JP2000232108A - Substrate heating method and substrate heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make treatment quality of heat treatment of a substrate uniform by preliminarily heating a pilot substrate prepared independently of a substrate for lot treatment during standby time before lot treatment. SOLUTION: When a precedent lot treatment is finished, a lot treatment ending signal is inputted. A pilot substrate for exclusive use to preliminary heating which is independent of a lot treatment substrate is positioned, carried to a heating chamber, and preliminary heating is started. When a lot start signal is inputted, a first treatment substrate is carried to the heating chamber after positioning, and there heat-treated instead of the pilot substrate during preliminary heating. Thereby the temperature distribution of a member facing the substrate in the heating chamber is maintained during standby time, and treatment quality of the lot treatment can be made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plurality of substrates to be processed under the same conditions, such as a plurality of semiconductor wafers, a glass substrate for a photomask, a glass substrate for a liquid crystal display, and a substrate for an optical disk (hereinafter simply referred to as a "substrate"). The present invention relates to a substrate heating method and a substrate heating apparatus for performing a lot process for heating each substrate of the lot, which is a group of the lots.

[0002]

2. Description of the Related Art Conventionally, a substrate heating apparatus for performing a heat treatment on a substrate, for example, a single-wafer-type substrate heating apparatus (an apparatus for heating a substrate one by one) is a furnace body having a heat source therein. After the substrate is carried into the heating chamber, an atmosphere of a processing gas such as nitrous oxide or oxygen gas is formed from the gas inlet into the chamber, and the substrate is heated by heat radiation from a heat source to perform processing such as film formation. It is carried out.

In such an apparatus, a lot, which is a group of a plurality of substrates to be processed under the same conditions, is used as a unit.
In each lot, each substrate is carried in alternately, and a heating process (lot process) is continuously performed.

However, when lot processing is performed on a plurality of lots, a standby time occurs between the plurality of lots due to the relationship with other processing. Therefore, when the next lot processing is started after a certain amount of standby time has elapsed, the temperature in the heating chamber is not stable during the heating processing of several substrates from the beginning in the lot, and the substrate in the same lot is not stable. Each time, the processing quality varies.

In order to solve this problem, the conventional substrate heating apparatus performs a heat retaining operation in the heating chamber by supplying a weak electric power to the heat source in a state where the substrate is not carried into the heating chamber even during the standby time. The processing quality of substrates in a lot is made uniform.

[0006]

By the way, in the above-described substrate heating apparatus, the highly reactive processing gas as described above is supplied to the inside, so that the heat source is prevented from corroding and is insulated from the surrounding environment. In addition, a quartz plate that transmits radiant heat from the heat source is provided between the substrate and the heat source.

FIG. 4A is a schematic diagram of the temperature distribution of the quartz plate during the heat-retention operation in the above-described conventional technique, and FIG. As shown in FIG. 4A, when the temperature is maintained without holding the substrate inside the heating chamber, the entire quartz plate has a substantially uniform temperature distribution. On the other hand, as shown in FIG. 4B, during the lot processing while holding the substrate, the quartz plate has a temperature distribution as shown in the drawing, that is, the edge portion of the quartz plate. The temperature of the portion facing the central processing substrate is higher than the temperature of. This is because the thermal conductivity of quartz is very small with respect to the thermal conductivity of the substrate.

As described above, in the conventional apparatus, there is a difference in the temperature distribution of the member facing the substrate between the substrate immediately after the start of the lot processing and the substrate after several lots of the processing, and the processing quality of the substrate is reduced. Variation was occurring.

An object of the present invention is to overcome the above-mentioned problems in the prior art, and an object of the present invention is to provide a substrate heating method and a substrate heating apparatus which can make processing quality uniform.

[0010]

In order to achieve the above object, the invention of claim 1 heats each substrate of a lot which is a group of a plurality of substrates to be processed under the same conditions. A substrate heating method for performing a lot process that includes a preliminary heating step of preliminarily heating a pilot substrate prepared separately from a substrate for the lot process during a standby time before the lot process.

According to a second aspect of the present invention, there is provided the substrate heating method according to the first aspect, wherein the preliminary heating step is started in response to the end of the lot processing performed before the standby time. .

According to a third aspect of the present invention, there is provided the substrate heating method according to the first or second aspect, wherein the heating temperature immediately before the lot processing in the preliminary heating step is substantially the same as the heating temperature during the lot processing. Temperature.

According to a fourth aspect of the present invention, a lot, which is a group of a plurality of substrates to be processed under the same conditions,
A substrate heating apparatus for performing a lot process for heating each substrate of the lot, wherein during a standby time before the lot process, control is performed so as to preliminarily heat a pilot substrate prepared separately from a substrate for the lot process. It has control means.

According to a fifth aspect of the present invention, there is provided the substrate heating apparatus according to the fourth aspect, wherein the preliminary heating is started in response to the end of the lot processing performed before the standby time.

Here, the standby time refers to the time from the end of the previous lot processing to the input of a signal for starting the lot processing.

According to a sixth aspect of the present invention, in the substrate heating apparatus of the fourth or fifth aspect, the heating temperature immediately before the lot processing during the preliminary heating is substantially the same as the heating temperature during the lot processing. Temperature.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

<1. Apparatus Configuration and Processing Procedure of Embodiment> FIG. 1 is a schematic diagram showing an apparatus configuration of a substrate heating apparatus 1 according to an embodiment of the present invention. As shown, in this apparatus, a cassette table 10, a pilot substrate stage 20, a heating chamber 30, a cooling unit 40, and a positioning stage 50 are provided so as to surround a transfer robot 60, and are further electrically connected to these components. And a command input unit 80 electrically connected thereto.

The cassette table 10 stores and unloads a cassette C storing a substrate to be actually subjected to a heat treatment before processing (hereinafter, referred to as a “processing substrate W”) and a processing substrate W after the processing. Is a table on which an empty cassette C is placed. Note that a group of processing substrates that perform the same processing is hereinafter referred to as a lot. Further, the pilot substrate stage 20 is not a processing substrate W for performing actual processing, but a substrate W (P
This is a stage for mounting the pilot substrate PW which is W) at a time other than the preheating described later. When the processing substrate W is a silicon wafer, the pilot substrate PW is formed of a material having a thermal characteristic close to that of the main component of the processing substrate W, such as a silicon substrate. Hereinafter, the processing substrate W and the pilot substrate PW are simply referred to as the substrate W (PW).

FIG. 2 is a longitudinal sectional view showing a schematic structure inside the heating chamber 30. The heating chamber 30 has a plurality of heat sources 31a to 31c on a ceiling surface and a quartz substrate holding and rotating unit 32 for holding and rotating a substrate W (PW) on a bottom surface. PW) a heating furnace, which is a processing gas (hereinafter referred to as “processing gas”) or an inert gas (hereinafter referred to as “inert gas”) such as nitrous oxide or oxygen from the outside when processing the processing substrate W
Gas inlet 33 for introducing the gas, gas outlet 34 for discharging the internal gas after the processing, and
A quartz plate 35 that transmits radiant heat from the heat sources 31a to 31c is provided so as to be close to and opposed to the substrate W (PW) held on the upper surface of the substrate 2. Further, a cooling pipe 36 through which a refrigerant flows is provided inside the bottom surface of the heating chamber 30 below the substrate holding / rotating section 32. Further, a reflection plate 37 is attached above the bottom surface, and a radiation thermometer is provided. 3
8a to 38c are attached, and they are electrically connected to a control unit 70 described later.

The radiation thermometers 38a, 38b, 38c
Are respectively combined with the heat sources 31a, 31b and 31c, and each of these sets is a central area CA, an intermediate area MA, and an edge area EA which are areas for controlling the temperature of the substrate W (PW).
The temperature of each of the above regions of the substrate W (PW) is measured by the radiation thermometers 38a to 38c, and the substrate W (PW) is measured based on the measured temperatures.
A control unit, which will be described later, controls the output of each of the heat sources 31a to 31c so that the temperature becomes uniform within the main surface.

In the lot processing, the heating chamber 3
The substrate W (PW) is heated by supplying electric power to the heat sources 31a to 31c in a state where the atmosphere of the processing gas is formed in the substrate 0 and the substrate W (PW) is held by the substrate holding / rotating section 32. In preheating using the pilot substrate PW, the heating chamber 30
The pilot substrate PW is held on the upper surface of the substrate holding / rotating portion 32 in a state where an inert gas atmosphere is formed therein, and a weak power (about several% of the rated power) is supplied to the heat sources 31a to 31c to supply the pilot substrate PW. PW and quartz plate 3 facing it
5 and the like are heated. In the heat treatment and the preliminary heating, the temperature of each of the above regions of the substrate W (PW) is controlled. Further, as described later, in this embodiment, the preliminary heating is performed during the waiting time of the lot processing.

Returning to the description of FIG. Cooling unit 4
Numeral 0 denotes a cooling furnace in which the pilot substrate PW after being heated and the processing substrate W after being subjected to the heat treatment are carried in, and the processing substrate W is exposed to a normal temperature atmosphere in the cooling unit 40 to thereby cool by radiation. It is. The positioning stage 50 performs alignment such as correcting the orientation flat or notch of the substrate W (PW) in a predetermined direction before performing the heat treatment, and positioning such as centering for correcting the center position of the substrate W (PW) to a correct position. A transfer robot 60 described later stores the substrate W (P
This is a stage to be performed before carrying in W). The transfer robot 60 can move forward and backward individually within a predetermined range.
(PW) is a robot that is provided with two hands 61a and 61b and that is capable of translational movement as a whole.
(PW) or the substrate W
(PW). The control unit 70 includes a C (not shown)
The control device includes a PU and a memory, and controls the temperature of the heating chamber 30 and the cooling unit 40 and the operation timing of the transfer robot 60. further,
The instruction input unit 80 is an input unit for performing various inputs from an operator such as a touch panel (not shown), particularly, an input for notifying the start and end of the lot processing. Send to

With the above-described apparatus configuration, this substrate heating apparatus performs the following substrate heating processing.

FIG. 3 is a timing chart showing an example of the substrate heating process in this embodiment. Hereinafter, each operation timing of the substrate heating processing by this apparatus will be described with reference to FIG. Unless otherwise specified below, the operation of transporting the substrate W (PW) is performed by the transport robot 60, and the transport operation and the operation of each unit are controlled by the control unit 70.

As shown in the figure, in this apparatus, when the previous lot processing is completed, the operator inputs a lot processing end signal through the instruction input unit 80. Then, the signal is sent to the control unit 70, and the transfer robot 60 transfers the pilot substrate PW from the pilot substrate stage 20 to the positioning stage 50 accordingly. Then, after positioning of the pilot substrate PW there, the heating chamber 3
0, and preheating is started. As described above, in the apparatus of this embodiment, the preheating is performed during the standby time until the start signal of the lot heating process is input, and in particular, the preheating is started immediately after the end of the previous lot process. I have. The preheating is performed for a predetermined time under a predetermined temperature control.

Next, when an operator inputs a lot start signal indicating the start of the lot heating process, the first processing substrate W is taken out of the cassette C on the cassette table 10 and positioned on the positioning stage 50. Is done. During this time, the pilot substrate PW is also preheated in the heating chamber 30. In this case, in particular, the heating process is performed under the same conditions as the heating temperature in the next lot heating process.

Next, the transfer robot 60 takes out the second processing substrate W from the cassette C, holds it with one hand 61a (61b), and holds it with the other hand 61b (61b).
a) moves to the positioning stage 50 in an empty state. Then, the empty hand 61b is positioned on the positioning stage 50.
(61a) holds the first processing substrate W, and the other hand 61a (61b) transfers the second processing substrate W to the positioning stage 50. The operation of taking out the substrate W (PW) with an empty hand and transferring the substrate W (PW) conveyed by the other hand in such one processing unit is hereinafter referred to as "exchange operation".

Further, the transfer robot 60 moves to the heating chamber 30 while holding the first processing substrate W with the one hand 61a, 61b, and performs an exchange operation of the first processing substrate W and the pilot substrate PW. Do. Then, the pilot substrate PW is transferred to the cooling unit 40 and cooled. Then, after a lapse of a predetermined cooling time for cooling the pilot substrate PW to a predetermined temperature, the pilot substrate PW is returned to the pilot substrate stage 20 to be in a standby state. After the first processing substrate W is subjected to the heat treatment in the heating chamber 30,
It is conveyed to the cooling unit 40 and cooled. Less than,
Similarly, the second substrate, the third substrate, and so on are transferred to the heating chamber 30 in this order, and when the heating processing of the previously heated processing substrate W is completed, the exchange operation is performed between the processing substrate W and the next processing substrate W. The heating process and the cooling process are sequentially performed while being performed. Note that the following transfer of the processing substrate W and the processing in each section are the same as those in the related art, and a detailed description thereof will be omitted.

Although not shown, when the heat treatment of this lot is completed, the lot end signal is again sent to the control unit 70.
To enter the standby state for the next lot. At the same time, the pilot substrate PW is taken out of the pilot substrate stage 20 and transported to the positioning stage 50. Thereafter, the same processing as described above is repeated.

Note that in this example, 1
The one pilot substrate PW is continued only once until the first processing substrate W is transferred to the heating chamber 30. However, in some cases, the preliminary heating under the same heating conditions as in the normal lot processing is performed. Multiple times, cooling unit 4
The cooling step with 0 may be alternately repeated. As described above, the preheating condition may be different depending on the characteristics of the processing substrate W of the lot to be performed later.

As described above, in the substrate heating apparatus 1 of this embodiment, the pilot substrate PW is loaded into the heating chamber 30 in response to the input of the end signal of the previous lot processing, and the preliminary heating is performed. Even at the start of the lot processing, it is possible to prevent the temperature inside the heating chamber 30 from extremely dropping.
Further, since the temperature distribution of the quartz plate 35 can be maintained in the same manner as in the lot processing, the processing quality of each substrate W (PW) in the lot can be made uniform, and a plurality of lots with the same processing conditions can be used. When processing, the processing quality between lots can be made uniform.

Further, in order to transport the pilot substrate PW in response to the end of the previous lot processing and start the preliminary heating,
The start of the lot processing, that is, the start of the heating of the first processing substrate W of the lot, can be earlier than in the case where the transfer of the pilot substrate PW and the preliminary heating are started in response to the input of the lot start signal of the lot processing. Therefore, the throughput can be improved.

<2. Modifications> In the above embodiment, an example of the substrate heating apparatus 1 and the substrate heating process by the apparatus has been described, but the present invention is not limited to this.

For example, in the above-described embodiment, the single-wafer-type substrate heating apparatus 1 is used. However, in the batch-type substrate heating apparatus 1 for simultaneously heating all the substrates of a lot or a plurality of substrates W (PW). Similarly, the transfer of the pilot substrate PW and the preliminary heating may be started in response to the end of the previous lot processing.

[0036]

As described above, according to the first to fourth aspects of the present invention, during the standby time before the lot processing,
Since the pilot substrate prepared separately from the substrate for the lot processing is preliminarily heated, the temperature distribution of the members facing the substrate can be maintained during the standby time in the same manner as during the lot processing. The processing quality of the substrate can be made uniform, and when processing a plurality of lots under the same processing conditions, the processing quality among the plurality of lots can also be made uniform.

According to the second and fourth aspects of the present invention, the preliminary heating is started in response to the end of the lot processing performed before the standby time. Since the start of the lot processing, that is, the start of the heating of the first processed substrate of the lot, can be earlier than in the case where the transfer of the pilot substrate and the preliminary heating are started, the throughput can be improved.

According to the third and sixth aspects of the present invention, the heating temperature immediately before the lot processing is substantially the same as the heating temperature during the lot processing, so that the reproducibility in the lot can be improved. .

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an apparatus configuration of a substrate heating apparatus according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a schematic structure inside a heating chamber.

FIG. 3 is a timing chart in an example of a substrate heating process in the embodiment.

FIG. 4 (a) is a diagram showing a state during a warming operation according to the related art.
(B) is a schematic diagram of the temperature distribution of the quartz plate during the lot processing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate heating device 30 Heating chamber 70 Control part PW Pilot substrate W Processing substrate

Claims (6)

[Claims] 1. A substrate heating method for performing a lot process of heating each substrate of a lot, which is a group of a plurality of substrates to be processed under the same condition, wherein the lot process is performed during a standby time before the lot process. A preheating step of preheating a pilot substrate prepared separately from a substrate for lot processing. 2. The substrate heating method according to claim 1, wherein the preliminary heating step is started in response to the end of the lot processing performed before the standby time. Substrate heating method. 3. The substrate heating method according to claim 1, wherein the heating temperature immediately before the lot processing in the preliminary heating step is substantially the same as the heating temperature during the lot processing. Substrate heating method. 4. A substrate heating apparatus for performing a lot process for heating each substrate of a lot which is a group of a plurality of substrates to be processed under the same condition, wherein the lot process is performed during a standby time before the lot process. And a control means for preliminarily heating a pilot substrate prepared separately from the substrate for the lot processing. 5. The substrate heating apparatus according to claim 4, wherein the preliminary heating is started in response to the end of the lot processing performed before the standby time. Heating equipment. 6. The substrate heating apparatus according to claim 4, wherein the heating temperature immediately before the lot processing during the preliminary heating is substantially the same as the heating temperature during the lot processing. Substrate heating device.