Substrate processing method using heater temperature control

Abstract

A substrate processing method using heater temperature control is disclosed, which can reduce the dielectric constant deviation of a deposited film in the thickness direction. The substrate processing method according to the present invention includes: a substrate loading step, loading the substrate onto a heater arranged in a reaction chamber; a stabilization step, maintaining the temperature of the heater at a first temperature; a deposition step, supplying a reaction gas into the reaction chamber to form a film on the substrate; and a purge step, purging the interior of the reaction chamber, and in the deposition step, raising the temperature of the heater to a temperature higher than the first temperature.

Description

Technical Field

[0001] The present invention relates to a substrate processing method. More specifically, the present invention relates to a substrate processing method using heater temperature control. Background Art

[0002] As a method for depositing a thin film with a thickness of about 1 μm or less on a wafer or substrate, representative methods include chemical vapor deposition (CVD) and physical vapor deposition (PVD). Among them, the CVD method is a method of depositing the required material through a chemical reaction of a reaction gas in a reaction chamber.

[0003] When a thin film is deposited by a CVD method, various process conditions such as radio frequency (RF) power, deposition time, and chamber temperature are controlled from the beginning in order to improve the characteristics of the deposited thin film. As an example, a thin film deposition device is disclosed in Patent Document 1, which includes: a crucible part, which sets two or more heating areas along the length direction to form a thin film on a substrate in a processing space located in a process chamber; a linear source, which includes two or more heater parts corresponding to each of the heating areas; one or more evaporation rate sensors, which are arranged corresponding to one of the heating areas and are used to measure the evaporation rate of the corresponding heating area; and a control part, which controls the heat generation of the heater parts corresponding to the remaining heating areas other than the heating area of ​​the measurement object based on the measured evaporation rate of the heating area whose evaporation rate is measured by the evaporation rate sensor, so as to control the evaporation rate of the linear source. According to Patent Document 1, the uniformity of thin film deposition can be improved by independently controlling the heat generation of each heater part based on the evaporation rate of the deposited material measured by the evaporation rate sensor.

[0004] [Prior art literature]

[0005] [Patent Document]

[0006] [Patent Document 1] Patent Publication No. 10-2017-0141486 (published on December 26, 2017) Summary of the invention

[0007] [Problems to be solved by the invention]

[0008] The problem to be solved by the present invention is to provide a substrate processing method using heater temperature control, which can adjust the temperature of a wafer on the heater by controlling the temperature of the heater disposed in a reaction chamber, thereby improving the characteristics of a deposited thin film.

[0009] In particular, the problem to be solved by the present invention is to provide a substrate processing method using heater temperature control, which can improve the characteristics of the deposited thin film by controlling the temperature of the center and edge portions of the chip on the heater through the actuation control of the heater using ramping, proportional-integral-derivative (PID), power ratio, etc.

[0010] [Technical means to solve the problem]

[0011] The substrate processing method according to the present invention for solving the above-mentioned problems includes: a substrate loading step of loading a substrate onto a heater arranged in a reaction chamber; a stabilization step of maintaining the temperature of the heater 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 interior of the reaction chamber, and in the deposition step, raising the temperature of the heater to a temperature higher than the first temperature.

[0012] In the depositing step, the temperature of the heater may be increased to a temperature 10° C. to 40° C. higher than the first temperature.

[0013] The surface of the heater may be divided into a central portion and an edge portion around the central portion, and in the deposition step, a temperature increase amount of the edge portion is made greater than a temperature increase amount of the central portion.

[0014] Control can be performed in the following manner: the ratio of the power applied to the edge portion to the power applied to the center portion in the deposition step (hereinafter, the second power ratio) is higher than the ratio of the power applied to the edge portion to the power applied to the center portion in the stabilization step (hereinafter, the first power ratio).

[0015] The second power ratio may be controlled to be 1.6-1.8.

[0016] The temperature of the edge portion may be controlled independently of the central portion.

[0017] [Effects of the Invention]

[0018] In the substrate processing method according to the present invention, the difference in the dielectric constant in the thickness direction of the deposited film can be reduced by the temperature control of the heater.

[0019] More specifically, in the substrate processing method according to the present invention, in the deposition step, the temperature of the heater is raised to a temperature higher than the first temperature, so that the difference in the dielectric constant in the thickness direction of the deposited film can be reduced. Furthermore, by additionally controlling the temperature of the edge portion of the heater, the difference in the dielectric constant in the thickness direction of the deposited film can be further reduced.

[0020] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art through the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 An amorphous carbon film formed on a substrate through two deposition processes is schematically shown.

[0022] Figure 2 The dielectric constants (K values) at various positions in the thickness direction of the amorphous carbon film formed in each deposition process are shown.

[0023] Figure 3 An etching profile corresponding to the difference in dielectric constant in the thickness direction of the amorphous carbon film is shown.

[0024] Figure 4 An ideal etch profile is shown.

[0025] Figure 5 An example of a temperature control system for a heater is shown.

[0026] Figure 6 The center and edge of the heater surface are shown.

[0027] Figure 7 FIG. 1 is a flowchart schematically showing a substrate processing method according to an embodiment of the present invention.

[0028] Figures 8a to 8c An example of a temperature profile of a substrate processing method including a temperature increase of a heater in a deposition step is shown.

[0029] Figures 9a to 9c 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 is shown.

[0030] Fig.10 49 measurement points on the wafer are shown.

[0031] Figures 11a to 11c The deposition is shown at 610°C using an edge to center power ratio of 1.5. and When an amorphous carbon film of different thickness is formed, (a) the dielectric constant (K value) of different wafer measurement points, (b) the heater setting temperature of each step, and (c) the power applied to the center and edge of each step.

[0032] Figures 12a to 12c The power ratio of the edge to the center is 1.5, which is used to deposit the and The dielectric constants (K values) of different wafer measurement points after forming an amorphous carbon film of a certain thickness, are as follows: (a) when the temperature of the heater is not further increased during the deposition step, (b) when the temperature of the heater is increased by 10°C during the deposition step, and (c) when the temperature of the heater is increased by 20°C during the deposition step.

[0033] Figures 13a to 13c Deposition at 610°C is shown and After forming an amorphous carbon film of thickness, the temperature of the heater was raised by 20°C in the deposition step, and the dielectric constants (K values) of different wafer measurement points were measured (a) when the power ratio of the edge to the center was 1.5, (b) when the power ratio of the edge to the center was 1.7, and (c) when the power ratio of the edge to the center was 2.0.

[0034] Figures 14a to 14f Deposition at 610°C is shown and The dielectric constant (K value) of different wafer measurement points after forming an amorphous carbon film of thickness in the following cases: (a) when the temperature of the heater is not increased in the deposition step and a power ratio of 1.5 is applied to the edge portion to the center portion in the deposition step, (b) when the temperature of the heater is increased by 20°C in the deposition step and a power ratio of 1.5 is applied to the edge portion to the center portion in the deposition step, (c) when the temperature of the heater is increased by 20°C in the deposition step and a power ratio of 1.7 is applied to the edge portion to the center portion in the deposition step, (d) when the temperature of the heater is increased by 20°C in the deposition step and a power ratio of 2.0 is applied to the edge portion to the center portion in the deposition step, (e) when 610°C and 595°C are applied to the temperature of the center portion and the temperature of the edge portion of the heater respectively, and when the temperature of the heater is not increased in the deposition step, (f) when 610°C and 595°C are applied to the temperature of the center portion and the temperature of the edge portion of the heater respectively, and when the temperature of the heater is increased by 10°C in the deposition step. DETAILED DESCRIPTION

[0035] The advantages and features of the present invention, and methods of achieving the same will become clear with reference to the embodiments and drawings described in detail below. However, the present invention is not limited to the embodiments disclosed below, but is implemented in various forms that are different from each other. This embodiment is only to complete the disclosure of the present invention and is provided to fully inform those with ordinary knowledge in the technical field to which the present invention belongs of the scope of the present invention, and the present invention is defined only by the scope of the claims. Throughout the specification, the same reference symbols refer to the same components. For the clarity of the description, the size and relative size of the layers and regions in the figures may be exaggerated.

[0036] The situation where an element or layer is said to be "above" or "on" another element includes not only being directly above another element or layer, but also including the situation where other layers or other elements are interposed in between. Conversely, the situation where an element is said to be "directly above" or "directly on" indicates that no other element or other layer is interposed in between. In addition, it should be understood that when a certain constituent element is recorded as being "connected", "combined" or "connected" to another constituent element, although the constituent elements may be directly connected or connected to each other, other constituent elements may be "interposed" between the constituent elements, or the constituent elements may be "connected", "combined" or "connected" through other constituent elements.

[0037] Spatially relative terms such as "below", "lower", "above", "upper", etc. can be used to easily describe the relationship between one element or constituent element and another element or constituent element as shown in the figure. Spatially relative terms should be understood as terms that include different directions of elements when used or operated in addition to the directions shown in the figure. For example, in the case where the elements shown in the figure are turned over, the element described as "below" another element may be placed "above" another element. Therefore, "below" as an exemplary term can include both directions of below and above.

[0038] The terms used in this specification are used to illustrate the embodiments and are therefore not intended to limit the present invention. In this specification, unless otherwise specifically mentioned in a sentence, the singular also includes the plural. The constituent elements, steps, actions and / or elements mentioned in the specification as "including" and / or "comprising" do not exclude the presence or addition of one or more other constituent elements, steps, actions and / or elements.

[0039] 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.

[0040] Figure 1 An amorphous carbon film formed on a substrate through two deposition processes is schematically shown. Figure 2 The dielectric constant (K value) at each position in the thickness direction of the amorphous carbon film formed in each deposition process is shown.

[0041] Reference Figure 1 and Figure 2 In the case of the amorphous carbon films 101 and 102 formed on the substrate by CVD, it can be observed that different dielectric constants (K values) are shown in the thickness direction. It can be observed that a relatively high K value of about 0.57 is shown in the lower part of the film, that is, the part formed in the early stage of each deposition process, but a relatively low K value of about 0.55 is shown in the upper part of the film, that is, the part formed in the late stage of each deposition process.

[0042] In addition, as in Figure 2 As can be seen from the situation observed in FIG. 1 , the phenomenon of showing different dielectric constants in the thickness direction of the film is manifested in both the film 101 formed by the first process and the film 102 formed by the second process.

[0043] Figure 3 An etching profile corresponding to the difference in dielectric constant in the thickness direction of the amorphous carbon film is shown. Figure 4 An ideal etch profile is shown.

[0044] Reference Figure 3 , it can be observed that in each of the amorphous carbon films 101, 102, there is a considerable degree of etching unevenness between the lower portion of the film and the upper portion of the film. As described above, it can be observed that this etching unevenness is due to the difference in dielectric constant in the thickness direction of the film. That is, in the lower portion of the film, that is, the portion formed in the early stage of each deposition process, a relatively high K value is shown, and therefore the etching amount is relatively small, whereas in the upper portion of the film, that is, the portion formed in the late stage of each deposition process, a relatively low K value is shown, and therefore the etching amount is relatively large.

[0045] In this Figure 3 The etching profile of the case increases the possibility of process failure, and the etching profile needs to be improved to be close to Figure 4 The ideal etching profile is shown. In order to improve this etching profile, it is necessary to reduce the difference in dielectric constant in the thickness direction of the film.

[0046] This difference in dielectric constant in the thickness direction of the film is believed to be due to the change in the radiant heat of the showerhead during the deposition step. As deposition progresses on the substrate, deposition gradually progresses at the showerhead, and this deposition at the showerhead becomes the main reason for the reduction in radiant heat of the showerhead.

[0047] Therefore, even if the same power is supplied to the heater and the same temperature is set, as deposition proceeds, the showerhead radiant heat gradually decreases, so that deposition is performed at a relatively low temperature in the later stage of deposition compared to the early stage of deposition.

[0048] The inventors of the present invention have learned through long-term studies that if the temperature of the heater is further controlled during the deposition step, this head radiation heat can be compensated, thereby reducing the difference in dielectric constant in the thickness direction of the film.

[0049] Figure 5 An example of a temperature control system for a heater is shown.

[0050] Reference Figure 5 In order to control the temperature of the heater 501, the temperature control unit 510 responds to the signal of the thermocouple (TC) or the like that measures the temperature of the heater 501, and sends control signals S1 and S2 to the heater center power supply unit 520a and the heater edge power supply unit 520b. The heater center power supply unit 520a responds to the control signal S1 and supplies a predetermined power P1 to the center of the heater. In addition, the heater edge power supply unit 520b responds to the control signal S2 and supplies a predetermined power P2 to the edge of the heater.

[0051] Figure 6 The center and edge of the heater surface are shown.

[0052] The heater 501 can be divided into a central portion 501a and an edge portion 501b of the outer contour of the central portion. If the radius of the entire heater is set to r1+r2, the width of the central portion 501a can be r1, and the width of the edge portion 501b can be r2. The ratio of the width r1 of the central portion 501a to the width r2 of the edge portion 501b (r1:r2) can be set to, for example, 3:1, 2.5:1, 2:1, etc.

[0053] There are two ways to control the temperature of the center and edge of the heater surface. The first way is to control the temperature of the center by thermocouples, filaments, etc., and control the power ratio of the edge to the center to control the temperature of the edge. The other way is to control the temperature of the center by thermocouples and control the temperature of the edge by hot wire temperature control.

[0054] Figure 7 FIG. 1 is a flowchart schematically showing a substrate processing method according to an embodiment of the present invention.

[0055] Reference Figure 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.

[0056] In the embodiments according to the present invention, the case of depositing an amorphous carbon film on a wafer is mainly described, but the present invention is not limited thereto and can also be applied to the deposition of other types of films.

[0057] In the substrate loading step S710, the substrate is loaded onto a heater disposed in the reaction chamber. Prior to the substrate loading step S710, a preheating step of preheating the heater may be additionally included. In the stabilization step S720, the temperature of the heater is maintained at a predetermined first temperature (for example, 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 to the interior of the reaction chamber to remove unreacted gas, reaction byproducts, etc. in the reaction chamber.

[0058] At this time, in the present invention, in the deposition step S730, the temperature of the heater is raised to a temperature higher than the first temperature. As described above, even if the same power is provided to the heater and the same temperature is set, as the deposition proceeds, the head radiation heat gradually decreases, so that the deposition is performed at a relatively low temperature in the later stage of the deposition compared to the early stage of the deposition. As shown 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, this reduction in the head radiation heat can be compensated. Therefore, as if the deposition is performed on the substrate at substantially the same temperature throughout the deposition step, the difference in the dielectric constant in the thickness direction of the film can be reduced.

[0059] In the deposition step S730, it is preferred that the heater gradually increases in temperature throughout the entire deposition step, thereby compensating for the gradual decrease in the radiant heat from the showerhead as the deposition proceeds.

[0060] In the deposition step S730, the temperature of the heater is preferably increased to a temperature 10°C to 40°C higher than the first temperature, and more preferably increased to a temperature 10°C to 20°C higher than the first temperature. If the temperature increase of the heater is too small, the effect brought about by the temperature increase may not be sufficient. If the temperature increase of the heater is too large, considering that the characteristics of the deposited film may change, the temperature increase of the heater is preferably 10°C to 40°C, and more preferably 10°C to 20°C.

[0061] Figures 8a to 8c FIG. 2 shows an example of a temperature profile of a substrate processing method including a temperature increase of a heater in a deposition step. More specifically, Figures 8a to 8cAn example of a temperature profile of a substrate processing method including the following steps is shown: a heater preheating step (Preheat), a substrate configuration (Place) step, a stabilization (Stable) step (including He plasma), a deposition (Dep) step, and a purging (Purge) step (including exhaust).

[0062] Figure 8a The temperature profile is shown in the case where the ratio of the power applied to the edge portion to the power applied to the center portion is 1.5, Figure 8b The temperature profile is shown when the ratio of the power applied to the edge portion to the power applied to the center portion is 1.7. Figure 8c The temperature profile for the case where the ratio of the power applied to the edge portion to the power applied to the center portion is 2.0 is shown.

[0063] like Figures 8a to 8c The temperature profiles shown are for forming The thicker the amorphous carbon film to be deposited, the longer the deposition time and the accompanying heating time become.

[0064] Reference Figures 8a to 8c In the stabilization step, after maintaining the temperature of the heater at about 610° C., the temperature of the heater is gradually increased to about 630° C. to 650° C. in the deposition step.

[0065] On the other hand, in the purge step S740 , the temperature of the heater may be restored to the first temperature again according to the type of deposition.

[0066] In addition, in the deposition step S730 , the temperature increase amount of the edge portion may be made greater than the temperature increase amount of the center portion.

[0067] As an example, control can be performed as follows: the ratio of the power applied to the edge portion to the power applied to the center portion in the deposition step (hereinafter, the second power ratio) (for example, 1.7 or 2.0) is higher than the ratio of the power applied to the edge portion to the power applied to the center portion in the stabilization step (hereinafter, the first power ratio) (for example, 1.5).

[0068] The experimental results show that when the first power ratio is 1.5, the dielectric constant difference in the film thickness direction can be effectively reduced when the second power ratio is controlled to be 1.7 to 2.0.

[0069] In the purge step S740 , the first power ratio may be restored according to the type of deposition.

[0070] Figures 9a to 9c 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 is shown.

[0071] like Figures 9a to 9c The power profiles shown represent the power used to form The power (PWR) of the center (CENTER) and edge (EDGE) of the amorphous carbon film with different thickness varies.

[0072] Figure 9a This is the case where the power of the edge to the center is maintained at 1.5 throughout the entire process. Figure 9b This is the case where the power of the edge to the center is increased to 1.7 during the deposition step. Fig.9c This is the case where the power of the edge portion to the center portion is increased to 2.0 during the deposition step.

[0073] Reference Figures 9a to 9c , it can be observed that the power applied to the edge portion is increased only in the deposition step.

[0074] On the other hand, in addition to controlling the power of the edge portion to the center portion during the deposition step, the temperature of the edge portion may also be controlled independently of the center portion.

[0075] Fig.10 49 measurement points of the wafer are shown. The numbers are numbered from 1 to 49 from the center toward the edge. In the following example, the dielectric constant (K value) is measured at 49 locations of the deposited film formed on the wafer.

[0076] Figures 11a to 11c The deposition is shown at 610°C using an edge to center power ratio of 1.5. When an amorphous carbon film of different thickness is formed, (a) the dielectric constant (K value) of different wafer measurement points, (b) the heater setting temperature of each step, and (c) the power applied to the center and edge of each step. Figures 11a to 11c The data are for the deposition step without heating and / or increasing the power at the edge, which can be regarded as the following Figure 12a-12c to Figure 14a-Figure 14c Reference data for the data.

[0077] Figures 12a to 12c The power ratio of the edge to the center is 1.5, which is used to deposit the and After forming an amorphous carbon film of a certain thickness, the dielectric constant (K value) of different wafer measurement points is shown in FIG. 1 , when (a) the temperature of the heater is not further increased during the deposition step, (b) the temperature of the heater is increased (Rmp) by 10°C during the deposition step, and (c) the temperature of the heater is increased by 20°C during the deposition step.

[0078] Refer to 12a to Fig.12c It can be observed that when the temperature of the heater is increased by 10° C. and 20° C. in the deposition step, the difference in the dielectric constant corresponding to the thickness of the amorphous carbon film decreases.

[0079] Figures 13a to 13c Deposition at 610°C is shown and After forming an amorphous carbon film of thickness, the temperature of the heater is raised (Rmp) by 20°C in the deposition step, and the dielectric constants (K values) of different wafer measurement points are measured (a) when the power ratio of the edge to the center is 1.5, (b) when the power ratio of the edge to the center is 1.7, and (c) when the power ratio of the edge to the center is 2.0.

[0080] Reference Figures 13a to 13c It can be observed that by increasing the power ratio of the edge portion to the center portion to 1.7 or 2.0 in the deposition step, when the temperature of the edge portion is further increased, the difference in the dielectric constant corresponding to the thickness of the amorphous carbon film is reduced.

[0081] Figures 14a to 14f Deposition at 610°C is shown and The dielectric constant (K value) of different wafer measurement points after forming an amorphous carbon film of thickness in the following cases: (a) when the temperature of the heater is not increased in the deposition step and a power ratio of 1.5 is applied to the edge to the center in the deposition step, (b) when the temperature of the heater is increased (Rmp) by 20°C in the deposition step and a power ratio of 1.5 is applied to the edge to the center in the deposition step, (c) when the temperature of the heater is increased by 20°C in the deposition step and a power ratio of 1.7 is applied to the edge to the center in the deposition step, (d) when the temperature of the heater is increased by 20°C in the deposition step and a power ratio of 2.0 is applied to the edge to the center in the deposition step, (e) when 610°C and 595°C are applied to the temperature of the center and the temperature of the edge of the heater respectively, and when the temperature of the heater is not increased in the deposition step, (f) when 610°C and 595°C are applied to the temperature of the center and the temperature of the edge of the heater respectively, and when the temperature of the heater is increased by 10°C in the deposition step.

[0082] Reference Figures 14a to 14f , it can be seen that the deposition step does not increase the temperature or adjust the edge power. Fig.14a and Fig.14e In contrast, the heater is heated up during the deposition step or the power at the edge is further controlled. Fig.14b , Fig.14c , Fig.14d , Fig.14fThe case shows a significantly improved dielectric constant difference in the film thickness direction.

[0083] 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 the dielectric constant in the thickness direction of the deposited film can be reduced. Furthermore, by additionally controlling the temperature of the edge portion of the heater, the difference in the dielectric constant in the thickness direction of the deposited film can be further reduced.

[0084] In addition, according to the present invention, since the difference in dielectric constant in the film thickness direction can be reduced, a relatively thick film can be formed on a substrate in one deposition process.

[0085] Although the above is described with the embodiment of the present invention as the center, various changes or deformations can be made at the level of those skilled in the art. Such changes and deformations can all belong to the present invention without departing from the scope of the present invention. Therefore, the scope of rights of the present invention should be judged according to the claims described above.

Claims

1. A substrate processing method, characterized in that: include: a substrate loading step, loading the substrate onto a heater disposed in the reaction chamber; a stabilization step of maintaining the temperature of the heater at a first temperature; A deposition step, supplying a reaction gas into a reaction chamber through a showerhead to form a film on a substrate; as well as A purge step is to purge the interior of the reaction chamber. In the deposition step, the temperature of the heater is increased to a temperature higher than the first temperature to compensate for the reduction in radiant heat transferred from the nozzle to the substrate due to the film deposited on the nozzle in the deposition step, and the heater is gradually heated throughout the entire deposition step so that the temperature at the end of the deposition step is higher than the temperature at the beginning of the deposition step.

2. The substrate processing method according to claim 1, characterized in that: In the deposition step, the temperature of the heater is increased to a temperature 10° C. to 40° C. higher than the first temperature.

3. The substrate processing method according to claim 1, characterized in that: The surface of the heater is divided into a central portion and an edge portion of the outer contour of the central portion. In the deposition step, the temperature increase amount of the edge portion is made larger than the temperature increase amount of the center portion.

4. The substrate processing method according to claim 3, characterized in that: Control is performed in the following manner: compared with the ratio of the power applied to the edge portion to the power applied to the center portion in the stabilization step, the ratio of the power applied to the edge portion to the power applied to the center portion in the deposition step is higher, wherein the ratio of the power applied to the edge portion to the power applied to the center portion in the stabilization step is a first power ratio, and the ratio of the power applied to the edge portion to the power applied to the center portion in the deposition step is a second power ratio.

5. The substrate processing method according to claim 4, characterized in that: When the first power ratio is 1.5, the second power ratio is controlled to be 1.7-2.

0.

6. The substrate processing method according to claim 3, characterized in that: The temperature of the edge portion is controlled independently of the center portion.

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