GB2393522A - Method of and apparatus for developing exposed photoresist to prevent impurities from being attached to a wafer surface - Google Patents

Abstract

A method of developing an exposed photoresist coated on a surface of a silicon wafer with a developing liquid, includes the steps of holding the silicon wafer horizontally such that the surface coated with the photoresist faces upwardly, rotating the silicon wafer, supplying a cleaning liquid to the surface of the silicon wafer while the silicon wafer is rotated, and supplying the developing liquid to the surface of the silicon wafer while the wafer continues to be rotated.

Description

METHOD OF AND APPARATUS FOR DEVELOPING EXPOSED

PHOTORESIST TO PREVENT IMPURITIES FROM BEING ATTACHED

TO A WAFER SURFACE

5 BACKGROUND OF THE INVENTION

1. Field of the Invention:

The present invention relates to a method of and an apparatus for developing an exposed photoresist coated on the surface of a silicon wafer, with a developing liquid, 10 a development control apparatus for controlling various components of a developing apparatus, and an information storage medium which stores, as software, a program for enabling a computer.to perform various processing operations.. 15 2. Description of the Related Art:.

At present, fine interconnection patterns of semiconductor circuit devices are formed by photolithography. According to the photolithographic process, it is necessary to develop an exposed 20 photoresist coated on the surface of a silicon wafer with a developing liquid by a developing apparatus..

one conventional developing apparatus will be described below with reference to Figs. la, lb through 5 of the accompanying drawings. The conventional 25 developing apparatus, denoted by 100, processes a silicon wafer 101 with a photoresist coated on its surface. As

shown in Fig. 4a, developing apparatus 100 has wafer chuck mechanism 102 as a wafer holding means. Wafer chuck mechanism 102 is mounted on the upper end of .. rotatable shaft 103 which extends vertically. Silicon 5 wafer 101 is detachably held by wafer chuck mechanism 102 such that the surface coated with the photoresist lies horizontally and faces upwardly.

Rotatable shaft 103 with wafer chuck mechanism 102 mounted on its upper end is rotatably supported by wafer 10 rotating mechanism 104 (see Fig. 3) as a wafer rotating means which comprises a drive motor or the like. Wafer rotating mechanism 104 rotates silicon wafer 101 supported by wafer chuck mechanism 102 in a horizontal plane. 15 As shown in Fig. 3, developing apparatus 100 also has developing liquid supply mechanism 105 as a developing liquid supply means which comprises a tank and a pump, and cleaning liquid supply mechanism 106 as a cleaning liquid supply means which comprises a tank and a 20 pump, Developing liquid supply mechanism 105 supplies developing liquid 107 comprising an aqueous alkaline liquid to the surface of silicon wafer 101 held by wafer chuck mechanism 102. Cleaning liquid supply mechanism 106 supplies pure water 108 as a cleaning liquid.

25 Developing liquid supply mechanism 105 has developing nozzle 109, and cleaning liquid supply

mechanism 106 has cleaning nozzle 110. Developing ndzzle 109 and cleaning nozzle 110 are movably supported by nozzle moving mechanism 111. As shown in Figs. la through 2b, a nozzle moving mechanism (not shown) moves developing 5 nozzle 109 and cleaning nozzle 110 between a position which faces the surface of silicon wafer 101 held by wafer chuck mechanism 102 and a position retracted away from the surface of silicon wafer 101.

Devel ping nozzle 109 has a slit structure capable 10 of supplying a screen of developing liquid 107 diametrically across silicon wafer 101, which is of a disk shape, at the center of silicon wafer 101. Cleaning nozzle 110 comprises a slender pipe capable of supplying pure water 108 to a central position on silicon wafer 101.

15 As shown in Fig. 3, wafer rotating mechanism 104, developing liquid supply mechanism 105, cleaning liquid supply mechanism 106, and nozzle moving mechanism 111 are connected to operation control apparatus 112 comprising a computer as a development control apparatus. A control 20 program for controlling a developing process is installed in operation control apparatus 112. Based on the installed control program, operation control apparatus 112 controls operation of the above mechanisms 104, 105, 106, 111 to perform the developing process.

25 Devel ping apparatus 100 can develop an exposed photoresiSt coated on the surface of the silicon wafer

101 with developing liquid 107 supplied thereto.

Supplied developing liquid can be washed away from the surface of the silicon wafer 101 by pure water 108.

More specifically, as shown in Fig. 4a, silicon 5 wafer 101 whose surface is coated with a photoresist is horizontally held by wafer chuck mechanism 102. Then, as shown in Fig. 5, silicon wafer 101 held by wafer chuck mechanism 102 is rotated at a high speed by wafer rotating mechanism 104.

10In a period 0 shown in Fig. 5, developing nozzle 109 of developing liquid supply mechanism 105 is moved to a position facing the surface of silicon wafer 101 by nozzle moving mechanism 111. Thereafter, as shown in Fig. 4b, in a period @0 shown in Fig. 5, developing liquid 15supply mechanism 105 supplies developing liquid 107 to the surface of silicon wafer 101 which is being rotated at a high speed.

While developing liquid 107 is being supplied to the surface of silicon wafer 101, the rotation of silicon 20 wafer 101 is gradually decelerated to a predetermined speed, after which the supply of developing liquid 107 is stopped. As shown in Fig. 4c, a puddle of developing liquid 107 is now formed on the surface of silicon wafer 101. In a period (9 shown in Fig. 5, the puddle of 25 developing liquid 107 is maintained on the surface of silicon wafer 101 to develop the exposed photoresist.

Developing nozzle 109 is moved to the position away from the surface of silicon wafer 101 by nozzle moving mechanism 111. At the same time, cleaning nozzle 110 of cleaning liquid supply mechanism 106 is moved to the 5 position facing the surface of silicon wafer 101 by nozzle moving mechanism 111.

After a predetermined developing tome has elapsed, silicon wafer 101 is rotated at a high speed. As shown in Fig. 4d, in a period (D shown in Fig. 5, pure water 10 108 is supplied to the surface of silicon wafer 101 which is being rotated at a high speed. Supplied pure water 108 cleans the surface of silicon wafer 101, removing developing liquid 107 from the surface of silicon wafer 101. 15 The supply of pure water 108 is stopped after elapse of a certain time. As shown in Fig. 4e, in a period () shown in Fig. 5, silicon wafer 101 is continuously rotated at a high speed even after the supply of pure water 108 is stopped, drying the surface 20 of silicon wafer 101 with air.

In illustrated conventional developing apparatus 100, developing nozzle 109 and cleaning nozzle 110 are supported by nozzle moving mechanism 111 (not shown) for movement between the position facing the surface of silicon 25 wafer 101 and the position retracted away from the surface of silicon wafer 101. However, as shown in Figs. 6a and 6b, s

another conventional developing apparatus 200 has developing nozzle 109 and cleaning nozzle 110 which are oriented toward the center of silicon wafer 101.

With conventional developing apparatus 200, it is 5 not possible to eject pure water 108 vertically from cleaning nozzle 110 to the surface of silicon wafer lot.

However, since it is not necessary to move developing nozzle 109 and cleaning nozzle 110 to the overlapping position, developing nozzle 109 and cleaning nozzle llO 10 do not need to be replaced with each other.

Therefore, a developing process can quickly be completed, since developing nozzle 109 and cleaning nozzle 110 are not required to move in the developing process.

However, even in this case, developing nozzle 109 and 15 cleaning nozzle 110 are moved for the replacement of silicon wafer 101.

With conventional developing apparatus loo, 200, the exposed photoresist coated on the surface of silicon wafer 101 can be developed with developing liquid 107, 20 and developing liquid 107 can be washed away from the surface of silicon wafer 101 with pure water 108.

However, actual developing processes performed on silicon wafer 101 by conventional developing apparatus 100, 200 have resulted in many developing defects.

25 Attempts that have been made to find out causes of such developing defects have revealed that when developing

liquid 107 is supplied to the surface of silicon wafer 101 that is rotating at a high speed, mist 120 is À Produced and contaminates developing nozzle 109, as shown.

in Fig. 4b.

5 Mist 120 is composed of the developing liquid containing particles of the photoresist. If mist 120 is deposited on developing nozzle 109 and supplied together with developing liquid 107 in the process of developing an exposed photoresist on next silicon wafer 101, then a 10 developing failure tends to occur on a resist pattern on silicon wafer 101.

In recent years, efforts are being made to increase the diameter of silicon wafer 101 and make resist patterns finer. In view of such efforts, there is a 15 tendency to use a longer developing nozzle 109 to apply developing liquid 107 uniformly to the surface of silicon wafer 101 at a high speed. Therefore, developing nozzle 109 necessarily has an increased area contaminated by mist 120 and hence is liable to cause a greater 20 developing failure on the resist pattern on silicon wafer 101. SUMMARY OF THE INVENTION

It is therefore an object of the preferred embodiment 25 of the present invention to provide a method of, and an apparatus for, developing an exposed photoresist coated on the surface of a silicon

wafer without causing a developing failure, a development control apparatus for controlling various components of a developing apparatus without causing a developing failure, and an information storage medium which stores, as 5 software, a program for enabling a computer to perform various processing operations without causing a developing failure.

According to an aspect of the present invention, there is provided a method of developing an exposed 10 photoresist coated on a surface of a silicon wafer with a developing liquid. In this method, a cleaning liquid is supplied to the surface of the silicon wafer held by wafer holding means to form a puddle of the cleaning liquid before a developing liquid is supplied to the 15 surface of the silicon wafer. Thereafter, the silicon wafer with the puddle of the cleaning liquid formed thereon is rotated in a horizontal plane, and the developing liquid is supplied to the surface of the silicon wafer.

20 Therefore' the developing liquid is supplied to the surface of the silicon wafer with the puddle of the cleaning liquid formed thereon. An impurity produced by a mist deposited on a developing nozzle and supplied with the developing liquid is suspended in the puddle of the 25 cleaning liquid, and is not attached to the surface of the silicon wafer. Therefore, no developing failure

occurs on a resist pattern of a photoresist on the surface of the silicon wafer, and the photoresist can well be developed to manufacture semiconductor integrated circuits with an increased yield.

5 According to another aspect of the present invention, there is also provided a method of developing an exposed photoresist coated on a surface of a silicon wafer with a developing liquid. In this method, before a developing liquid is supplied from developing liquid 10 supply means to a surface of a silicon wafer held by wafer holding means, the silicon wafer is rotated by wafer rotating means, and a cleaning liquid is supplied from cleaning liquid supply means to the surface of the silicon wafer. Then, the developing liquid is supplied 15 from the developing liquid supply means to the surface of the silicon wafer which is being supplied with the cleaning liquid while the silicon wafer is being rotated.

In the above method, the developing liquid is supplied to the surface of the silicon wafer which is 20 being supplied with the cleaning liquid. An impurity contained in the developing liquid is suspended in the cleaning liquid that is being supplied, and is prevented from being attached to the surface of the silicon wafer.

According to still another aspect of the present 25 invention, there is provided an apparatus for developing an exposed photoresist coated on a surface of a silicon

wafer with a developing liquid, comprising wafer holding means, wafer rotating means, developing liquid supply means, cleaning liquid supply means, cleaning control means, and development control means. The wafer holding 5 means holds the silicon wafer horizontally such that the surface coated with the photoresist faces upwardly. The wafer rotating means rotates the silicon wafer held by the wafer holding means in a horizontal plane. The developing liquid supply means supplies a developing 10 liquid to the surface of the silicon wafer held by the wafer holding means. The cleaning liquid supply means supplies a cleaning liquid to the surface of the silicon wafer held by the wafer holding means. The cleaning control means and the development control means control 15 the developing liquid supply means, the cleaning liquid supply means, and the wafer rotating means.

specifically, the cleaning control means controls the cleaning liquid supply means to supply the cleaning liquid to form a puddle of the cleaning liquid on the 20 surface of the silicon wafer before the developing liquid is supplied from the developing liquid supply means to the surface of the silicon wafer held by the wafer holding means. The development control means controls the wafer rotating means to start rotating the silicon 25 wafer and controlling the developing liquid supply means to start supplying the developing liquid after the puddle

of the cleaning liquid is formed on the surface of the silicon wafer by the cleaning control means. Therefore, the developing liquid is supplied to the surface of the silicon wafer with the puddle of the cleaning liquid 5 formed thereon.

According to yet another aspect of the present invention, there is also provided an apparatus for developing an exposed photoresist coated on a surface of a silicon wafer with a developing liquid. In this 10 apparatus, the cleaning control means and the development control means control the developing liquid supply means, the cleaning liquid supply means, and the wafer rotating means in a manner different from the pattern described above. Specifically, the cleaning control means controls 15 the wafer rotating means to rotate the silicon wafer held by the wafer holding means and controlling the cleaning liquid supply means to supply the cleaning liquid to the surface of the silicon wafer before the developing liquid is supplied from the developing liquid supply means to 20 the surface of the silicon wafer. The development control means controls the developing liquid supply means to supply the developing liquid to the surface of the silicon wafer which is being supplied with the cleaning liquid while the silicon wafer is being rotated by the 25 cleaning control means. Therefore, the developing liquid is supplied to the surface of the silicon which is being

supplied with the cleaning liquid.

In the above apparatus, the cleaning control means stops supplying the cleaning liquid after the developing liquid starts being supplied, and the development control 5 means ends supplying the developing liquid after stopping supplying the cleaning liquid. Specifically, the surface of the silicon wafer is supplied with both the cleaning liquid and the developing liquid. Then, the supply of the cleaning liquid is stopped. Thereafter, the supply 10 of the developing liquid is stopped. Consequently, the photoresiSt on the surface of the silicon wafer is well developed by the developing liquid that is eventually supplied solely.

The apparatus also has wafer cleaning means for 15 controlling the cleaning liquid supply means to supply the cleaning liquid to the surface of the silicon wafer after the photoresist thereon is developed. The developing liquid on the surface of the silicon wafer after the photoresist thereon is developed is removed by 20 the cleaning liquid supplied from the cleaning liquid supply means. Thus, means for supplying the cleaning liquid to the silicon wafer before the developing liquid is supplied is also used as means for supplying the cleaning liquid to remove the developing liquid. It is 25 therefore possible to provide a developing apparatus which is simple in structure and capable of preventing

exposure defects, without the need for adding dedicated hardware. The apparatus further has developing liquid deaerating means for deaerating the developing liquid 5 supplied to the surface of the silicon wafer. Since the developing liquid supplied to the surface of the silicon wafer is deaerated by the developing liquid deaerating means, a developing liquid containing air bubbles is not supplied to the surface of the silicon wafer.

10 A development control apparatus according to the present invention is provided in the above developing apparatus for controlling operation of the wafer holding means, the wafer rotating means, the cleaning liquid supply means, and the developing liquid supply means.

15 According to an aspect of the present invention, the development control apparatus has cleaning control means and development control means. The cleaning control means controls the cleaning liquid supply means to supply the cleaning liquid to form a puddle of the 20 cleaning liquid on the surface of the silicon wafer before the developing liquid is supplied from the developing liquid supply means to the surface of the silicon wafer held by the wafer holding means. The development control means controls the wafer rotating 25 means to start rotating the silicon wafer and controlling the developing liquid supply means to start supplying the

developing liquid after the puddle of the cleaning liquid is formed on the surface of the silicon wafer by the cleaning control means.

According to another aspect of the present 5 invention' the development control apparatus controls the developing liquid supply means, the cleaning liquid supply means, and the wafer rotating means in a manner different from the above pattern. Specifically, the cleaning control means controls the wafer rotating means . 10 to rotate the silicon wafer held by the wafer holding means and controlling the cleaning liquid supply means to supply the cleaning liquid to the surface of the silicon wafer before the developing liquid is supplied from the developing liquid supply means to the surface of the 15 silicon wafer. The development control means controls the developing liquid supply means to supply the developing liquid to the surface of the silicon wafer which is being supplied with the cleaning liquid while the silicon wafer is being rotated by the cleaning 20 control means.

The various means referred to in the present invention may be arranged to operate depending on their functions. These means may be implemented by dedicated hardware that operates depending on the functions, a 25 computer that operates depending on the functions according to a program, a program for enabling a computer

to operate depending on the functions, or a combination thereof. An information storage medium according to the present invention stores a program for controlling 5 operation of the wafer holding means, the wafer rotating means, the cleaning liquid supply means, and the developing liquid supply means in the above developing apparatus.. According to an aspect of the present invention, 10 the information storage medium stores a program which enables a computer to perform a process including the steps of controlling the cleaning liquid supply means to supply the cleaning liquid to form a puddle of the cleaning liquid on the surface of the silicon wafer 15 before the developing liquid is supplied from the developing liquid supply means to the surface of the silicon wafer held by the wafer holding means, and controlling the wafer rotating means to start rotating the silicon wafer and controlling the developing liquid 20 supply means to start supplying the developing liquid after the puddle of the cleaning liquid is formed on the surface of the silicon wafer by the cleaning control means. According to another aspect of the present 25 invention, the information storage medium stores a program which enables a computer to perform a process

including the steps of controlling the wafer rotating means to rotate the silicon wafer held by the wafer holding means and controlling the cleaning liquid supply means to supply the cleaning liquid to the surface of the 5 silicon wafer before the developing liquid is supplied from the developing liquid supply means to the surface of the silicon wafer, and controlling the developing liquid supply means to supply the developing liquid to the surface of the silicon wafer which is being supplied with 10 the cleaning liquid while the silicon wafer is being rotated by the cleaning control means.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred features of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figs. la and lb are perspective views showing a 20 central.strUCtUre of a first conventional developing apparatus; Figs. 2a and 2b are plan views of the central structure of the first conventional developing apparatus shown in Figs. la and lb;., 25. Fig. 3 is a block diagram of the first conventional developing apparatus shown in Figs. la and lb;

Figs. 4a through 4e are views illustrative of a developing process carried out by the first conventional developing apparatus shown in Figs. la and lb; Fig. 5 is a sequence chart showing the developing 5 process carried out by the first conventional developing apparatus shown in Figs. la and lb; Figs. 6a and 6b are perspective view and plane view showing a central structure of a second conventional developing apparatus, respectively; 10 Figs. 7a through 7g are views illustrative of a developing process carried out by a developing apparatus according to the present invention; Figs. 8a and 8b are perspective views showing a central structure of the developing apparatus shown in 15 Fig. 7a; Fig. 9 is a block diagram of the developing apparatus shown in Fig. 7a; Fig. 10 is a perspective view of a computer for serving as an operation control circuit shown in Fig. 9; 20 Fig. 11 is a sequence chart showing the developing process carried out by the developing apparatus shown in Fig. 7a; Fig. 12 is a flowchart of the developing process carried out by the developing apparatus shown in Fig. 7a; 25 Figs. 13a and 13b are perspective view and plane view showing a central structure of a modified developing

apparatus according to the present invention, respectively; Fig. 14 is a sequence chart showing a developing process carried out by the developing apparatus shown in 5 Figs. 13a and lab; and, . Fig. 15 is a flowchart of the developing process carried out by the developing apparatus shown in Figs. 13a and lab.

10 DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in Figs. 7a through 10, developing apparatus 300 according to the present invention has a hardware arrangement that is similar to the conventional developing apparatus 100. Specifically, developing 15 apparatus 300 comprises wafer chuck mechanism 302 as a wafer holding means, wafer rotating mechanism 304 as a wafer rotating means, developing liquid supply mechanism 305 as a developing liquid supply means, cleaning liquid supply mechanism 306 as a cleaning liquid supply means, 20 nozzle moving mechanism 311, and operation control circuit 312 as a development control apparatus.

Operation control circuit 312 comprises computer 315 shown in Fig. 10 and a control program for enabling computer 315 to perform its operation. The program is 25 stored in memory 316 that serves as an information storage medium in computer 315.

The control program: installed in operation control circuit 312 is different from the control program installed in conventional developing apparatus 100.

Therefore' details of a developing process carried out by 5 mechanisms 304 - 306, 311 are different from those of the developing process carried out by conventional developing apparatus 100.

specifically, operation control circuit 312 is operated according to the installed control program to 10 function as a cleaning contra!. means, a development control means, and a wafer cleaning means. Before the surface of silicon wafer 301 held by wafer chuck mechanism 302 is supplied with developing liquid 307 by developing liquid supply mechanism 305, operation control 15 circuit 312 controls cleaning liquid supply mechanism 306 to supply pure water 308 to form a puddle on the surface of silicon wafer 301. A program for performing such an operation and computer 315 for outputting command signals to carry out the operation according to the program are 20 combined into cleaning control circuit 313 as the cleaning control means.

After the puddle of cleaning liquid 308 is formed, operation control circuit 312 controls wafer rotating mechanism 304 to start rotating silicon wafer 301 and 25 also controls developing liquid supply mechanism 305 to start supplying developing liquid 307. After the

development of the photoresist with developing liquid 307 is completed, operation control circuit 312 controls cleaning liquid supply mechanism 306 to supply pure water 308 to the surface,of silicone wafer 301 to remove 5 developing 1iquid 307. A program for performing such an Operation and computer 315 for outputting command signals to carry out the operation according to the program are combined into development control circuit 314 as the development control means.,, 10 In developing apparatus,300, a developing liquid deaerating means comprising a vacuum pump or the like is connected to developing liquid supply mechanism 305. The developing liquid deaerating means deaerates developing liquid 307 that is supplied from developing liquid supply 15 mechanism 305 to the surface of silicon wafer 301.

A process of developing an exposed photoresist with developing apparatus 300 according to the present invention will be described below. As shown in Fig. 7a, silicon wafer 301 whose surface is coated with a 20 photoresist is horizontally held by wafer chuck mechanism 302. Then, as shown in Fig. 11, silicon wafer 301 held by wafer chuck mechanism 302 is rotated at a high speed by wafer rotating mechanism 304.

In a period 09 shown in Fig. 11, cleaning nozzle 310 25 of cleaning liquid supply mechanism 306 is moved to a position facing the surface of silicon wafer 301 by

nozzle moving mechanism 311. Thereafter, as shown in Fig. 7b, in a period (a) shown in Fig. 11, pure water 308 is supplied to the surface of silicon wafer 301 which is being rotated at a high speed.

5 while pure water 308 is being supplied to the surface of silicon wafer 301, the rotation of silicon wafer 301 is gradually decelerated to a predetermined speed, after which the supply of pure water 308 is stopped. As shown in Fig. 7c, a puddle of pure water 308 10 is now formed on the surface of silicon wafer 101.

In a period (A shown in Fig. 11, developing nozzle 309 of developing liquid supply mechanism 305 is moved to a position facing the surface of silicon wafer 301 by nozzle moving mechanism 311. Thereafter, as shown in Fig. 15 7d, in a period (I) shown in Fig. 11, wafer rotating mechanism 304 rotates silicon wafer 301 and developing liquid supply mechanism 305 supplies developing liquid 307 to the surface of silicon wafer 301. Therefore, developing liquid 307 is supplied to the surface of 20 silicon wafer 301 on which the puddle of pure water 308 has been formed.

While developing liquid 307 is being supplied to the surface of silicon wafer 301, the rotation of silicon wafer 301 is gradually accelerated and then gradually 25 decelerated to a predetermined speed, after which the supply of developing liquid 307 is stopped. The pure

water 308 is progressively removed from the surface of silicon wafer 301, and a puddle of developing liquid 307 is now formed on the surface of silicon wafer 301. As shown in Fig. 7e, in a period (shown in Fig. 11, the 5 puddle of developing liquid 307 is maintained on. the surface of silicon wafer 301 for a predetermined time to develop the exposed photoresist. À Thereafter, silicon wafer 301 is processed in the same manner as with

the developing process carried out by 10 conventional developing apparatus 100. After elapse of a certain tome, silicone wafer 301 is rotated at a high speed, developing liquid 307 is removed by pure water 308, thereafter the supply of pure water 308 is stopped, and the surface of silicon wafer 301 is dried by air.

15 With developing apparatus 300 according to the present embodiment, as described above, before developing liquid 307 is supplied from developing liquid supply mechanism 305 to the surface of silicon wafer 301, pure water 308 is supplied from cleaning liquid supply À20 mechanism 306 to form a puddle of pure water 308 on the surface of silicon wafer 301. After the puddle of pure water 308 is on the surface of silicon wafer 301, silicon wafer 301 is rotated by wafer rotating mechanism 304 and the surface of silicon wafer 301 is supplied with 25 developing liquid 307 from developing liquid supply mechanism 305..

Therefore, even if a mist is produced from developing liquid 307 supplied to the surface of silicon wafer 301 and deposited on developing nozzle 309, and even if an impurity contained in the mist is supplied S together with developing liquid 307 to silicon wafer 301, the impurity contained in supplied developing liquid 307 is suspended in the puddle of pure water 308 and is not attached to the surface of silicon wafer 301.

According to the developing process carried gut by 10 developing apparatus 300, therefore, no developing failure occurs on the resist pattern of the photoresist on the surface of silicon wafer 301, and the photoresist can well be developed to manufacture semiconductor integrated circuits with an increased yield.

15 Cleaning liquid supply mechanism 306 that supplies pure water 308 to remove developing liquid 307 from the surface of silicon wafer 301 whose photoresist has been developed is also used to supply pure water 308 to the surface of silicon wafer 301 to prevent a developing 20 failure from occurring on the resist pattern. Therefore, no additional dedicated equipment is required, and developing apparatus 300 is relatively simple in structure. With developing apparatus 300, furthermore, 25 developing liquid 307 supplied from developing liquid supply mechanism 305 to the surface of silicon wafer 301

is deaerated by the developing liquid deaerating means.

Therefore, the surface of the photoresist is not supplied with developing liquid 307 which contains air bubbles.

Consequently, the resist pattern of the photoresist 5 on the surface of silicon wafer 301 does not suffer a developing failure due to air bubbles which would otherwise be contained in developing liquid 307. It is not necessary to form a puddle of pure water 308 on the surface of silicon wafer 301 in order to prevent a 10 developing failure on the resist pattern due to air bubbles which would otherwise be contained in developing liquid 301.

The present invention is not limited to details shown in the above embodiment, but various modifications 15 may be made therein without departing from the scope thereof. For example, while in the above embodiment developing nozzle 309 and cleaning nozzle 310 are supported by nozzle moving mechanism 311 for movement between the position which faces the surface of silicon 20 wafer 301 and the position retracted away from the surface of silicon wafer 301. However, as shown in Figs. 13a and lab, the principles of the present invention are also applicable to a developing apparatus 400 which has developing nozzle 309 and cleaning nozzle 310 which are 25 oriented toward the center of silicon wafer 301.

In such a modification, after a puddle of pure

water 308 is formed, developing liquid 307 may start to be supplied and silicon wafer 301 may start to be rotated.

However, the following processing operation may be performed. As shown in Fig. 15, in a period 0) shown in 5 Fig. 14, wafer rotating mechanism 304 rotates silicon wafer 301, and developing nozzle 309 and cleaning nozzle 310 are set in a position facing the surface of silicon wafer 301.

Then, in a period (0 shown in Fig. 14, before 10 developing liquid 307 is supplied from developing liquid supply mechanism 305, pure water 308 is supplied from cleaning liquid supply mechanism 306 to the surface of silicon wafer 301, and thereafter, in a period (0 shown in Fig. 14, developing liquid 307 is supplied from 15 developing liquid supply mechanism 305 to the surface of silicon wafer 301 which is being supplied with pure water 308 while in rotation. After developing liquid 307 starts to be supplied, the supply of pure water 308 i" stopped. After the supply of pure water 308 is stopped, 20 the supply of developing liquid 307 is stopped.

Thereafter' silicon wafer 301 is processed in the same manner as with the developing process carried out by conventional developing apparatus 100.

As described above, only pure water 308 is supplied 25 at first, then both pure water 308 and developing liquid 307 are supplied, and finally only developing liquid 307

is supplied. Accordingly, a contaminant from developing nozzle 309 is also prevented from being attached to the surface of silicon wafer 301, so that the resist pattern is prevented from suffering a developing failure and the' 5 photoresiSt can well be developed.

According to the developing process carried ou;t by the developing apparatus 400 which has both developing nozzle 309 and cleaning nozzle 310 oriented toward the center of silicon wafer 301, since developing nozile 309 10 and cleaning nozzle 310 do not need to be moved during the developing process, silicon wafer 301 can be processed more quickly than according to the developing process carried out by the developing apparatus 300.

In the above embodiments, pure water 308 is used as 15 the cleaning liquid. However, the cleaning liquid may comprise a liquid which does not produce any residues when dried with air and which is capable of cleaning developing liquid 307 without affecting the photoresist, such as a solution of alcohol or pure water mixed with a 20 surface active agent.

In the above embodiments, suitable software is installed in operation control circuit 312, which comprises a computer, to provide various means including the cleaning control means and the development control 25 means. However, these various means may be implemented by respective dedicated pieces of hardware, or may be

partly implemented by software and partly implemented by hardware. While preferred embodiments of the present invention have been described using specific terms, such description

5 is for illustrative purposes only, and it is to be under-

stood that changes and variations may be made without departing from the scope of the following claims.

Each feature disclosed in this specification (which

term includes the claims) and/or shown in the drawings may 10 be incorporated in the invention independently of other disclosed and/or illustrated features.

The text of the abstract filed in the parent application is repeated here as part of the specification.

With a silicon wafer held horizontally such that a 15 surface thereof coated with a photoresist faces upwardly, the surface of the silicon wafer is supplied with a cleaning liquid to form a puddle thereon before a developing liquid is supplied. After the puddle of the cleaning liquid is formed, the silicon wafer starts to be 20 rotated and the developing liquid starts to be supplied to the surface of the silicon wafer. The developing liquid is supplied to the surface of the silicon wafer with the puddle of the cleaning liquid being formed thereon. Al-

ternatively, developing liquid is supplied to the surface 25 of the silicon wafer which is being supplied with cleaning liquid while the silicon wafer is being rotated.

Claims (35)

CLAIMS:

1. A method of developing an exposed photoresist coated on a surface of a silicon wafer with a developing liquid, comprising the steps of: holding the silicon wafer horizontally such that the surface coated with the photoresist faces upwardly; rotating the silicon wafer; supplying a cleaning liquid to the surface of the silicon wafer while the silicon wafer is rotated; and, supplying said developing liquid to the surface of the silicon wafer while the silicon wafer continues to be rotated.

2. A method according to claim 1, wherein the step of supplying a cleaning liquid uses a liquid-supplying nozzle.

3. A method according to claim 1, wherein the step of supplying said developing liquid uses a liquid-

supplying nozzle.

4. A method according to claim 1, wherein the step of supplying said developing liquid includes supplying said developing liquid while gradually decelerating rotation of the silicon wafer.

5. A method according to claim 1, further

comprising: after supplying said developing liquid, supplying pure water to the silicon wafer.

6. A developing apparatus, comprising a wafer holding means, a wafer rotating means, a cleaning-liquid supply means, a developing-liquid supply means, and a development control means, wherein the development control means is adapted to exercise control such that: the wafer holding means is able to hold a silicon wafer horizontally such that a surface thereof coated with a photoresist faces upwardly; the wafer rotating means is able to rotate the silicon wafer; the cleaning-liquid supply means is able to supply cleaning liquid to the surface of the silicon wafer while the silicon wafer is rotated; and, the developing-liquid supply means is able to supply developing liquid to the surface of the silicon wafer while the silicon wafer continues to be rotated.

7. The developing apparatus according to claim 6, wherein the cleaningliquid supply means includes a liquid-supplying nozzle.

8. The developing apparatus according to claim 6, wherein the developingliquid supply means includes a liquid-supplying nozzle.

9. The developing apparatus according to claim 6, wherein the wafer rotating means is able to, while the developing liquid is being supplied, gradually decelerate rotation of the silicon wafer.

10. The developing apparatus according to claim 6, wherein the cleaningliquid supply means is able to, after the developing liquid has been supplied, supply pure water to the silicon wafer.

11. A development control apparatus for controlling a wafer holding means, a wafer rotating means, a cleaning-

liquid supply means, and a developing-liquid supply means of a developing apparatus, the development control apparatus being adapted to exercise control such that: the wafer holding means is able to hold a silicon wafer horizontally such that a surface thereof coated with a photoresist faces upwardly; the wafer rotating means is able to rotate the silicon wafer; the cleaning-liquid supply means is able to supply cleaning liquid to the surface of the silicon wafer while the silicon wafer is rotated; and, the developing-liquid supply means is able to supply developing liquid to the surface of the silicon wafer while the silicon wafer continues to be rotated.

12. The development control apparatus according to

claim 11, wherein the cleaning-liquid supply means includes a liquidsupplying nozzle.

13. The development control apparatus according to claim 11, wherein the developing-liquid supply means includes a liquid-supplying nozzle.

14. The development control apparatus according to claim 11, wherein the development control apparatus is able to exercise control such that the wafer rotating means is able to, while the developing liquid is being supplied, gradually decelerate rotation of the silicon wafer.

15. The development control apparatus according to claim 11, wherein the development control apparatus is able to exercise control such that the cleaning-liquid supply means is able to, after the developing liquid has been supplied, supply pure water to the silicon wafer.

16. An information storage medium storing a program for controlling a computer to perform the method of developing that is set out in any one of claims 1 to 5.

17. A method of developing an exposed photoresist coated on a surface of a silicon wafer, the method being substantially as herein described with reference to and as shown in Figures 13a to 15 of the accompanying drawings.

18. An apparatus for developing an exposed photo-

resist coated on a surface of a silicon wafer, the apparatus being substantially as herein described with reference to and as shown in Figures 13a to 15 of the accompanying drawings.

19. A development control apparatus in a developing apparatus, the development control apparatus being sub-

stantially as herein described with reference to and as shown in Figures 13a to 15 of the accompanying drawings.

20. An information storage medium storing a program for controlling a computer to perform a process in a developing apparatus, the information storage medium being substantially as herein described with reference to and as shown in Figures 13a to 15 of the accompanying drawings.

21. A method of developing, with a developing liquid, an exposed photoresist coated on a surface of a silicon wafer, comprising the steps of: holding the silicon wafer horizontally and rotatably such that the surface coated with the photoresist faces upwardly; supplying a cleaning liquid to the surface of the silicon wafer thus held; and, supplying a developing liquid to the surface of the silicon wafer whilst rotating the silicon wafer.

22. A method as in claim 21, wherein the step of supplying the cleaning liquid to the surface of the silicon wafer takes place before the rotation of the silicon wafer, the supplied cleaning liquid forming a puddle on the surface before rotation.

23. A method as in claim 21, wherein the step of supplying the cleaning liquid to the surface of the silicon wafer takes place during the rotation of the silicon wafer.

24. A method as in claim 23, wherein the step of supplying the developing liquid commences before, and finishes after, the time at which step of supplying the cleaning liquid finishes.

25. A method as in any preceding claim, comprising the additional step of supplying further cleaning liquid to the surface of the silicon wafer after the step of supplying the developing liquid finishes.

26. An apparatus for developing, with a developing liquid, an exposed photoresist coated on a surface of a silicon wafer, comprising: wafer holding means for holding the silicon wafer horizontally such that the surface coated with the photo-

resist faces upwardly; wafer rotating means for rotating the silicon wafer

held by said wafer holding means in a horizontal plane; developing liquid supply means for supplying the developing liquid to the surface of the silicon wafer held by said wafer holding means; cleaning liquid supply means for supplying a cleaning liquid to the surface of the silicon wafer held by said wafer holding means; cleaning control means for controlling said cleaning liquid supply means to supply said cleaning liquid to the surface of the silicon wafer before said developing liquid supply means supplies developing liquid to the surface of the silicon wafer; and, development control means for controlling said wafer rotating means to rotate said silicon wafer and to control said developing liquid supply means to start supplying developing liquid to the surface of the silicon wafer while the silicon wafer is rotating.

27. An apparatus as in claim 26, wherein the cleaning control means is adapted to supply the cleaning liquid to the surface of the silicon wafer before said development control means controls said wafer rotating means to rotate said silicon wafer.

28. An apparatus as in claim 26, wherein the cleaning control means is adapted to supply the cleaning liquid to the surface of the silicon wafer after said development control means controls said wafer rotating

means to rotate said silicon wafer.

29. An apparatus according to claim 28, wherein said cleaning control means comprises means for stopping supplying said cleaning liquid after said developing liquid starts being supplied, and said development control means comprises means for ending supplying said developing liquid after stopping supplying said cleaning liquid.

30. An apparatus as in any one of claims 26 to 29, further comprising: wafer cleaning means for controlling said cleaning liquid supply means to supply said cleaning liquid to the surface of said silicon wafer after the photoresist thereon is developed.

31. An apparatus as in any one of claims 26 to 29, further comprising: developing liquid deaerating means for deaerating the developing liquid supplied to the surface of said silicon wafer.

32. A development control apparatus for a developing apparatus having wafer holding means for holding a silicon wafer horizontally such that a surface thereof coated with a photoresist faces upwardly, wafer rotating means for rotating the silicon wafer held by said wafer holding means in a horizontal plane, developing liquid supply

means for supplying a developing liquid to the surface of the silicon wafer held by said wafer holding means, and cleaning liquid supply means for supplying a cleaning liquid to the surface of the silicon wafer held by said wafer holding means, said development control apparatus being arranged to control said wafer holding means, said wafer rotating means, said cleaning liquid supply means, and said developing liquid supply means, and comprising: cleaning control means for controlling said cleaning liquid supply means to supply said cleaning liquid to the surface of the silicon wafer before said developing liquid is supplied from said developing liquid supply means to the surface of the silicon wafer held by said wafer holding means; and, development control means for controlling said wafer rotating means and said developing liquid supply means such that developing liquid is supplied to the surface of the silicon wafer while the silicon wafer is being rotated.

33. A development control apparatus as in claim 32, wherein the cleaning control means controls said cleaning liquid supply means to supply said cleaning liquid to the surface of the silicon wafer before said cleaning control means controls said wafer rotating means to rotate said silicon wafer.

34. A development control apparatus as in claim 32,

wherein the cleaning control means controls said cleaning liquid supply means to supply said cleaning liquid to the surface of the silicon wafer after said cleaning control means controls said wafer rotating means to rotate said silicon wafer.

35. An information storage medium storing a program for controlling a computer to perform the method of developing set out in any one of claims 1 to 5.