TWI220767B - Ionized physical vapor deposition process and apparatus thereof - Google Patents

Abstract

An ionized physical vapor deposition process is described. A chamber having a metal target, a wafer pedestal, an ionized unit set between the metal target and the wafer pedestal and a conductive mesh disposed between the wafer pedestal and the ionized unit therein is provided A wafer is put on the wafer pedestal. The metal target is set with negative bias and the conductive mesh is set with another less negative bias to deposit a thin film on the wafer. In the present invention, the incident ionized metal accelerates toward the conductive mesh and decelerates after passing the conductive mesh. Therefore, the step coverage of the deposited thin film can be increased and the substrate damage can be prevented.

Description

1220767 V. Description of the invention (1) [Technical field to which the invention belongs] The present invention relates to a semiconductor process and its equipment, and in particular, to an ionized physical vapor deposition (i ο nizedphysica 1 vapor deposition, I-PVD). ) Process and equipment. [Previous technology] In the semiconductor manufacturing process, a physical vapor deposition process or a chemical vapor deposition process can be used for metal thin film deposition, and a physical vapor deposition process is generally used. Compared with the chemical vapor deposition process, the step coverage of the physical gas deposition process (s t e p c 0 v e r a g e) is poor. It is known that in order to improve the step coverage of the physical vapor deposition process, an ionized physical vapor deposition process has been proposed, which uses the design of an ionization unit such as an electromagnetic induction coil or a magnetic pole to make part of the neutral metal ionized (Ionized), and the ionized metal (field between the target and the wafer) under the action of the force, the direction of the wafer force α speed, so that the ionized metal will be vertical It is directed at the wafer to increase the step coverage of the deposited film. In the above-mentioned conventional techniques, a negative bias voltage is usually applied to the leather material and another smaller radio frequency negative bias voltage (RF negati ν ebias) is applied to the wafer to make the positively charged ionized metal cause The wafer is accelerated toward the wafer by being attracted by the negatively biased wafer, but because of this, impact damage is often found on the wafer surface, especially at the contact window, resulting in contact resistance (c ntact resistance). It is abnormally high, and the damage is even more serious. [Summary of the Invention] Therefore, the object of the present invention is to provide an ionized physical vapor deposition

11439twf.ptd Page 5 1220767 V. Description of the invention (2) Process and its degree, and at the same time the equipment 'will not be used to improve the wafer table. The distance from the golden seat to the base-based conductive sieve is used, and facing. Of course, the room and wafer belong to. In addition, it is much smaller than the distance between the seats. It can be placed on the surface of the crystal core, or it can be used as a base, and a wafer is provided as a distance from the system. The crystal is provided as a target system. It has been configured with a guide ionization unit for plasma reaction. The room material and a single electric sieve element that is separated from another wafer, and a small negative bias, is used to apply a sieve on and on the conductive sieve, such as a one-by-one wafer base to use as the electrode on the opposite side. In the meantime, the target of the electric sieve electrode is between 1 and 2 ions, among which the base, the element, and the. Then press the metal to make a negative bias close to the crystal, resulting in a physical base of 4 daggers and a round base from the physical surface. The target is a reaction chamber. In addition, it is used for S, and distance, cm. Chemical physics Plasma and ionization of gold applied crystal leather material to the wafer circle, which was damaged by the step coverage of the 4D metallographic deposition process. Vapor deposition (I-PVD) equipment-an ion system, an S system, and an S system are separately installed in the chamber. Ionization is carried out on an ion conductive screen. For example, a conversion unit is placed on the reverse top cover. The grid distance is the guide element, and the chamber should be used as the electrode element. The upper element is a plate within one bar of the crystal electric sieve, and the impacted wafer-based grid distance material is arranged on the bottom to cover the electrode. Take the ionic deposition process where the target hits the round base. First, it consists of a gold material and a wafer base, and a wafer base is placed on the wafer base to open the negative bias. Pressure, the corresponding target unit of the conductive screen gas is rounded to a layer where a thin film is deposited. A conductive screen will be set in this area, and the metal will be accelerated to shoot more vertically on the crystal.

11439t.wf. Pt.d Page 6 1220767 V. Description of the invention (3), round, and further improve the step coverage of the film. After the ionized metal passes through the conductive screen, the positively charged ionized metal is attracted by the negatively biased conductive screen, and it will be deposited in the direction of the wafer at a reduced speed. Will not be damaged by the impact of accelerated ionized metal. In order to make the above and other objects, features, and advantages of the present invention more comprehensible, a preferred embodiment is described below in detail with the accompanying drawings, as follows: [Embodiment] Please refer to FIG. 1 It shows a schematic diagram of an ionized physical vapor deposition apparatus according to a preferred embodiment of the present invention. The ionized physical gas phase deposition equipment of the present invention includes a reaction chamber 100, a wafer base 104, a target 106, an ionization unit 108, and a conductive screen 1110. Μ Among them, the wafer base 104 is disposed at the bottom of the reaction chamber 100, and is used to place a wafer 1 12. The target 106 is fixed at the top of the reaction chamber 100. In a preferred embodiment, the top cover 102 of the reaction chamber 100 is a conductive plate and can be used as an electrode, and the top cover 102 is connected to a power supply 1220. It is, for example, a direct current (DC) power supply. Therefore, the target material 106 is fixed on the surface of the top cover 102, and the dry material 106 is oriented toward the wafer base 104. In another preferred embodiment, an electrode plate 102 is additionally installed at the top of the reaction chamber 100, and the electrode plate 102 is connected to a direct current (DC) power supply 120. The target material 106 is fixed on the surface of the electrode plate 102, and the target material 106 faces the wafer base 104. In addition, the target material 106 is, for example, a metal target material, such as a metal material such as titanium, cobalt, nickel, group, hafnium, shaw, or copper.

1 1439twf.ptd Page 7 1220767 V. Description of the Invention (4) ^ The ionization unit 1 0 8 is arranged in the reaction chamber 1 0 0 and is located between the target 10 6 and the wafer base 1 0 4 It is used to ionize the metal impacted by the target 106. The ionization unit 108 is, for example, an electromagnetic induction coil, a magnetic pole, or the like. Therefore, the ionized physical vapor deposition device of the present invention may be an ionized metal p 1 as in a, I M depending on its ionization unit. P) a physical vapor deposition device, a self-ionized plasma (SIP) physical vapor deposition device, and a concave cathode magnetron sputtering (HCM sputtering) device. If it is applied to a concave cathode magnetron hidden money device, the electrode plate 102 in the figure will be designed into a concave structure in accordance with the design of the magnetic pole. The conductive screen 1 10 is arranged between the wafer base 104 and the ionization unit "108, and the distance between the conductive screen 1 10 and the wafer base 104 is much smaller than the conductive screen The distance between the mesh 1 10 and the target material 106. In a preferred embodiment, the distance between the conductive screen 1 10 and the wafer base 104 is, for example, between 1 cm and 2 cm. In addition, the material of the conductive screen 1 10 is preferably the same as that of the target material 106 to avoid contamination during the deposition process. The conductive screen 1 10 is a metal having a mesh structure. The top view of the material is shown in Figure 2. Therefore, the conductive screen 1 1 0 itself has conductivity to serve as an electrode, and the conductive screen 1 10 is connected to a power supply 1 1 8. For example, it is Radio frequency (RF) power supply. In addition, the ionized physical vapor deposition device of the present invention further includes a gas supply device 1 1 6 which is used to pass a degrading gas such as argon for physical Vapor deposition process to form metal thin film.

114'39twf. Pt.d Page 8 1220767 V. Description of the invention (5) ^ A reaction gas is introduced into the reaction chamber 100 so that the reaction gas participates in deposition to form a metal compound film. For example, when titanium is used as the target material 106, argon and nitrogen are passed into the reaction chamber 100 using the gas supply device 116, and a titanium nitride film can be deposited on the surface of the wafer 1 12 . The detailed description of the ionized physical vapor deposition process using the above-mentioned ionized physical vapor deposition equipment is as follows. Referring to FIG. 1, the wafer 1 12 is first placed on the wafer base 104 in the reaction chamber 100, and a thin film is prepared to be deposited on the surface of the wafer 1 12. A schematic cross-sectional view of the wafer 1 12 is shown in FIG. 3, which includes a silicon substrate 200, and a dielectric layer 202 formed on the substrate 200. The dielectric layer 202 has an opening 204. After that, the power supply devices 1 1 8 and 1 2 0 were started to apply a negative bias to the target 10 6 and another small negative bias to the conductive screen 1 1 0 to make the electricity The slurry hits the target 10 6 while bombarding the metal 1 1 3. At the same time, the ionization unit 1 0 8 is turned on so that the bombarded metal 1 1 3 is ionized into a positively charged ionized metal 1 1 4. At this time, the electric field generated between the ionized metal 1 1 4 and the conductive screen 1 1 0 will force the ionized metal 1 1 4 to shoot toward the conductive screen 1 1 0 with acceleration. As a result, the ionized metal 1 14 will shoot vertically to the wafer 1 1 2 to increase the step coverage of the deposited film. After the ionized metal 1 1 4 passes through the conductive screen 1 1 0, the positively charged ionized metal 1 1 4 is attracted by the conductive screen 1 1 0 that is applied with a negative bias, and therefore will decelerate toward the crystal. The circle 1 1 0 is deposited, and # reduces the force of the ionized metal 1 1 4 to hit the wafer 1 1 2. Referring to FIG. 3, a thin film 206 deposited on the surface of the dielectric layer 202 and the substrate 200 is shown in FIG.

1 1439 twf. Pr.d Page 9 1220767 V. Description of the invention (6) The step coverage is very good, and the surface of the dielectric layer 202 and the substrate 200 will not be damaged by the impact of the accelerated ionized metal 1 1 4 . In the above-mentioned ionized physical vapor deposition equipment for the ionized physical vapor deposition process, taking the ionized metal plasma (IMP) physical vapor deposition equipment deposition as an example, the negative bias applied to the titanium leather material For example, a direct current (DC) power source of 100-300 watts (W), and a negative bias applied to the conductive screen is, for example, a radio-frequency (RF) power source of 50-200 watts (W). In another preferred embodiment of the present invention, before depositing the thin film 206, it further includes depositing a thin layer on the surface of the dielectric layer 202 and the substrate 200, which is described in detail below. Please refer to FIG. 1 and FIG. 4A. Similarly, after placing the wafer 1 12 on the crystal base 1 104 in the reaction chamber 100, first turn on the power supply 1 2 0 to The target 10 6 is given a negative bias, and the conductive screen 1 10 is not biased. At the same time, the ionization unit 108 is turned on so that the bombarded metal 1 1 3 is ionized into a positively charged ionized metal 1 1 4. At this time, since the conductive screen 1 10 is not biased, the ionized metal 1 1 4 passes through the conductive screen 1 10 and shoots toward the wafer 1 12 with a low acceleration. Please refer to FIG. 4A. At this time, a thin layer 2 1 0 is deposited on the surface of the dielectric layer 202 and the substrate 200, and the thickness of the thin layer 2 1 0 is about 20% to 30% of the final thickness of the film. , Which is, for example, 40 angstroms to 50 angstroms. Since the above steps are not biased on the conductive screen, the step coverage of the deposited thin layer 210 is not good. But * here the thin layer 2 10 is quite thin, so it will not affect the step coverage of the final film. After that, please refer to Fig. 1 and Fig. 4 B to apply a negative bias to the target material 10 6

1 1 439 t.wf .ptd Page 10 1220767 V. Description of the invention (7) Apply another small negative bias to the conductive screen 1 1 0 and turn on the ionization unit 1 0 8 so that The bombarded metal 1 1 3 is ionized into a positively charged ionized metal 114. At this time, the electric field generated between the target material 106 and the conductive screen 1 1 0 will force the ionized metal 1 1 4 to shoot toward the wafer 1 1 2 at an acceleration. As a result, the ionized metal 1 1 4 It will be shot perpendicularly to the wafer 11 2 to improve the step coverage of the deposited film. After the ionized metal 1 1 4 passes through the conductive screen 1 1 0, the positively charged ionized metal 1 1 4 is attracted by the conductive screen 1 1 0 that is applied with a negative bias, and therefore will decelerate toward the crystal. Deposition in the circle 1 10 direction reduces the force of the ionized metal 1 1 4 to hit the wafer 1 12. Therefore, a thin film 2 06 (as shown in FIG. 4B) is deposited on the surface of the thin layer 2 10, and the thickness of the thin film 2 06 is, for example, more than 200 angstroms. The formed thin film 206 has excellent step coverage, and the surface of the dielectric layer 202 and the substrate 200 is covered with a thin layer 210, so that the ionized metal 1 4 can be prevented from directly hitting the wafer and causing damage. It is worth mentioning that, in the above embodiment, if the film to be deposited is a metal compound film, during the deposition process, a reaction gas is simultaneously introduced into the reaction chamber 100, and a metal compound film can be deposited. . Since a conductive screen is provided near the wafer and a negative bias is applied to the conductive screen, the ionized metal will be accelerated toward the conductive screen and the step coverage of the film is improved. After the ionized metal passes through the conductive screen, the ionized metal is attracted to the conductive screen applied with a negative bias, and will be deposited in the direction of the wafer at a reduced speed. For example, the wafer surface will not be accelerated. Damage caused by the impact of ionized metal.

11439twf.ptd Page 11 1220767 V. Description of the invention (8) The invention can deposit a thin layer on the surface of the crystallite without applying a bias voltage on the conductive grid before depositing the thin film, which can protect the crystal The round surface is protected from damage caused by the direct impact of the ionized metal during subsequent film deposition. Although the present invention has been disclosed in the preferred embodiment as above, it is not intended to limit the present invention. Anyone skilled in the art can make some changes and "decorations" without departing from the spirit and scope of the present invention. The protection scope of the present invention shall be determined by the scope of the attached patent application.

114'39twf. Ptd Page 12 1220767 Brief description of the drawing Figure 1 is the intention of the ionized physical vapor deposition equipment according to a preferred embodiment of the present invention; Figure 2 is above the conductive screen in Figure 1 FIG. 3 is a schematic cross-sectional view of a thin film having a very good step and low coverage deposited on a wafer according to a preferred embodiment of the present invention; and FIGS. 4A to 4B are another views according to the present invention. A schematic cross-sectional view of a preferred embodiment for depositing a thin film with excellent low-level coverage on a wafer. [Illustration of Graphical Indications] 1 0 0: reaction chamber 1 0 2: top cover (electrode plate) 1 0 4 · wafer base 1 0 6: target 1 0 8: ionization unit 1 1 0: conductive screen 1 1 2: wafer 1 1 3: metal 1 1 4: ionized metal 1 1 6: gas supply device 1 1 8, 1 2 0: power supply 200: substrate 2 0 2: dielectric layer 204: opening 2 0 6: thin film 2 1 0: thin layer

1 1 439t.wf.ptd Page 13

Claims (1)

1220767 VI. Scope of patent application1. An ionized physical vapor deposition (I-PVD) device, including: a reaction chamber; a target fixed at the top of the reaction chamber; a wafer base disposed in the At the bottom of the reaction chamber; an ionization unit is disposed between the target and the wafer base; and a conductive screen is disposed between the ionization unit and the wafer base. 2. The ionized physical vapor deposition equipment as described in item 1 of the scope of patent application, wherein the material of the conductive screen is the same as that of the leather material. 3. The ionized physical vapor deposition equipment according to item 1 of the scope of patent application, wherein the distance of the conductive screen from the wafer base is smaller than the distance of the conductive screen from the target. 4. The ionized physical vapor deposition equipment according to item 3 of the scope of patent application, wherein the distance between the conductive screen and the wafer base is between 1 and 2 cm. 5. The ionized physical vapor deposition device according to item 1 of the scope of patent application, wherein the top cover of the reaction chamber is used as a first electrode, and the conductive screen is used as a second electrode. 6. The ionized physical vapor deposition equipment described in item 1 of the scope of patent application, further comprising a first electrode fixed on the top of the reaction chamber, and the leather material is fixed on the surface of the first electrode The conductive screen is used as a second electrode. 7. — An ionized physical vapor deposition process, including: 1 1439twf. Pt.d 页 page 12 1220767 6. The scope of the patent application provides a plasma reaction chamber, wherein the plasma reaction chamber includes a leather material and a wafer base, and the dry material and the An ionization unit is arranged between the wafer bases, and a conductive screen is arranged between the ionization unit and the wafer base; a wafer is placed on the wafer base, and the target is A negative bias is applied, and another smaller negative bias is applied to the conductive screen to deposit a thin film on the wafer. 8. The ionized physical vapor deposition process as described in item 7 of the scope of the patent application, wherein before depositing the thin film on the wafer, it further includes applying a negative bias to the leather material and the conductive screen No bias is applied on the net to form a thin layer on the surface of the wafer, then a negative bias is applied to the target, and another smaller negative bias is applied to the conductive screen to The film is deposited on a thin layer surface. 9. The ionized physical vapor deposition process according to item 8 of the scope of the patent application, wherein the thickness of the thin layer is 20% to 30% of the final thickness of the thin film. The ionized physical vapor deposition as described in item 7 of the scope of the patent application, wherein when depositing the thin film, a reaction gas is passed to the reaction, an ionized physical vapor deposition process, including: An ionized metal, and the ionized metal is directed toward a wafer at an acceleration; and in a 10-step process, the chamber 11 passes through a conductive screen before the first ionized metal reaches the wafer, and the The ionized metal will slow down after passing through the conductive screen, and 1 1439t.wf.ptd Page 15 1220767 6. Scope of patent application A metal thin film is formed on the wafer. 12. The ionized physical vapor deposition process according to item 11 of the scope of patent application, wherein before forming the metal thin film on the wafer, further comprising: generating the ionized metal in the reaction chamber, and the ions The metallized metal passes through the conductive screen and reaches the wafer with a second acceleration, and a thin layer is formed on the surface of the wafer, wherein the second acceleration is smaller than the first acceleration; and after the thin layer is formed, , The ionized metal accelerates toward the wafer with the first acceleration, and the ionized metal passes through the conductive screen before reaching the wafer, and the ionized metal decelerates after passing through the conductive screen , And the metal thin film is formed on the surface of the thin layer. 1 3 · The ionized physical vapor deposition process as described in item 11 of the scope of patent application, wherein the generation of the ionized metals further includes passing a reaction gas into the reaction chamber. 11439t.wf.ptd p. 16