JPH09162116A - Method for manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate surplus photoresist building up around the peremiter of the wafer while preventing contamination of baking apparatus and the film thickness from being asymmetrical. SOLUTION: A first major surface of a rotating wafer 2 is coated with photoresist liquid 21 by dripping and a second major surface of the wafer 2 is cleaned by jetting a solvent 18. A baking film 25 is formed by heating the wafer 2 on which a coating film 23 is formed without a residue 24 on its second major surface. The solvent 18 is jetted to the periphery of the second major surface while rotating the wafer 2 to eliminate the residue 24 and an edging film 27 is formed. In this way, since the residue of the second major surface is eliminated before baking the coating film 23, the baking apparatus is not contaminated. Also, since the edging is performed after baking, the photoresist does not flow during edging and the film thickness does not become asymmetrical.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a technique for depositing a photoresist on a first main surface of a semiconductor wafer (hereinafter referred to as a wafer). Hereinafter, it will be referred to as an IC).

[0002]

2. Description of the Related Art In a method of manufacturing an IC, when a semiconductor element, a circuit or the like is patterned on a substrate (wafer substrate itself), an oxide film, a nitride film or a metal film, the wafer is first patterned. A lithographic process in which a pattern of a photomask is exposed to a photoresist coated on the main surface and transferred is widely used. In this lithography process, a spin coater (hereinafter referred to as a spinner) is used when the photomask is coated on the first main surface of the wafer. In the photoresist coating process using a spinner, the most important issue is to deposit the photoresist on the first main surface of the wafer to have a uniform film thickness. This is because the variation in the film thickness of the photoresist causes a decrease in the alignment accuracy in the exposure apparatus for transferring the pattern of the photomask, which in turn leads to the variation in the size of the pattern transferred to the first main surface of the wafer. This is because they are invited.

When the photomask is coated on the first main surface of the wafer by the spinner, the wafer is rotated horizontally at a predetermined speed while being held horizontally on the spin chuck of the coating cup, and is directly above the spin chuck. A liquid photoresist is dropped onto the central portion of the first main surface of the wafer from the nozzle arranged at. Since the liquid photoresist dropped and adhered to the first main surface of the wafer is caused to flow in the peripheral direction of the wafer by the centrifugal force, the liquid photoresist uniformly spreads over the first main surface of the wafer. At this time, most of the surplus photoresist reaching the peripheral portion of the wafer is shaken off from the wafer by the centrifugal force, but a part thereof is accumulated in the peripheral portion of the wafer. If the photoresist accumulated on the peripheral portion of the wafer becomes a foreign substance after drying and adheres to the first main surface of the wafer, it may cause a pattern transfer failure or the like.

For the above reasons, in the photoresist coating process using the spinner, after the photoresist is coated on the first main surface of the wafer, the photoresist solvent (hereinafter referred to as a solvent for photoresist) is formed on the peripheral portion of the second main surface of the wafer. , So-called solvent) is sprayed by a nozzle to melt and remove the excess photoresist accumulated in the peripheral portion with the solvent.

However, when the edging operation is performed, the photoresist uniformly applied to the first main surface of the wafer flows to the peripheral portion of the wafer due to the centrifugal force of the rotating wafer. There is a problem that the film thickness of the photoresist becomes asymmetric between the center side and the peripheral side of the wafer in the step portion of the alignment pattern, and the alignment accuracy of the exposure apparatus deteriorates.

Therefore, as a means for solving this problem, Japanese Patent Laid-Open No. 4-239721 discloses a method in which a photoresist is applied to the first main surface while rotating the wafer and then the photoresist is baked. Next, a technique has been proposed in which the excess photoresist accumulated on the peripheral portion of the wafer is removed by ejecting a solvent onto the peripheral portion of the wafer while rotating the wafer. According to this technique, since the photoresist is hardened by baking before the edging process for removing the excess photoresist accumulated on the peripheral portion of the wafer, the centrifugal force of the rotating wafer during the edging work is performed. The photoresist is prevented from flowing in the peripheral direction of the wafer, and it is possible to avoid the phenomenon that the photoresist film thickness becomes asymmetric at the step portion of the wafer after the edging work is performed. .

[0007]

However, in the above technique for preventing the photoresist film thickness from becoming asymmetric during the edging operation, the photoresist is hardened by baking prior to the edging process. It has been revealed by the present inventor that there is a problem that excess photoresist adhered to the main surface contaminates a baking apparatus for performing baking.

An object of the present invention is to provide a method of manufacturing a semiconductor device capable of removing excess photoresist accumulated on the peripheral portion of a wafer while preventing contamination of the baking apparatus and asymmetrical film thickness. To provide.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0010]

The outline of a typical invention among the inventions disclosed in the present application is as follows.

That is, a liquid photoresist is supplied to the first main surface of the rotating semiconductor wafer to apply the photoresist, and a solvent for the photoresist is supplied to the second main surface of the semiconductor wafer. The second main surface is washed, and the semiconductor wafer coated with the photoresist is heated to bake the photoresist while the excess photoresist is not attached to the second main surface. Then, the semiconductor wafer having the photoresist baked thereon is rotated, and the solvent for the photoresist is supplied to the outer peripheral portion of the second main surface of the semiconductor wafer, so that the outer peripheral portion of the first main surface of the semiconductor wafer is exposed. Excess photoresist accumulated in the area is removed in a ring shape and trimmed.

According to the above-mentioned means, since the surplus photoresist adhering to the second main surface of the wafer is removed prior to the baking of the photoresist, the baking apparatus is contaminated in advance. Will be prevented. On the other hand, since the edging work is performed after the photoresist is baked and cured, the phenomenon that the photoresist flows and the asymmetrical shape between the center side and the peripheral side of the wafer is not caused during the edging work. become.

[0013]

1 is a schematic view showing a photoresist applying step in an IC manufacturing method according to an embodiment of the present invention. FIG. 1A is a photoresist coating and washing step, and FIG. After the photoresist coating and cleaning step, (c) shows the baking step, (d) shows the edging step, and (e) shows the edging step. 2A and 2B show a photoresist deposition apparatus used for the same. FIG. 2A is a schematic plan view, FIG. 2B is a front sectional view of a photoresist coating and cleaning apparatus, and FIG. 2C is a front view of a baking apparatus. . FIG. 3 shows the edging process, (a) is a front sectional view of the edging device, (b) is an enlarged sectional view during edging processing, and (c) is an enlarged sectional view after edging. FIG. 4 is each schematic front view showing a patterning step in the method of manufacturing an IC according to one embodiment of the present invention, and FIG. 5 is each schematic plan view of the same.

In this embodiment, the method of manufacturing a semiconductor device according to the present invention is configured as a method of manufacturing an IC, and includes a photoresist deposition step. This photoresist deposition process is carried out by the photoresist deposition apparatus 1 shown in FIG. This photoresist deposition apparatus 1 generally accommodates a plurality of wafers 2 and pays out one by one, and a liquid photoresist is supplied to the first main surface of the wafer while rotating the wafer 2. A photoresist coating / cleaning device 4 for coating the photoresist and supplying a solvent for the photoresist (for example, ethyl lactate; hereinafter referred to as a solvent) to the second main surface of the wafer 2 to clean the second main surface. A baking device 5 for heating the photoresist-coated wafer 2 to bake the photoresist; rotating the photoresist-baked wafer 2; and applying a solvent to the outer peripheral portion of the second main surface of the wafer 2. A edging device 6 for annularly removing the excess photoresist supplied and accumulated in the outer peripheral portion of the first main surface of the wafer, and a series of steps. And a unloading device 7 for accommodating receive a completed wafer 2. A first transfer arm 8 is provided between the photoresist coating / cleaning device 4 and the baking device 5, and a second transfer arm 8 is provided between the baking device 5 and the edging device 6.
A third transfer arm 10 is installed between the transfer arm 9 and the edging device 6 and the unloading device 7.

Next, the photoresist depositing process according to this embodiment using the photoresist depositing apparatus 1 will be described with reference to the process diagram shown in FIG.

First, the wafer 2 is loaded by the loading device 3.
Is delivered to one and supplied to a pretreatment device (not shown). For example, the pretreatment apparatus includes a first constant temperature plate and a second constant temperature plate, and the wafer 2 supplied to the first constant temperature plate and adsorbed and held is heated to about 150 ° C. to remove water adsorbed on its surface. To be done. On this occasion,
In order to enhance the adhesiveness of the first main surface of the wafer 2, for example, a hydrophobizing treatment using hexamethyldisilazane (HMDS) is performed. The wafer 2 which has been dehydrated by the first constant temperature plate is sent to the second constant temperature plate to be adsorbed and held, and cooled by the second constant temperature plate to the optimum temperature for photoresist coating. This optimum temperature is about 23 ° C.

The wafer 2 adjusted to the optimum temperature is sent to the photoresist coating / cleaning apparatus 4. The photoresist coating / cleaning device 4 is configured as shown in FIG. That is, the photoresist coating and cleaning device 4
Is provided with a substantially cylindrical cup 11 having upper and lower openings, and a spin chuck 12 for vacuum-holding a wafer is horizontally arranged in the center of the cup 11. The spin chuck 12 is rotated by a motor 13 in a horizontal plane at a speed of several hundreds to several thousands of revolutions per minute. A photoresist supply nozzle 14 for dropping a liquid photoresist onto the first main surface of the wafer 2 is arranged vertically downward on the rotation axis of the spin chuck 12. Further, on the wall surface of the cup 11, a readhesion preventive portion 15 is formed on a sloping surface which spreads toward the end at a position approximately the same height as the wafer 2, and the readhesion preventive portion 15 is shaken off from the wafer 2. By splashing the splashes of No. 2 downward, the splashes of the photoresist are prevented from splashing back onto the wafer 2 and reattaching. Further, a discharge port 16 is opened on the bottom wall of the cup 11, and a solvent supply nozzle 17 for supplying a solvent 18 for cleaning the second main surface of the wafer 2 is inserted. The solvent supply nozzle 17 is adapted to inject the solvent obliquely upward to the outer periphery of the second main surface of the wafer 2.

The wafer 2 sent to the photoresist coating / cleaning apparatus 4 configured as described above is vacuum-sucked and held by the spin chuck 12 as shown in FIGS. 2 (b) and 1 (a). It When the wafer 2 is held by the spin chuck 12, the motor 13 is rotated at a predetermined speed. When the rotation of the motor 13 is stabilized at a predetermined speed, a liquid photoresist (hereinafter referred to as a photoresist liquid) 21 is dropped from the photoresist supply nozzle 14 onto the central portion of the first main surface of the wafer 2. The dropped photoresist liquid 21 adheres to the first main surface of the wafer 2 and is flown in the peripheral direction by the centrifugal force of the wafer 2 rotating at a high speed to wet and spread on the entire surface. The rotation speed of the wafer 2 at this time is 2000 rpm to 3000 rpm, and the processing time as the coating step is about 20 seconds. The film thickness of the photoresist coating film (hereinafter referred to as coating film) 23 formed by wetting and spreading is about 1 μm to 2
μm.

Here, the surplus portion of the photoresist liquid 21 reaching the outer peripheral edge of the first main surface of the wafer 2 is the wafer 2
Since it is shaken off from the outer peripheral edge by the centrifugal force of, the droplets (hereinafter referred to as droplets) 22 of the photoresist are scattered toward the inner wall of the cup 11 and collide with the readhesion preventing portion 15. However, the droplet 2 that collided with the reattachment prevention unit 15
Since 2 is repelled downward and is carried by the downward airflow 19 formed in the chamber of the cup 11 toward the discharge port 16, it is not rebound and reattached to the first main surface of the wafer 2.

Most of the photoresist liquid 21 reaching the outer peripheral edge of the first main surface of the wafer 2 in this way is separated and removed by the centrifugal force of the wafer 2, but a part of the photoresist liquid 21 adheres. Wafer 2 depending on its properties and surface tension
Of the wafer 2 around the outer peripheral edge of the wafer 2 toward the second main surface side.
On the outer peripheral surface and the outer peripheral portion of the second main surface, a photoresist residual portion (hereinafter referred to as a residual portion) 24 is formed. When the wafer 2 in which the residual portion 24 remains on the outer peripheral portion of the second main surface is sent to the baking apparatus and baked, the baking apparatus is contaminated or the fragile residual portion 24 is accidentally dropped. And cause troubles such as generation of foreign matter.

Therefore, in the present embodiment, the wafer 2
By performing the cleaning process of cleaning the photoresist that has wrapped around the second main surface of the wafer 2 subsequent to the coating process, it is possible to prevent the residual portion 24 from being formed on the outer peripheral portion of the second main surface of the wafer 2. To be done. That is, when a predetermined time elapses after the start of dropping the photoresist solution 21 in the coating step, the solvent 18 is directed from the solvent supply nozzle 17 to the outer peripheral portion of the second main surface of the wafer 2 while the wafer 2 is rotated at a predetermined speed. Is jetted. At this time, the rotation speed of the wafer 2 is preferably 1000 rotations per minute to 1500 rotations per minute.
This is because when the rotation speed is low, the solvent 18 sprayed on the second main surface of the wafer 2 overcomes the centrifugal force of the wafer 2 on the outer peripheral edge of the wafer 2 due to its adhesiveness, surface tension, etc. As a result, the phenomenon that the coating film 23 on the first main surface is dissolved as well as the residual portion 24 that has wrapped around the second main surface of the wafer 2 occurs. On the contrary, if the number of rotations is too high, not only the solvent 18 sprayed on the second main surface of the wafer 2 is shaken off by the centrifugal force before the residual portion 24 is dissolved, but also the flexible coating film 23 is still strong. This causes a phenomenon in which the center side and the peripheral side become asymmetrical by being deformed by being subjected to such a centrifugal force. Incidentally, the processing time of the cleaning process of the second main surface of the wafer 2 with the solvent is about 1
0 seconds.

When the cleaning process of the second main surface of the wafer 2 is completed, the wafer 2 is idled and the solvent 18 attached to the wafer 2 is removed.
Is centrifugally dried. That is, when the wafer 2 is idled, the solvent 18 attached to the wafer 2 is centrifugally separated and forcibly removed, so that the wafer 2 is relatively dried.
The rotational speed of the wafer 2 during the centrifugal drying is preferably 1000 rpm to 1500 rpm for the same reason as in the cleaning step. By the way, the processing time of centrifugal drying is about 10 seconds.

The solvent 18 that has been shaken off from the wafer 2 by centrifugal force and the residue of the residual portion 24 that has spilled over to the second main surface of the wafer 2 are reattachment prevention portion 15 and downdraft 1.
By the action of 9, all the particles are discharged to the discharge port 16 without going toward the wafer 2.

In the wafer 2 that has undergone the photoresist coating and cleaning process as described above, the residual portion 2 is left on the outer peripheral surface of the wafer 2.
4 but the second main surface has no residual portion, the coating film 23 is applied to the first main surface as shown in FIG. 1B. The wafer 2 is sent to the baking device 5 by the first transfer arm 8. The baking device 5 is configured as shown in FIG. That is, the baking apparatus 5 includes a hot plate 31 formed in a square flat plate shape having one side having a diameter larger than the diameter of the wafer 2, and inside the hot plate 31, an electric heater 32 with adjustable temperature is provided. It has been incorporated.

The wafer 2 sent to the baking device 5
Is transferred onto the hot plate 31 with the first main surface of the coating film 23 side facing upward. 1 (c) and 2
When the wafer 2 is transferred to the hot plate 31 as shown in (c), the wafer 2 is transferred to the hot plate 31.
The electric heater 32 is heated to a predetermined temperature and baked to be baked. The degree of baking in this baking step is sufficient to cure the surface of the coating film 23 and is not completely cured. The heating temperature at this time is 90 ° C. to 100 ° C., and the treatment time is about 2 minutes.

Here, if the residual portion 24 is attached even to the outer peripheral portion of the second main surface of the wafer 2, the photoresist of the residual portion 24 is attached to the hot plate 31. To be polluted. However, in the present embodiment, the residual portion 24 is left on the second main surface of the wafer 2 by being cleaned in the photoresist coating cleaning process.
Since the hot plate 31 is not formed, the hot plate 31 is not contaminated.

By the way, the hot plate 31 is used for the wafer 2.
Is supported in a slightly floating state (proximity support)
It is desirable that the second
Since the residual portion 24 is not formed on the main surface by being already cleaned, it may be configured to support the contact. When the wafer 2 is heated by the hot plate 31 in the contact state, not only the heating efficiency becomes good, but also the temperature distribution becomes uniform over the entire wafer 2.

By performing the baking process as described above, the photoresist film (hereinafter referred to as a baking film) 25 obtained by baking the coating film 23 on the first main surface of the wafer 2 is formed. Become.

By the way, in the above-mentioned cleaning step, since the remaining portion of the second main surface of the wafer 2 is only cleaned, the remaining portion 24 is formed up to the outer peripheral surface of the wafer 2. In this state, if the wafer 2 is discharged from the photoresist deposition apparatus 1 to the unloading apparatus 7 and sent to a subsequent step such as an exposure step, when the wafer 2 is housed in the unloading apparatus 7 or the wafer 2 When the wafer 2 is transferred to the carrier jig, the wafer 2 rubs against a holding groove (described later), so that the residual portion 24 formed up to the outer peripheral surface of the first main surface of the wafer 2 is scraped off. If the scraped off chips and the like become foreign matter and are reattached to the baking film 25 of the wafer 2, this may cause defective transfer of the pattern in the exposure process. Further, the baking film 25 may be damaged as the residual portion 24 falls off.

Therefore, in the present embodiment, the wafer 2
By performing the edging process on the baking film 25 having the residual portion 24 formed on the outer peripheral surface thereof, the residual portion 24 formed on the outer peripheral surface of the first main surface of the wafer 2 is scraped off. Occurrence of pattern transfer failure is prevented.

That is, the wafer 2 on which the baking film 25 obtained by baking the coating film 23 by the baking process is applied is transferred to the edging device 6 by the second transfer arm 9. The edging device 6 has the same structure as the photoresist coating and cleaning device as shown in FIG. That is, the edging device 6 is provided with a cup 41 having a substantially cylindrical shape with an opening at the top and bottom, and a spin chuck 42 for holding a wafer by vacuum suction is provided at the center of the cup 41.
Are arranged horizontally. The spin chuck 42 is rotated by a motor 43 in a horizontal plane at a speed of several hundreds to several thousand revolutions per minute. The readhesion preventive portion 45 is provided on the wall surface of the cup 41 at a position substantially the same height as the wafer 2.
Is formed on the sloping slope, and the redeposition preventing portion 45 repels the solvent or the dissolved photoresist dissolved from the wafer 2 downward,
The solvent and the dissolved material of the dissolved photoresist are prevented from bouncing and reattaching to the wafer 2.
Further, a discharge port 46 is opened on the bottom wall of the cup 41, and the residual portion 2 formed on the outer peripheral surface of the wafer 2 is formed.
A solvent supply nozzle 47 for supplying a solvent 48 for edging the 4 is inserted. The solvent supply nozzle 47 is adapted to inject the solvent obliquely upward to the outer periphery of the second main surface of the wafer 2.

The wafer 2 sent to the edging device 6 configured as described above is vacuum-sucked and held by the spin chuck 42 as shown in FIGS. 3 (a) and 1 (d). When the wafer 2 is held by the spin chuck 42, the motor 43 is rotated at a predetermined speed. Motor 43
When the rotation of is stable at a predetermined speed, the solvent 48 is sprayed from the solvent supply nozzle 47 toward the outer peripheral portion of the second main surface of the wafer 2. The solvent 48 sprayed on the second main surface of the wafer 2 overcomes the centrifugal force of the wafer 2 at the outer peripheral edge of the wafer 2 due to its adhesiveness, surface tension, etc., and as shown in FIG. 1 Go around to the main surface side. The solvent 48 that has spilled around to the first main surface side is left on the remaining portion 24 of the outer peripheral surface of the wafer 2 in the baking film 25 and the first film.
By penetrating into the portion formed on the outer peripheral portion of the main surface, the photoresist in this portion is dissolved. The melted and softened photoresist (hereinafter referred to as a melt) 26 is separated by the centrifugal force acting on the rotating wafer 2 and shaken off from the wafer 2. In this manner, when the residual portion 24 on the outer peripheral surface of the wafer 2 and the outer peripheral portion of the baking film 25 are melted and the melted material 26 is shaken off, as shown in FIG. A baking film (hereinafter, referred to as an edging film) 27 having an edging portion 28 on the outer peripheral portion is formed on one main surface.

Here, the wafer 2 in this edging process
It is desirable that the number of revolutions is about 500 revolutions per minute. This is because when the rotation speed is low, the adhesiveness and surface tension of the solvent 48 sprayed on the second main surface of the wafer 2 overcome the centrifugal force of the wafer 2 and the solvent 48 flows in a large amount on the first main surface side. As a result, the baking film 25 is melted not only in the outer peripheral portion but also in the central portion, causing damage. On the other hand, if the rotation speed is too high, the solvent 48 sprayed on the second main surface of the wafer 2 is shaken off by the centrifugal force, and thus cannot go around to the first main surface side of the wafer 2.
The border is not executed. Incidentally, the processing time of the edging step with the solvent is about 10 seconds.

When a predetermined time elapses after the supply of the solvent 48 is started, the wafer 2 is spun and the solvent 4 attached to the wafer 2 is rotated.
8 and lysate 26 are centrifuged. The rotation speed of the wafer 2 at the time of centrifuging the solvent 48 and the dissolved substance 26 may be higher than the rotation speed in the cleaning step, and is preferably 1000 rotations per minute to 3000 rotations per minute. This is because the baking film 25 is already maintained at an appropriate hardness, so that even if the wafer 2 is rotated at a high speed, a phenomenon in which the center side and the peripheral side are asymmetrical is prevented from occurring. On the other hand,
Since the melt 26 is a part of the baking film 25, a centrifugal force having a certain degree of strength is required for separation from the surface of the wafer 2. Also, by completely shaking off the solvent 48,
Since the wafer 2 can be centrifugally dried, the final drying step such as heating the wafer 2 can be omitted. Incidentally, the processing time of this centrifugation is about 10 seconds.

The solvent 48 and the dissolved substance 26, which have been shaken off from the wafer 2 by the centrifugal force, are all discharged to the discharge port 46 without going toward the wafer 2 due to the action of the readhesion preventing portion 45 and the descending air flow 49.

As described above, the edging film 27 is formed on the first main surface.
The wafer 2 on which is formed is transferred to the unloading device 7 by the third transfer arm 10 and accommodated by the unloading device 7. At this time, since the edging portion 28 is formed on the outer peripheral portion of the wafer 2, the edging film 27 is not scraped off even when the wafer 2 is inserted into the holding groove. Therefore, it is possible to prevent foreign matter from being generated due to the photoresist adhered to the wafer 2 in the subsequent wafer 2 transfer process.

Next, the method of manufacturing an IC according to one embodiment of the present invention will be described with reference to FIGS.

First, as shown in FIGS. 4A and 5A, a silicon oxide film 51 is formed on the first main surface of the wafer 2 by heat treatment or film formation.

Next, as shown in FIGS. 4 (b) and 5 (b), the edging film 27 made of photoresist is formed on the silicon oxide film 51 of the wafer 2 in the photoresist deposition process described above. Is put on.

The wafer 2 coated with the edging film 27 is transferred from the unloading device 7 of the photoresist deposition device 1 to a carrier jig. At this time, since the edging process is performed, the edging portion 28 to which the photoresist is not attached is formed on the outer peripheral surface and the outer peripheral portion of the wafer 2, and therefore, as shown in FIGS. 4 (c) and 5 (c). As shown, even if the wafer 2 is inserted into the holding groove 52 of the carrier jig, generation of foreign matter due to peeling of the photoresist is prevented.

The wafer 2 housed in the carrier jig is sent to the exposure process. As shown in FIGS. 4D and 5D, in the exposure process, the rimming film 27 of the wafer 2 is exposed to the photomask 5 by an exposure device (not shown).
3 pattern is transferred. By this exposure step, a photosensitive film (hereinafter, referred to as a photosensitive film) 54 to which the latent image 55 of the pattern of the photomask 53 is transferred is formed on the silicon oxide film 51 of the wafer 2. At this time, as described above, in the photoresist deposition step, the second main surface of the wafer 2 is cleaned and the edging film 27 is subjected to the edging process, so that no foreign matter is generated. Therefore, it is possible to prevent occurrence of pattern transfer failure due to foreign matter. In addition, since the edging process is performed after baking, the occurrence of an asymmetrical phenomenon in the edging film 27 is prevented.
A latent image 55 of the pattern of the photomask 53 is formed on the photosensitive film 54.
Is properly and accurately transferred.

As shown in FIGS. 4E and 5E, a peripheral exposure device 57 performs a peripheral exposure process on the outer peripheral portion of the photosensitive film 54 of the wafer 2. On this occasion,
Since the edging portion 28 is properly formed on the photosensitive film 54, the peripheral exposure latent image 56 is properly and accurately formed on the outer peripheral portion of the photosensitive film 54. That is, if the edging portion 28 is not properly formed and the portion where the photoresist component of the photoresist is melted out is present intermittently in the outer peripheral portion of the edging film 27, a portion that does not undergo photosensitization due to the peripheral exposure processing occurs. However, there arises a problem that it remains without being developed in the next developing step. By the way, the width w of the edging portion 28 of the edging film 27 is about 1 mm, and the width W of the peripheral exposure latent image 56 of the photosensitive film 54 from the outer peripheral edge of the wafer is about 3 mm.

Next, the wafer 2 is developed in the developing process. By this development processing, FIG. 4 (f) and FIG.
As shown in (f), on the silicon oxide film 51 of the wafer 2, a photoresist development film (hereinafter, a latent image 55 having a pattern latent image 55 and a peripheral exposure latent image 56) is developed. A developing film) 58 is formed. Since the peripheral exposure latent image 56 of the photosensitive film 54 is properly formed during this developing process, the peripheral exposure latent image rimming portion (hereinafter, referred to as peripheral exposure rimming portion) 60 is formed on the outer peripheral portion of the developing film 58. Is in a state of being properly formed in a ring shape with a constant width.

Next, the wafer 2 is etched by a dry etching device (not shown) in the etching process. By this etching process, as shown in FIGS. 4G and 5G, a pattern 61 corresponding to the visible image 59 of the developing film 58 is formed on the silicon oxide film 51 of the wafer 2. become. At the time of this etching process, the peripheral exposure edge portion 60 is provided outside the developing film 58.
Are properly formed, the peripheral portion of the wafer 2 can be reliably held by the holder 63 of the dry etching apparatus. Further, even if the wafer 2 is held by the holder 63, the developing film 58 is not damaged at all.
Since the peripheral exposure edging portion 60 is properly formed on the outer side of the developing film 58, the edging portion used for holding the wafer 2 in a later step is formed on the outer side portion of the pattern 61 by this etching process. (Hereinafter, it is referred to as a holding edging portion.) 62 is in a state where it is properly formed in a ring shape with a constant width.

Finally, the wafer 2 is subjected to the asher process (developing film removing process) to remove the developing film 58 as shown in FIGS. 4 (h) and 5 (h). By this developing film removal processing, a pattern 61 made of the silicon oxide film 51 is formed on the first main surface of the wafer 2, and a holding edging portion 62 outside the pattern 61 has a certain width and is suitable for a ring shape. It will be in the state formed. When the holding edging portion 62 is formed on the outer peripheral portion of the first main surface of the wafer 2 in this manner, the wafer 2 can be held properly and surely by using the holding edging portion 62 in the subsequent process. Therefore, each process can be performed appropriately and with high accuracy.

In the above embodiments, the patterning process for the silicon oxide film has been described as an example, but the same patterning process is performed in the process of forming the electric wiring on the first main surface of the wafer 2. Become. Further, in the step of implanting ions into the first main surface of the wafer 2, the ions may be implanted instead of performing the etching process, or the ions may be implanted using the pattern 61 of the silicon oxide film as a mask. Good.

According to the above embodiment, the following effects can be obtained. (1) By removing the excess photoresist adhering to the second main surface of the wafer before the photoresist is baked, it is possible to prevent the baking apparatus from being contaminated.

(2) When the edging operation is performed after the photoresist is baked and cured, the photoresist flows during the edging operation, and the asymmetrical shape occurs between the center side and the peripheral side of the wafer. Since it can be prevented from occurring in advance, the pattern of the photomask can be appropriately and highly accurately transferred to the photoresist in the exposure step.

(3) By performing an edging process on the baking film formed up to the outer peripheral surface of the first main surface of the wafer, the edge of the baking film formed up to the outer peripheral surface of the first main surface of the wafer is removed. Since it is possible to prevent the portion from being scraped off, it is possible to prevent the occurrence of a pattern transfer failure or the like due to a foreign substance generated by the scraping off.

(4) By forming the holding edging portion on the outer peripheral portion of the first main surface of the wafer, the wafer can be properly and surely held by using the holding edging portion in the subsequent process. Therefore, each process can be performed appropriately and with high accuracy.

FIG. 6 is a schematic view showing a step of depositing a photoresist and an antireflection film in an IC manufacturing method according to another embodiment of the present invention. FIG. 7 shows the edging process, (a) is a front sectional view, (b) is an enlarged sectional view during edging, and (c) is an enlarged sectional view after edging.

The second embodiment differs from the first embodiment in that the antireflection film is simultaneously applied in the edging process.

That is, the wafer 2 sent to the edging device 6 is vacuum-sucked and held by the spin chuck 42 as shown in FIGS. 6 (d) and 7 (a). When the wafer 2 is held by the spin chuck 42, the motor 43 is rotated at a predetermined speed. When the rotation of the motor 43 stabilizes at a predetermined speed, the antireflection film solution supply nozzle 64 drops an antireflection film solution (hereinafter referred to as an antireflection film solution) 65 onto the central portion of the first main surface of the wafer 2. To be done. The dropped anti-reflection film liquid 65 adheres to the surface of the baking film 25 of the wafer 2 and is flown in the peripheral direction by the centrifugal force of the wafer 2 rotating at a high speed to spread over the entire surface. The rotation speed of the wafer 2 at this time is 2 per minute.
The rotation speed is 000 to 3000 rpm, and the processing time as the coating step is about 20 seconds. The film thickness of the coating film of the antireflection film liquid (hereinafter, antireflection film) formed by being wet and spread is about 50 nm to 100 nm.

Here, most of the surplus portion of the anti-reflection film liquid 65 that has reached the outer peripheral edge of the first main surface of the wafer 2 is shaken off from the outer peripheral edge by the centrifugal force of the wafer 2, but a part of the anti-reflective film. Due to the adhesiveness of the liquid 65, the surface tension, and the like, the liquid 65 wraps around the outer peripheral edge of the wafer 2 toward the second main surface side and tends to remain on the outer peripheral portion of the second main surface.

However, in the second embodiment, the solvent supply nozzle 47 is rotated while the wafer 2 is rotated at a predetermined speed when a predetermined time elapses after the drop of the antireflection film liquid 65 is started.
The solvent 48 is sprayed from the outer peripheral portion of the second main surface of the wafer 2. Most of the solvent 48 sprayed on the second main surface of the wafer 2 wraps around from the first main surface side of the wafer 2 to the second main surface side, as shown in FIG. 7B. The antireflection film liquid 65 to be washed is washed out to the outside of the wafer 2. In addition, a part of the solvent 48 sprayed on the second main surface of the wafer 2 is caused by its adhesiveness, surface tension, etc.
At the outer peripheral edge of the wafer 2, the centrifugal force of the wafer 2 is overcome, and the wafer 2 wraps around to the first main surface side as shown in FIG. 7B.
The solvent 48 that has flowed to the first main surface side permeates the outer peripheral surface of the wafer 2 in the baking film 25 and the outer peripheral portion of the first main surface to dissolve the baking film 25 in this portion. . The melted material 26 in the melted and softened state is separated by the centrifugal force acting on the rotating wafer 2 and shaken off from the wafer 2.

In this way, when the baking film 25 on the outer peripheral surface of the wafer 2 and the outer peripheral portion of the first main surface is melted and the melt 26 is shaken off, FIGS. 6 (e) and 7 (c).
As shown in FIG. 4, the edging film 27 having the edging portion 28 is formed on the first main surface of the wafer 2.
Then, the antireflection film 66 is applied on the edging film 27.

The antireflection film liquid 65, the solvent 48, and the melt 26, which have been shaken off from the wafer 2 by the centrifugal force, do not move toward the wafer 2 due to the action of the anti-redeposition portion 45 and the descending air flow 49. Are all discharged to.

According to the second embodiment, since the antireflection film 66 is deposited on the edging film 27, the transfer accuracy in the exposure process can be further improved.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, the antireflection film is not limited to being applied in the edging process, but may be applied after the baking process and before the edging process. A process of cleaning the second main surface of the wafer may be performed in the coating process of the antireflection film.

The photoresist coating / cleaning device and the edging device are not limited to being installed independently of each other, but they may be combined.

[0062]

The effects obtained by typical aspects of the invention disclosed in the present application will be briefly described as follows. Excessive photoresist accumulated on the peripheral portion of the wafer can be removed while preventing contamination of the baking apparatus and asymmetrical film thickness.

[Brief description of the drawings]

FIG. 1 is each schematic diagram showing a photoresist deposition step in an IC manufacturing method according to an embodiment of the present invention,
(A) is a photoresist coating washing step, (b) is a photoresist coating washing step, (c) is a baking step,
(D) shows the edging process, and (e) shows the edging process.

2A and 2B show a photoresist deposition apparatus used therefor; FIG. 2A is a schematic plan view, FIG. 2B is a front sectional view of a photoresist coating and cleaning apparatus, and FIG. 2C is a front view of a baking apparatus. is there.

FIG. 3 shows an edging step, (a) is a front sectional view of the edging device, (b) is an enlarged sectional view of the edging process,
(C) is an enlarged sectional view after trimming.

FIG. 4 is a schematic front view showing a patterning step in the method of manufacturing an IC according to the embodiment of the present invention.

FIG. 5 is likewise a schematic plan view.

FIG. 6 is a schematic diagram showing a step of depositing a photoresist and an antireflection film in an IC manufacturing method according to another embodiment of the present invention.

7A and 7B show the edging process. FIG. 7A is a front sectional view, FIG. 7B is an enlarged sectional view during edging, and FIG. 7C is an enlarged sectional view after edging.

[Description of sign]

DESCRIPTION OF SYMBOLS 1 ... Photoresist deposition apparatus, 2 ... Wafer, 3 ... Loading apparatus, 4 ... Photoresist coating cleaning apparatus, 5 ... Baking apparatus, 6 ... Bordering apparatus, 7 ... Unloading apparatus, 8 ... 1st conveyance arm, 9 ... Second transfer arm, 10
... third transfer arm, 11 ... cup, 12 ... spin chuck, 13 ... motor, 14 ... photoresist supply nozzle,
15 ... Re-attachment prevention part, 16 ... Discharge port, 17 ... Solvent supply nozzle, 18 ... Solvent, 19 ... Downdraft, 21 ... Liquid photoresist (photoresist liquid), 22 ... Photoresist droplets, 23 ... Photoresist coating film (coating film), 24 ... Photoresist remaining portion (residual portion), 25
... Bake photoresist film (baking film), 26 ... Dissolved and softened photoresist (dissolved material), 27 ... Edged baking film (edging film), 28 ... Edged portion, 31 ... Hot plate, 32 …
Electric heater, 41 ... Cup, 42 ... Spin chuck, 4
3 ... Motor, 45 ... Reattachment prevention part, 46 ... Discharge port, 47
... solvent supply nozzle, 48 ... solvent, 49 ... downdraft, 51
... Silicon oxide film, 52 ... Carrier jig holding groove, 53
Photomask, 54 ... Photosensitive film (photosensitive film) on which pattern latent image is transferred, 55 ... Pattern latent image, 56 ... Peripheral exposure latent image, 57 ... Peripheral exposure device, 58 ... Photoresist having visible image Development film (development film), 59 ... Visual image, 60 ... Edged portion by peripheral exposure latent image (peripheral exposure edged portion), 61
... a pattern corresponding to the visible image, 62 ... a holding edge portion, 6
3 ... Holder of dry etching device, 64 ... Antireflection film solution supply nozzle, 65 ... Antireflection film solution (antireflection film liquid), 66 ... Antireflection film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Saito 5-20-1, Josuihonmachi, Kodaira-shi, Tokyo Inside the Semiconductor Business Division, Hitachi, Ltd. (72) Inventor Kazuyuki Sugai, Kodaira-shi, Tokyo 5-20-1 Honmachi, Ltd. Semiconductor Company, Hitachi Ltd. (72) Inventor Masahiro Kurihara 3-3, Fujibashi, Ome City, Tokyo 2 Inside Hitachi Tokyo Electronics Co., Ltd.

Claims (4)

[Claims] 1. A method of manufacturing a semiconductor device by lithography for forming a pattern on a semiconductor wafer includes the following steps. (A) A liquid photoresist is supplied to the first main surface of the rotating semiconductor wafer to apply the photoresist, and a solvent for photoresist is supplied to the second main surface of the semiconductor wafer to supply the first solvent. 2 A photoresist coating and cleaning step in which the main surface is cleaned. (B) A baking step in which the semiconductor wafer coated with the photoresist is heated to bake the photoresist. (C) The semiconductor wafer baked on the photoresist is rotated and the second wafer of the semiconductor wafer is rotated.
A edging process in which a solvent for photoresist is supplied to the outer peripheral portion of the main surface, and excess photoresist accumulated in the outer peripheral portion of the first main surface of the semiconductor wafer is removed in a ring shape. 2. In the coating and cleaning step, the supply of the solvent is stopped after a lapse of a predetermined time, and the rotation speed when the semiconductor wafer is idled and the solvent adhering to the semiconductor wafer is dried is 3000 per minute. The method for manufacturing a semiconductor device according to claim 1, wherein the rotation speed is set to be equal to or less than rotation. 3. In the edging step, the number of rotations when the solvent is supplied to the semiconductor wafer is 500 to per minute.
The rotation speed is set to 1000 rpm, and when the supply of the solvent is stopped after a lapse of a predetermined time and the semiconductor wafer is idled to dry the solvent adhering to the semiconductor wafer, the rotation speed is 2000 to 3000 rpm. The method for manufacturing a semiconductor device according to claim 1, wherein the method is set. 4. The method of manufacturing a semiconductor device according to claim 1, wherein in the edging step, an antireflection film forming solution is simultaneously supplied to the first main surface of the semiconductor wafer.