KR20020096609A - Method for controlling temperature of bake equipment - Google Patents

Abstract

According to the present invention, when baking a substrate coated with a photosensitive film having a high baking temperature and then baking another kind of substrate coated with a photosensitive film having a low baking temperature, a temperature drop in the baking chamber is achieved within the shortest time to reduce the waiting time of the baking equipment. A method of temperature control in a baking plant is minimized. In particular, when baking two kinds of substrates with different baking temperatures, the temperature difference can be overcome in the shortest time, which greatly improves productivity and enables baking of multiple substrates with a minimum baking facility. Has

Description

METHOOD FOR CONTROLLING TEMPERATURE OF BAKE EQUIPMENT}

The present invention relates to a temperature control method in a baking facility, and more particularly, after baking a substrate coated with a high baking temperature photosensitive film and baking another kind of substrate coated with a low baking temperature photosensitive film within the shortest time. The present invention relates to a temperature control method in a baking facility in which a temperature drop in a baking chamber is achieved to minimize the waiting time of the baking facility.

Recently, with the development of semiconductor manufacturing technology, the number of data that can be accumulated per unit area has increased dramatically, and semiconductor products (semiconductor devices) capable of processing more data per unit time have been developed and distributed.

Such semiconductor products are highly precise semiconductor thin film processes, for example, a deposition process for forming various thin films having inherent characteristics, an etching process for scraping off some of the already formed thin films to form a desired pattern, It is divided into a diffusion process of changing the properties of the thin film, a process of injecting impurities into the already formed thin film to improve the thin film properties, and the like.

When performing such a variety of semiconductor thin film process, most of the semiconductor thin film process is a photographic process as a prior process.

In the photolithography process, a photoresist film (hereinafter referred to as a photoresist thin film) reacting with light is formed on an upper surface of a pre-formed thin film, and then a desired portion of the photoresist thin film is exposed, and then the exposed portion is developed by a developer. (develop) and in addition to the cleaning process for cleaning the developer.

The formation of the photoresist thin film is formed by a spin coater which mainly has a very uniform thickness by dropping a photoresist material and a material containing a volatile solvent on a high-speed rotating substrate.

The photoresist thin film formed by the spin coater is cured while the volatile solvent is volatilized. However, when a predetermined thin film process is performed while the photoresist thin film is patterned by exposing and developing the volatile solvent not completely volatilized, the sidewall of the patterned photoresist thin film collapses and thus a desired thin film pattern is not formed. Occurs frequently.

For example, in the process of forming contact holes in the thin film, the photoresist thin film pattern collapses and is formed to be smaller than the diameter of the actually required contact hole or no contact hole is formed.

To prevent this, after the photoresist thin film is formed, the substrate is loaded into a “baking facility” and artificial energy is applied to the photoresist thin film to completely remove volatile solvent from the photoresist thin film, that is, to completely cure the photoresist thin film. Bar "baking process" proceeds.

However, in the baking process, the following problem occurs when baking a substrate on which two or more kinds of photoresist thin films having different baking temperatures are formed in one baking facility.

The problem is that after baking a substrate on which a photoresist thin film having a high bake temperature is formed, a photoresist thin film having a relatively low bake temperature is formed.

The problem is that the temperature rise in the bake plant can reach the desired temperature in a short time by performing by an artificial heat generating device such as an electric heater, but the temperature drop is only performed by heat conduction with the chamber of the bake plant closed. Because.

For example, it is possible to raise the temperature in the chamber of the baking equipment from 100 ° C to 150 ° C in a very short time. However, if the temperature in the baking facility is lowered from 150 ° C to 100 ° C, there are some differences depending on the installation. For example, it takes about 60 minutes longer than the time required to raise the temperature.

This means that in order to bake two or more kinds of photoresist thin films having a difference in baking temperature, a time loss of about 60 minutes occurs as a waiting time, and thus a productivity decrease occurs.

In order to prevent such time loss, it is necessary to increase the bake facility, but when the bake facility is expanded, another problem occurs due to excessive facility investment.

Accordingly, the present invention has been made in view of such a conventional problem, and an object of the present invention is to minimize the waiting time for baking two or more types of photoresist thin films having a difference in baking temperature, thereby maximizing the productivity of the baking equipment. To provide a temperature control method in.

1 is a block diagram of a baking facility for implementing a temperature control method in the baking facility according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram illustrating the entry and exit of a wafer in a baking facility according to an embodiment of the present invention.

3 is a conceptual view illustrating that cooling is performed by convection and heat conduction in a temperature control method in a baking apparatus according to an embodiment of the present invention.

4 is a conceptual view illustrating that cooling is performed only by heat conduction in a temperature control method in the baking apparatus according to an embodiment of the present invention.

5 is a conceptual diagram illustrating that baking of the substrate is performed after the temperature is controlled by the temperature adjusting method in the baking apparatus according to an embodiment of the present invention.

6 is a flow chart for implementing a temperature control method in the baking facility according to an embodiment of the present invention.

The temperature control method in the baking facility according to the present invention for realizing the object of the present invention comprises the steps of determining whether the target bake temperature is changed in accordance with the type of substrate, if the target bake temperature is changed as a result of the determination, Determining whether the target bake temperature to be lower than the current bake temperature, and when the target bake temperature is lower than the current bake temperature, cools the current bake temperature to become the target bake temperature by heat radiation by heat conduction and heat radiation by convection. Steps.

Hereinafter, with reference to the accompanying drawings, the temperature control method in the baking facility according to an embodiment of the present invention.

First, the structural features of the baking equipment will be described, and then the temperature control method in the baking equipment will be described.

1 is a conceptual diagram of the baking installation 700. The baking apparatus 600 generally includes a chamber unit, a heating unit 200, a temperature sensing unit 300, a substrate loading / unloading unit 400, and a central processing unit 100 for precisely controlling them. ). Reference numeral 410 denotes a data bus through which a data signal flows, and reference numeral 420 denotes a control bus through which a control signal flows.

In detail, the chamber unit 500 includes an upper chamber 510 and a lower chamber 520, as shown in FIG. 2.

More specifically, when the upper chamber 510 and the lower chamber 520 are in contact with each other, a predetermined space is formed therein, and the lower chamber 520 includes a heating unit 200 that consumes electrical energy to generate heat. do.

At this time, the heating unit 200 is used as a heating wire coil to generate heat by consuming electrical energy in one embodiment. If the heating unit 200 is easy to control the temperature, various heating devices may be used in addition to the heating coil.

Meanwhile, the chamber units 500 including the upper chamber 510 and the lower chamber 520 may be spaced apart from each other by a predetermined interval for the entry and exit of the substrate 600 or may be in close contact with each other to minimize the temperature change caused by the entry and exit of heat during baking. Should be.

Reference numeral 620 denotes a wafer, and 610 denotes a photoresist thin film.

As such, the substrate loading / unloading unit 400 is installed in the upper chamber 510 and the lower chamber 520.

The substrate loading / unloading unit 400 again consists of a chamber separation unit (not shown) and a substrate transfer arm 410.

The chamber separation unit serves to closely space the upper chamber 510 and the lower chamber 520 to each other or to closely contact the spaced upper and lower chambers 510 and the lower chamber 520, and to perform a precise linear reciprocating motion. You can also use an instrument.

On the other hand, the inside of the chamber unit 500 is installed a temperature sensing unit 400 for outputting a temperature signal for measuring the temperature and the temperature control for accurate temperature of the interior space of the chamber unit 500.

The temperature sensing unit 400 is preferably to use a temperature sensor capable of precise temperature measurement.

Hereinafter, with reference to Figures 1 to 6 attached to the temperature control method in the baking facility in the baking facility including such a configuration as an embodiment as follows.

First, as shown in FIG. 2, the process currently being performed at the baking facility is performed by the substrate transfer arm 410 of the substrate loading / unloading unit 500, where the first substrate 600 is baked at the first temperature. This is defined as the unloading process.

The CPU 100 checks whether the baking process of the first substrate 600 is finished and whether the subsequent baking process to be successively performed is the same type as the first substrate 600 with reference to a previously input process sequence.

As a result of the CPU 100 determining that the subsequent baking process is a second substrate 650 (see FIG. 5) that is different from the first substrate 600, the CPU 100 may include the first substrate 600. While changing from the second substrate 650 to determine whether the temperature change is necessary in the chamber unit 500 (step 10).

At this time, when the determination result of the central processing unit 100, the type of substrate is different, the temperature needs to be changed, the central processing unit 100 should be lower or higher than the internal temperature of the current chamber unit 500 to be changed (Step 20).

If the baking temperature of the second substrate 650 to be changed as a result of the determination of the central processing unit 100 is equal to or higher than the internal temperature of the current chamber unit 500, the temperature inside the chamber unit 500 is heated to a specified temperature. 200), followed by a baking process.

On the other hand, if the baking temperature of the second substrate 650 is lower than the baking temperature of the first substrate 600 as a result of the determination of the central processing unit 100, the central processing unit 100 again the temperature deviation is the first temperature difference It is judged whether it is abnormal (step 40). At this time, it is preferable that the first temperature difference is 3 ° C. in one embodiment.

At this time, the determination result of the central processing unit 100, when the temperature deviation when baking the first substrate 600 and when baking the second substrate 650 is less than the first temperature difference, the upper chamber 510 ) And the lower chamber 520 are sealed by heat conduction until the temperature of the inner space becomes a temperature suitable for baking the second substrate 650.

For example, when the temperature required to bake the first substrate 600 is 150 ° C and the temperature required to bake the second substrate 650 is 147 ° C, the first substrate 600 and the second substrate 650 Baking temperature deviation of the) is included in the first temperature difference is 3 ℃ bar, the cooling is performed only by the heat conduction in a sealed state of the upper chamber 510 and the lower chamber 520.

On the other hand, when the temperature difference between baking the first substrate 600 and baking the second substrate 650 is greater than the first temperature difference, as a result of the determination of the central processing unit 100, the central processing unit ( As shown in FIG. 3, the control command is transmitted to the chamber separation unit so that the upper chamber 510 and the lower chamber 520 are spaced apart from each other, so that the inner space of the upper chamber 510 and the lower chamber 520 is separated from each other. Heat dissipation by convection occurs with heat dissipation by heat conduction so that rapid cooling of the internal space is achieved (step 50).

For example, when the temperature required to bake the first substrate 600 is 150 ° C and the temperature required to bake the second substrate 650 is 100 ° C, the first substrate 600 and the second substrate 650 Baking temperature deviation of the) is 50 ℃ is not included in the first temperature difference bar, the central processing unit 100 is a complex cooling by the heat conduction and convection in the state in which the upper chamber 510 and the lower chamber 520 is separated. Is performed.

As described above, the temperature of the inner spaces of the upper chamber 510 and the lower chamber 520 is gradually lowered by performing the complex cooling by heat conduction and convection.

At this time, the CPU 100 receives the temperature sensing signal from the temperature sensing unit 300 at predetermined time intervals and determines whether the temperature difference in the chamber unit 500 is included in the second temperature difference (step 60).

In this case, the second temperature difference refers to a difference between a current temperature of the chamber unit 500 and a temperature after cooling (hereinafter, referred to as a target temperature), and may be the same as or different from the first temperature difference described above. In the present invention, the second temperature difference is defined as 2 ° C in one embodiment.

As a result of the determination of the CPU 100, if the difference between the current temperature and the target temperature of the chamber unit 500 is not included in the second temperature difference, the feedback is returned to step 50 to continuously perform cooling.

For example, the temperature at which the upper chamber 510 and the lower chamber 520 are opened to start cooling by heat conduction and convection is 150 ° C., and the current temperature input by the temperature sensing unit 300 is 130 ° C., When the target temperature is 100 ° C, when the difference between the target temperature and the present temperature is not included in the second temperature difference at 30 ° C, the CPU 100 continues to open the upper chamber 510 and the lower chamber 520. Allow cooling by heat conduction and convection.

On the other hand, when the internal space temperature of the chamber unit 500 is included in the second temperature difference, the central processing unit 100 transmits a control command to the chamber separation unit to the upper chamber 510 and the lower chamber as shown in FIG. The 520 is brought into close contact with each other so that cooling is performed only by thermal conduction (step 70).

For example, the temperature at which the upper chamber 510 and the lower chamber 520 are opened to start cooling by heat conduction and convection is 150 ° C., and the current temperature input by the temperature sensing unit 300 is 102 ° C., If the target temperature is 100 ° C. and the difference between the target temperature and the present temperature is only 2 ° C., the central processing unit seals the upper chamber 510 and the lower chamber 520 until the target temperature is reached only by heat conduction. To be done.

Thereafter, when the target temperature is reached, the baking process of the second substrate 650 proceeds as shown in FIG. 5 (step 80). Reference numeral 640 denotes a wafer and 630 denotes a photoresist thin film.

As described in detail above, when baking two kinds of substrates having a difference in baking temperature, the temperature difference can be overcome in the shortest time, thereby greatly improving productivity and minimizing baking of a plurality of substrates with a minimum of baking equipment. Has the effect of being able to perform.

Claims (5)

Determining whether the target bake temperature is changed according to the type of substrate; Determining that the target bake temperature to be changed is lower than the current bake temperature when the target bake temperature is changed; Determining that the target bake temperature is lower than the current bake temperature, cooling the current bake temperature to be the target bake temperature by heat radiation by heat conduction and heat radiation by convection. . The method of claim 1, wherein heat dissipation by heat conduction and heat dissipation by convection are performed when the difference between the target bake temperature and the current bake temperature is equal to or greater than a first temperature difference. The temperature control method in a baking installation of Claim 1 whose said 1st temperature difference is 3 degreeC or more. The method of claim 1, wherein the cooling of the current bake temperature to be the target bake temperature by the heat radiation by the heat conduction and the heat radiation by the convection is performed when the current bake temperature and the target bake temperature are greater than or equal to a second temperature difference. The method of temperature control in a baking installation which performs complex cooling by convection, and performs single cooling only by heat conduction, when the present baking temperature and the said target baking temperature are below 2nd temperature difference during cooling. The method of claim 4, wherein the second temperature difference is 2 ° C. 6.