JP6778882B2 - Plasma processing equipment, plasma processing method, and tray for plasma processing equipment - Google Patents

Description

The present invention relates to a plasma processing apparatus, a plasma processing method, and a tray for a plasma processing apparatus.

A plasma processing apparatus is known in which a plurality of substrates are placed on a tray to perform batch processing. This type of plasma processing device is used in the manufacture of mass-produced LEDs (Light Emitting Diodes), SAW (Surface Acoustic Wave) devices, and the like.

In the plasma processing apparatus of Patent Document 1, a tray containing a substrate is placed on a substrate susceptor that functions as a lower electrode. The substrate and tray are brought into close contact with the substrate susceptor by electrostatic adsorption. The substrate susceptor is provided with a cooling mechanism, and the substrate and the tray are in surface contact with the substrate susceptor and are cooled by direct heat conduction.

Japanese Patent No. 5539436

During plasma processing, not only the substrate but also the tray is irradiated with plasma. When the plasma is irradiated, the temperature of the tray rises. As the temperature of the tray rises, the tray is thermally deformed and the flatness of the lower surface of the tray is lowered. If the degree of adhesion of the tray to the substrate susceptor varies due to the decrease in flatness, the cooling of the tray varies. If the tray is not cooled uniformly, a temperature difference will occur in the tray, and this temperature difference may cause damage such as cracking in the tray.

Further, as the tray material, SiC (silicon carbide), quartz, alumina or the like is used depending on the process. SiC trays are hard to break but expensive. Quartz trays are fragile and difficult to handle large diameter substrates. Alumina trays are inexpensive, but they are vulnerable to thermal shock, and when plasma treatment is performed under high power conditions, they may crack due to the temperature difference in the trays as described above.

An object of the present invention is to prevent damage to the tray during plasma treatment.

The plasma processing apparatus of the first aspect of the present invention has a decompressable chamber, a plasma generation source for generating static electricity in the chamber, and a substrate accommodating portion for accommodating a substrate, and can be carried in and out of the chamber. A dielectric member including a tray, a tray mounting portion on which the lower surface of the tray provided in the chamber and carried into the chamber is mounted, and a substrate mounting portion on which the substrate is mounted. And the electrostatic adsorption electrode built in the dielectric member for electrostatically attracting the substrate to the substrate mounting portion and electrostatically attracting the tray to the tray mounting portion, and the electrostatic attraction. A DC voltage applying mechanism for applying a DC voltage to the adsorption electrode and a cooling mechanism for cooling the dielectric member including the tray mounting portion and the substrate mounting portion are provided, and the lower surface of the tray has the tray. a metal layer having a high conductivity of a material constituting has a region that has been overturned to be, and a non-coated region exposed without material constituting the tray is covered by the metal layer.

In the plasma processing apparatus, a DC voltage is applied to the electrostatic adsorption electrode by the DC voltage application mechanism, so that the tray is electrostatically attracted to the dielectric member in which the electrostatic adsorption electrode is built. The dielectric member is cooled by a cooling mechanism, and the tray is cooled by direct heat conduction by making surface contact with the dielectric member. At this time, if the tray is irradiated with plasma and the tray is thermally deformed, this surface contact is not performed accurately, the cooling of the tray varies, a temperature difference occurs in the tray, and the tray may be damaged such as cracks. There is. On the other hand, as in the above configuration, since the lower surface of the tray is partially covered with the metal layer, the conductivity of the covered portion is improved, and the portion is strongly electrostatically adsorbed to the tray mounting portion. it can. Therefore, a portion that is easily cooled can be provided in the tray. When there is a cooling variation in the tray, the cooling variation can be eliminated and the temperature of the tray can be made uniform by providing a portion that is easily cooled as described above in a portion that is difficult to be cooled. Therefore, according to this configuration, it may be possible to suppress the occurrence of warpage of the tray during plasma processing, and as a result, prevent damage such as cracking of the tray.

The central portion of the lower surface of the tray may be covered with a metal layer in a larger proportion than the outer peripheral portion.

Generally, when the tray is irradiated with plasma, the central portion of the tray bulges upward with respect to the outer peripheral portion due to the heat spreading of the tray. Therefore, the central portion of the tray is more difficult to cool because the distance from the tray mounting portion is larger than that of the outer peripheral portion. That is, the temperature tends to be relatively high in the central portion of the tray and low in the outer peripheral portion of the tray. On the other hand, as in the above configuration, the central portion of the lower surface of the tray is more covered with the metal layer than the outer peripheral portion, so that the central portion of the tray is easily attracted to the tray mounting portion. That is, it is easy to cool. Therefore, the temperature difference between the central portion and the outer peripheral portion of the tray is reduced, the bulge (warp) of the tray is alleviated, and damage such as cracking can be prevented.

The outer peripheral portion of the lower surface of the tray may not be covered with a metal layer over the entire circumference of the outer peripheral end, and the lower surface of the tray may be exposed.

Since the central portion of the tray bulges upward as described above, the outer peripheral end of the tray is the portion closest to the tray support portion. That is, the outer peripheral edge of the tray is the portion of the tray that is most likely to be cooled. Therefore, as in the above configuration, by having a region where the outer peripheral edge of the tray is not covered with the metal layer and the lower surface of the tray is exposed, the temperature of the outer peripheral portion is relatively raised, and the temperature of the outer peripheral portion is relatively increased to the central portion. The temperature difference in the outer peripheral portion can be further reduced.

The metal layer may surround the substrate accommodating portion.

The substrate accommodating portion of the tray accommodates the substrate to be irradiated with plasma. Both the tray and the substrate are electrostatically attracted to the cooled dielectric member and cooled, but the tray has a lower flatness than the substrate, so that the heat conduction with the dielectric member is poor and the temperature is higher than that of the substrate. Will also be higher. Further, in order to surely cool the substrate, a cooling gas hole is temporarily provided in the substrate mounting portion, and a cooling gas such as helium is introduced between the substrate and the substrate mounting portion through the gas hole. When cooling the substrate, the temperature difference between the substrate and the tray tends to be even larger. In this way, when the temperature of the tray is higher than the temperature of the substrate, the outer peripheral portion of the substrate is close to the tray and is affected by the heat radiation from the tray, and the temperature rises compared to the central portion of the substrate. It's easy to do. Therefore, as in the above configuration, since the periphery of the substrate accommodating portion is covered with the metal layer, the substrate accommodating portion of the tray is easily attracted to the tray mounting portion, that is, it is easily cooled, and the radiant heat of the tray is easily absorbed. It is possible to suppress the temperature rise of the outer peripheral portion of the substrate due to the above.

The substrate accommodating portion includes a substrate accommodating hole penetrating in the thickness direction and a substrate supporting portion projecting from the hole wall of the substrate accommodating hole and supporting the outer edge portion of the lower surface of the substrate accommodated in the substrate accommodating hole. You may prepare.

When the substrate accommodating portion is a through hole (substrate accommodating hole), the strength is lowered as compared with the case of the bottomed hole, and there is a high possibility that the tray is cracked. Therefore, it is effective to adopt a tray structure that is hard to break as described above, particularly when the substrate accommodating portion is a through hole (substrate accommodating hole).

The tray may consist of ceramics containing alumina as a main component.

Alumina trays are fragile but inexpensive. Therefore, by adopting a tray structure that is hard to crack as described above, particularly for an alumina tray, plasma treatment that overcomes problems such as cracking at low cost is possible. Here, the "main component" means that the mass% in the whole is 98.5% or more, preferably 99.5% or more.

The metal layer may contain nickel as a main component.

Since nickel is difficult to react with chlorine or fluorine, which is usually used in plasma treatment processes, by using nickel as the main component of the metal layer, even in plasma treatments with chlorine-based processes or fluorine-based processes. A tray having the above structure can be used. Here, the "main component" means that the mass% in the whole is 98% or more.

The plasma processing apparatus according to the second aspect of the present invention has a decompressable chamber, a plasma generation source for generating plasma in the chamber, and a substrate accommodating portion for accommodating a substrate, and can be carried in and out of the chamber. A dielectric member including a tray, a tray mounting portion on which the lower surface of the tray provided in the chamber and carried into the chamber is mounted, and a substrate mounting portion on which the substrate is mounted. And the electrostatic adsorption electrode built in the dielectric member for electrostatically attracting the substrate to the substrate mounting portion and electrostatically attracting the tray to the tray mounting portion, and the electrostatic attraction. A DC voltage applying mechanism for applying a DC voltage to the adsorption electrode and a cooling mechanism for cooling the dielectric member including the tray mounting portion and the substrate mounting portion are provided, and the outer peripheral portion of the lower surface of the tray is provided with a cooling mechanism. It has a concave shape formed by providing a step with respect to the central portion.

With this configuration, the outer peripheral portion of the lower surface of the tray has a concave shape with respect to the central portion, so that the outer peripheral portion is less likely to come into contact with the tray mounting portion than the central portion. That is, the outer peripheral portion is less likely to be cooled than the central portion, the temperature difference between the central portion and the outer peripheral portion of the tray is reduced, and damage such as cracking of the tray can be prevented.

The third aspect of the plasma processing method of the present invention accommodates the substrate to the substrate receiving portion of the tray, the lower surface of the tray is overturned be a metal layer having high conductivity than the material constituting the tray area And the uncoated region in which the material constituting the tray is exposed without being covered by the metal layer, and the tray containing the substrate is conveyed to a dielectric member arranged in the chamber. The tray is placed on a tray mounting portion included in the dielectric member, and the substrate is mounted on a substrate mounting portion included in the dielectric member, and an electrostatic adsorption electrode built in the dielectric member. By applying a DC voltage to the substrate, the substrate is electrostatically attracted to the substrate mounting portion, and the tray is electrostatically attracted to the tray mounting portion, so that the tray mounting portion of the dielectric member and the tray mounting portion are described. A plasma processing method comprising cooling a substrate mounting portion and generating plasma in the chamber to perform plasma treatment on the substrate.

The tray for a plasma processing apparatus according to a third aspect of the present invention is a tray for a plasma processing apparatus, which has a substrate accommodating portion for accommodating a substrate , a region covered with a metal layer, and a material constituting the tray. There comprises one side and a region exposed without being covered by the metal layer, a large proportion of the central portion of the one side is covered by the metal layer as compared with the outer peripheral portion.

According to the present invention, since the temperature inside the tray during plasma processing can be made uniform, cracking of the tray can be prevented.

The schematic sectional view of the plasma processing apparatus which concerns on 1st Embodiment of this invention. The perspective view which shows the tray and the dielectric member of FIG. Top plan view showing the tray of FIG. The lower plan view which shows the tray of FIG. FIG. 5 is a cross-sectional view before mounting the tray of FIG. 1 on a dielectric member. FIG. 5 is a cross-sectional view after the tray of FIG. 1 is placed on the dielectric member. The upper plan view which shows the tray of the plasma processing apparatus which concerns on 2nd Embodiment. The lower plan view which shows the tray of the plasma processing apparatus which concerns on 2nd Embodiment. The cross-sectional view before mounting the tray which concerns on 2nd Embodiment on a dielectric member. FIG. 5 is a cross-sectional view of the tray according to the second embodiment after being placed on the dielectric member. The upper plan view which shows the tray of the plasma processing apparatus which concerns on 3rd Embodiment. The lower plan view which shows the tray of the plasma processing apparatus which concerns on 3rd Embodiment. The cross-sectional view before mounting the tray which concerns on 3rd Embodiment on the dielectric member. FIG. 5 is a cross-sectional view after the tray according to the third embodiment is placed on the dielectric member.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(First Embodiment)
FIG. 1 shows a dry etching apparatus (plasma processing apparatus) 10 according to the first embodiment of the present invention. The dry etching apparatus 10 of the present embodiment is an ICP (inductively coupled plasma) type, and the substrate 7 housed in the tray 1 is subjected to plasma treatment for dry etching.

First, the configuration of the dry etching apparatus 10 will be described.

The dry etching apparatus 10 has a chamber 11 capable of reducing the pressure. The chamber 11 is provided with a gate 12 that can be opened and closed in order to carry in and out the tray 1 holding the substrate 7. The tray 1 in this embodiment can hold seven 4-inch (diameter: about 100 mm) substrates 7 (see FIG. 2). The chamber 11 is provided with an etching gas supply port 14 connected to the etching gas supply source 13 and an exhaust port 16 connected to the vacuum exhaust device 15. Further, a substrate susceptor 18 having a function as a lower electrode to which a bias voltage is applied and a function as a mounting base for the substrate 7 and the tray 1 is arranged at the bottom of the chamber 11. The upper end opening of the chamber 11 facing the substrate susceptor 18 is closed by a top plate 19 made of a dielectric material such as quartz. An ICP coil 20 is arranged above the top plate 19, and the ICP coil 20 is electrically connected to the high frequency power supply 21. In the present embodiment, the plasma is generated by these plurality of elements, that is, these plurality of elements function as a plasma generation source.

With reference to FIG. 2, the substrate susceptor 18 is composed of an ESC (dielectric member) 22 which is an electrostatic chuck made of a dielectric such as ceramics, aluminum or the like having an alumite coating formed on the surface, and in the present embodiment. A metal plate 24 that functions as a pedestal electrode and a spacer plate 25 made of a dielectric material such as ceramics are provided. Further, the elevating pin 26 is arranged so as to be vertically movable through the ESC 22, the metal plate 24, and the spacer plate 25, and the elevating pin 26 is used for mounting the tray 1 on the ESC 22 as described later. Will be done.

The ESC 22 constituting the uppermost portion of the substrate susceptor 18 has a thin disk shape as a whole and has a circular outer shape in a plan view. The upper part of the ESC 22 constitutes a tray mounting portion 22A, and seven board mounting portions 22C corresponding to the number of substrates 7 held by the tray 1 from the tray mounting surface 22B which is the upper end surface of the tray mounting portion 22A. Is protruding upward. In the present embodiment, the substrate mounting portion 22C is a flat short columnar shape. One board mounting portion 22C is arranged in the center of the tray mounting surface 22B, and the remaining six board mounting portions 22C are arranged at equal angular intervals in a plan view around the board mounting portion 22C. ing.

The tray mounting portion 22A and the individual substrate mounting portions 22C have a built-in electrostatic adsorption electrode 22D. The electrostatic adsorption electrode 22D is connected to a DC power supply 27 which is a DC voltage application mechanism. The metal plate 24 is electrically connected to a high frequency power supply 28 that applies a high frequency voltage as a bias voltage. Further, the metal plate 24 is provided with a refrigerant flow path 24A connected to the refrigerant circulation device 29 as a cooling mechanism.

The tray 1 includes a thin disc-shaped tray body 2 having a uniform thickness. Both the upper surface 2A and the lower surface 2B of the tray body 2 are flat surfaces. The tray body 2 is provided with seven substrate accommodating holes 3 which are circular holes penetrating from the upper surface 2A to the lower surface 2B in the thickness direction. The substrate 7 is accommodated in each substrate accommodating hole 3. One substrate accommodating hole 3 is arranged in the center of the tray main body 2, and the remaining six substrate accommodating holes 3 are arranged at equal angular intervals in a plan view around the substrate accommodating hole 3.

On the lower surface 2B side of the tray body 2 of the hole wall 3A of each substrate accommodating hole 3, a substrate supporting portion 3B projecting toward the center of the substrate accommodating hole 3 is provided. In the present embodiment, the substrate support portion 3B is provided on the entire circumference of the hole wall 3A of the substrate accommodating hole 3, and is an annular shape having a constant width in a plan view. As described above, in the present embodiment, the substrate accommodating portion is composed of the substrate accommodating hole 3 and the substrate supporting portion 3B. The substrate support surface 3C, which is the upper surface of the substrate support portion 3B, supports the vicinity of the peripheral edge of the lower surface 2B of the substrate 7 accommodated in the substrate accommodating hole 3. Therefore, when viewed from the lower surface 2B side of the tray body 2, the lower surface of the substrate 7 is exposed.

The tray 1 (tray body 2) of the present embodiment is composed of ceramics containing alumina as a main component. However, in addition to alumina, ceramic materials such as aluminum nitride, zirconia, yttria, silicon nitride, and silicon carbide can be used.

As shown in FIGS. 3 and 4, the lower surface 2B of the tray 1 of the present embodiment is partially covered with a nickel-based metal layer 4 having a higher conductivity than the material (alumina) constituting the tray body 2. Has been done. Specifically, the metal layer 4 is formed in a covering region having a width w provided around each substrate accommodating hole 3. The width w is larger than the distance d1 between the substrate accommodating holes 3, that is, the covering regions around the substrate accommodating holes 3 overlap each other. In the present embodiment, with respect to the lower surface 2B of the tray 1, the portion covered with the metal layer 4 (hatched portion in FIG. 4) represents the central portion 5, and the outer portion of the central portion 5 (non-shaded portion in FIG. 4) is. Represents the outer peripheral portion 6. In particular, in the present embodiment, since the covering regions are overlapped to cover the entire surface of the central portion 5, coating leakage does not occur in the central portion 5 and the cooling variation described later is suppressed. Further, the width w is smaller than the distance d2 between the substrate accommodating hole 3 and the outer peripheral edge. That is, the outer peripheral portion 6 of the lower surface 2B of the tray 1 has an annular uncovered region that is not covered by the metal layer 4 and the lower surface 2B of the tray 1 is exposed over the entire circumference of the outer peripheral end. The metal layer 4 is coated by plating, thermal spraying, vapor deposition, or the like. As a result, in the tray 1 of the present embodiment, the region covered by the metal layer 4 (hatched portion in FIG. 4) has higher conductivity than the region not covered by the metal layer 4 (non-shaded portion in FIG. 4). Have. In the present embodiment, nickel is used as the material of the metal layer 4, but titanium, aluminum, or the like may be used in addition to nickel.

Next, the operation of the dry etching apparatus 10 will be described.

As shown in FIG. 5, the substrate 7 is preliminarily accommodated in the individual substrate accommodating holes 3 of the tray 1 from the upper surface 2A side of the tray main body 2. The accommodation of the substrate 7 in the tray 1 may be performed manually by an operator, or may be performed by an automatic transfer machine. In the substrate 7 accommodated in the substrate accommodating hole 3, the vicinity of the peripheral edge of the lower surface 2B is supported by the substrate supporting surface 3C of the substrate supporting portion 3B.

The plurality of trays 1 in which the substrate 7 is accommodated in each of the substrate accommodating holes 3 are accommodated in a cassette (not shown), and this cassette is set in the dry etching apparatus 10. The work of setting the cassette in the dry etching apparatus 10 is usually performed manually by an operator. Subsequently, the tray 1 is carried into the chamber 11 from the cassette via the gate 12 by a transport arm (not shown) provided in the transport device juxtaposed with the dry etching apparatus 10, and the elevating pin 26 (FIG. 1) is transferred to the tip. At this time, the tip of the elevating pin 26 is located above the substrate susceptor 18. Next, when the elevating pin 26 is lowered, as shown in FIG. 6, the substrate 7 and the tray 1 are lowered and placed toward the ESC 22 of the substrate susceptor 18. The diameter D1 of the region surrounded by the tip of the substrate support portion 3B in each substrate accommodating hole 3 of the tray 1 is set to be larger than the diameter D2 of the substrate mounting portion 22C. Therefore, when the tray 1 descends toward the tray mounting surface 22B, the substrate mounting portion 22C enters the substrate accommodating hole 3 from the lower surface 2B side of the tray main body 2. The thickness TH1 of the board support portion 3B of the board accommodating hole 3 is shorter than the distance from the tray mounting surface 22B to the upper end of the board mounting portion 22C (height TH2 of the board mounting portion 22C). Therefore, when the tray 1 is mounted on the tray mounting surface 22B, the substrate 7 in each substrate accommodating hole 3 is lifted from the substrate supporting surface 3C and mounted on the upper end of the substrate mounting portion 22C.

As shown in FIG. 1, the inside of the chamber 11 is evacuated by the vacuum exhaust device 15, and then the etching gas is supplied from the etching gas supply source 13 and maintained at a predetermined pressure. After the etching gas is supplied, a DC voltage is applied from the DC power supply 27 to the electrostatic adsorption electrode 22D, and the substrate 7 is electrostatically adsorbed on the upper end of each substrate mounting portion 22C. Further, high frequency voltages are applied from the high frequency power supplies 21 and 28 to the ICP coil 20 and the substrate susceptor 18, respectively. An induced electric field is generated in the chamber 11 by a high-frequency magnetic field generated by the ICP coil 20, electrons are accelerated to generate plasma, and the substrate 7 is irradiated. The upper surface of the substrate 7 is etched by this plasma irradiation. During etching, the refrigerant circulation device 29 cools the ESC 22 by circulating the refrigerant in the refrigerant flow path 24A of the metal plate 24, and the individual substrates 7 are cooled by heat conduction with the substrate mounting portion 22C.

After the etching is completed, the elevating pin 26 is raised, so that the tray 1 in which the substrate 7 is housed in the board accommodating hole 3 is raised from the substrate susceptor 18. After that, the tray 1 holding the substrate 7 is carried out from the chamber 11 to the cassette through the gate 12 by a transfer arm (not shown). The dry-etched substrate 7 is taken out from the tray 1, and a new untreated substrate 7 is accommodated in the substrate accommodating hole 3. In the above procedure, the tray 1 is repeatedly used for the dry etching process.

Generally, when the tray 1 is irradiated with plasma, the central portion 5 of the tray 1 bulges upward with respect to the outer peripheral portion 6 due to the heat spreading of the tray 1. Therefore, the central portion 5 of the tray 1 has a larger distance from the tray mounting portion 22A than the outer peripheral portion 6, and is difficult to be cooled. That is, the temperature of the central portion 5 of the tray 1 is relatively high, and the temperature of the outer peripheral portion 6 of the tray 1 is likely to be low. On the other hand, as in the above configuration, the central portion 5 of the lower surface 2B of the tray 1 is covered with the metal layer 4 in a larger proportion than the outer peripheral portion 6, so that the tray 1 is placed on the tray mounting portion 22A. The central portion 5 of the above is easily adsorbed, that is, it is easy to cool. Therefore, the temperature difference between the central portion 5 and the outer peripheral portion 6 of the tray 1 is reduced, the bulge (warp) of the tray 1 is alleviated, and damage such as cracking can be prevented.

Further, since the central portion 5 of the tray 1 bulges upward, the outer peripheral end of the tray 1 is the portion closest to the tray mounting portion 22A. That is, the outer peripheral end of the tray 1 is the portion of the tray 1 that is most likely to be cooled. Therefore, as in the above configuration, by having the outer peripheral end of the tray 1 having a region not covered by the metal layer 4, the temperature of the outer peripheral portion 6 is relatively raised, and the temperature difference between the central portion 5 and the outer peripheral portion 6 is increased. Is further reduced.

Further, both the tray 1 and the substrate 7 are electrostatically adsorbed by the cooled ESC 22 and cooled. However, since the tray 1 has a lower flatness than the substrate 7, heat conduction with the ESC 22 is poor and the temperature is high. It is higher than the substrate 7. Further, in order to reliably cool the substrate 7, a cooling gas hole is temporarily provided in the substrate mounting portion 22C, and a cooling gas such as helium is provided between the substrate 7 and the substrate mounting portion 22C from this gas hole. When the substrate 7 is cooled by introducing the above, the temperature difference between the substrate 7 and the tray 1 tends to be further large. As described above, when the temperature of the tray 1 is higher than the temperature of the substrate 7, the outer peripheral portion of the substrate 7 is close to the tray 1, and is therefore affected by the heat radiation from the tray 1, and the central portion of the substrate 7. The temperature tends to rise compared to. Therefore, as in the above configuration, the periphery of the substrate accommodating hole 3 is covered with the metal layer 4, so that the tray mounting portion 22A can easily attract the vicinity of the substrate accommodating hole 3 of the tray 1, that is, cooling. This facilitates the process and suppresses the temperature rise of the outer peripheral portion of the substrate 7 due to the radiant heat of the tray 1.

In particular, when the substrate accommodating portion is a through hole (substrate accommodating hole 3) as in the present embodiment, the strength is lowered as compared with the case of the bottomed hole, and there is a high possibility that damage such as cracking of the tray will occur. Therefore, it is effective to adopt the structure of the tray which is hard to break as described above, especially when the substrate accommodating portion has a through hole (the substrate accommodating hole 3).

Further, the alumina tray 1 is fragile but inexpensive. Therefore, by adopting the structure of the tray 1 which is hard to break as described above for the tray 1 of alumina in particular, plasma treatment which overcomes the problem of damage such as cracking can be performed at low cost.

In addition, nickel does not easily react with chlorine or fluorine, which is usually used in plasma treatment processes. Therefore, by using nickel as the main component of the metal layer, plasma treatment having a chlorine-based process or a fluorine-based process The tray 1 having the above structure can also be used in the above.

Table 1 below shows the results of experiments in which the structure of the tray 1 was changed as in conditions 1 to 3 in order to quantitatively verify these effects. As a common condition, when a high-power and long-time plasma treatment is performed on an alumina tray, specifically, about 2500 (W) is applied to the ICP coil 20 and about 1000 (W) is applied to the substrate susceptor 18. , The case where the processing was performed for 720 seconds was verified. Other conditions set values that are generally common in plasma processing.

Condition 1 is a case where the tray is not subjected to nickel treatment such that the lower surface is covered with a metal layer. That is, in the tray under condition 1, ceramics containing alumina as a main component are exposed on the lower surface of the tray body. In the case of condition 1, the tray does not have sufficient conductivity and is unlikely to be electrostatically adsorbed by the ESC 22. Therefore, the tray cannot dissipate heat to the ESC 22 due to heat conduction, and the temperature of the entire tray rises. As a result, the temperature inside the tray reaches equilibrium at a high temperature of about 250 to 280 ° C., and the temperature difference between the central portion and the outer peripheral portion of the tray is 0 ° C. Under condition 1, since there is no temperature difference between the central portion and the outer peripheral portion of the tray, cracks do not occur, but the temperature of the outer peripheral portion of the substrate 7 rises due to heat radiation from the overheated tray 1, and the substrate It has an adverse effect such as deterioration of the etching shape of the outer peripheral portion of 7.

Condition 2 is a case where the tray is nickel-treated so as to cover the entire lower surface with a metal layer. That is, in the tray of condition 2, the ceramics containing alumina as a main component on the lower surface of the tray body are not exposed. In the case of condition 2, the tray has conductivity by nickel treatment and is electrostatically adsorbed on ESC22. Therefore, the tray can dissipate heat to the ESC 22 by heat conduction, and the temperature rise of the tray is suppressed. However, since the entire lower surface of the tray is treated with nickel, the central portion of the tray bulges above the outer peripheral portion as described above, and the temperature of the central portion becomes higher than the temperature of the outer peripheral portion. .. Specifically, the temperature inside the tray is about 170 ° C. at the central portion and about 100 ° C. at the outer peripheral portion, and the temperature difference between the central portion and the outer peripheral portion of the tray is about 70 ° C. As a result, under condition 2, the tray is cracked due to the temperature difference in the tray.

Condition 3 is the case of this embodiment. In the case of condition 3, the tray 1 is nickel-treated, and the central portion 5 has high conductivity, and the central portion 5 is easily electrostatically adsorbed by the ESC 22. Therefore, the central portion 5 of the tray 1 can dissipate heat to the ESC 22 by heat conduction, and the temperature rise of the central portion 5 of the tray 1 is suppressed. As a result of the central portion 5 of the tray 1 being cooled more than the outer peripheral portion 6, the temperature difference between the central portion 5 and the outer peripheral portion 6 is reduced. Specifically, the temperature inside the tray 1 is about 150 ° C. at the central portion 5, about 135 ° C. at the outer peripheral portion 6, and the temperature difference between the central portion 5 and the outer peripheral portion 6 of the tray 1 is about 15 ° C. .. Further, in the case of the condition 3, since the outer peripheral portion 6 of the tray 1 is not nickel-treated, it is difficult to be electrostatically adsorbed by the ESC 22. Therefore, the outer peripheral portion 6 of the tray 1 is less likely to dissipate heat to the ESC 22 due to heat conduction, and the outer peripheral portion 6 is not excessively cooled. Therefore, since the warp of the tray 1 is suppressed, the electrostatic adsorption of the central portion 5 of the tray 1 is maintained, the temperature of the central portion 5 is suppressed to 150 ° C., and the temperature difference in the tray 1 is reduced to about 15 ° C. It can be suppressed. As a result, under the condition 3, the tray 1 is not cracked and the tray 1 is suppressed from overheating, so that the in-plane distribution of the temperature of the substrate 7 becomes uniform and the uniformity of the etching shape is improved.

From the above, as a result of comparative examination by changing the structure of the tray 1, it can be confirmed that the tray 1 of the condition 3 (the present embodiment) is the best result from the viewpoint of preventing cracking and improving the shape accuracy. The structure of the tray 1 is not limited to the structures of the conditions 1 to 3, but the substrate by heat radiation of the overheated tray 1 while eliminating the temperature difference in the tray 1 to the extent that cracks can be prevented even in various deformations. It is necessary that the tray 1 can be cooled to such an extent that deterioration of the temperature distribution of 7 can be prevented.

Further, in the present embodiment, the metal layer 4 is covered on the entire surface of the central portion 5 of the lower surface 2B of the tray 1, but the coating method is not limited to the entire surface coating. It suffices if the central portion 5 is covered with the metal layer 4 more than the outer peripheral portion 6, and for example, a dot-shaped covering region may be formed on the central portion 5 more than the outer peripheral portion 6. Good.

(Second Embodiment)
In the dry etching apparatus 10 of the present embodiment shown in FIGS. 7 to 10, unlike the first embodiment, the substrate accommodating portion of the tray 1 has a bottomed hole 8. Except for the configuration related to this, the configuration is the same as that of the dry etching apparatus 10 of the first embodiment of FIGS. 3 to 6. Therefore, the same parts as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIGS. 7 and 8, the substrate accommodating portion of the tray 1 of the present embodiment is composed of seven bottomed holes 8. The arrangement of the seven bottomed holes 8 is the same as that of the seven substrate accommodating holes 3 of the first embodiment. On the lower surface of the tray 1, for example, a metal layer 4 containing nickel as a main component is provided at positions corresponding to the seven bottomed holes 8. The area of the metal layer 4 is substantially the same as that of the first embodiment, but in the present embodiment, the lower surface 2B of the seven bottomed holes 8 is also covered with the metal layer 4, so that the metal layer 4 is made of metal as compared with the first embodiment. The area of layer 4 is large.

As shown in FIGS. 9 and 10, the upper surface of the ESC 22 of the present embodiment is a flat surface. Since the substrate 7 and the tray 1 are mounted directly or indirectly on the upper surface of the ESC 22, the upper portion of the ESC 22 of the present embodiment constitutes both the substrate mounting portion 22C and the tray mounting portion 22A. There is.

As described above, the structure of the tray 1 is not limited to the structure having a through hole as in the first embodiment, and may be a structure having a bottomed hole 8 as in the present embodiment.

(Third Embodiment)
In the dry etching apparatus 10 of the present embodiment shown in FIGS. 11 to 14, unlike the first embodiment, the lower surface 2B of the tray 1 is not covered with the metal layer 4, and the lower surface 2B of the tray 1 is partially uneven. Is provided. Except for the configuration related to this, the configuration is the same as that of the dry etching apparatus 10 of the first embodiment of FIGS. 3 to 6. Therefore, the same parts as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The lower surface 2B of the tray 1 of the present embodiment has a relatively convex shape at the central portion 5 and a concave shape at the outer peripheral portion 6. The area range of the central portion 5 and the outer peripheral portion 6 in a plan view is the same as that of the first embodiment. The height (depth) of this uneven shape is about several tens of μm to several hundreds of μm, and varies depending on the material of the tray 1 and the voltage applied to the electrostatic adsorption electrode 22D.

The tray 1 of the present embodiment is composed of ceramics containing silicon carbide as a main component. When the tray 1 is provided with an uneven shape, it is preferable to use the above material from the viewpoint of ease of processing and the like, but for example, it may be made of ceramics containing alumina as a main component as in the first embodiment.

As in the configuration of the present embodiment, the outer peripheral portion 6 of the lower surface 2B of the tray 1 has a concave shape as compared with the central portion 5, so that the outer peripheral portion 6 of the tray 1 is less likely to come into contact with the tray mounting portion 22A. That is, it is difficult to cool. Therefore, similarly to the first and second embodiments, the temperature difference between the central portion 5 and the outer peripheral portion 6 of the tray 1 is reduced, the bulge (warp) of the tray 1 is alleviated, and damage such as cracking can be prevented.

Further, since the outer peripheral end of the tray 1 is provided with a concave shape, the temperature of the outer peripheral portion 6 is relatively increased, and the temperature difference between the central portion 5 and the outer peripheral portion 6 is further reduced.

Further, since the area other than the periphery of the substrate accommodating hole 3 has a relatively concave shape, it is easy for the tray mounting portion 22A to come into contact with the vicinity of the periphery of the substrate accommodating hole 3 of the tray 1, that is, it is easy to cool the tray 1. It is possible to suppress the temperature rise of the outer peripheral portion 6 of the substrate 7 due to the radiant heat of the substrate 7.

Although specific embodiments of the present invention and variations thereof have been described above, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention. For example, an embodiment of the present invention may be a combination of the contents of the individual embodiments as appropriate.

1 Tray 2 Tray body 2A Upper surface 2B Lower surface 3 Substrate accommodating hole 3A Hole wall 3B Substrate support 3C Substrate support surface 4 Metal layer 5 Central part 6 Outer circumference 7 Substrate 8 Bottom hole 10 Dry etching equipment 11 Chamber 12 Gate 13 Etching gas Supply source 14 Etching gas supply port 15 Vacuum exhaust device 16 Exhaust port 18 Substrate susceptor 19 Top plate 20 ICP coil 21 High frequency power supply 22 ESC (dielectric member)
22A Tray mounting part 22B Tray mounting surface 22C Board mounting part 22D Electrostatic adsorption electrode 24 Metal plate 24A Refrigerant flow path 25 Spacer plate 26 Lifting pin 27 DC power supply (DC voltage application mechanism)
28 High frequency power supply 29 Refrigerant circulation device

Claims (10)

Decompressable chamber and
A plasma source that generates plasma in the chamber and
A tray that has a substrate accommodating portion for accommodating a substrate and can be carried in and out of the chamber.
A dielectric member provided in the chamber and provided with a tray mounting portion on which the lower surface of the tray carried into the chamber is placed and a substrate mounting portion on which the substrate is mounted.
Electrostatic adsorption electrodes built into the dielectric member for electrostatically adsorbing the substrate to the substrate mounting portion and electrostatically adsorbing the tray to the tray mounting portion.
A DC voltage application mechanism that applies a DC voltage to the electrostatic adsorption electrode,
A cooling mechanism for cooling the dielectric member including the tray mounting portion and the substrate mounting portion is provided.
Lower surface of the tray, non of the area being overturned be a metal layer having high conductivity than the material constituting the tray, the material constituting the tray is exposed without being covered by the metal layer A plasma processing apparatus having a covering area and . The plasma processing apparatus according to claim 1, wherein the central portion of the lower surface of the tray is covered with a metal layer in a larger proportion than the outer peripheral portion. The plasma processing apparatus according to claim 1 or 2, wherein the outer peripheral portion of the lower surface of the tray is not covered with a metal layer and the lower surface of the tray is exposed over the entire circumference of the outer peripheral end. The plasma processing apparatus according to any one of claims 1 to 3, wherein the metal layer surrounds the periphery of the substrate accommodating portion. The substrate accommodating portion
A substrate accommodating hole that penetrates in the thickness direction,
The invention according to any one of claims 1 to 4, further comprising a substrate support portion that protrudes from the hole wall of the substrate accommodating hole and supports the outer edge portion of the lower surface of the substrate accommodated in the substrate accommodating hole. Plasma processing equipment. The plasma processing apparatus according to any one of claims 1 to 5, wherein the tray is composed of ceramics containing alumina as a main component. The plasma processing apparatus according to any one of claims 1 to 6, wherein the metal layer contains nickel as a main component. Decompressable chamber and
A plasma source that generates plasma in the chamber and
A tray that has a substrate accommodating portion for accommodating a substrate and can be carried in and out of the chamber.
A dielectric member provided in the chamber and provided with a tray mounting portion on which the lower surface of the tray carried into the chamber is placed and a substrate mounting portion on which the substrate is mounted.
Electrostatic adsorption electrodes built into the dielectric member for electrostatically adsorbing the substrate to the substrate mounting portion and electrostatically adsorbing the tray to the tray mounting portion.
A DC voltage application mechanism that applies a DC voltage to the electrostatic adsorption electrode,
A cooling mechanism for cooling the dielectric member including the tray mounting portion and the substrate mounting portion is provided.
A plasma processing apparatus having a concave shape formed by providing a step on the outer peripheral portion of the lower surface of the tray with respect to the central portion. Accommodating the substrate to the substrate receiving portion of the tray, the lower surface of the tray cover material constituting the tray and area being overturned be a metal layer having high conductivity than the material constituting the tray by the metal layer Has uncovered areas that are exposed without being
The tray containing the substrate is conveyed to a dielectric member arranged in the chamber, and the tray is conveyed.
The tray is placed on the tray mounting portion included in the dielectric member, and the substrate is placed on the substrate mounting portion included in the dielectric member.
By applying a DC voltage to the electrostatic adsorption electrode built in the dielectric member, the substrate is electrostatically attracted to the substrate mounting portion, and the tray is electrostatically attracted to the tray mounting portion. ,
A plasma treatment method comprising cooling the tray mounting portion and the substrate mounting portion of the dielectric member and generating plasma in the chamber to perform plasma treatment on the substrate. A tray for a plasma processing apparatus, which has a substrate accommodating portion for accommodating a substrate, and a region covered with a metal layer and a region where the material constituting the tray is exposed without being covered by the metal layer. comprising a single-sided with bets, a large proportion of the central portion of the one side is covered by the metal layer as compared with the outer peripheral portion, the tray for plasma processing apparatus.

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