KR20230007939A - Method of processing substrate using heater temperature control - Google Patents

Abstract

Disclosed is a substrate processing method capable of reducing a dielectric constant deviation toward the thickness direction of a deposited film. The substrate processing method according to the present invention comprises: a substrate loading step of loading a substrate onto a heater disposed in a reaction chamber; a stabilization step of maintaining a heater temperature at a first temperature; a deposition step of supplying a reaction gas into the reaction chamber to form a film on the substrate; and a purge step of purging the reaction chamber interior. In the deposition step, the heater temperature is raised to a temperature higher than the first temperature.

Description

Substrate processing method using heater temperature control {METHOD OF PROCESSING SUBSTRATE USING HEATER TEMPERATURE CONTROL}

The present invention relates to a substrate processing method. More specifically, the present invention relates to a substrate processing method using heater temperature control.

Representative methods for depositing a thin film having a thickness of about 1 μm or less on a wafer or substrate include a chemical vapor deposition (CVD) method and a physical vapor deposition (PVD) method. Among them, the CVD method is a method of depositing a desired material through a chemical reaction of reactive gases in a reaction chamber.

In depositing a thin film by the CVD method, various process conditions such as RF power, deposition time, and chamber temperature have conventionally been controlled in order to improve the properties of the deposited thin film. As an example, Patent Document 1 includes a crucible in which two or more heating regions are set along the longitudinal direction to form a thin film on a substrate located in a processing space in a process chamber, and two or more heaters installed corresponding to each of the heating regions. A linear source including a unit, at least one evaporation rate sensor installed to correspond to one of the heating regions to measure the evaporation rate of the corresponding heating region, and measurement of the heating region where the evaporation rate is measured through the evaporation rate sensor Disclosed is a thin film deposition apparatus including a control unit for controlling the evaporation rate of a linear source by controlling the heat generation amount of a heater unit installed to correspond to the remaining heating regions other than the heating region to be measured based on the evaporation rate. According to Patent Document 1, the uniformity of thin film deposition can be improved by independently controlling the heating value of each heater part based on the evaporation rate of the deposition material measured by the evaporation rate sensor.

Publication No. 10-2017-0141486 (published on December 26, 2017)

An object to be solved by the present invention is to provide a substrate processing method using a heater temperature change that can adjust the temperature of a wafer on a heater through temperature control of a heater disposed in a reaction chamber and further improve the characteristics of a thin film to be deposited. is to do

In particular, the problem to be solved by the present invention is to control the temperature of the center portion and the edge portion of the wafer on the heater through operation control of the heater such as ramping, PID (Proportional-Integral-Derivative), power ratio, etc. It is to provide a substrate processing method using a heater temperature change that can be improved.

A substrate processing method according to the present invention for solving the above problems includes a substrate loading step of loading a substrate on a heater disposed in a reaction chamber; a stabilization step of maintaining the heater temperature at a first temperature; a deposition step of supplying a reaction gas into a reaction chamber to form a film on the substrate; and a purge step of purging the inside of the reaction chamber, wherein the temperature of the heater is raised to a temperature higher than the first temperature in the deposition step.

In the deposition step, the temperature of the heater may be raised to a temperature 10 to 40° C. higher than the first temperature.

The surface of the heater may be divided into a center portion and an edge portion outside the center portion, and in the deposition step, a temperature increase amount of the edge portion may be greater than a temperature increase amount of the center portion.

The ratio of the power applied to the edge portion to the power applied to the center portion in the stabilization step (hereinafter referred to as a first power ratio) is applied to the edge portion to the power applied to the center portion in the deposition step. The power ratio (hereinafter referred to as the second power ratio) may be controlled to be higher.

The second power ratio may be controlled to 1.6 to 1.8.

A temperature of the edge portion may be controlled independently of the center portion.

In the substrate processing method according to the present invention, it is possible to reduce the difference in dielectric constant in the thickness direction of the deposited film through temperature control of the heater.

More specifically, in the substrate processing method according to the present invention, as a result of raising the temperature of the heater to a temperature higher than the first temperature in the deposition step, the difference in dielectric constant of the deposited film in the thickness direction can be reduced. Furthermore, the difference in dielectric constant in the thickness direction of the deposited film could be further reduced through additional temperature control of the edge portion of the heater.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the detailed description below.

1 schematically shows an amorphous carbon film formed on a substrate through two deposition processes.
2 shows dielectric constants (K values) at various positions in the thickness direction of an amorphous carbon film formed in each deposition process.
3 shows an etching profile according to a difference in permittivity in the thickness direction of an amorphous carbon film.
4 shows an ideal etch profile.
5 shows an example of a temperature control system of a heater.
6 shows a center portion and an edge portion of the heater surface.
7 is a flowchart schematically illustrating a substrate processing method according to an embodiment of the present invention.
8 shows examples of temperature profiles of a substrate processing method including increasing the temperature of a heater in a deposition step.
9 illustrates examples of power profiles of a substrate processing method including increasing a power ratio of an edge portion of a heater in a deposition step.
10 shows 49 measurement points on the wafer.
FIG. 11 shows (a) permittivity (K value) for each wafer measurement point, (b) each step It shows the heater set temperature, (c) the power applied to the center part and the edge part at each stage.
12 shows that amorphous carbon films having thicknesses of 8000 Å, 12000 Å, and 14000 Å are deposited at 610° C. by applying a power ratio of 1.5 for the edge portion to the center portion, but (a) when the temperature of the heater is not additionally raised in the deposition step, (b ) When the temperature of the heater is raised by 10 ° C in the deposition step, (c) when the temperature of the heater is raised by 20 ° C in the deposition step, it shows the permittivity (K value) for each wafer measurement point.
FIG. 13 deposits amorphous carbon films with thicknesses of 8000 Å, 12000 Å and 14000 Å at 610° C., the temperature of the heater is raised by 20° C. in the deposition step, and (a) a power ratio of 1.5 is applied to the edge portion to the center portion in the deposition step. (b) when a power ratio of 1.7 of the edge to the center is applied in the deposition step, (c) when a power ratio of 2.0 is applied to the edge to the center in the deposition step, the permittivity (K value) is shown.
14 is a case where amorphous carbon films having thicknesses of 8000 Å, 12000 Å, and 14000 Å are deposited at 610° C., but (a) a power ratio of 1.5 for the edge portion to the center portion is applied in the deposition step without raising the temperature of the heater in the deposition step. , (b) when the temperature of the heater is raised by 20 ° C in the deposition step and a power ratio of 1.5 for the edge portion to the center portion is applied in the deposition step, (c) the temperature of the heater is raised by 20 ° C in the deposition step, and the deposition step When a power ratio of 1.7 for the edge to the center is applied in (d) when the temperature of the heater is raised by 20° C. in the deposition step and a power ratio of 2.0 for the edge to the center is applied in the deposition step, (e) When the temperature of the center of the heater is 610 ° C and the temperature of the edge is 595 ° C, but the temperature of the heater is not raised in the deposition step, (f) the temperature of the center of the heater is 610 ° C and the temperature of the edge is 595 ° C It shows the permittivity (K value) for each wafer measurement point when the temperature of the heater is raised by 10 ° C in the deposition step, although individually applied.

Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the detailed description of the following embodiments taken in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, only these embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention pertains. It is provided to completely inform the person who has the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numbers designate like elements throughout the specification. The sizes and relative sizes of layers and regions in the drawings may be exaggerated for clarity of explanation.

When an element or layer is referred to as “on” or “on” another element, it includes both the case where another element or layer is intervened as well as directly on another element or layer. On the other hand, when an element is referred to as "directly on" or "directly on", it indicates that no other element or layer is intervening. In addition, when a component is described as being “connected”, “coupled” or “connected” to another component, the components may be directly connected or connected to each other, but other components may be “connected” between each component. It will be understood that "intervening", or that each component may be "connected", "coupled" or "connected" through another component.

The spatially relative terms "below", "lower", "above", "upper", etc. facilitate correlation between one element or component and another element or component as shown in the drawings. can be used to describe Spatially relative terms are to be understood as terms encompassing different orientations of elements in use or operation in addition to the directions shown in the figures. For example, when an element shown in the figure is inverted, an element described as “below” another element may be placed “above” the other element. Thus, the exemplary term “below” may include directions of both below and above.

Terminology used herein is for describing the embodiments, and therefore is not intended to limit the present invention. In this specification, singular forms also include plural forms unless specifically stated otherwise in a phrase. As used herein, “comprising” and/or “comprising” does not exclude the presence or addition of one or more other components, steps, operations and/or elements in which the stated components, steps, operations and/or elements are present. .

Hereinafter, a substrate processing method according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 schematically shows an amorphous carbon film formed on a substrate through two deposition processes. 2 shows dielectric constants (K values) at various positions in the thickness direction of an amorphous carbon film formed in each deposition process.

Referring to FIGS. 1 and 2 , it can be seen that the amorphous carbon films 101 and 102 formed on the substrate by the CVD method exhibit different dielectric constants (K values) in the thickness direction. The lower part of the film, that is, the part formed at the beginning of each deposition process, shows a relatively high K value of about 0.57, but the upper part of the film, that is, the part formed at the end of each deposition process, shows a relatively low K value of about 0.55. can be seen indicating

In addition, as can be seen in FIG. 2 , the phenomenon of exhibiting different dielectric constants in the thickness direction of the film appears in common in the film 101 formed through the first process and the film 102 formed through the second process.

3 shows an etching profile according to a difference in permittivity in the thickness direction of an amorphous carbon film. 4 shows an ideal etch profile.

Referring to FIG. 3 , in each of the amorphous carbon films 101 and 102 , it can be seen that etching non-uniformity between a lower portion of the film and an upper portion of the film is significant. As described above, such etching non-uniformity can be attributed to the difference in permittivity in the thickness direction of the film. That is, the lower portion of the film, that is, the portion formed at the beginning of each deposition process, shows a relatively high K value and thus the etching amount is relatively small, while the upper portion of the film, that is, the portion formed at the end of each deposition process, has a relatively low K value. value and, accordingly, the etching amount is relatively large.

In the case of the etching profile of FIG. 3, since the possibility of process defects increases, it is necessary to improve the etching profile to be close to the ideal etching profile shown in FIG. In order to improve the etching profile, it is necessary to reduce the difference in permittivity in the thickness direction of the film.

This difference in dielectric constant in the thickness direction of the film is considered to be due to a change in radiant heat from the showerhead in the deposition step. As deposition progresses on the substrate, deposition gradually progresses on the showerhead, and the progress of deposition on the showerhead becomes a factor in reducing showerhead radiant heat.

Therefore, even if the same power is provided to the heater and set to the same temperature, as the deposition progresses, the showerhead radiant heat is gradually reduced, so that the deposition proceeds at a relatively low temperature in the later phase of the deposition compared to the initial phase.

As a result of long-term research, the inventors of the present invention have found that if the temperature of the heater is additionally controlled in the deposition step, such showerhead radiant heat can be compensated, and thus the difference in dielectric constant in the thickness direction of the film can be reduced.

5 shows an example of a temperature control system of a heater.

Referring to FIG. 5 , in response to a signal such as a thermocouple (TC) for measuring the temperature of the heater 501, the temperature control unit 510 controls the temperature of the heater 501, and the heater center power supply unit 520a and Control signals S1 and S2 are transmitted to the heater edge power supply unit 520b. The heater center power supply unit 520a supplies predetermined power P1 to the center unit of the heater in response to the control signal S1. In addition, the heater edge portion power supply unit 520b supplies predetermined power P2 to the edge portion of the heater in response to the control signal S2.

6 shows a center portion and an edge portion of the heater surface.

The heater 501 may be divided into a center portion 501a and an edge portion 501b outside the center portion. If the radius of the entire heater is r1+r2, the width of the center portion 501a may be r1 and the width of the outer portion 501b may be r2. The ratio (r1:r2) of the width r1 of the center portion 501a and the width r2 of the outer portion 501b (r1:r2) may be set to, for example, 3:1, 2.5:1, or 2:1.

The temperature of the center portion and the edge portion of the heater surface can be controlled in two ways. The first method is a method of controlling the temperature of the center portion through a thermocouple, a filament, or the like, and controlling the temperature of the edge portion by controlling a power ratio of the edge portion to the center portion. Another method is a method of controlling the temperature of the center portion through a thermocouple and controlling the temperature of the edge portion through hot wire temperature control.

7 is a flowchart schematically illustrating a substrate processing method according to an embodiment of the present invention.

Referring to FIG. 7 , the substrate processing method according to the present invention includes a substrate loading step (S710), a stabilization step (S720), a deposition step (S730), and a purge step (S740).

In the embodiments according to the present invention, deposition of an amorphous carbon film on a wafer is mainly described, but the present invention is not limited thereto and may be applied to deposition of other types of films.

In the substrate loading step (S710), a substrate is loaded onto a heater disposed in the reaction chamber. A pre-heating step of pre-heating the heater before the substrate loading step ( S710 ) may be additionally included. In the stabilization step ( S720 ), the heater temperature is maintained at a predetermined first temperature (eg, 610° C. in the case of depositing an amorphous carbon film). In the deposition step ( S730 ), a reaction gas is supplied into the reaction chamber to form a film on the substrate. In the purge step (S740), argon gas, nitrogen gas, etc. are supplied into the reaction chamber to remove unreacted gas, reaction by-products, and the like in the reaction chamber.

At this time, the present invention is characterized in that the temperature of the heater is raised to a temperature higher than the first temperature in the deposition step (S730). As described above, even if the same power is provided to the heater and set at the same temperature, as the deposition progresses, the showerhead radiant heat is gradually reduced, so that the deposition proceeds at a relatively low temperature in the later stage of the deposition compared to the initial stage of the deposition. , As in the present invention, if the temperature of the heater is raised to a temperature higher than the first temperature in the deposition step (S730), the decrease in radiant heat from the showerhead can be compensated for. Therefore, it is as if deposition proceeds at substantially the same temperature on the substrate throughout the entire deposition step, and as a result, the difference in dielectric constant in the thickness direction of the film can be reduced.

In the deposition step (S730), it is preferable that the temperature of the heater is gradually raised throughout the deposition step. Through this, it is possible to compensate for a gradual decrease in radiant heat from the showerhead as deposition progresses.

In the deposition step (S730), it is preferable to raise the temperature of the heater to a temperature 10 to 40° C. higher than the first temperature, and more preferably to a temperature 10 to 20° C. higher than the first temperature. Considering that if the temperature increase of the heater is too small, the effect of the temperature increase may be insufficient, and if the temperature increase of the heater is too large, the characteristics of the deposited film may change. It is preferable, and it is more preferable that it is 10-20 degreeC.

8 shows examples of temperature profiles of a substrate processing method including increasing the temperature of a heater in a deposition step. More specifically, FIG. 8 shows a heater preheating step, a substrate placement step, a stabilization step (including He plasma), a deposition step, and a purge step (including pumping). It shows examples of the temperature profile of the substrate processing method including.

In (a) of FIG. 8, when the ratio of power applied to the edge portion to power applied to the center portion is 1.5, (b) of FIG. 8 shows the ratio of power applied to the edge portion to power applied to the center portion. In the case of 1.7, FIG. 8(c) shows the temperature profile when the ratio of the power applied to the edge portion to the power applied to the center portion is 2.0.

The temperature profile shown in FIG. 8 is for forming 8000 Å (8K), 12000 Å (12K), and 14000 Å (14K) thick amorphous carbon films, respectively. this gets longer

Referring to FIG. 8 , after maintaining the temperature of the heater at about 610° C. in the stabilization step, the temperature of the heater is gradually raised to about 630 to 650° C. in the deposition step.

Meanwhile, in the purge step ( S740 ), the temperature of the heater may be returned to the first temperature according to the completion of deposition.

Also, in the deposition step ( S730 ), the temperature increase amount of the edge portion may be greater than the temperature increase amount of the center portion.

For example, the ratio of the power applied to the edge portion to the power applied to the center portion in the stabilization step (hereinafter, a first power ratio) (eg, 1.5) is higher than that of power applied to the center portion in the deposition step. A ratio of power applied to the edge portion (hereinafter referred to as a second power ratio) (eg, 1.7 or 2.0) may be controlled to be higher.

As a result of the experiment, when the first power ratio was 1.5 and the second power ratio was controlled to be 1.7 to 2.0, the difference in dielectric constant in the film thickness direction could be effectively reduced.

In the purge step ( S740 ), the first power ratio may be restored according to the end of deposition.

9 illustrates an example of a power profile of a substrate processing method including increasing a power ratio of an edge portion of a heater in a deposition step.

The power profile shown in FIG. 9 shows the change in power (PWR) of the center portion (CENTER) and the edge portion (EDGE) for forming 8000 Å (8K), 12000 Å (12K), and 14000 Å (14K) thick amorphous carbon films, respectively. .

In (a) of FIG. 9, when the power of the edge portion to the center portion is maintained at 1.5 throughout the entire section, (b) is when the power of the edge portion to the center portion is increased to 1.7 in the deposition step, (c) is the deposition This is a case where the power of the edge part relative to the center part is increased to 1.7 in the step.

Referring to FIG. 9 , it can be seen that the power applied to the edge portion increased only in the deposition step.

Meanwhile, in addition to the method of controlling the power of the edge portion relative to the center portion in the deposition step, it is also possible to control the temperature of the edge portion independently of the center portion.

10 shows 49 measurement points on a wafer. Starting at 1 from the center, the edges were numbered 49. In the following example, the permittivity (K value) is measured at 49 points of the deposited film formed on the wafer.

11 shows when an amorphous carbon film having a thickness of 8000 Å (8K), 12000 Å (12K), and 14000 Å (14K) is deposited by applying a power ratio of 1.5 for the edge portion to the center portion at 610 ° C., (a) permittivity per wafer measurement point ( K value), (b) heater set temperature for each step, (c) power applied to the center part and edge part of each step. The data of FIG. 11 is not subjected to temperature increase and/or edge power increase in the deposition step, and can be regarded as reference data for the data of FIGS. 12 to 14 below.

FIG. 12 deposits 8000 Å (8K), 12000 Å (12K), and 14000 Å (14K) thick amorphous carbon films by applying a power ratio of 1.5 for the edge portion to the center portion at 610° C., (a) the temperature of the heater in the deposition step When the temperature is not additionally increased, (b) when the temperature of the heater is increased by 10°C (Rmp) in the deposition step, (c) when the temperature of the heater is increased by 20°C in the deposition step, the permittivity (K value) for each wafer measurement point ) is shown.

Referring to FIG. 12 , it can be seen that the difference in permittivity according to the thickness of the amorphous carbon film is reduced when the temperature of the heater is raised by 10° C. and 20° C. in the deposition step.

FIG. 13 deposits 8000 Å (8K), 12000 Å (12K), and 14000 Å (14K) thick amorphous carbon films at 610 ° C., in the deposition step, the temperature of the heater is raised by 20 ° C. (Rmp), and (a) in the deposition step When a power ratio of 1.5 for the edge to the center is applied, (b) when a power ratio of 1.7 for the edge to the center is applied in the deposition step, (c) a power ratio of 2.0 for the edge to the center in the deposition step When applied, it shows the permittivity (K value) for each wafer measurement point.

Referring to FIG. 13 , when the temperature of the edge portion is further increased by increasing the power ratio of the edge portion to the center portion to 1.7 or 2.0 in the deposition step, it can be seen that the difference in dielectric constant according to the thickness of the amorphous carbon film is reduced.

14 is depositing 8000 Å (8K), 12000 Å (12K), and 14000 Å (14K) thick amorphous carbon films at 610 ° C. When a negative power ratio of 1.5 is applied, (b) the temperature of the heater is raised by 20°C (Rmp) in the deposition step, and when a power ratio of 1.5 is applied to the edge part to the center part in the deposition step, (c) in the deposition step When the temperature of the heater is raised by 20°C and a power ratio of 1.7 for the edge portion to the center portion is applied in the deposition step, (d) the temperature of the heater is raised by 20°C in the deposition step and the edge portion to the center portion in the deposition step is When a power ratio of 2.0 is applied, (e) the temperature of the center of the heater is 610 ° C and the temperature of the edge is 595 ° C, but the temperature of the heater is not raised in the deposition step, (f) the center of the heater The temperature is 610 ° C and the temperature of the edge is 595 ° C., but the dielectric constant (K value) for each wafer measurement point is shown when the temperature of the heater is raised by 10 ° C in the deposition step.

Referring to FIG. 14, compared to (a) and (e) in which the temperature was not raised or the edge power was not adjusted in the deposition step, (b) and (c) in which the heater was heated or the edge power was additionally controlled in the deposition step. , (d), and (f), it can be seen that the dielectric constant difference in the film thickness direction was significantly improved.

As described above, in the substrate processing method according to the present invention, by raising the temperature of the heater to a temperature higher than the first temperature in the deposition step, the difference in dielectric constant in the thickness direction of the deposited film can be reduced. Furthermore, the difference in dielectric constant in the thickness direction of the deposited film can be further reduced through additional temperature control of the edge portion of the heater.

In addition, according to the present invention, since the dielectric constant difference in the film thickness direction can be reduced, a relatively thick film can be formed on the substrate in one deposition process.

Although the above has been described based on the embodiments of the present invention, various changes or modifications may be made at the level of those skilled in the art. As long as these changes and modifications do not depart from the scope of the present invention, it can be said to belong to the present invention. Therefore, the scope of the present invention will be determined by the claims described below.

501: heater
501a: center part
501b: edge portion
510: temperature controller
520a: heater center power supply unit
520b: Heater edge power supply unit

Claims (7)

a substrate loading step of loading a substrate onto a heater disposed in the reaction chamber;
a stabilization step of maintaining the heater temperature at a first temperature;
a deposition step of supplying a reaction gas into a reaction chamber to form a film on the substrate; and
A purge step of purging the inside of the reaction chamber,
In the deposition step, the temperature of the heater is increased to a temperature higher than the first temperature.
According to claim 1,
The heater is a substrate processing method, characterized in that the temperature is gradually raised throughout the deposition step.
According to claim 1,
In the deposition step, the temperature of the heater is increased to a temperature 10 to 40 ° C higher than the first temperature.
According to claim 1,
The surface of the heater is divided into a center portion and an edge portion outside the center portion,
In the deposition step, the temperature increase amount of the edge portion is greater than the temperature increase amount of the center portion.
According to claim 4,
The ratio of the power applied to the edge portion to the power applied to the center portion in the stabilization step (hereinafter referred to as a first power ratio) is applied to the edge portion to the power applied to the center portion in the deposition step. A substrate processing method comprising controlling a power ratio (hereinafter referred to as a second power ratio) to be higher.
According to claim 5,
When the first power ratio is 1.5, the substrate processing method characterized in that for controlling the second power ratio to 1.7 ~ 2.0.
According to claim 4,
The substrate processing method characterized in that for controlling the temperature of the edge portion independently of the center portion.

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