Electric heating – Heating devices – Combined with container – enclosure – or support for material...
Reexamination Certificate
2002-09-30
2004-06-01
Fuqua, Shawntina (Department: 3742)
Electric heating
Heating devices
Combined with container, enclosure, or support for material...
C219S405000, C219S411000, C392S416000, C392S418000, C118S724000, C118S725000, C118S050100
Reexamination Certificate
active
06744018
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a substrate processing apparatus and a method for manufacturing a semiconductor device,
2. Description of the Related Art
In an individual substrate type substrate processing apparatus, a substrate is typically processed in a state in which the substrate is forcefully adsorbed onto a susceptor. In this case, if a degree of contact of the substrate with the susceptor remains uncontrolled, there is a problem that the substrate with a bad degree of contact will have a remarkably deteriorated substrate property when moving to a subsequent film formation step.
In the individual substrate type substrate processing apparatus, as shown in
FIG. 3
, in a state in which a substrate
1
is adsorbed and supported onto a susceptor
2
which is heated by a resistance heating heater
3
, a gas is blown like a shower on the substrate
1
from a gas dispersion plate
5
which is located above the substrate
1
, and consequently, a processing such as a film formation and the like will be performed on the substrate
1
. A surface of the resistance heating heater
3
heats the susceptor
2
such that a temperature of the susceptor
2
is always maintained at a constant temperature.
Here, when warpage amounts d
1
and d
2
representing a degree of contact change which are space distances from the substrate
1
to the susceptor
2
, a heat of the susceptor
2
which is always uniformly heated in an unchanging state by the resistance heating heater
3
can not be equally transferred to the substrate
1
. As a result, a malfunction occurs a the substrate surface, as will be described below, due to temperature distribution nonuniformity depending on the above-noted substrate warpage amount d (a generic name for dl an d
2
)
Here, a warpage amount of a substrate refers to a maximum value of a gap formed between the susceptor
2
surface and the substrate
1
underside due to an uncontacted portion of the substrate
1
with the susceptor
2
occurring as a result of a deformation of the substrate
1
In a state in which the substrate
1
is supported onto the surface the susecptor
2
.
The longer the distance d between the substrate
1
and the susceptor
2
is, the worse thermal conductivity from the susceptor
2
is. Accordingly, the temperature in the substrate surface will have thermal variations generated depending on the distance d. As a result, in the case of d
1
>d
2
, the substrate temperature near d
2
is higher than the substrate temperature near d
1
.
In a technique with regard to such a warpage of a substrate, there are conventionally known examples as follows.
(a) Japanese Patent Application Laid-Open No. 7-316811
Since occurrence of a large difference in a temperature distribution in a wafer generates a warpage in the wafer which leads to a cause for occurrence of a slip and the like, an attempt has been made to realize uniformity in the temperature in the wafer surface when being in a steady state or in a transient state (when raising a temperature) by allowing a heating state of a division type heater to be variable based on temperature differences between respective zones in the wafer each temperature of which is measured with a thermocouple.
In addition, heating of the temperature difference in the surface of the wafer, mentioned here, is controlled such that the temperature difference is equal to 10° C. or less based on a maximum temperature difference 10° C. wherein no warpage occurs at a processing temperature of 300° C. That is, the temperature difference value is controlled by one fixed temperature difference in the surface.
(b) Japanese Patent Application Laid-Open No. 6-260426
Since a contact area between a wafer and a susceptor changes due to deformation of the wafer when raising a temperature, the change will affect an outermost circumferential temperature of the wafer so that a temperature difference in the surface occurs to generate a slip.
Therefore, temperature measuring points and a heating method are disclosed in order to inhibit the slip from occurring. That is, by measuring temperatures at a plurality of points of a circumferential portion of the wafer at a distance equal to 70% or more of a radius of the wafer from a center of it, and by controlling heating of a heater such that a temperature difference between the temperature measuring points is within 5° C. (this value is a value wherein no slip occurs at 800° C. or more), a heating processing without occurrence of a slip is performed without depending uniformity in a heat density of the heater and without depending a contact area between the wafer and the susceptor.
However, in the above-described prior art, there have been problems as follows.
(1) In the known example (a), a temperature rise is controlled by one value of a temperature difference &Dgr;t in the surface (a value wherein no warpage occurs at a processing temperature (at a setpoint temperature when raising a temperature)). Since this makes it required that the heating be severely controlled when being at a low wafer temperature with a large margin of a &Dgr;t, by using a &Dgr;t when being at a high temperature (the &Dgr;t when being at a low wafer temperature is larger than the &Dgr;t when being at a high wafer temperature), restriction on a control response is required so as to make a sacrifice of a temperature rising speed. As a result, since the &Dgr;t margin becomes also small when being at a low temperature, a warpage can be inhibited, however, it can not be ensured that the temperature rising speed is increased.
(2) In the known example (b) which is similar to the known example (a), since heating is controlled by one value (a temperature difference in the surface), there is also a defect similar to the one in the known example (a).
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method for processing a substrate and a method for manufacturing a semiconductor device wherewith, by resolving the problems with the prior art noted in the foregoing, occurrence of a warpage of a substrate can be effectively prevented.
A first invention is a substrate processing apparatus which heats a substrate using a heating member capable of performing an unequal heating in a substrate surface, comprising a controller, the controller being adapted to obtain in accordance with a heating state of the substrate such a temperature deviation &Dgr;t in the substrate surface, which varies in accordance with the heating state of the substrate, that no warpage of the substrate occurs, and the controller being adapted to control the heating member such that a temperature deviation in the surface of the substrate which is heated by the heating member is maintained within the &Dgr;t. Since heating of the substrate can be controlled based on the temperature deviation &Dgr;t in the substrate surface, occurrence of a warpage of the substrate can be effectively prevented. Moreover, since the temperature deviation &Dgr;t in the substrate surface is allowed not to be fixed but to be variable, heating need not be severely controlled when the substrate is at a low temperature with a large margin of a &Dgr;t, by using a &Dgr;t value when being at a high temperature. Accordingly, since the heating is controlled with a large &Dgr;t margin when being at a low temperature, it can be ensured that the temperature rising speed is increased while a warpage can be inhibited at the same time. The above-noted heating member capable of performing an unequal heating in the substrate surface is, for example, a division type heater which is divided into a plurality of zones.
A second invention is a substrate processing apparatus which heats a substrate using a heating member capable of performing an unequal heating in a substrate surface, comprising a controller, the controller being adapted to obtain a &Dgr;t, which varies in accordance with a temperature when heating, for each of a plurality of temperatures which are selected from the temperatures when heating, the temperature when heating
Fuqua Shawntina
Hitachi Kokusai Electric Inc.
Oliff & Berridg,e PLC
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