JP2948501B2 - Coating method of coating liquid in semiconductor device manufacturing process - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for applying a coating liquid such as SOG or photoresist on a semiconductor substrate in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art In a semiconductor device such as a semiconductor integrated circuit, a step on a device surface accompanying a wiring is becoming steep as a device is highly integrated. Therefore,
As one of means for reducing the steep step, SOG (Sp
in On Glass) There is a method using a coating film. This is a technique in which a step is embedded by applying a heat treatment after applying an SOG liquid on a semiconductor substrate. Since the SOG at the time of application is a liquid having a relatively low viscosity, the SOG can sufficiently spread to the bottom of the step and the step can be reduced. On the other hand, when a heat treatment is performed on the SOG liquid, a dehydration condensation reaction of silanol groups in the SOG occurs and SOG becomes SiO ₂ , so that the SOG film becomes a thin film applicable to a semiconductor integrated circuit as an insulating film.

When the SOG liquid is applied onto the semiconductor substrate, the SOG liquid is dropped on the center of the semiconductor substrate, and then the excess SOG liquid is scattered by centrifugal force when the semiconductor substrate is rotated at a high speed. At the same time, a so-called spin coating (spin coating) method of uniformly spreading the SOG liquid on the substrate is generally used. The spin coating method is the most general coating method in terms of stability and uniformity among various coating methods such as spray coating and dip coating. FIG. 6 shows an example of a spin coating method of an inorganic SOG solution (SOG includes inorganic SOG and organic SOG).

First, as shown in FIG. 6A, a semiconductor substrate W is set on a spinner 1 and 1-3 c
About S c liquid s is dropped. Then, as shown in FIG. 6B, the semiconductor substrate W is
By rotating at a rotational speed of about pm, the SOG liquid s
Is spread over the semiconductor substrate W flat. At this time, the SOG liquid s naturally adheres to the back surface side of the semiconductor substrate W due to the influence of the SOG liquid s wrapping around due to the surface tension of the SOG liquid s at the time of low rotation immediately after the start of rotation or splashing from the periphery of the scattered SOG liquid s. Therefore, after this spreading step, FIG.
As shown in FIG.
By discharging the cleaning liquid r from the back surface cleaning nozzle 2 toward the back surface of the semiconductor substrate W while rotating at a rotation speed of about m, excess SOG adhered to the back surface of the semiconductor substrate W
Wash off the liquid s.

[0005]

FIG. 6D shows the state of the peripheral portion of the semiconductor substrate W on which the SOG film s has been formed by the above procedure. Although the thickness of the SOG film s is almost uniform over most of the surface of the semiconductor substrate W,
In the peripheral portion of the surface, particularly in a region of about 0.5 mm from the outermost periphery, the SOG liquid s rises due to the influence of the surface tension of the SOG liquid s, and the thickness of the SOG film s is increased only in this region. However, when the subsequent process is continued in such a state where the thickness of the SOG film s at the peripheral portion is large, thermal contraction of the SOG film s occurs in the heat treatment process, and the internal stress at that time is reduced by the thick portion. Concentration, the SOG film s may be broken. Then, the scattered fragments of the SOG film s become foreign matters in the manufacturing process, and cause a reduction in the yield of the device.

Therefore, as a means for solving this problem,
In the procedure of the spin coating method, a method of cooling only the peripheral portion of the semiconductor substrate when rotating the semiconductor substrate to spread the SOG liquid on the substrate has been introduced. In this method, the surface tension of only the SOG liquid existing in the cooling area is changed by cooling the peripheral portion of the substrate, and the thickness of the SOG film in this area is controlled so as not to increase.
However, when this method is adopted, the thickness of the SOG film on the surface side of the peripheral portion of the semiconductor substrate is surely suppressed from being increased, but the SOG film having a large thickness still remains on the end surface of the semiconductor substrate. This method cannot be a sufficient countermeasure for preventing the generation of foreign matters because it causes the generation of foreign matters.

Further, the peripheral portion of the semiconductor substrate is more likely to cause foreign matters than the central portion, such as contact with a jig or the like during handling. Therefore, when the demand for improving the yield is more severe, the above-described thick SOG is used especially at the peripheral portion of the substrate to prevent the generation of foreign matter.
It is necessary to reliably remove not only the film but also the thin SOG film, and it has been desired to provide a means for more reliably removing the SOG film at the periphery of the semiconductor substrate.

In the above, the case of the SOG liquid has been described as an example. However, during the manufacturing process of a semiconductor device, a coating liquid using a similar spin coating method is used as a photoresist and as an agent for improving the adhesion of the photoresist. There are organic silanes such as polysilazane and the like, and these coating solutions have the same problem as the SOG solution.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method of applying a coating liquid in a semiconductor device manufacturing process which does not cause foreign matter to be generated in a subsequent process and lowers the yield of a device. The purpose is to provide.

[0010]

According to a first aspect of the present invention, there is provided a method of applying a coating solution in a semiconductor device manufacturing process, wherein the coating solution is dropped on a surface of a semiconductor substrate. In the method of applying a coating liquid in a semiconductor device manufacturing process in which the coating liquid is spread over the semiconductor substrate by rotating the semiconductor substrate, the semiconductor substrate is rotated while cooling a peripheral portion of the semiconductor substrate onto which the coating liquid has been dropped. Thereby, the coating liquid is applied to the semiconductor substrate so that a thin portion of the coating liquid is formed on a peripheral portion of the surface of the semiconductor substrate in comparison with a film thickness of the coating liquid at a portion other than the peripheral portion. A spreading step of applying a cleaning liquid to the back surface of the semiconductor substrate while rotating the semiconductor substrate at a rotation speed at which the cleaning liquid wraps around the front surface of the semiconductor substrate. And a, is characterized in that it has a border step of removing the coating solution in the range from the outermost periphery of the semiconductor substrate surface to an arbitrary position of the thin portion.

According to a second aspect of the present invention, in the method of manufacturing a semiconductor device, the periphery of the semiconductor substrate is cooled by supplying a cleaning liquid to the rear side periphery of the semiconductor substrate. It is assumed that.

According to a third aspect of the present invention, in the method of applying a coating liquid in the semiconductor device manufacturing process, the rotation speed of the semiconductor substrate in the edging process is set lower than the rotation speed of the semiconductor substrate in the spreading process. It is characterized by the following.

According to a fourth aspect of the present invention, there is provided a method of applying a coating solution in a semiconductor device manufacturing process, wherein
G or a photoresist, and the number of rotations of the semiconductor substrate in the edging step is set to 600 to 1
It is characterized in that it is set in the range of 200 rpm.

According to a fifth aspect of the present invention, in the method of manufacturing a semiconductor device, the coating liquid is spread over the semiconductor substrate by rotating the semiconductor substrate onto which the coating liquid has been dropped. In the method for applying a coating liquid in the above, a spread step of spreading the coating liquid on the semiconductor substrate by rotating the semiconductor substrate onto which the coating liquid has been dropped, and removing the coating liquid on the peripheral portion of the semiconductor substrate surface with a cleaning liquid And the rimping step is to supply the cleaning liquid to the back surface of the semiconductor substrate while rotating the semiconductor substrate at a rotation speed at which the cleaning liquid wraps around the surface of the semiconductor substrate,
A first cleaning step of cleaning and removing a coating liquid on a peripheral portion of the semiconductor substrate surface; and a cleaning liquid removing step of removing a cleaning liquid that wraps around the surface of the semiconductor substrate and stays in the peripheral portion by the first cleaning step. Cleaning and removal of the coating solution from the back surface of the semiconductor substrate to an arbitrary position on the peripheral edge of the surface by rotating the semiconductor substrate at a rotation speed at which the cleaning solution wraps around the surface of the semiconductor substrate while supplying the cleaning solution to the back surface of the semiconductor substrate. And a second cleaning step of repeating the step once or a plurality of times.

According to a sixth aspect of the present invention, in the method of applying a coating liquid in the semiconductor device manufacturing process, the cleaning liquid is removed by stopping the supply of the cleaning liquid to the back surface of the semiconductor substrate in the cleaning liquid removing step. It is characterized by the following.

According to a seventh aspect of the present invention, in the method of applying a coating solution in the semiconductor device manufacturing process, the semiconductor substrate is rotated at a higher rotation speed than the first cleaning process in the cleaning solution removing process. The cleaning liquid is removed by the following method.

The method of applying a coating solution in a semiconductor device manufacturing process according to claim 8 is characterized in that in the second cleaning step,
The cleaning and removal of the coating liquid are performed by rotating the semiconductor substrate at a rotation speed higher than the rotation speed of the first cleaning step and lower than the rotation speed of the cleaning liquid removal step. Things.

According to a ninth aspect of the present invention, in the method of manufacturing a semiconductor device, the coating liquid is spread on the semiconductor substrate by rotating the semiconductor substrate onto which the coating liquid has been dropped. In the method for applying a coating liquid, the semiconductor substrate onto which the coating liquid has been dropped is cooled, and the semiconductor substrate is rotated in a cooled state. A spreading step of spreading the coating liquid on the semiconductor substrate so that a thin portion is formed as compared with the film thickness of the coating liquid in a portion other than the portion, and the cleaning liquid while supplying the cleaning liquid to the back surface of the semiconductor substrate. By rotating the semiconductor substrate at a number of rotations around the surface of the semiconductor substrate, any of the thin portion from the outermost periphery of the semiconductor substrate surface And a rimping step of removing the coating liquid in the range up to the position, the rimping step is to supply the cleaning liquid to the back surface of the semiconductor substrate while the cleaning liquid wraps around the surface of the semiconductor substrate at the number of revolutions. A first step of removing a coating solution in a range from the outermost periphery of the semiconductor substrate surface to an arbitrary position of the thin portion by rotating the first portion;
A cleaning step, a cleaning liquid removing step of removing a cleaning liquid that wraps around the surface of the semiconductor substrate by the first cleaning step and stays at the peripheral portion, and while supplying the cleaning liquid to the back surface of the semiconductor substrate, the cleaning liquid removes the cleaning liquid from the semiconductor substrate. A second cleaning step of repeating one or more times cleaning and removal of the coating liquid from the back surface of the semiconductor substrate to an arbitrary position on the peripheral edge of the surface by rotating the semiconductor substrate at a rotation speed around the front surface. It is assumed that.

[0019]

In the method of applying a coating liquid in the semiconductor device manufacturing process according to the first aspect, first, in the spreading step, when the semiconductor substrate on which the coating liquid has been dropped is rotated, the periphery thereof is cooled. The coating liquid is spread on the semiconductor substrate, and a portion where the thickness of the coating liquid is thinner than other portions is formed on the peripheral portion of the semiconductor substrate surface. Next, in the trimming step, when the semiconductor substrate is rotated while supplying the cleaning liquid to the back surface of the semiconductor substrate to flow the cleaning liquid to the surface of the semiconductor substrate, the coating liquid on the surface of the semiconductor substrate is removed. At this time, the coating liquid is removed within the range from the outermost periphery of the semiconductor substrate to the thin portion formed in the spread process, so that the film is formed on the periphery of the semiconductor substrate and the edge of the coating liquid at the end face. It does not remain thick.

In the method of applying a coating liquid in the semiconductor device manufacturing process according to the second aspect, the cooling of the semiconductor substrate in the spreading step is performed by supplying a cleaning liquid to the back side of the semiconductor substrate. Thereafter, the trimming process is performed only by adjusting the number of revolutions while the cleaning liquid is supplied.

According to a third aspect of the present invention, in the method of applying a coating liquid in the semiconductor device manufacturing process, the semiconductor substrate is rotated at a high speed in order to spread the coating liquid on the semiconductor substrate in the spread step. In the process, the number of revolutions is set lower than that in the spread process, so that the cleaning liquid flows from the back side to the front side of the semiconductor substrate using the surface energy of the cleaning liquid.

According to a fourth aspect of the present invention, in the method of applying a coating solution in the semiconductor device manufacturing process, SOG or photoresist is used as the coating solution, and the number of revolutions of the semiconductor substrate in the trimming process is set to 600 to 120.
By setting the rotation speed within the range of 0 rpm, the removal of the coating liquid can be reduced to a range where the thickness of the coating liquid at the periphery of the semiconductor substrate is small.

According to a fifth aspect of the present invention, in the method for applying a coating liquid in a semiconductor device manufacturing process, the coating liquid is spread on a semiconductor substrate in a spread step.
In the edging step, the coating liquid on the periphery of the substrate surface is removed by the cleaning liquid. At that time, the cleaning liquid containing the coating liquid stays at the peripheral portion of the substrate due to the cleaning liquid flowing around the substrate surface in the first cleaning step, but the cleaning liquid is removed in the next cleaning liquid removing step, so that the coating liquid in the cleaning liquid is removed. Is also removed at the same time. In this state, in the second cleaning step, cleaning and removal of the coating liquid by the cleaning liquid are repeated once or more than once, whereby the coating liquid on the peripheral portion of the substrate surface is sufficiently removed. Therefore, the cleaning efficiency is improved and the coating liquid can be more sufficiently removed as compared with the case where the coating liquid is continuously washed and removed with the cleaning liquid, so that the coating liquid is prevented from remaining in a thin film state. Can be.

In the method of applying a coating liquid in a semiconductor device manufacturing process according to a sixth aspect of the present invention, the cleaning liquid removing step is performed by stopping the supply of the cleaning liquid to the back surface of the semiconductor substrate. The cleaning liquid is sufficiently dried, and the cleaning liquid is efficiently removed.

In the method of applying a coating liquid in the semiconductor device manufacturing process according to the present invention, the cleaning liquid removing step is performed by rotating the semiconductor at a higher rotation number than the rotation number in the first cleaning step. In the washing liquid removing step, the washing liquid that has flowed to the surface side in the first washing step is removed by being shaken off by centrifugal force.

In the method of applying a coating liquid in a semiconductor device manufacturing process according to the present invention, the second cleaning step is higher than the rotation number in the first cleaning step and is higher than the rotation number in the cleaning liquid removing step. Since the cleaning is performed by rotating the semiconductor substrate at a low rotation speed, in the second cleaning step, the cleaning liquid flows around the substrate surface without being shaken off by the centrifugal force as in the cleaning liquid removing step. In addition, the second cleaning process is more difficult than the first cleaning process.
Since the centrifugal force in the cleaning step is larger, the wraparound distance of the cleaning liquid in the second cleaning step is smaller than the wraparound distance in the first cleaning step, so that the cleaning liquid in the second cleaning step does not contact the coating liquid, The cleaning efficiency increases.

According to a ninth aspect of the present invention, in the method of applying a coating solution in a semiconductor device manufacturing process, when the coating solution is spread in the spreading step, the periphery of the coating solution may be cooled. Then, a portion where the film thickness of the coating liquid is reduced is formed. Then, in the first cleaning step of the edging step, the range for removing the coating solution is set within the range from the outermost periphery of the semiconductor substrate to the thin portion formed in the spreading step, thereby forming the peripheral portion of the semiconductor substrate or the like. The film does not remain in a thick state at the edge of the coating liquid on the end face. Further, the coating liquid is removed together with the cleaning liquid in the cleaning liquid removing step, and then the coating liquid is washed and removed again in the second cleaning step, whereby the coating liquid on the peripheral portion of the substrate surface is sufficiently removed. Does not remain even in the state of a thin film.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2 are views showing a method of applying a coating solution in a semiconductor device manufacturing process according to the first embodiment. In the coating method of the present embodiment, a coating solution having a large thickness remains on the periphery of a semiconductor substrate. It is to try to prevent. In this embodiment, a case where inorganic SOG is used as an example of a coating solution will be described.

First, as shown in FIG. 1A, a wafer W (semiconductor substrate) having a diameter of 6 inches is set on the spinner 1, and about 1 to 3 cc of the SOG liquid s is dropped on the center of the wafer W. Next, as shown in FIG. 1B, the SOG liquid s is spread evenly on the wafer W by rotating the wafer W at a rotation speed of about 2000 to 4000 rpm. At this time, by simultaneously discharging the cleaning liquid r from the back surface cleaning nozzle 2 toward the back surface of the wafer W, the SOG liquid s adhered to the back surface side of the wafer W is washed off and the peripheral portion of the wafer W is cooled. The temperature of the wafer W is
Before cooling, the temperature almost coincides with the room temperature (for example, about 24 ° C.), but is lowered by about 1 to 2 ° C. by cooling with the SOG liquid s. The cleaning liquid r used here has a property of dissolving the SOG liquid s, and for example, isopropyl alcohol (IPA) is used.

FIG. 1C shows the state of the periphery of the wafer W on which the SOG film s has been formed by the above procedure. Although the thickness of the SOG film s is uniform over most of the surface of the wafer W, the film thickness fluctuates as shown in the figure at the peripheral portion of the surface of the wafer W, particularly in a region E2 of about 1 mm from the outermost periphery. That is, from the central portion of the wafer W toward the peripheral portion,
A portion s2 having a slightly larger film thickness is formed from the region E1 having a uniform film thickness, a portion s3 having a smaller film thickness is formed outside the region E1 having a uniform film thickness, and an SOG film s4 is formed on the end surface of the wafer W. It will remain. As described above, FIGS. 1 (a) to 1 (c)
Is a step of spreading the SOG liquid s on the wafer W,
In the following description, it will be referred to as a spread process.

Next, from the state of FIG. 2A (the same as FIG. 1C), the number of rotations of the wafer W is increased from 600 to 1200 rpm.
m, and at the same time, the cleaning liquid r is discharged from the back surface cleaning nozzle 2 toward the back surface of the wafer W. Then
Since the number of rotations of the wafer W is lower than the number of rotations in the spread process, as shown in FIG.
The surface energy (indicated by arrow A) at the interface between the wafer W and the wafer W is the centrifugal force (indicated by arrow B) due to the rotation of the wafer W.
The cleaning liquid r wraps around to the surface side of the wafer W up to the position C where the SOG film s is removed. At this time, the distance that the cleaning liquid r wraps around the front surface side of the wafer W can be adjusted by the rotation speed of the wafer W. Therefore,
The distance at which the cleaning liquid r wraps around to the front surface side of the wafer W is set to be within the range of the thin film region s3 of the region E2 where the film thickness of the SOG film s at the peripheral portion of the wafer W varies.
The number of rotations of the wafer W is selected within the range of 1200 rpm. As described above, FIGS. 2A and 2B show a process of removing the SOG film s on the peripheral portion of the surface of the wafer W, and will be referred to as a trimming process in the following description.

FIG. 3 shows an experimental result obtained by investigating the relationship between the rotational speed of the wafer W and the shape of the SOG film s in the trimming process.

(1) When the rotational speed of the wafer W is extremely low at 300 rpm or less, the centrifugal force is extremely small, so that a phenomenon occurs in which the cleaning solution r enters the wafer W surface unevenly and considerably into the center of the wafer W surface. It was found that the portion of the SOG film s could not be used because it was removed.

(2) The rotation speed of the wafer W is 300 to 600
If the rotation speed is as low as about rpm, the distance that the cleaning liquid r goes to the front surface side of the wafer W becomes too large. That is, as shown in FIG. 3A, the distance at which the cleaning liquid r wraps around the surface of the wafer W is reduced by the thinner portion s3 of the region E2 where the thickness of the SOG film s at the peripheral portion of the wafer W varies. S2 or a region E having a uniform film thickness
As a result, the region s5 where the film thickness is increased due to the presence of the cleaning liquid r outside the SOG film s is extremely raised. Then, the extremely thick portion s5
Was found to be broken by the subsequent heat treatment.

(3) The rotation speed of the wafer W is 1200 rpm
When the cleaning liquid r is higher than the above, the cleaning liquid r hardly enters the front surface side of the wafer W. That is, 2000 rp
m or more, most of the SOG liquid remains on the end surface of the wafer W, and even at 1300 to 1400 rpm,
As shown in FIG. 3B, the position where the cleaning liquid r flows around remains at the end face of the wafer W, and the SOG film s4 on the end face of the wafer W is originally formed relatively thick. The region s5 where the film thickness is increased under the influence of the cleaning liquid r is also relatively thick. Then, it was found that this portion was also broken by the subsequent heat treatment.

(4) The rotation speed of the wafer W is 600 to 120
In the case of about 0 rpm, as shown in FIG. 3C, the distance that the cleaning liquid r wraps around the surface of the wafer W is small in the region E2 where the thickness of the SOG film at the peripheral portion of the wafer W varies. It falls within the area s3. Then, since the film thickness in this region is small, the region s5 where the film thickness becomes large under the influence of the cleaning liquid r only slightly increases, and the rotation speed is too low or too high. ) Is much thinner than in the case of). And it turned out that this part does not break by the subsequent heat treatment.

Therefore, as a conclusion of this experiment, it was found that when the inorganic SOG liquid was used as the coating liquid, it was optimal to set the rotation speed of the wafer W in the rimping step in the range of 600 to 1200 rpm.

The feature of the coating method of the first embodiment is that the rotation speed of the wafer W is optimized in the edging step so that a thick portion is not formed at the periphery of the SOG film s as much as possible. is there. That is, in the conventional coating method, the supply of the cleaning liquid to the back surface of the wafer is performed only for the purpose of removing the SOG film on the back surface, that is, the S
Since it is only necessary to remove the OG film, the cleaning liquid was not intentionally fed to the surface side. On the other hand, in the coating method according to the present embodiment, the cleaning liquid r is made to flow toward the front surface side by lowering the rotation speed of the wafer W in the bordering process, and the rotation speed is optimized in the range of 600 to 1200 rpm. In this way, the wraparound distance is appropriately controlled so that the position where the cleaning liquid r reaches is within the range of the thin portion s3 formed in the previous spreading step.

Therefore, in the case of this embodiment, the SOG film s
Since an extremely thick portion cannot be formed in the peripheral portion of the SOG film s, even if thermal shrinkage of the SOG film s occurs in a later heat treatment step, the internal stress does not concentrate on a part of the film, and the SOG film s
Does not break. Therefore, it is possible to prevent the generation of foreign matter due to the cracking of the SOG film, which is a conventional problem, and to improve the yield of the device.

In the present embodiment, the supply of the cleaning liquid r to the back surface of the wafer W is performed by controlling the film thickness by cooling the peripheral portion of the wafer W and wrapping around the front surface of the wafer W in addition to the conventional so-called back surface cleaning. Since all the three purposes of edging are performed, the transition from the spread process to the edging process requires only switching of the number of revolutions. Therefore, a special mechanism is added to the coating apparatus to cool the peripheral portion of the wafer, or the edging is performed. It is not necessary to provide a special process for the purpose. Therefore, in order to obtain the effect of improving the device yield as described above, it is not necessary to complicate the coating apparatus, and the processing time of the entire coating process can be kept short.

In the coating method of the first embodiment,
Although an example using an inorganic SOG liquid as the coating liquid has been described, an organic SOG liquid or a photoresist can also be used, and when these are used, a difference in the characteristics of the coating liquid itself or a combination of the coating liquid and the cleaning liquid is used. Needless to say, the optimum rotation speed of the wafer slightly differs from that in the case of the inorganic SOG liquid. However, when selecting a cleaning liquid suitable for each of the SOG liquid and the photoresist, if the cleaning liquid is selected so that it can be used stably in terms of process from the viewpoint of solubility and wettability, the optimum value of the rotation number of the wafer is obtained. Is naturally 600 to 1200 rpm, which is naturally almost the same as in the present embodiment. Although it is not possible to specifically describe the number of rotations, the present invention can be applied to other coating solutions using a spin coating method, such as organic silanes such as polysilazane.

Further, in this embodiment, the peripheral portion of the wafer is cooled by back surface cleaning, but another cooling means may be used instead. For example, a coating apparatus is usually provided with a cup air conditioner, and since laminar air is supplied into the coater cup surrounding the wafer from the cup air conditioner, the temperature of this air is reduced at the wafer peripheral portion. It is also possible to cool by. Also, even if the temperature of the spinner is set higher and the temperature of the cup air conditioning is lowered, only the peripheral portion of the wafer can be cooled.

Next, a second embodiment of the present invention will be described with reference to FIGS. FIGS. 4 and 5 are views showing a method of applying a coating solution in a semiconductor device manufacturing process of the second embodiment. In the coating method of the present embodiment, the coating solution remains in a thin film on the peripheral portion of the semiconductor substrate. It is to try to prevent. In this embodiment, as in the case of the first embodiment, a case where inorganic SOG is used as an example of the coating solution will be described.

First, as shown in FIG. 4A, a wafer W (semiconductor substrate) having a diameter of 6 inches is set on the spinner 1, and about 1 to 3 cc of the SOG liquid s is dropped on the center of the wafer W. Next, as shown in FIG. 4B, the SOG liquid s is spread evenly on the wafer W by rotating the wafer W at a rotation speed of about 2000 to 4000 rpm. As described above, FIGS. 4A and 4B show a step of spreading the SOG liquid s on the wafer W, and will be referred to as a spread step in the following description.

Thereafter, as shown in FIG. 5A, the cleaning liquid r is directed from the back surface cleaning nozzle 2 toward the back surface of the wafer W while rotating the wafer W at a rotation speed of about 400 to 1200 rpm.
To discharge the SOG liquid s adhering to the back side of the wafer W and to remove the cleaning liquid r from the wafer W
(See a broken line in the figure) from the back surface to the peripheral portion on the front surface side, and the SOG solution s in that portion is washed away (first cleaning step). The cleaning liquid r used here is the same as in the first embodiment. Note that the steps after FIG.
This is a step of removing the SOG film s on the peripheral edge of the surface, and will be referred to as a trimming step in the following description.

After that, as shown in FIG. 5B, the rotation speed of the wafer W is increased to about 2,000 to 4,000 rpm, whereby the cleaning liquid r wrapped around the surface of the wafer W is shaken off by the centrifugal force. At the same time, by stopping the discharge of the cleaning liquid r, the cleaning liquid r is removed and dried. At this time, along with the drying of the cleaning liquid r, the components of the SOG liquid s remaining in the cleaning liquid r wrapped around the surface of the wafer W are deposited on the peripheral portion of the wafer W (cleaning liquid removing step).

Thereafter, as shown in FIG. 5C, the cleaning liquid r is discharged from the back cleaning nozzle 2 toward the back surface of the wafer W while rotating the wafer W again at a rotational speed of about 420 to 1300 rpm. r is wrapped from the back surface of the wafer W to the peripheral portion on the front surface side (indicated by a broken line in the figure), and the components of the SOG liquid s deposited on the portion are washed away (second cleaning step).

Here, as described above (the number of rotations of the second cleaning step is about 420 to 1300 rpm with respect to the number of rotations of 400 to 1200 rpm of the first cleaning step), the second cleaning step shown in FIG. The rotation speed of the wafer W is shown in FIG.
The rotation speed in the first cleaning step shown in FIG.
It is desirable to select a rotation speed that is about 0% higher. By selecting such a high rotation speed, the distance in which the cleaning liquid r wraps around to the surface side of the wafer W in the second cleaning step becomes smaller than the distance wrapped in the first cleaning step. Therefore, the cleaning liquid r in the second cleaning step is S
Since it does not reach the OG film s, it is possible to clean only the components of the SOG liquid slightly remaining on the peripheral portion of the wafer W,
The cleaning efficiency at the peripheral portion of the wafer W increases.

The feature of the coating method according to the second embodiment is that the sequence of the edging step includes a first cleaning step, a cleaning liquid removing step, and a second cleaning step, so that the cleaning of the SOG liquid s at the peripheral portion of the wafer W can be further improved. It is completely done. That is, in the coating method of the present embodiment, after the first cleaning step, the cleaning liquid r in which the SOG liquid s is dissolved stays at the peripheral portion of the wafer W, but the cleaning liquid r is once removed in the next cleaning liquid removing step. Next, the components of the SOG liquid s at the peripheral edge are sufficiently removed by performing the cleaning with the cleaning liquid r again in the second cleaning step.

Further, the number of rotations of the wafer W in the second cleaning step is 5 to 10% lower than the number of rotations in the first cleaning step.
The cleaning liquid r in the second cleaning step is set to a high degree.
Is prevented from contacting the SOG film s, so that the cleaning efficiency of the SOG liquid s at the peripheral portion of the wafer W can be further increased. Therefore, only the S
The cleaning efficiency is greatly improved as compared with the case where the OG liquid s is cleaned and removed, and the SOG liquid s can be sufficiently removed. Therefore, it is possible to prevent the SOG film from remaining in a thin state on the peripheral portion of the wafer W. it can.

Therefore, in the wafer W processed by the coating method of the present embodiment, even if the peripheral portion of the wafer W may be impacted due to, for example, handling in a later step, the thin SOG film s does not peel off. Therefore, it is possible to prevent the generation of foreign matter due to the separation of the SOG film, which is a conventional problem, and to improve the yield of the device.

In the coating method of the second embodiment,
Although the example using the inorganic SOG liquid as the coating liquid has been described, the present invention is also applied to other coating liquids using a spin coating method, such as an organic SOG liquid, a photoresist, and an organic silane such as polysilazane. What can be done is the same as in the first embodiment. Furthermore, various conditions other than those described above, such as the number of rotations of the wafer W and the discharge amount of the back surface cleaning liquid in the spread process in both the first and second embodiments, can be set as appropriate.

In the first embodiment, a thick SOG film is prevented from being formed on the peripheral portion of the wafer W by controlling the film thickness by cooling in the spread process and controlling the wraparound distance in the edging process. In the above, the thin S is controlled by the three-step processing (the first cleaning, the cleaning liquid removal, and the second cleaning) of the edging step and the control of the wraparound distance in the first and second cleaning steps.
The OG film was prevented from remaining. However, not only the methods of these embodiments are performed alone, but also the feature points of these embodiments are combined, that is, the film thickness control in the spreading process, the wraparound distance control in the edging process, and the three-step processing of the edging process. (First cleaning, cleaning liquid removal,
The control of the wraparound distance in the (second cleaning) and the first and second cleaning steps may be performed simultaneously. This makes it possible to prevent both the case where the SOG film is formed thick on the periphery of the wafer and the case where the SOG film remains in a thin film form, although the application sequence is somewhat complicated. An optimal coating method can be obtained. The present invention can of course be applied not only to a semiconductor integrated circuit manufacturing process but also to other semiconductor device manufacturing processes such as a liquid crystal display substrate manufacturing process.

[0054]

As described in detail above, claim 1 is as follows.
According to the method for applying a coating liquid in the semiconductor device manufacturing process described in the above, the peripheral portion of the semiconductor substrate is cooled in the spread process to form a thin film portion on the peripheral portion of the semiconductor substrate surface, and the cleaning liquid in the edging process Is spread around the surface of the semiconductor substrate, and the range for removing the coating liquid is set within the range from the outermost periphery of the semiconductor substrate to the portion having the small thickness, so that the film thickness is large at the edge of the coating liquid on the semiconductor substrate. Will not remain in the state. Therefore, even if heat shrinkage of the coating film occurs in the subsequent heat treatment step, the coating film does not crack, so that it is possible to prevent the generation of foreign matter due to the cracking of the coating film, which was a conventional problem, and The yield can be improved.

According to the method of applying a coating liquid in the semiconductor device manufacturing process of the present invention, the cooling of the semiconductor substrate in the spreading step is performed by supplying the cleaning liquid to the back side of the semiconductor substrate. After the completion, the trimming step can be performed only by adjusting the number of revolutions while the cleaning liquid is supplied. Therefore,
In order to obtain the effect of improving the device yield, it is not necessary to complicate the coating apparatus, and the processing time of the entire coating process can be kept short.

According to the method for applying a coating liquid in the semiconductor device manufacturing process of the present invention, the semiconductor substrate is rotated at a high speed in order to spread the coating liquid on the semiconductor substrate in the spreading step. Since the number of revolutions is set lower in the bordering process than in the spread process, the range in which the cleaning liquid flows from the back surface to the front surface of the semiconductor substrate and the coating liquid is removed can be rationally controlled.

According to the method of applying a coating liquid in the semiconductor device manufacturing process of the present invention, the coating liquid may be S
OG or photoresist is used, and the number of revolutions of the semiconductor substrate in the trimming process is set to 600 to 1200.
By setting the rotation speed in the range of rpm, it is possible to perform processing under the optimal conditions in the SOG and photoresist coating steps with respect to prevention of generation of foreign matter due to cracks in the coating liquid.

According to a fifth aspect of the present invention, in the first cleaning step of the edging step, the cleaning liquid remaining on the peripheral portion of the semiconductor substrate is removed in the next cleaning liquid removing step. However, by performing the cleaning and removal of the coating liquid with the cleaning liquid again in the second cleaning step, the cleaning efficiency of the coating liquid is improved as compared with the case where the cleaning and removal of the coating liquid are continuously performed with the cleaning liquid.
The coating solution can be more sufficiently removed, and the coating solution can be prevented from remaining in a thin film. Therefore, since the coating film on the peripheral portion of the semiconductor substrate does not crack in a later step, it is possible to prevent the generation of foreign matter due to the cracking of the coating film, which is a conventional problem, and to improve the yield of the device. be able to.

According to the method of applying a coating liquid in the semiconductor device manufacturing process of the present invention, the cleaning liquid removing step is performed by stopping the supply of the cleaning liquid to the back surface of the semiconductor substrate. Since the cleaning liquid is sufficiently dried and the cleaning liquid is efficiently removed, the processing time can be reduced.

According to the method for applying a coating liquid in the semiconductor device manufacturing process of the present invention, the cleaning liquid removing step is performed by rotating the semiconductor at a higher rotation number than the rotation number in the first cleaning step. Therefore, in the cleaning liquid removing step, the cleaning liquid that has flowed to the surface side in the first cleaning step is removed by being shaken off by centrifugal force, so that the cleaning liquid removal efficiency can be improved.

According to the method for applying a coating solution in the semiconductor device manufacturing process of the present invention, the centrifugal force in the second cleaning process is larger than that in the first cleaning process. Distance of the washing liquid in
It becomes smaller than the wraparound distance in the cleaning step. Therefore, the cleaning liquid in the second cleaning step does not come into contact with the coating liquid, and the cleaning efficiency of the coating liquid is improved, so that it is possible to more reliably prevent the coating liquid from remaining.

According to a ninth aspect of the present invention, a thinner portion of the coating solution is formed on the peripheral portion of the surface of the semiconductor substrate in the spreading step, and the edging step is performed. In the first cleaning step, the coating liquid is removed in a range up to a portion having a small thickness, so that the coating liquid does not remain in a thick state at the edge of the coating liquid. Furthermore, after the coating liquid is removed together with the cleaning liquid in the cleaning liquid removing step, the coating liquid is sufficiently removed by washing and removing the coating liquid again in the second cleaning step, so that the coating liquid remains even in a thin film form. Nothing. Therefore, it is possible to prevent both a case where the coating film is formed thick on the peripheral portion of the semiconductor substrate and a case where the coating film remains in a thin film shape, and it is possible to use an optimum coating method for improving the yield.

[Brief description of the drawings]

FIG. 1 is a diagram showing a procedure of a spread step in a coating method of a coating liquid according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a procedure of a bordering step in a method of applying a coating liquid.

FIG. 3 is a view showing an experimental result obtained by investigating a relationship between a rotation number of a wafer and a shape of an SOG film in a bordering step in the example.

FIG. 4 is a diagram showing a procedure of a spread step in a coating method of a coating liquid according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a procedure of a bordering step in the application method of the application liquid.

FIG. 6 is a diagram showing a procedure of a method of applying a coating liquid, which is an example of the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spinner 2 Back surface cleaning nozzle W Wafer (semiconductor substrate) s SOG liquid (coating liquid) r Cleaning liquid E1 Region with uniform film thickness E2 Region with varying film thickness s1 Part with uniform film thickness s2 Part with large film thickness s3 film Part where thickness is small s4 Part remaining on the end face s5 Part where film thickness becomes large due to the influence of cleaning liquid

Claims (9)

(57) [Claims] In a method of applying a coating liquid in a semiconductor device manufacturing step of spreading the coating liquid on the semiconductor substrate by rotating the semiconductor substrate onto which the coating liquid has been dropped, a method of applying the coating liquid to the semiconductor substrate, By rotating the semiconductor substrate in a state where the peripheral portion is cooled, a portion where the film thickness of the coating liquid is thinner than the film thickness of the coating liquid in a portion other than the peripheral portion is formed on the peripheral portion of the semiconductor substrate surface. A spreading step of spreading the application liquid on the semiconductor substrate, and supplying the cleaning liquid to the back surface of the semiconductor substrate while rotating the semiconductor substrate at a rotation speed at which the cleaning liquid wraps around the surface of the semiconductor substrate. A bordering step of removing a coating solution within a range from the outermost periphery of the semiconductor substrate surface to an arbitrary position of the thin portion. A method of applying a coating liquid in a semiconductor device manufacturing process. 2. The method of applying a coating liquid in a semiconductor device manufacturing process according to claim 1, wherein the cooling of the peripheral portion of the semiconductor substrate is performed by supplying a cleaning liquid to the peripheral portion on the back surface side of the semiconductor substrate. A method for applying a coating liquid in a semiconductor device manufacturing process. 3. The method of applying a coating liquid in a semiconductor device manufacturing process according to claim 1, wherein a rotation speed of the semiconductor substrate in the trimming process is compared with a rotation speed of the semiconductor substrate in the spreading process. A method of applying a coating liquid in a semiconductor device manufacturing process, wherein the setting is set low. 4. The method for applying a coating liquid in a semiconductor device manufacturing process according to claim 1, wherein SOG or photoresist is used as the coating liquid and the number of revolutions of the semiconductor substrate in the trimming step is reduced. A method for applying a coating liquid in a semiconductor device manufacturing process, wherein the coating liquid is set in a range of 600 to 1200 rpm. 5. A method of applying a coating liquid in a semiconductor device manufacturing step of spreading the coating liquid on the semiconductor substrate by rotating the semiconductor substrate onto which the coating liquid has been dropped. A spreading step of spreading the coating liquid on the semiconductor substrate by rotating, and a edging step of removing the coating liquid on a peripheral portion of the semiconductor substrate surface with a cleaning liquid, wherein the edging step is performed on the semiconductor substrate. A first cleaning step of cleaning and removing a coating liquid on a peripheral portion of the semiconductor substrate surface by supplying a cleaning liquid to the back surface and rotating the semiconductor substrate at a rotation speed at which the cleaning liquid goes around the surface of the semiconductor substrate; A cleaning liquid removing step of removing a cleaning liquid that wraps around the surface of the semiconductor substrate in the first cleaning step and stays at the peripheral portion; Cleaning and removal of the coating liquid from the back surface of the semiconductor substrate to an arbitrary position on the peripheral edge of the surface by rotating the semiconductor substrate at a rotation speed at which the cleaning liquid wraps around the surface of the semiconductor substrate while supplying the cleaning liquid to the back surface of the conductive substrate. A second cleaning step of repeating the step once or a plurality of times, and a method of applying a coating liquid in a semiconductor device manufacturing step. 6. The method of applying a coating liquid in a semiconductor device manufacturing process according to claim 5, wherein in the cleaning liquid removing step, the cleaning liquid is removed by stopping the supply of the cleaning liquid to the back surface of the semiconductor substrate. A method for applying a coating liquid in a semiconductor device manufacturing process, characterized by comprising: 7. The method for applying a coating liquid in a semiconductor device manufacturing process according to claim 5, wherein in the cleaning liquid removing step, the semiconductor substrate is rotated at a higher rotation number than the rotation number in the first cleaning step. A method of applying a coating liquid in a semiconductor device manufacturing process, wherein the cleaning liquid is removed by rotating the coating liquid. 8. The method of applying a coating liquid in a semiconductor device manufacturing process according to claim 7, wherein in the second cleaning step, the number of rotations is higher than the number of rotations in the first cleaning step, and in the cleaning liquid removal step. A method of applying a coating liquid in a semiconductor device manufacturing process, wherein the coating liquid is washed and removed by rotating the semiconductor substrate at a lower rotation number than the rotation number. 9. A method of applying a coating liquid in a semiconductor device manufacturing step of spreading the coating liquid on the semiconductor substrate by rotating the semiconductor substrate onto which the coating liquid has been dropped. By rotating the semiconductor substrate in a state where the peripheral portion is cooled, a portion where the film thickness of the coating liquid is thinner than the film thickness of the coating liquid in a portion other than the peripheral portion is formed on the peripheral portion of the semiconductor substrate surface. A spreading step of spreading the application liquid on the semiconductor substrate, and supplying the cleaning liquid to the back surface of the semiconductor substrate while rotating the semiconductor substrate at a rotation speed at which the cleaning liquid wraps around the surface of the semiconductor substrate. A step of removing a coating liquid within a range from the outermost periphery of the semiconductor substrate surface to an arbitrary position of the thin portion. A step of supplying a cleaning liquid to the back surface of the semiconductor substrate and rotating the semiconductor substrate at a rotation speed at which the cleaning liquid wraps around the surface of the semiconductor substrate, so that an arbitrary position of the thin portion from the outermost periphery of the semiconductor substrate surface A first cleaning step of cleaning and removing a coating liquid within the range of up to; a cleaning liquid removing step of removing a cleaning liquid that wraps around the surface of the semiconductor substrate and stays at the peripheral portion by the first cleaning step; One time washing and removal of the coating liquid from the back surface of the semiconductor substrate to an arbitrary position on the peripheral edge of the surface by rotating the semiconductor substrate at a rotation speed at which the cleaning solution wraps around the surface of the semiconductor substrate while supplying the cleaning solution to the back surface. Or a second cleaning step that is repeated a plurality of times.