TW201541536A - Plasma processing apparatus and electrostatic chuck thereof - Google Patents

Abstract

The present invention provides a plasma processing apparatus and an electrostatic chuck thereof. The electrostatic chuck includes an insulation layer and a heat conduction layer set under the insulation layer. A heating device is arranged under the heat conduction layer. The heat conduction layer includes a first heat conduction region and a second heat conduction region. The second heat conduction region surrounds the first heat conduction layer. The thicknesses of the first and second heat conduction regions of the heat conduction layer are different. Because of the different thicknesses of the heat conduction layers, the heat conduction speeds thereof are different, the temperature of a partial region of the electrostatic chuck can be elevated or lowered rapidly, and the purpose of keeping a uniform temperature or a certain temperature difference with other regions can be achieved. This invention provides a solution for the control over the electrostatic chuck by regions, accomplishes another adjustment solution in addition to the adjustment in the heating power source of the heating device, it can cooperate with the adjustment in the heating power source of the heating device to achieve the temperature control over the electrostatic chuck.

Description

Plasma processing device and electrostatic chuck thereof

The present invention relates to semiconductor processing techniques and, more particularly, to the field of electrostatic chuck heating technology.

In the process of plasma etching or chemical vapor deposition, an electrostatic chuck (Electro Static Chuck, ESC for short) is often used to fix, support and transfer the substrate (Wafer) to the workpiece. The electrostatic chuck is disposed in the reaction chamber, and the electrostatic chucking method is used instead of mechanically fixing the substrate, which can reduce the possible mechanical loss to the substrate and completely contact the electrostatic chuck with the substrate, thereby facilitating heat conduction. .

The existing electrostatic chuck usually comprises an insulating layer and a heating layer. The insulating layer is provided with a DC electrode, and the DC electrode is applied with an electrostatic attraction force to the substrate; in order to increase the temperature of the electrostatic chuck, the substrate is etched. Uniformity, a heating layer is arranged under the insulating layer, and a heating device is arranged in the heating layer for heating the substrate through the electrostatic chuck; a pedestal is arranged under the heating layer, and a cooling liquid flow channel is arranged on the pedestal, and the filling is performed The coolant cools the electrostatic chuck.

In the prior art, due to the large area of the electrostatic chuck, it is difficult to ensure the uniformity of the temperature of each region of the electrostatic chuck while the temperature of the electrostatic chuck is rapidly rising, and the temperature of different regions may be significantly different or even form a cold zone. The hot zone causes the electrostatic chuck to heat the substrate unevenly, which will adversely affect the plasma etching process. In order to solve the technical problem of uneven heating of the electrostatic chuck, the heating layer can be controlled by partitioning, but in some plasmas In the processing device, only the heating layer partition control does not completely solve the problem of uneven temperature distribution of the electrostatic chuck.

An object of the present invention is to provide an electrostatic chuck comprising an insulating layer with a built-in DC electrode and a heat conducting layer under the insulating layer, the heat conducting layer comprising a first heat conducting region and a second heat conducting region, the second heat conducting region surrounding The first heat conduction region is disposed, and the first heat conduction region and the second heat conduction region are different in thickness of the heat conduction layer.

A first heating device is disposed below the thermal region, and the thermally conductive layer preferably has a second heating device disposed below the second thermally conductive region of the first conductive layer of the thermally conductive layer.

Preferably, the heat conductive layer is made of aluminum or aluminum alloy or aluminum nitride.

Preferably, the thickness of the heat conducting layer where the first heat conducting region is located is greater than the thickness of the heat conducting layer where the second heat conducting region is located.

Preferably, the thickness of the heat conducting layer where the first heat conducting region is located is smaller than the thickness of the heat conducting layer where the second heat conducting region is located.

Preferably, the heat conducting layer further comprises a third heat conducting region, the third heat conducting region is disposed around the second heat conducting region, and a third heating device is disposed below the third heat conducting region.

Preferably, the thickness of the heat conducting layer in the third heat conducting region is the same as or different from the thickness of the heat conducting layer in the first heat conducting region and the second heat conducting region.

Preferably, the heating device comprises a heating wire and an insulating layer encasing the heating wire.

Further, the present invention also discloses a plasma processing apparatus including a vacuum reaction chamber, an electrostatic chuck disposed under the vacuum reaction chamber and supporting the electrostatic card The susceptor of the disk is characterized in that: the electrostatic chuck comprises an insulating layer with a built-in DC electrode and a heat conducting layer under the insulating layer, the heat conducting layer comprising a first heat conducting region and a second heat conducting region, the second The heat conducting region is disposed around the first heat conducting region, and the first heat conducting region and the second heat conducting region are different in thickness of the heat conducting layer.

Preferably, a support layer formed of a metal material or a ceramic material is disposed between the heating device and the base.

Preferably, the plasma processing apparatus is a capacitive coupling type plasma processing apparatus or an inductive coupling type plasma processing apparatus.

An advantage of the present invention is that the present invention provides a plasma processing apparatus and an electrostatic chuck thereof, the electrostatic chuck comprising an insulating layer and a heat conducting layer disposed under the insulating layer, and a heating device is disposed under the heat conducting layer, the heat conducting The layer includes a first heat conduction region and a second heat conduction region, the second heat conduction region is disposed around the first heat conduction region, and the first heat conduction region and the second heat conduction region are different in thickness of the heat conduction layer due to the heat conduction layer Different thicknesses, different speeds of conducting heat, realizing rapid heating or cooling of parts of the electrostatic chuck to achieve uniform temperature or a certain temperature difference with other regions, the present invention provides a scheme for partitioning the temperature of the electrostatic chuck The utility model realizes another adjustment scheme in addition to adjusting the heating power source of the heating device, and can cooperate with the heating power source of the adjusting heating device to realize the temperature control of the electrostatic chuck.

100‧‧‧reaction chamber

115‧‧‧Cooling runner

120‧‧‧Electrostatic chuck

121‧‧‧Insulation

122‧‧‧thermal layer

1221‧‧‧First heat conduction area

1222‧‧‧Second heat conduction area

123‧‧‧Support layer

124‧‧‧DC electrode

125‧‧‧ heating device

1251‧‧‧First heating unit

1252‧‧‧second heating device

130‧‧‧ gas supply

140‧‧‧Substrate

150‧‧‧Upper electrode

160‧‧‧ Plasma

170‧‧‧RF power source

180‧‧‧Air pump

221‧‧‧Insulation

222‧‧‧thermal layer

2221‧‧‧First heat conduction area

2222‧‧‧Second heat conduction area

2223‧‧‧3rd heat conduction zone

2251‧‧‧First heating unit

2252‧‧‧second heating device

2253‧‧‧3rd heating device

225‧‧‧ heating device

Fig. 1 is a schematic view showing the structure of a plasma reaction chamber of the present invention.

2 is a schematic view showing the structure of an electrostatic chuck and a base thereunder according to the present invention.

FIG. 3 is a schematic view showing the structure of an electrostatic chuck and a base thereunder according to another embodiment of the present invention.

The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

The technical solution described in the present invention is applicable to a capacitively coupled plasma reaction chamber or an inductively coupled plasma reaction chamber, and other plasma reaction chambers that use an electrostatic chuck to heat the temperature of a substrate to be processed. Illustratively, FIG. 1 is a schematic view showing the structure of a plasma reaction chamber according to the present invention; the plasma reaction chamber is a capacitive coupling type plasma reaction chamber, and the technical solution disclosed by the present invention is not inventive. All modifications made by labor are within the scope of protection of the present invention.

1 is a schematic view showing a structure of a plasma reaction chamber, comprising a substantially cylindrical reaction chamber 100. The reaction chamber 100 is provided with upper and lower corresponding upper electrodes 150 and lower electrodes 110. The upper electrode 150 is connected to the gas supply device 130. The electrode 150 simultaneously enters the gas distribution plate of the plasma reaction chamber as a reaction gas; the lower electrode 110 is connected to the RF power source 170, and the electrostatic chuck 120 is supported above the electrostatic chuck 120 for supporting the substrate 140. The working principle of the plasma reaction chamber in this embodiment is that the upper electrode 150 and the lower electrode 110 dissociate the gas injected into the plasma reaction chamber 100 under the action of radio frequency power to generate plasma 160, plasma 160 pairs of substrates. The physical bombardment or chemical reaction is performed 140 to effect processing of the substrate 140. The by-products after the reaction and the exhausted gas are discharged from the plasma reaction chamber 100 through the air pump 180.

Fig. 2 is a view showing the structure of the electrostatic chuck of the present invention and the base therebelow. As shown in FIG. 2, an electrostatic chuck 120 is disposed above the susceptor 110 for carrying the substrate 140. A coolant flow path 115 is provided in the susceptor 110, which is typically used to inject coolant to cool the electrostatic chuck. The electrostatic chuck 120 includes an insulating layer 121 and a heat conductive layer 122 disposed under the insulating layer 121. A DC electrode 124 is embedded in the insulating layer 121. The DC electrode is connected to a DC power source (not shown). The DC power source acts on the DC electrode 124 to generate an electrostatic attraction on the surface of the electrostatic chuck 120 for fixing the substrate 140. A heat conductive layer 122 is disposed under the insulating layer 121. The material of the heat conductive layer 122 may be a metal material or a ceramic material, such as aluminum or aluminum oxide, or may be a material such as aluminum nitride. In this embodiment, the heat conducting layer 122 includes a first heat conducting region 1221 and a second heat conducting region 1222 surrounding the first heat conducting region. Below the heat conducting layer 122, a heating device 125 is disposed. Between the heating device 125 and the pedestal 110 A support layer 123 is further included. The material of the support layer 123 may be a metal material or a ceramic material, which may or may not be the same as the heat conductive layer material. The vacuum reaction chamber 100 heats the substrate 140 through the electrostatic chuck 120 to cause the substrate to react with the plasma in the reaction chamber, thereby enabling processing of the substrate. Corresponding to the first heat conduction region 1221 and the second heat conduction region 1222, the heating device 125 below it includes at least a first heating device 1251 and a second heating device 1252. With the development of the semiconductor industry, the size of the substrate is getting larger and larger, and the size of the electrostatic chuck 120 for supporting the fixed substrate 140 is also increasing. As the size of the electrostatic chuck becomes larger, the electrostatic chuck Uniform temperature has become a key factor in controlling the smooth progress of the etching process. In the present embodiment, the heating device is provided as a first heating device 1251 and a second heating device 1252 that independently control the temperature, and the second heating device 1252 is disposed around the first heating device 1251.

It can be seen from FIG. 2 that the thickness of the heat conducting layer of the first heat conducting region 1221 and the second heat conducting region 1222 of the heat conducting layer 122 is not completely the same. In this embodiment, the thickness of the heating layer of the first heat conducting region 1221 is greater than that of the second layer. The thickness of the heating layer of the heat conducting region 1222, the distance of the corresponding second heating device in the vertical direction to the insulating layer 121 of the electrostatic chuck is smaller than the distance from the first heating device 1251 to the electrostatic chuck insulating layer 121, due to the thickness of the heat conducting layer 122 Differently, the speed at which heat is generated by the heating device 125 is different, and due to the first heating device 1251 and the second The temperature of the heating device 1252 can be separately controlled and adjusted. In order to accurately adjust the temperature uniformity of the electrostatic chuck 120 in the etching process, the temperature can be adjusted by separately setting the temperatures of the first heating device 1251 and the second heating device 1252, and It can be adjusted by setting different thicknesses of the heat conduction layer of the first heat conduction region 1221 and the heat conduction layer of the second heat conduction region 1222. By adjusting the heating power of the first heating device 1251 and the second heating device 1252 in cooperation with the thickness of the heat conducting layer corresponding thereto, the temperature uniformity of the electrostatic chuck 120 is effectively adjusted, especially for some large diameters. The electrostatic chuck has obvious effects.

In order to facilitate the fixing process, a bonding layer is disposed between the insulating layer 121 and the heat conducting layer 122. Since the thickness of the bonding layer is small, the present invention is not shown in FIG. Since the heat conductive layer 122 needs to be bonded and fixed to the insulating layer 121, keeping the upper surface of the heat conductive layer 122 flat can better achieve bonding with the insulating layer 121. When the thickness of the corresponding heat conducting layer 122 above the different heating devices of the electrostatic chuck 120 is inconsistent, the upper surface is kept flat, so that the upper surface is better adhered and fixed to the insulating layer through the bonding layer, because the lower surface of the heat conducting layer 122 and the partition heating device Connected, the heating device is usually sandwiched between the heat conducting layer 122 and the support layer 123, and can be easily fabricated. The heating device 125 includes a heating wire and an insulating material wrapped around the heating wire. In some embodiments, the heating device 125 may be attached to the lower surface of the heat conductive layer 122 and then fixed to the support layer 123.

In addition to the implementation shown in FIG. 2, the technical solution described in the present invention includes other embodiments. Fig. 3 is a view showing the structure of an electrostatic chuck according to another embodiment of the present invention. In the embodiment shown in FIG. 3, the heat conducting layer 222 includes a first heat conducting region 2221, a second heat conducting region 2222, and a third heat conducting region 2223. The second heat conducting region 2222 is disposed around the first heat conducting region 2221, and the third heat conducting region is disposed. 2223 is disposed around the second heat conduction region 2222, correspondingly, heating under the heat conduction layer The device 225 includes a first heating device 2251, a second heating device 2252 and a third heating device 2253. The three heating devices are disposed between the insulating layers 221 to provide a heat conducting layer 222, and the thickness of the heat conducting layer above the different heating devices is different. The three heating unit temperatures can be independently controlled. In this embodiment, the thickness of the heat conducting layer above the first heating device 2251 is greater than the thickness of the heat conducting layer above the second heating device 2252, and the thickness of the heat conducting layer above the second heating device 2252 is greater than the thickness of the heat conducting layer above the third heating region. Since the processing processes performed in the plasma reaction chamber are different, the temperature distribution on the electrostatic chuck is affected by other parameters in the plasma reaction chamber, so the thickness of the heat conducting layer 222 of the electrostatic chuck may be different from the above. Example. In some embodiments, the thickness of the thermally conductive layer above the heating means of the central region may be set to be less than the thickness of the thermally conductive layer of the edge region. The specific conditions are not limited to the above embodiments, and the other components in this embodiment are labeled as the above embodiment. In contrast to the above embodiment, 1xx is labeled as 2xx, and the specific working principle is the same as above. I will not repeat them here.

The heat conductive layer of the present invention may be aluminum or aluminum alloy, or may be other good heat conductor materials, or materials such as aluminum nitride. The thickness of the heat conducting layer is different, the heat transfer speed is different, and the temperature of the electrostatic chuck is uniformly adjusted, which increases the new way of adjusting the heating power of the heating device for the temperature adjustment of the electrostatic chuck. The temperature of the electrostatic chuck can be adjusted in coordination. In order to achieve uniform temperature adjustment of the electrostatic chuck, a temperature measuring component (not shown) is disposed in the vicinity of each heating device, and the plurality of temperature measuring components are connected to a temperature control system (not shown) and controlled by temperature. The system performs adjustment control in a unified manner to achieve the purpose of adjusting the temperature of the electrostatic chuck.

According to the plasma processing apparatus provided by the above embodiments of the present invention, while the electrostatic chuck is rapidly heated, the temperature uniformity of each region is effectively ensured, thereby making the respective regions of the substrate The uniform temperature of the domain is beneficial to the progress of the plasma treatment process and improves the processing yield of the substrate.

The above are only the preferred embodiments of the present invention, and the embodiments are not intended to limit the scope of the patent protection of the present invention. Therefore, equivalent structural changes made by using the description of the present invention and the contents of the drawings should be included in the same manner. Within the scope of protection of the present invention.

100‧‧‧vacuum reaction chamber

110‧‧‧Base

120‧‧‧Electrostatic chuck

130‧‧‧ gas supply

140‧‧‧Fixed substrate

150‧‧‧Upper electrode

160‧‧‧ Plasma

170‧‧‧RF power source

180‧‧‧Air pump

Claims (11)

An electrostatic chuck, comprising: an insulating layer with a built-in DC electrode; and a heat conducting layer under the insulating layer, the heat conducting layer comprising a first heat conducting region and a second heat conducting region, the second The heat conducting region is disposed around the first heat conducting region, and the first heat conducting region and the second heat conducting region are different in thickness of the heat conducting layer. The electrostatic chuck according to claim 1, wherein a first heating device is disposed under the first heat conduction region of the heat conduction layer, and a second heating device is disposed below the second heat conduction region of the heat conduction layer. The electrostatic chuck according to claim 1, wherein the heat conductive layer is made of aluminum or aluminum alloy or aluminum nitride. The electrostatic chuck according to claim 1, wherein the thickness of the heat conducting layer in the first heat conducting region is greater than the thickness of the heat conducting layer in the second heat conducting region. The electrostatic chuck according to claim 1, wherein the thickness of the heat conducting layer in the first heat conducting region is smaller than the thickness of the heat conducting layer in the second heat conducting region. The electrostatic chuck of claim 1, wherein the heat conductive layer further comprises a third heat conduction region, the third heat conduction region is disposed around the second heat conduction region, and the third heat conduction region A third heating device is provided below. The electrostatic chuck of claim 1, wherein the thickness of the heat conducting layer in the third heat conducting region is the same as or different from the thickness of the heat conducting layer in the first heat conducting region and the second heat conducting region. . The electrostatic chuck according to claim 1, wherein the heating device comprises a heating wire and an insulating layer covering the heating wire. A plasma processing apparatus, comprising: a reaction chamber, an electrostatic chuck and a base supporting the electrostatic chuck disposed under the reaction chamber, wherein the electrostatic chuck comprises a built-in An insulating layer of the DC electrode and a heat conducting layer under the insulating layer, the heat conducting layer comprising a first heat conducting region and a second heat conducting region, the second heat conducting region being disposed around the first heat conducting region, the first heat conducting region The thickness of the heat conductive layer where the second heat conduction region is located is different. The plasma processing apparatus according to claim 9, wherein a support layer formed of a metal material or a ceramic material is disposed between the heating device and the susceptor. The plasma processing apparatus according to claim 9, wherein the plasma processing apparatus is a capacitive coupling type plasma processing apparatus or an inductive coupling type plasma processing apparatus.