JP2717108B2 - Resist treatment method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist processing method, and more particularly, to a resist processing method suitable for transporting an object to be processed such as a semiconductor wafer between semiconductor devices in a semiconductor manufacturing process.

[Prior Art] In a semiconductor manufacturing process, automatic transfer of a semiconductor wafer is generally performed due to a demand for unmanned and dust-free operation. In particular, in a system in which several processes are connected, a semiconductor wafer is transferred between each process. An automatic transfer device is indispensable. For example, surface treatment step AD and resist coating step C as shown in FIG.
In the photoresist film forming apparatus in which T, the baking step HP and the cooling step CL are connected, a plurality of processing steps, for example, a coating station 2, a surface processing station 3, a cooling station 4, and heating are connected to a loader / unloader section 1. The station 5 is disposed to face, and such a transfer device 6 is provided between the steps facing each other.

The transport device 6 of the photoresist film forming apparatus includes a carriage 61 that is moved in a lateral direction by a driving mechanism (not shown).
And two vacuum tweezers 62 attached to the carriage 61. These tweezers are configured to be independently movable in their longitudinal, vertical, and rotational directions.

Then, for example, the wafer at the load position 11 of the loader / unloader unit 1 is sucked and held by the tweezers 1 and transferred to the surface treatment station 3. While the first wafer is preheated, the second wafer (loader
The unloader unit 1 sequentially holds the load position 11) by suction using a pair of tweezers. The surface-treated first wafer is suction-held by a pair of tweezers at a surface processing station 3 and transferred to a cooling station 4. After that, the second wafer is transported and placed on the surface treatment station 3. Next, the cooled first wafer is held by suction using tweezers 2 and transported to a station for the next step, for example, the coating station 2. After the coating is completed, the wafer is transferred to the heating station 5 for the next step. Hereinafter, similarly, the processing of the wafer in each station proceeds by sequentially transferring the wafer between the stations by using two tweezers.

[Problems to be Solved by the Invention] In such a semiconductor wafer processing step, uniform processing of the wafer is an important issue regardless of resist coating, heat exposure, and the like. In order to achieve the above, various measures have been taken such as using a heating device having a large heat capacity and excellent heat distribution uniformity.

However, when a wafer is transferred between stations having different processing temperatures, in a conventional transfer device, in order to hold such a uniformly heated transferred object with normal-temperature tweezers, for example, a wafer after surface processing is processed. When cooling sequentially in the cooling station, the temperature of the surface treatment station is usually higher than the normal temperature of the tweezers, so the temperature drops sharply at the part where the wafer is held during transfer to the coating station, maintaining an even temperature distribution of the transferred object Can not do it. Further, when the wafer is transferred from the cooling station to the heating station, a uniform temperature distribution of the transferred object cannot be similarly maintained due to the opposite temperature relationship. Such disturbance in the temperature distribution has a significant effect on the uniformity of the thickness of the resist film applied in the application step. In addition, there is a problem that it takes a long time to heat or cool the conveyed body to a temperature condition necessary for the next process while the apparatus is in a standby state for delivery during transfer.

[Object of the invention] The present invention solves such conventional problems,
It is possible to provide a resist processing method that can prevent the temperature of an object to be processed from being lowered, preheat or cool the object to be processed, and improve a product yield as a whole system to which the resist processing method is applied and effectively use the system. The purpose is to aim.

[Means for Solving the Problems] A resist processing method of the present invention for achieving the above object includes a housing for housing an object to be processed, a heat treatment section for heating the object to be processed to a predetermined temperature, A cooling unit that cools the processing object to a predetermined temperature; a surface processing unit that performs surface treatment of the processing object; a coating processing unit that applies a coating liquid to the processing object; a container, a heating processing unit, and a cooling process When performing resist processing of the object to be processed by a resist processing apparatus having a unit, a surface processing unit, and a holding unit that holds and transports the object to the coating processing unit, a plurality of holding units including a temperature adjustment mechanism are used. When the object is transferred to the heat treatment unit, the object is heated, and when the object is transferred to the cooling unit, the object is cooled and the processing is sequentially performed.

[Operation] Since the object to be processed is held by the holding unit which has been set to a predetermined temperature in advance by the temperature adjustment mechanism, the temperature of the object to be processed is adjusted by heating or cooling the object according to the state of the object to be processed. be able to.

Example An example in which the resist processing method of the present invention is applied to a photoresist film forming apparatus will be described below.

The photoresist film forming apparatus 100 includes a loader unit 102 for loading and unloading a semiconductor wafer W (hereinafter, referred to as a wafer) as an object to be processed, and two rows of processing stations opposed to each other. The processing station includes a surface processing station 103 serving as a surface processing unit, a cooling station 104 serving as a cooling processing unit, a first heating station 105 and a second heating station 106 serving as a heat processing unit, and the other processing station is a coating station. A first coating station 107 and a second coating station 108 as processing units are provided. A transport device 101 is provided between the two rows of processing stations (FIG. 1).

In the loader unit 102, cassettes 122 and 123, which are storage units for accommodating a plurality of unprocessed wafers WB or processed wafers WF, are placed, and the unprocessed wafers WB are taken out of the cassette 122 one by one or the processed wafers WF are loaded into the cassette. A robot arm 121 to be stored in 123 is provided.

Surface treatment station 103, first heating station 1
05 and the second heating station 106 are composed of, for example, pins for holding three points of the wafer W and a hot plate, and the hot plate is lowered when the wafer is carried in and out, so that the wafer can be delivered. Similarly, for example, the cooling station 104
The cooling plate is composed of a pin for holding a point and a cooling plate, and the cooling plate is lowered when the wafer is carried in and out, so that the wafer can be transferred. Each of the hot plate and the cooling plate is provided with a heater or a cooling means inside, and heats or cools the wafer to a predetermined temperature.

The coating stations 107 and 108 are devices for coating the photoresist on the wafer surface, and include, for example, a spin coater that holds the wafer on a rotating chuck and applies the photoresist dropped on the wafer by rotating the wafer.

The transport device 101 is provided between these stations, and a carriage 111 that moves in the Y direction by a drive mechanism (not shown) such as a stepping motor and a ball screw connected to the stepper motor, and two carriages that are attached to the carriage 111 in a superimposed manner. Arms 112 and 113 serving as holding parts are provided. The arms 112 and 113 are independently moved in a longitudinal direction (Y direction), a front-rear direction (X direction), a vertical direction (Z direction), and a rotation direction (θ direction) by a driving mechanism provided in the carriage 111. Can be. Such a carriage 11
The driving of the arm 1 and the arms 112 and 113 is controlled by a control system (not shown). As shown in FIG. 2, these arms 112 and 113 have two suction holes 113a for sucking a wafer, and these suction holes are connected to a vacuum system (not shown) via arm hollow portions. Is the same).

Further, the arms 112 and 113 have an insulating layer 201, a thin-film heating element 200, and an insulating layer 201 laminated on the surface thereof, and are configured to generate heat by energizing the thin-film heating element (FIG. 3).
Further, cooling coils 203 are embedded in the arms 112 and 113, respectively. The above-mentioned thin-film heating element 200 and cooling coil 203 form a temperature control mechanism, and the heating by energization of the thin-film heating element 200 and the flow of water to the cooling coil 203 are adjusted by a temperature controller 204 to a desired temperature. Make adjustments.

Such thin film heating elements include nickel, platinum, chromium, tantalum, tungsten, tin, iron, lead, alumel, beryllium, antimony, indium, chromel,
In addition to simple metals such as cobalt, strontium, rhodium, palladium, magnesium, molybdenum, lithium and rubidium, and carbon-based simple substances such as carbon black and graphite, alloys such as nichrome, stainless steel SUS, bronze and brass, and polymers such as polymer-grafted carbon Any material, including a composite ceramic material and a composite ceramic material such as molybdenum silicide, can be suitably used as long as it has conductivity and can become a resistance heating element when energized, and an appropriate material may be selected according to the heat generation temperature. . These are deposited on the surface of the arm,
The film is formed to a thickness of 0.1 to 1000 μm, preferably 1 to 100 μm by a method such as thermal spraying or bombardment. Since the thin-film heating element has a small heat capacity, the temperature can be changed with good responsiveness by changing the applied voltage.

It is sufficient that such a thin film heating element 200 is provided at least in a portion where the wafer is held by suction. Preferably, a heating element is provided on the front and back surfaces of the portion where the wafer is held, and the thin film heating element on the front surface is also provided. The body and the heating element on the back side are continuous only at the tip of the arm, and a pair of electrodes 20 are placed on the surface of the base of the arm.
2 is provided, and a voltage of a predetermined power supply is applied to this electrode. As a result, current flows almost uniformly through the thin-film heating element on the arm surface, so that the arm surface generates heat at a uniform temperature.

The insulating layers 201 provided on the upper and lower portions of the thin-film heating element can be made of any material having excellent electrical insulation and good thermal conductivity, that is, any material that easily emits far-infrared rays. In addition to ceramics represented by silicon, silicon nitride, diamond and the like, metal oxides such as quartz and rutile, and plastics such as Teflon having good heat resistance can be used. These are formed into a film thickness of, for example, 10 to 1000 μm by thermal spraying, bombardment, or the like.

In the above configuration, for example, when performing a processing step of “preheating-cooling-resist coating-heating-heating”, first, the unprocessed wafer WB in the cassette 122 is taken out by the robot arm 121 in the loader unit 102, It is held by the chuck. Next, one arm 113 of the transport device 101
Performs predetermined X, Y, and Z movements to hold the first unprocessed wafer held by the chuck. At this time, since the one arm 113 is set to the same temperature as the surface processing station 103 by energizing the heating element, the unprocessed wafer is held by the arm 113 and preheating starts at the same time. Arm holding this wafer
The wafer is placed on the pins of the surface treatment station 103 by rotating the 113 and further moving it in the X, Y, and Z directions. In the surface treatment station 103, the hot plate rises to perform a predetermined surface treatment.

During this time, in the loader unit 102, the second unprocessed wafer WB is transferred onto the chuck by the robot arm 121, and is held by the arm 113 of the transfer device as described above. Wait until finished. During this time, the next wafer is preheated by the arm 113. After the surface treatment, the wafer is taken out by the arm 112 at room temperature, placed on the cooling station 104, and the unprocessed wafer waiting is carried into the surface treatment station 103 by the arm 113.

Next, from the cooling station 104 to the coating station 107,
Since it is preferable that the transfer to 108 is performed at room temperature, the transfer is performed while the temperature of the heating element of the arm is adjusted to room temperature.

That is, the wafer on the cooling station 104 is held by one arm 112, and the wafer on the surface treatment station 103 is placed on the cooling station 104 by the second arm 113. The wafer held by one arm 112 is transferred to, for example, the coating station 107 and placed on the chuck of the coating station 107.

When transferring the resist-coated wafer to the heating station 105 and when transferring the wafer from the first heating station 105 to the second heating station 106, the heating element of the arm is energized again and transferred while heating. As a result, the preheating of the wafer is performed between the coating station 107 and the heating station 105, and the wafer is transported from the first heating station 105 to the second heating station 106 while the heated state of the wafer is maintained. The wafer does not cool down rapidly during transfer, and it is possible to prevent a rapid change in temperature, particularly when the wafer is held by tweezers at room temperature.

In the above-described embodiment, an example is described in which a heating element is provided only on the two arms of the transfer device. However, such a heating element is also provided on the holding section of the robot arm, which is a transfer mechanism of the loader section, and the cassette is removed. It goes without saying that the taken-out wafer can be preheated immediately.

Also, in the present embodiment, an example in which a vacuum suction type arm is used as a holding unit of a transported object and a thin film heating element is used as a heating element has been described, but the holding unit and the heating element are limited to this embodiment. It can be freely changed within the scope described in the claims.

[Effects of the Invention] As is clear from the above description, according to the resist processing method of the present invention, since the temperature adjustment mechanism is provided in the holding portion of the object to be processed, the transfer is performed without changing the temperature of the object to be processed. The object can be preheated or cooled as required.

Therefore, the resist treatment method of the present invention is useful for treatment involving heat treatment, particularly for semiconductor structures.

Furthermore, when a thin film heating element is used as the heating element, the temperature of the holding section can be changed with good responsiveness while cooling the holding section depending on the presence or absence of electricity or the amount of electricity, so that various processes are connected to the resist processing apparatus. It is suitable for resist processing of an integrated processing system.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a semiconductor processing apparatus to which the resist processing method of the present invention is applied, and FIGS. 2 and 3 are plan views each showing an embodiment of a holding section to which the present invention is applied. FIG. 4 is a diagram showing a conventional resist processing apparatus. 100: Photoresist film forming apparatus 101: Transport device 103: Surface treatment station (Surface treatment unit) 104: Cooling station (Cooling treatment unit) 105: First heating station (Heat treatment unit) 106 Second heating station (heating section) 107: first coating station (coating section) 108: second coating station (coating section) 112, 113: arm (holding section) 200: temperature Adjustment mechanism (heating element) 203: Temperature adjustment mechanism (cooling coil) 204: Temperature adjustment mechanism (temperature controller) W: Wafer (conveyed body)

Continuation of the front page (56) References JP-A-63-78546 (JP, A) JP-A-63-316428 (JP, A) JP-A-62-129846 (JP, A) JP-A-63-12176 (JP, A) , A) JP-A-63-68378 (JP, A)

Claims (1)

(57) [Claims] A container for storing the object to be processed, a heating unit for heating the object to a predetermined temperature, a cooling unit for cooling the object to a predetermined temperature, A surface treatment unit that performs surface treatment of the body, a coating treatment unit that applies a coating liquid to the object to be treated, the container, the heat treatment unit,
When performing the resist processing of the object to be processed by a resist processing apparatus having a cooling processing unit, a surface processing unit and a holding unit that holds and transports the object to the coating processing unit, a temperature adjustment mechanism is provided. By the plurality of holding units provided, when the object to be processed is transported to the heat treatment unit, heating is performed,
A resist processing method, wherein when the object to be processed is transported to the cooling processing unit, the object is cooled and sequentially processed.