JP3171196B2 - Resist coating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a resist coating apparatus.

(Prior Art) Generally, a semiconductor device is manufactured by using a precision photo transfer technique. In such a semiconductor manufacturing process, for example, a resist liquid is applied to a semiconductor wafer or the like to form a photoresist film. A coating device is used.

As such a resist coating apparatus, a so-called spin coating apparatus for uniformly applying a resist liquid by rotating an object to be processed at high speed is widely used.

That is, in the resist coating apparatus, a semiconductor wafer is sucked and held by, for example, a vacuum chuck or the like on a wafer support mechanism configured to be rotatable at high speed, and a resist supply nozzle provided above the wafer support mechanism is used to send a resist by a resist solution sending mechanism. The liquid is supplied, and a predetermined amount of resist liquid is supplied to a substantially central portion of the semiconductor wafer. Then, by rotating the semiconductor wafer at a high speed, the resist liquid is diffused by centrifugal force, and the resist liquid is applied on the semiconductor wafer so as to have a uniform thickness.

In the above-described resist coating apparatus, for example, a suck back valve or the like is provided in the resist supply line, and after supplying the resist liquid, the resist liquid at the tip of the resist supply nozzle is drawn into the nozzle to prevent so-called dripping of the resist liquid. There is an apparatus configured to prevent the resist liquid from adhering to the tip of the resist supply nozzle and to prevent the resist liquid from solidifying at the tip of the nozzle.

(Problems to be Solved by the Invention) However, in general, in a coating process by a resist coating device, there is a time interval between the coating processes by the resist coating device due to, for example, a pre-treatment or a post-treatment of the resist coating. After the end of the coating process, it may be in a standby state for several minutes to several tens of minutes or for one hour or more before the next coating process is performed.

In such a case, even if the resist liquid at the tip of the resist supply nozzle is drawn into the nozzle by a suck back valve or the like, the resist liquid at the tip contacts the air in the nozzle, so The solvent evaporates and the viscosity of the resist solution increases. Then, the resist liquid having the increased viscosity is supplied onto the object to be processed at the time of the next resist coating, and adheres in a lump or, in some cases, solidifies in the nozzle, making it difficult to deliver the resist liquid. Had to be.

The present invention has been made in view of such conventional circumstances, and even when the waiting time, that is, the waiting time until the next resist coating process is lengthened, the resist liquid having a high viscosity remains on the object to be processed. An object of the present invention is to provide a resist coating apparatus which can prevent the resist liquid from being supplied or solidified in the resist supply nozzle, and can always perform a good coating process.

[Structure of the Invention] (Means for Solving the Problems) That is, the present invention relates to a resist coating apparatus provided with a resist liquid sending mechanism for sending a resist solution from a resist supply nozzle and applying the resist solution to an object to be processed. Measuring the elapsed time after stopping the resist solution delivery by the resist solution delivery mechanism; and measuring the elapsed time after stopping the resist solution delivery, the first time before the resist solution solidifies and cannot be delivered from the resist supply nozzle. When a predetermined time is exceeded, a predetermined amount of the resist solution is discarded from the resist supply nozzle, and an elapsed time after the stoppage of the resist solution delivery is a second set time shorter than the first set time. If the resist liquid having a higher viscosity due to evaporation of the solvent exceeds a second set time at which the resist liquid is supplied to the object to be processed,
A predetermined amount of the resist solution is discarded from the resist supply nozzle immediately before the resist solution is supplied to the workpiece.

The invention of claim 2 is the resist coating apparatus according to claim 1, wherein the first and second set times of the resist solution sending mechanism are different from each other by the type of the resist solution and / or the temperature and / or the temperature. Alternatively, it is characterized in that it is configured to differ depending on the condition of humidity.

(Operation) In the resist coating apparatus of the present invention, the elapsed time after the stoppage of the resist solution delivery by the resist solution delivery mechanism is measured. Then, the elapsed time is compared with the time stored in the memory in advance, and if the time exceeds a preset time (predetermined by the type of the resist solution), for example, immediately after the elapse of the set time, or After the lapse of time, before the next application of the resist, the resist liquid delivery mechanism is operated by the instruction of the computer, and a predetermined amount of the resist liquid existing in the tip of the nozzle is discarded from the resist supply nozzle. When the waiting time is long, it is executed not only once but intermittently a plurality of times.

Therefore, even when the waiting time until the next resist coating process becomes long, it is possible to prevent the resist liquid having increased viscosity from being supplied onto the object to be processed or the resist liquid from being hardened in the resist supply nozzle. It is possible to always carry out a good coating treatment.

(Embodiment) An embodiment in which the present invention is applied to a resist coating apparatus for coating a semiconductor wafer with a resist solution will be described below with reference to the drawings.

As shown in FIG. 1, a wafer support mechanism 1 is configured such that a semiconductor wafer 2 as an object to be processed is sucked and held on an upper surface thereof by, for example, a vacuum chuck, and the semiconductor wafer 2 is rotated at a high speed by a rotation drive mechanism 3. Have been. Since the drive motor of the rotary drive mechanism 3 generates heat,
The rotation drive mechanism 3 is cooled by, for example, cooling water or the like,
It is preferable that the configuration is such that heat is not transmitted to the semiconductor wafer 2.

Further, the resist coating apparatus is provided with a resist liquid storage bottle 4 for storing a predetermined resist liquid, and the resist liquid storage bottle 4 is filled with the resist liquid in the resist liquid storage bottle 4 by a predetermined amount. A resist solution delivery mechanism 5 configured to allow delivery is connected. The resist solution delivery mechanism 5 includes, for example, a suck-back valve, a pump, and the like, which suck the resist solution at the tip of the nozzle after stopping the supply of the resist solution, similarly to a well-known conventional resist coating apparatus.

Further, a resist supply nozzle 6 is connected to the resist solution delivery mechanism 5 so as to be located above the wafer support mechanism 1. The resist supply nozzle 6 is configured to be rotatable by a nozzle driving mechanism 7 as shown by an arrow in the drawing, and the tip of the nozzle is located above the center of the semiconductor wafer 2 (coating position) and above the waste liquid collecting unit 8 (standby position). It is configured to move between

A cup 9 is provided around the wafer support mechanism 1 so as to surround the wafer support mechanism 1. The cup 9 is for preventing the resist solution from scattering around when the semiconductor wafer 2 is rotated at a high speed as described later.

Further, the rotation drive mechanism 3, the resist solution delivery mechanism 5, and the nozzle drive mechanism 7 are connected to a control unit 10 composed of, for example, a microcomputer or the like, and are configured to be totally controlled by the control unit 10. I have.

When a predetermined resist liquid is applied to the semiconductor wafer 2 by the resist coating apparatus of this embodiment having the above-described configuration to form a photoresist film of a predetermined thickness, a resist liquid storage bottle is previously prepared as in the conventional resist coating apparatus. 4, a predetermined resist solution is stored, and the amount of the resist solution delivered by the resist solution delivery mechanism 5 is set.

In the resist coating apparatus of this embodiment, two types of set times T ₁ and T ₂ are set in the control unit 10 in advance.

The T ₁ may cause to resist liquid completely solidifies in the resist supply nozzle 6 is for the resist solution delivery is prevented from becoming disabled, waiting time is not performed the coating process set this in advance If a is the stored time above T _1, regardless of whether or not to carry out the coating, sends the operation command signal to the resist liquid discharging mechanism 5, the disposal of the resist solution preset amount (dummy dispense) It is for implementing. Therefore, the time T ₁ is set to a longer time compared to like T _2, for example, 30 minutes or 1 hour. Of course T ₁ is different from the kind of the resist solution, temperature, atmospheric conditions such as humidity.

Further, the T ₂ are, by evaporation of the solvent, is intended to prevent the raised resist solution viscosity is supplied to the semiconductor wafer 2, the waiting time that does not implement the coating process the T ₂ or more and If this happens, the dummy dispense is performed immediately before the application to the semiconductor wafer 2. Therefore, it is set to be shorter compared to example 10 minutes or 20 minutes, etc. T _1.

Note that these T ₁ and T ₂ are set in consideration of the above-described conditions depending on the type of the resist solution to be subjected to the coating treatment.
For example, in the case of a resist solution in which the solvent is easily evaporated and hardened, T ₁ and T ₂ are set to short times. In addition, in the case of a resist solution that is difficult to harden, the consumption of the resist solution can be suppressed by setting T ₁ and T ₂ to a relatively long time.

Next, the operation of the resist coating apparatus will be described with reference to FIG.

For example, when a main switch (not shown) of the resist coating device is turned on, the control unit 10 causes the nozzle driving mechanism 7 to move the resist supply nozzle 6 to a standby position (above the waste liquid collecting unit 8).
And the resist solution delivery mechanism 5
The resist liquid in the resist liquid storage bottle 4 is delivered to the tip of the resist supply nozzle 6, and a predetermined amount of the resist solution is delivered from the tip of the resist supply nozzle 6 in the next delivery operation, so that the resist coating process can be performed. State (standby state) (21).

Thereafter, measurement of the elapsed time t after the end of the operation of the resist solution delivery mechanism 5 is started (22).

When the semiconductor wafer 2 is mounted on the wafer support mechanism 1 by an automatic transfer mechanism (not shown) or the like, the control unit 10 is configured to receive a wafer mounting signal from the automatic transfer mechanism. Next, the control unit 10 waits for the input of the wafer mounting signal (23).

When there is no input of the wafer placement signal,
Comparing the T ₁ and the elapsed time t (24), when the elapsed time becomes above T _1, carried out dummy dispense (25), resets the elapsed time t to zero (26), new The measurement of the elapsed time t is started (22).

Therefore, if the semiconductor wafer 2 is not placed on the wafer support mechanism 1 during the above T ₁ and there is no input of a wafer placement signal, a dummy dispense is performed every T _1, and the inside of the resist supply nozzle 6 A predetermined amount of resist solution is collected in a waste liquid collecting unit 8.
Discarded in For this reason, it is possible to prevent the resist liquid in the resist supply nozzle 6 from solidifying even when waiting for several hours, for example, so that the resist liquid cannot be delivered.

Meanwhile when an input of the wafer mounting preamble signal is, first, it compares the elapsed time t and T ₂ as described above (27), the elapsed time t is T ₂
In these cases, after a dummy dispense (28),
A coating process is performed (29). Further, the elapsed time is carried out coating treatment without dummy dispense if it is less than T ₂ (29).

In the coating process, the resist supply nozzle 6 is moved to the coating position by the nozzle driving mechanism 7, and thereafter, a predetermined amount of the resist liquid is sent out by the resist liquid sending mechanism 5, and the resist liquid is sent to a substantially central portion of the semiconductor wafer 2. A fixed amount of resist solution is supplied, the semiconductor wafer 2 is rotated at high speed by the rotation drive mechanism 3, and the resist solution is diffused by centrifugal force, so that the thickness becomes uniform.

Thereafter, the elapsed time t is reset to zero (30),
The measurement of the elapsed time t is started again (22).

By repeating such a series of operations, a coating process for a desired number of semiconductor wafers 2 is performed.

That is, in this embodiment the resist coating apparatus, for example, a T ₁ 1 hour, if you set the T ₂ to about 10 minutes, waiting time, i.e. the time between the coating process and the subsequent coating treatment is less than 10 minutes Time, apply the coating process as it is, and wait for 10 minutes.
If the next coating process is to be performed when the time is equal to or longer than one minute and less than one hour, a dummy dispense is performed immediately before the coating process. Therefore, it is possible to prevent the resist liquid having the increased viscosity from being supplied to the semiconductor wafer 2 due to the evaporation of the solvent, and it is possible to perform a favorable coating process.

If the time until the next coating process is one hour or more, dummy dispensing is performed every hour,
It is possible to prevent the resist liquid in the resist supply nozzle 6 from hardening and the resist liquid from being unable to be delivered.

In the coating process of the conventional resist coating apparatus, a long time over (e.g. over 1 hour), since it is rarely a standby state, for example a dummy dispense function for each said T _1, it is omitted , it is also possible to only dummy dispense function by T _2. Further, by setting the T _1, for example, 10 minutes to a short time, and only the dummy dispense function for each T _1, it can be omitted dummy dispense function by T _2.

Further, for example, the cleaning may be performed by supplying a solvent into the cup 9 for each coating process, or by supplying the solvent to the tip of the resist supply nozzle 6 for cleaning. Further, when the waste liquid collecting section 8 is set to an atmosphere in which the solvent of the resist liquid is evaporated, more excellent application of the resist liquid is realized.

[Effects of the Invention] As described above, according to the resist coating apparatus of the present invention, even when the waiting time, that is, the waiting time until the next coating processing is lengthened, the resist liquid having a high viscosity can be used for the object to be processed. It is possible to prevent the resist liquid from being supplied to the top or to be hardened in the resist supply nozzle, and it is possible to always perform a favorable coating process.

[Brief description of the drawings]

FIG. 1 is a view showing the configuration of a resist coating apparatus according to one embodiment of the present invention, and FIG. 2 is a view for explaining the operation of the resist coating apparatus shown in FIG. DESCRIPTION OF SYMBOLS 1 ... Wafer support mechanism, 2 ... Semiconductor wafer, 3 ... Rotation drive mechanism, 4 ... Resist liquid storage bottle, 5 ... Resist liquid delivery mechanism, 6 ... Resist supply nozzle, 7 ... Nozzle drive mechanism, 8 ... waste liquid collecting section, 9 ... cup, 10 ...
... Control unit.

Claims (2)

(57) [Claims] 1. A resist coating apparatus provided with a resist solution sending mechanism for sending a resist solution from a resist supply nozzle and applying the resist solution to an object to be processed. When the time elapsed after the stoppage of the resist solution supply exceeds a first set time before the resist solution solidifies and cannot be delivered from the resist supply nozzle, a predetermined time is taken from the resist supply nozzle. Along with discarding a fixed amount of the resist solution, the elapsed time after the stoppage of the resist solution delivery is a second set time shorter than the first set time, and the resist solution having increased viscosity due to evaporation of the solvent is When a second set time period during which the resist solution is supplied to the object is exceeded, the resist supply is performed immediately before the resist solution is supplied to the object. Resist coating apparatus characterized by discarding a prescribed amount of the resist solution from the nozzle. 2. The resist coating apparatus according to claim 1, wherein the first and second set times of the resist solution sending mechanism are different from each other by the type and / or temperature of the resist solution.
Alternatively, the resist coating apparatus is configured to be different depending on humidity conditions.