of the processing chamber is obtained through the peephole provided in the processing chamber. For this reason, if deposits due to etching adhere to the observation window, a measurement error will increase, and accurate etching control cannot be performed.

The present invention has been made in view of these problems, and an object of the present invention is to provide a semiconductor processing method and a processing apparatus capable of performing optimum etching without installing a monitor device in the etching apparatus. .

[0012]

The present invention adopts the following means in order to solve the above problems.

In a semiconductor processing method, a thin film is formed on a semiconductor substrate, a resist is applied on the formed thin film, exposed and developed, and the thin film is etched by using the exposed and developed resist. Measuring the film thickness distribution of the thin film, calculating the etching rate uniformity of a plurality of etching processing apparatus for etching the semiconductor substrate on which the thin film is formed, the measured film thickness distribution and the calculated etching And a step of selecting an etching apparatus having etching rate uniformity adapted to the film thickness distribution based on the rate uniformity.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a diagram for explaining a semiconductor processing method according to the first embodiment of the present invention, and exemplifies a process of forming holes in a silicon oxide film SiO ₂ on a Si substrate. FIG. 2 is a diagram for explaining a method for obtaining the etching rate uniformity in the etching apparatus, and FIG. 3 is a diagram for explaining the compatibility between the film thickness distribution of the laminated film and the etching rate uniformity.

In FIG. 1, 1 is a silicon substrate, 2 is a silicon oxide film formed on the silicon substrate 1 by CVD (Chemical Vapor Deposition) or the like, and 3 is a photoresist having an opening formed in a region to be processed by etching.

FIG. 1A shows the state of the central portion and the peripheral portion of the wafer when a uniform silicon oxide film is laminated. Further, FIG. 1B shows an etching result when the etching rate uniformity in the outer peripheral portion of the wafer is lower than that in the central portion due to the deviation of the etching rate uniformity due to the generation of deposits accompanying the wafer processing. FIG. That is, as shown in FIG. 1B, etching residue is generated on the outer peripheral portion of the wafer having a low wafer etching rate.

In such a case, as will be described later, the film thickness distribution of the laminated film (silicon oxide film 2) laminated in the pre-etching step is measured in advance, and the etching suitable for the film thickness distribution of the laminated film is performed. An etching device having rate uniformity is selected, and the laminated film is etched using the selected etching device. As a result, as shown in FIG. 1C, it is possible to obtain a uniform etching result with no etching residue on the entire surface of the wafer.

Next, a method for obtaining the etching rate uniformity will be described. FIG. 2 shows a method of obtaining the etching rate uniformity from the usage time of the consumable parts of the apparatus. The relationship between the etching rate and the usage time of the consumable part that affects the etching rate can be obtained by multiple regression analysis. For example, if the number of consumable parts is three (consumable parts A, B, and C), the etching rate uniformity (Y) and the usage time of the consumable parts A, B, and C (X _A ,
The relational expression of (X _B , X _C ) is as follows.

[0019]   Y = δ + αX_A+ ΒX_B+ ΓX_C                  (1) Coefficients δ, α, β, γ in the formula are the use of consumable parts A, B, C
Time (X_A, X_B, X _C) And etching rate uniformity
By performing multiple regression analysis on the measured value of (Y)
You can ask. Coefficients δ, α, β, γ in equation (1)
The method of obtaining is as follows.

That is, etching rate uniformity (Y)
And the consumable parts A at the time of the actual measurement,
Etching rate uniformity (Y) with respect to a plurality of data obtained by combining use times of B and C (X _A , X _B , X _C )
By using the multiple regression equation for the relationship between and the usage time of the consumable parts A, B, and C, the coefficients δ, α, β, and γ in the equation (1) can be obtained.

Next, a method of predicting the etching rate uniformity using the equation (1) will be described. First, in FIG. 2, the predicted value (Y) of the etching rate uniformity at the time point [I] is obtained by substituting the usage time of the consumable parts A, B, C at the time point [I] into the equation (1). Consumable parts A, B, C in the range from time [I] to [II]
By substituting the increment value of the usage time of, the predicted value of the etching rate uniformity can be obtained.

At time point [II], maintenance is performed to replace the consumable part A. At this point, the usage time of the consumable part A is set to 0, and the value of the usage time increment is substituted thereafter. On the other hand, for the remaining consumable parts B and C, the increment value of the cumulative use time from the time point [I] is substituted. This makes it possible to obtain a predicted value of the etching rate uniformity from the time point [II] to the time point [III].

At time point [III], maintenance is performed to replace the consumable parts B and C. At this time, the usage time of the consumable parts B and C is set to 0, and the value of the usage time increment is substituted thereafter. On the other hand, for the consumable part A, the cumulative usage time from the time point [II] is used. In this way, when the parts are replaced by maintenance, the increment value of the usage time is substituted. This makes it possible to obtain a predicted value of etching rate uniformity from time [III] to time [IV].

As shown in FIG. 2, the predicted value and the actually measured value of the etching rate uniformity are almost the same. Therefore, it is possible to accurately predict the etching rate uniformity based on the equation (1).

That is, according to this method, a detector is not required for obtaining the etching rate uniformity, so that the equipment cost can be reduced. Further, it is possible to immediately obtain the etching rate uniformity only by grasping the usage time of the consumable component. Therefore, it becomes easy to select an etching apparatus having an etching rate uniformity suitable for the stack thickness distribution, and as shown in FIG. 1C, it is possible to easily perform an etching process that does not cause etching residue on the entire surface of the wafer. it can.

FIG. 3 is a diagram for explaining the compatibility between the film thickness distribution of the laminated film and the etching rate uniformity.

As described above, the film thickness of the laminated film (silicon oxide film 2) laminated in the pre-etching step varies depending on the state of the apparatus and the process conditions. Figure 3
(A) shows the film thickness distribution in the central portion and the peripheral portion of the wafer in such a case. For example, the film thickness tends to be thick at the central portion of the wafer and thin at the peripheral portion.

FIG. 3 (b) shows the result of etching the laminated film having the distribution shown in FIG. 3 (a) for a time adapted only to the film thickness of the peripheral portion of the wafer. In this case, etching residue is generated in the thick portion of the wafer center portion.

On the other hand, as shown in FIG. 3A, an etching apparatus having a high etching rate at the center of the wafer and a slow etching rate at the periphery of the wafer with respect to a wafer having a thick film at the center of the wafer and a thin film thickness distribution at the peripheral portion ( If an etching apparatus having an etching rate uniformity suitable for the film thickness distribution is selected and the wafer is subjected to an etching process using this etching apparatus, a substantially uniform etching result as shown in FIG. 3C is obtained. It becomes possible.

Next, a second embodiment will be described with reference to FIGS. FIG. 4 is a diagram for explaining a semiconductor processing method according to the second embodiment of the present invention, and FIG. 5 is a sectional view of a semiconductor element. Further, FIG. 6 is a diagram for explaining a method for obtaining the etching rate of the etching apparatus.

As shown in FIG. 4, in the case of mass-producing semiconductor devices, one or a plurality of film forming devices are prepared, and a wafer formed by these film forming devices is subjected to an etching process using a plurality of etching devices. . Therefore, the film thickness of the wafer formed by the film forming apparatus varies, and the etching rates of the etching apparatus also vary. That is, for wafers with such variations in film thickness,
When etching is uniformly performed using an etching apparatus having a variation in etching rate, an etching residue may occur or excessive etching may result.

FIG. 5A shows a state in which a silicon oxide film 2 is formed on a silicon substrate 1 using a certain film forming apparatus and a resist 3 is applied thereon. As shown in FIG. 5B, this wafer is distributed to two etching apparatuses (apparatus A and apparatus B) and subjected to the same etching time etching process. As shown in the figure, if the etching is performed for the same etching time, an etching residue is generated in the etching process by the device B, for example, due to a difference in etching rate caused by the state of the device.

FIG. 6 is a diagram for explaining a method of obtaining the etching rate from the usage time of consumable parts. For example, three the number of consumable parts (consumable parts A, B, C) When the etching rate (Z) and consumable parts A, B, C of the operating time _{(X A, X B, X} C) of the equation Is as follows.

[0034]   Z = d−aX_A-BX_B-CX_C                      (2) Coefficients d, a, b, and c in the formula are consumable parts A, B, and C
Time (X_A, X_B, X _C) (X_A, X_B, X_C) And ed
It can be obtained from the relationship between the measured values of the ching rate (Z). sand
That is, the coefficient is a measured value of the etching rate (Z).
And the use of consumable parts A, B, C at the time of actual measurement.
Usage time (X_A, X_B, X_C) Combined multiple days
The etching rate (Z) and consumable parts A,
By using the multiple regression equation in relation to the usage time of B and C
Can be requested.

Next, a method of predicting the etching rate using the equation (2) will be described. First, the predicted value (Z) of the etching rate at the time point [I] is obtained by substituting the use time of the consumable parts A, B, C at the time point [I] in FIG. 6 into the equation (1). From time [I] to time [II]
In the range up to, the predicted value of the etching rate can be obtained by substituting the increment value of the usage time of the consumable parts A, B, and C. At time point [II], the consumable part A is replaced. At this time, the usage time of the consumable part A is set to 0, and the remaining consumption parts B and C can be substituted with the increments of the usage time to obtain the predicted etching rate at the time point [II]. Also, at the time [I
I] to time point [III] range from consumable parts A, B,
The estimated value of the etching rate is obtained by substituting the increment value of the usage time of C. At time point [III], the consumable parts B and C are replaced. At this time, the use time of the consumable parts B and C is set to 0, and the remaining consumable part A can be substituted with the increment value of the use time to obtain the predicted value of the etching rate at the time point [III]. In this way, the estimated value of the etching rate can be obtained by substituting the usage time of the consumable component in the equation (2).

FIG. 6 is a diagram showing the predicted etching rate and the actually measured etching rate obtained as described above. As shown in the figure, the measured value and the predicted value are almost the same, and the measured value of the etching rate can be predicted almost accurately. That is, according to the present embodiment, the etching rate can be obtained by grasping the usage time of the consumable component. Therefore, by measuring the film thickness of the laminated film in advance, it becomes possible to accurately set the etching time based on the obtained etching rate. As a result, a good etching result as shown in FIG. 5C can be obtained.

Next, a third embodiment will be described with reference to FIG. FIG. 7 is a diagram illustrating a flow of processing when a wafer formed by a plurality of film forming apparatuses is subjected to an etching processing by using a plurality of etching apparatuses. First, in step (1) (previous step), the film thickness and film thickness distribution of the laminated film are measured. Next, in step (2), the measured film thickness distribution is compared with the etching rate uniformity of the apparatus calculated in step (5), incompatible etching apparatuses are excluded, and the remaining compatible apparatuses are replaced. One (for example, the most suitable device) is selected as an etching device that actually performs the processing.

Next, in step (3), the etching time is calculated for the selected etching apparatus based on the film thickness measured in step (1) and the etching rate calculated in step (5). Etching is performed in (4). Next, in step (6), the etching rate uniformity and the etching rate of the etched wafer are measured. In step (5), the current etching rate and etching rate uniformity of the etching apparatus are calculated. In the calculation, the coefficient of the calculation formula (1) or (2) can be corrected by feeding back the etching rate uniformity and the etching rate measured in the step (6).

As described above, according to the embodiment of the present invention, the etching apparatus having the etching rate uniformity suitable for the film thickness distribution is selected based on the film thickness measurement result of the laminated film in the previous step. Since the etching is performed, the etching adapted to the film thickness distribution of the laminated film can be performed, and the etching time adapted to the laminated film thickness can be set. For this reason, it is possible to perform uniform etching processing on the entire surface of the wafer, and it is possible to perform highly accurate processing. Further, the product yield can be improved and the manufacturing cost can be reduced.

[0040]

As described above, according to the present invention, it is possible to provide a semiconductor processing method and a processing apparatus capable of performing optimum etching without installing a monitor device in the etching apparatus.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a semiconductor processing method according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a method of obtaining etching rate uniformity.

FIG. 3 is a diagram for explaining consistency between film thickness distribution and etching rate uniformity.

FIG. 4 is a diagram illustrating a semiconductor processing method according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view of a semiconductor device.

FIG. 6 is a diagram illustrating a method of obtaining an etching rate from a usage time of a consumable component.

FIG. 7 is a diagram illustrating a processing flow when a wafer formed by a plurality of film forming apparatuses is subjected to an etching processing by using a plurality of etching apparatuses.

[Explanation of symbols]

1 Silicon substrate 2 Silicon oxide film 3 photoresist

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yutaka Ito             5-20-1 Kamimizuhonmachi, Kodaira-shi, Tokyo Stock             Ceremony Company within Hitachi Semiconductor Group F-term (reference) 5F004 AA01 CB20

Claims (6)

[Claims] 1. A semiconductor processing method in which a thin film is formed on a semiconductor substrate, a resist is applied on the formed thin film, exposed and developed, and the thin film is etched using the exposed and developed resist. And a step of calculating the etching rate uniformity of a plurality of etching processing devices for etching the semiconductor substrate on which the thin film is formed, the measured film thickness distribution and the calculated etching rate uniformity A method of processing a semiconductor, the step of selecting an etching apparatus having an etching rate uniformity suitable for the film thickness distribution based on the property. 2. A semiconductor processing method in which a thin film is formed on a semiconductor substrate, a resist is applied on the formed thin film, exposed and developed, and the thin film is etched using the exposed and developed resist. A step of measuring the film thickness, a step of calculating an etching rate of an etching processing apparatus for etching the semiconductor substrate on which the thin film is formed, and a step of calculating the etching rate based on the measured film thickness and etching rate. And a step of setting an etching time. 3. A step of measuring a film thickness and a film thickness distribution of a thin film formed on a semiconductor substrate, a step of calculating etching rate uniformity of a plurality of etching processing apparatuses, respectively, A step of selectively removing an etching device having etching rate uniformity that does not match the film thickness distribution based on etching rate uniformity, and an etching device that matches the film thickness based on the measured film thickness and etching rate And a step of setting the etching time of the selected etching apparatus. 4. A semiconductor processing apparatus for forming a thin film on a semiconductor substrate, applying a resist on the formed thin film, exposing and developing the thin film, and etching the thin film using the exposed and developed resist. Means for measuring the film thickness distribution, a means for respectively calculating the etching rate uniformity of a plurality of etching processing devices for etching the semiconductor substrate on which the thin film is formed, and the measured film thickness distribution and etching rate uniformity And a means for selecting an etching apparatus having an etching rate uniformity adapted to the film thickness distribution. 5. A semiconductor processing apparatus in which a thin film is formed on a semiconductor substrate, a resist is applied onto the formed thin film, exposed and developed, and the thin film is etched using the exposed and developed resist. Means for calculating an etching rate of an etching processing apparatus for etching a semiconductor substrate having formed thereon, and means for setting an etching time suitable for the film thickness based on the film thickness and the etching rate of the thin film measured in advance. A semiconductor processing apparatus comprising: 6. A means for measuring a film thickness and a film thickness distribution of a thin film formed on a semiconductor substrate, a means for respectively calculating an etching rate uniformity of a plurality of etching processing apparatuses, and the measured film thickness distribution and etching. A means for selectively removing an etching apparatus having an etching rate uniformity that does not conform to the film thickness distribution based on rate uniformity, and an etching apparatus adapted to the film thickness based on the measured film thickness and etching rate. And a means for setting the etching time of the selected etching apparatus.