TW201535457A - Plasma processing chamber and the manufacturing method of its electrostatic chuck - Google Patents

Abstract

Disclosed is a plasma processing chamber and the manufacturing method of its electrostatic chuck, wherein the manufacturing method of the said electrostatic chuck comprises the following steps: providing a ceramic substrate; forming several through holes on the said ceramic substrate in which the said through holes are used to receive metal connection wires; providing several metal connection wires which are cooled to a temperature below the room temperature and then the cooled metal connection wires are embedded into the said several through holes of the said ceramic substrate respectively; placing the ceramic substrate embedded with the metal connection wires in the room temperature; disposing DC electrodes on the said ceramic substrate; and coating the ceramic substrate with an anti-corrosion layer, with the DC electrodes being disposed on the ceramic substrate. The metal connection wires fabricated by this invention will not damage the DC electrodes, and the anti-corrosion layer continually coated thereon is extremely stable.

Description

Plasma processing chamber and method for manufacturing same thereof

The present invention relates to the field of semiconductor manufacturing, and in particular, to a plasma processing chamber and a method of manufacturing the same.

The plasma processing apparatus processes the semiconductor substrate and the plasma plate using the working principle of the vacuum reaction chamber. The working principle of the vacuum reaction chamber is to pass a reaction gas containing a suitable etching source into the vacuum reaction chamber, and then input RF energy into the vacuum reaction chamber to start the reaction gas to excite and maintain the plasma to respectively etch the base. The material layer on the surface of the sheet or a layer of material is deposited on the surface of the substrate to process the semiconductor substrate and the plasma plate.

The plasma processing chamber includes a submount on which the substrate to be processed is placed. An electrostatic chuck is disposed above the abutment, and the electrostatic chuck is used to hold the substrate. A DC electrode is embedded in the insulating layer of the upper layer of the electrostatic chuck, and a DC power source is connected to the DC electrode. Before the start of the substrate process, a DC power source is applied to the DC electrode, so that the DC electrode generates an adsorption force to clamp the substrate on the base. When the process is finished, the DC power applied to the DC electrode is turned off, thereby releasing the adsorption force between the substrate and the electrostatic chuck, the robot arm extends into the chamber from outside the chamber, and the substrate is smoothly removed from the chamber. .

The DC electrode is typically embedded in the insulating layer of the electrostatic chuck and the DC electrode is typically very thin. There must be a metal connection between the DC electrode and the DC power supply, in the electrostatic chuck The part is usually a metal wire as a connecting wire. However, a very thin DC electrode is prone to cracking during the setting of the wire. The present invention has been made based on this.

In view of the above problems in the background art, the present invention proposes a plasma processing chamber and a method of manufacturing the same.

A first aspect of the present invention provides a method of manufacturing an electrostatic chuck of a plasma processing chamber, wherein the manufacturing method includes the steps of: providing a ceramic substrate; and performing a plurality of through holes on the ceramic substrate The hole is for accommodating the metal connection line; the plurality of metal connection lines are provided, the plurality of metal connection lines are cooled to below room temperature, and the plurality of cooled metal connection lines are respectively embedded in the plurality of through holes of the ceramic substrate The ceramic substrate in which the metal connecting wire is embedded is placed at a normal temperature; a DC electrode is placed on the ceramic substrate; and an anti-corrosion layer is deposited on the ceramic substrate on which the DC electrode is placed.

Further, the diameter of the through hole is larger than the diameter of the metal connecting wire after cooling.

Further, the metal connecting wire has a thermal expansion rate much larger than that of the ceramic substrate and the direct current electrode.

Further, the material of the metal connecting wire comprises: copper, silver, aluminum, gold.

Further, the material of the ceramic substrate comprises alumina.

Further, the material of the DC electrode comprises tungsten.

Further, the manufacturing method further includes the following steps: providing a plurality of copper metals Connecting wires, cooling the plurality of copper metal connecting wires to below -100 ° C, and inserting the cooled metal connecting wires into the plurality of through holes of the ceramic substrate.

Further, the manufacturing method further includes the step of placing a DC electrode on the ceramic substrate by vacuum deposition or printing.

Further, the material of the anti-corrosion layer comprises hafnium oxide or tantalum nitride.

Further, the anti-corrosion layer is formed by physical vapor deposition or plasma spraying.

Further, the manufacturing method further includes the step of connecting the soft metal connecting line below the metal connecting line.

A second aspect of the invention provides a method of manufacturing a plasma processing chamber, wherein the manufacturing method comprises the method of manufacturing the electrostatic chuck according to the first aspect of the invention.

The plasma processing chamber and the method for manufacturing the same according to the present invention can smoothly set a metal connecting line in an electrostatic chuck region below the direct current electrode without causing damage to the direct current electrode, so as to facilitate subsequent electrostatic chucks. The top layer is coated with an anti-corrosion layer.

100‧‧‧plasma processing chamber

101‧‧‧Electrical chuck

1012‧‧‧Ceramic substrate

1016‧‧‧Metal cable

1017‧‧‧Soft metal cable

1017a‧‧‧ connector

1018‧‧‧Anti-corrosion layer

1019‧‧‧Anti-corrosion layer

102‧‧‧ side wall

103‧‧‧ gas source

104‧‧‧RF power supply

105‧‧‧vacuum pump

106‧‧‧Abutment

107‧‧‧plasma confinement ring

108‧‧‧resistance

109‧‧‧ gas sprinkler

110‧‧‧DC electrode

111‧‧‧DC power supply

W‧‧‧ substrates

P‧‧‧Processing area

1 is a schematic view showing the structure of a plasma processing chamber and a lifting device.

2(a)-2(d) are flow diagrams showing the fabrication of an electrostatic chuck of a plasma processing chamber in accordance with an embodiment of the present invention.

3 is a schematic block diagram of a submount of a plasma processing chamber in accordance with an embodiment of the present invention.

Specific embodiments of the present invention will be described below with reference to the accompanying drawings. It is to be noted that the terms "semiconductor process", "wafer" and "substrate" will be used interchangeably in the following description. In the present invention, they all refer to process parts that are processed in the processing chamber. The process member is not limited to a wafer, a substrate, a substrate, a large-area flat substrate, or the like. For convenience of description, the "substrate" will be mainly exemplified in the description and illustration of the embodiments herein.

Figure 1 shows a schematic view of the structure of a plasma processing chamber and a lifting device. The plasma processing chamber 100 has a processing chamber (not shown), the processing chamber is substantially cylindrical, and the processing chamber sidewall 102 is substantially vertical, and the processing chamber has upper and lower electrodes disposed in parallel with each other. Typically, the area between the upper and lower electrodes is the processing area P which will form high frequency energy to ignite and sustain the plasma. A substrate W to be processed is placed over the substrate 106, which may be a semiconductor substrate to be etched or processed or a glass plate to be processed into a flat panel display. The base 106 is used to clamp the substrate W. The reaction gas is input from the gas source 103 to the gas shower head 109 in the processing chamber, and the one or more radio frequency power sources 104 may be separately applied to the lower electrode or simultaneously applied to the upper and lower electrodes, respectively. The RF power is delivered to the lower electrode or to the upper and lower electrodes to create a large electric field inside the processing chamber. Most of the electric field lines are contained in the processing region P between the upper electrode and the lower electrode, and this electric field accelerates a small amount of electrons existing inside the processing chamber to collide with gas molecules of the input reaction gas. These collisions result in ionization of the reactive gas and excitation of the plasma, thereby generating a plasma within the processing chamber. The neutral gas molecules of the reactive gas lose electrons when subjected to these strong electric fields, leaving positively charged ions. The positively charged ions accelerate toward the lower electrode and combine with the neutral species in the substrate being processed to excite substrate processing, i.e., etching, deposition, and the like. An exhaust region is provided at a suitable position of the plasma processing chamber 100, and the exhaust region is An external exhaust device, such as vacuum pump 105, is coupled to draw used reactive gas and by-product gases out of the chamber during processing. Among them, the plasma confinement ring 107 is used to confine the plasma in the processing region P. A grounding end is connected to the side wall 102 of the chamber, and a resistor 108 is disposed therein.

As is well known, an electrostatic chuck (ESC) is a core component in a plasma processing chamber. Since the electrostatic chuck 101 is a carrier for the lower electrode and the substrate, it is necessarily rigid and structurally stable to prevent plasma bombardment and substrate wear during the manufacturing process of the product. However, the prior art electrostatic chuck 101 is mostly formed on a bonded solid ceramic disc on an anodized aluminum substrate. The ceramic disc of the electrostatic chuck 101 is typically made of Al ₂ O ₃ or AlN and contains some metal and cerium-based mixtures such as TiO ₂ , SiO ₂ and the like. When the electrostatic chuck operates in an environment containing a halogen element (eg, F, Cl, etc.) plasma, the ceramic substrate (Al ₂ O ₃ or AlN) of the electrostatic chuck 101 and other components contained therein will be subjected to plasma. Bombardment, however, other components contained therein will be eroded at relatively higher corrosion rates. Therefore, plasma etching changes the morphology, composition, and characteristics of the ceramic substrate (surface roughness, resistivity, etc.) of the surface of the electrostatic chuck, and further causes changes in the function of the electrostatic chuck 101, such as leakage current, helium leak rate. , to clamp time, and so on.

In order to stabilize the composition, structure and characteristics of the electrostatic chuck 101, the prior art generally coats or encapsulates a plasma corrosion resistant material on the surface of the electrostatic chuck 101 to prevent the electrostatic chuck 101 from being corroded by plasma. However, it is not preferable to apply a corrosion-resistant layer on the electrostatic chuck 101 by means of plasma spray (PS) because the anti-corrosion layer of the plasma spray such as ruthenium oxide has pores and is structurally brittle. Moreover, the anti-corrosion layer of antimony oxide is softer than the antimony wafer, which causes particle contamination in the process. In the prior art, plasma enhanced physical vapour deposition is also used on the ceramic disk of the electrostatic chuck 101. PEPVD) deposits a dense, hard plasma anti-corrosion layer, such as yttria or yttria/alumina mixed. However, deposition directly on the surface of the electrostatic chuck 101 is technically limited because the deposition temperature is usually easily reached to 100 ° C and above because the plasma or coated deposition source heats the electrostatic chuck during the physical vapor deposition process. Disk 101. However, since the melting point of the adhesive between the ceramic substrate and the aluminum substrate is low, the temperature of the electrostatic chuck 101 cannot be higher than 100 ° C or higher.

Methods of improving the performance of an electrostatic chuck disclosed in the prior art include (1) first applying an improved corrosion resistant layer on a ceramic substrate of the electrostatic chuck 101, and (2) then coating the corrosion resistant layer ceramic substrate by bonding and The aluminum substrate forms an electrostatic chuck 101. The prior art has many specific properties by coating an anti-corrosion layer on the electrostatic chuck 101, such as high hardness, good thermal conductivity, and durable structure to resist corrosion of various plasma chemistries. In fact, according to the prior art electrostatic chuck 101 production process, there are many technical problems in forming an electrical joint in the alumina substrate below the DC electrode. Specifically, it has been mentioned above that the DC electrode in the electrostatic chuck 101 is also connected to a DC power source, and therefore the process requires that the alumina substrate of the electrostatic chuck 101 be used as a connecting line directly below the DC electrode. The thickness of the DC electrode is relatively thin, only 10~20um of metal tungsten, and the texture of the upper anti-corrosion layer is softer. Therefore, after the DC electrode is formed, the metal connection line is formed, and the metal connection line may greatly damage the DC. electrode.

The present invention provides a plasma processing chamber and a method of manufacturing the same. As shown in FIG. 1, the electrostatic chuck 101 is located above the base 106 for holding the substrate W thereon. A DC electrode 110 is disposed in the material layer above the electrostatic chuck 101, and the DC electrode 110 is directly The DC power source 111 is connected so that the DC electrode 110 generates a clamping force for holding the substrate W thereon by the application of the DC power source 111. Therefore, at the DC electrode 110 and DC There must be a connection line for electrical connection between the sources 111, and it is also necessary to provide a metal connection in the electrostatic chuck 101. The object of the present invention is to form an electrical joint in the field of the material layer of the electrostatic chuck 101 between the DC electrode 110 and its connection line connected to the DC power source 111.

A first aspect of the invention provides a method of making an electrostatic chuck of a plasma processing chamber. 2 is a flow diagram of the fabrication of an electrostatic chuck of a plasma processing chamber in accordance with an embodiment of the present invention. According to a preferred embodiment of the present invention, it utilizes the cooling and expansion principle to form a region of the material layer of the electrostatic chuck 101 between the DC electrode 110 and its connection line to the DC power source 111. Electrical joint. In the embodiment, the manufacturing method of the electrostatic chuck 101 includes the following steps: first, as shown in FIG. 2(a), a ceramic substrate 1012 is first provided; then, a plurality of through holes 1014 are formed on the ceramic substrate 1012. The through hole 1014 is for receiving a metal connecting wire. For the sake of simplicity, only one via 1014 is shown in FIG. 2(a); then, as shown in FIG. 2(b), a plurality of metal connecting wires 1016 are provided to cool the plurality of metal connecting wires 1016 to room temperature. In the following, the volume of the metal connecting wire 1016 will be reduced according to the principle of thermal expansion and contraction. At this time, a plurality of cooled metal connecting wires 1016 are respectively embedded in the plurality of through holes 1014 of the ceramic substrate 1012; Then, the ceramic substrate 1012 in which the metal connecting wires 1016 are mounted is placed in the normal temperature. At this time, since the metal connection line 1016 is made of a metal having a high thermal expansion rate as compared with the previous temperature, the metal connection line 1016 will expand to fill the through hole 1014; As shown in 2(b), a DC electrode 110 is placed on top of the ceramic substrate. Since the DC electrode 110 is manufactured after the metal connection line 1016 is formed, there is no defect that the DC electrode 110 is broken by the later formed metal connection line 1016 due to the thinness, which fully demonstrates the superiority of the present invention. Wherein, the thickness of the DC electrode 110 The degree is about 0.2 mm or less; finally, as shown in Fig. 2(d), an anti-corrosion layer 1018 is deposited on the ceramic substrate 1012 on which the DC electrode 110 is placed, and the electrostatic chuck 101 is completed. At this time, an electrical connection is smoothly formed in the ceramic substrate 1012 under the DC electrode 110 of the electrostatic chuck 101.

In particular, the diameter of the through hole 1014 is larger than the diameter of the cooled metal connecting wire 1016, so that the metal connecting wire 1016 can be smoothly embedded in the through hole 1014 in a cooled state, and expands to almost almost after returning to room temperature. Fill the through hole 1014. Illustratively, the through hole 1014 has a diameter of 1 mm.

In particular, the metal connection line 1016 has a thermal expansion rate much larger than that of the ceramic substrate 1012 and the direct current electrode 110. The table below gives the thermal expansion rates of the metal materials of the ceramic substrate 1012, the direct current electrode 110, and the metal connecting wires 1016.

Further, the material of the metal connecting wire 1016 includes: copper, silver, aluminum, gold, the material of the ceramic substrate 1012 includes aluminum oxide, and the material of the direct current electrode 110 includes tungsten. As shown in the above table, the metal material of the metal connecting wire 1016, aluminum, copper, silver, gold, brass, has a thermal expansion coefficient much larger than that of the material as the ceramic substrate 1012, aluminum oxide and aluminum nitride, and metal tungsten as the direct current electrode 110. Therefore, under the same room temperature condition, the metal connecting wire 1016 expands even more, so that the metal connecting wire 1016 is smoothly embedded in the ceramic substrate 1012 of the electrostatic chuck 101, because the present invention utilizes the electrostatic chuck The difference between the thermal expansion rates of the ceramic substrate 2012 of 101 and the metal connection line 1016.

Further, the manufacturing method further includes the following steps: providing a plurality of copper metals Connecting wires, cooling the plurality of copper metal connecting wires to below -100 ° C, and inserting the cooled metal connecting wires into the plurality of through holes of the ceramic substrate.

It should be noted that in the above embodiment, the diameter of the metal connecting wire 1016 is carefully selected and calculated so that it is cooled down to a through hole which can fit on the ceramic substrate 1012 of the electrostatic chuck 101.

Further, the manufacturing method further includes the step of placing the DC electrode 110 on the ceramic substrate 1012 by vacuum deposition or printing.

Further, the material of the anti-corrosion layer 1018 includes hafnium oxide or tantalum nitride. Specifically, the corrosion-resistant layer 1018 of the surface layer of the electrostatic chuck 101 is coated by physical vapor deposition or plasma spraying, has a dense and high porosity structure, and has plasma corrosion resistance.

3 is a schematic block diagram of a submount of a plasma processing chamber in accordance with an embodiment of the present invention. Further, the method for manufacturing the electrostatic chuck of the plasma processing chamber provided by the present invention further comprises the step of connecting the soft metal connecting line 1017 below the metal connecting line 1016, thereby completing all the connecting lines of the direct current electrode 110 and the direct current power source. Wherein, at the lower end of the soft metal connecting line 1017, that is, a soft metal connecting line 1017 is formed under the base 106 to form a joint 1017a extending to connect to the DC power source 111 shown in FIG.

As shown in FIG. 3, according to an embodiment of the present invention, two layers of anti-corrosion layer may be coated on the electrostatic chuck 101, that is, an anti-corrosion layer 1019 is further coated on the original anti-corrosion layer 1018 to The electrostatic chuck 101 is made to have an enhanced function. The method for manufacturing the electrostatic chuck 101 provided by the present invention can continuously apply a plurality of layers of the anti-corrosion layer on the electrostatic chuck 101, and the DC electrode 110 is not damaged even if the texture of the anti-corrosion layer is soft.

A second aspect of the invention provides a manufacturer of a plasma processing chamber The method, wherein the manufacturing method comprises the method of manufacturing an electrostatic chuck according to the first aspect of the invention.

Although the present invention has been described in detail by the above embodiments, it should be understood that the foregoing description should not be construed as limiting. Various modifications and alterations of the present invention will be apparent to those skilled in the art. Therefore, the scope of the invention should be defined by the appended claims. In addition, any reference signs in the claims should not be construed as limiting the claims; the word "comprising" does not exclude the means or steps that are not listed in the other claims or the description; "first", " Words such as "two" are used only to denote a name, and do not denote any particular order.

106‧‧‧Abutment

1012‧‧‧Ceramic substrate

1016‧‧‧Metal cable

1017‧‧‧Soft metal cable

1017a‧‧‧ connector

1018‧‧‧Anti-corrosion layer

1019‧‧‧Anti-corrosion layer

110‧‧‧DC electrode

Claims (12)

A manufacturing method of an electrostatic chuck for a plasma processing chamber, wherein the manufacturing method comprises the steps of: providing a ceramic substrate; and forming a plurality of through holes on the ceramic substrate, the through holes for accommodating metal connecting wires Providing a plurality of metal connecting wires, cooling the plurality of metal connecting wires to below room temperature, and inserting the cooled metal connecting wires into the plurality of through holes of the ceramic substrate respectively; The ceramic substrate of the connecting wire is placed at a normal temperature; a DC electrode is placed on the ceramic substrate; and an anti-corrosion layer is deposited on the ceramic substrate on which the DC electrode is placed. The manufacturing method according to claim 1, wherein the diameter of the through hole is larger than the diameter of the metal connecting wire after cooling. The manufacturing method according to claim 2, wherein said metal connecting wire has a thermal expansion rate much larger than that of the ceramic substrate and the direct current electrode. The manufacturing method according to claim 3, wherein the material of the metal connecting wire comprises: copper, silver, aluminum, gold. The manufacturing method according to claim 3, wherein the material of the ceramic substrate comprises alumina. The manufacturing method according to claim 3, wherein the material of the direct current electrode comprises tungsten. The manufacturing method according to claim 1, wherein the manufacturing method further comprises the steps of: providing a plurality of copper metal connecting wires, cooling the plurality of copper metal connecting wires to below -100 ° C, and cooling the plurality of metals Connecting wires are respectively embedded in the plurality of through holes of the ceramic substrate. The manufacturing method according to claim 1, wherein the manufacturing method further comprises the step of placing a DC electrode on the ceramic substrate by vacuum deposition or printing. The manufacturing method according to claim 1, wherein the material of the anti-corrosion layer comprises ruthenium oxide or ruthenium nitride. The manufacturing method according to claim 1, wherein said corrosion resistant layer is formed by physical vapor deposition Formed by plasma or plasma spray. The manufacturing method according to claim 1, wherein the manufacturing method further comprises the step of connecting the soft metal connecting wires below the metal connecting wires. A method of manufacturing a plasma processing chamber, wherein the manufacturing method comprises the method of manufacturing an electrostatic chuck according to any one of claims 1 to 11.