Wafer processing apparatus and wafer processing method using the same

An integrated in situ cluster type wafer processing apparatus which can be used for forming metal wiring layers having a multi-layered structure and a wafer processing method using the same are provided. The wafer processing apparatus includes a transfer chamber which can be exhausted and has a plurality of gate valves, a plurality of vacuum processing chambers each of which can be connected to the transfer chamber via one of the gate valves, and a load lock chamber which can be exhausted and is connectable to a first gas feed line for feeding an oxygen-based gas into the load lock chamber. In a wafer processing method, a predetermined layer is formed on a wafer in one of the vacuum processing chambers. The predetermined layer on the wafer is oxidized in the load lock chamber or an oxygen atmosphere chamber.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a wafer processing apparatus and a wafer processing method using the same, and more particularly, to a wafer processing apparatus which can be used to form metal wiring layers having a multi-layered structure and a wafer processing method using the same.

2. Description of the Related Art

As the integration density of semiconductor devices increases, it is necessary to introduce metal wiring layers having a multi-layered structure into circuits. Because metal wiring layers transmit electrical signals, it is advantageous to use an economical material for the metal wiring layers which has low electrical resistance and high reliability. To meet these demands, aluminum is widely used for the material of the metal wiring layers. It is also advantageous to electrically connect such aluminum wiring layers in a way that is reliable, economical, and has low electrical resistance. Metal wiring layers are typically connected by a contact hole, which is a contact between a lower device and an upper wiring layer, or a via hole, which is a contact between a lower metal wiring layer and an upper aluminum wiring layer. Aluminum is preferably used as the metal to fill a contact hole or a via hole because it is economical and has superior conductivity.

To obtain superior electrical characteristics and filling characteristics when filling a contact hole or a via hole with aluminum, a variety of processing techniques have been developed. The processes for filling a contact hole or a via hole typically include steps such as chemical vapor deposition (CVD), physical vapor deposition (PVD), heat treatment, an oxidation process, and an etching process. Various cluster tool type wafer processing apparatuses have been developed to perform the steps for filling a contact hole or via hole.

However, a conventional integrated cluster tool type wafer processing apparatus typically does not have every facility required for performing all the processes for filling a contact hole or a via hole on a wafer. Accordingly, a vacuum break inevitably occurs during the contact hole or via hole filling processes. If a wafer is exposed to the atmosphere during the processes for filling a contact hole or a via hole, the exposed surface of the wafer may be contaminated by air, water vapor, or particles in the air, which may adversely affect the performance and yield of the resulting semiconductor device. In addition, the distance the wafer moves is increased significantly because the wafer is moved into a processing equipment or processing atmosphere which is not installed in the wafer processing apparatus during the contact hole or via hole filling process and through put is decreased.

SUMMARY OF THE INVENTION

According to certain embodiments of the invention, a wafer processing apparatus includes: a transfer chamber which is exhaustible and has a plurality of gate valves; a plurality of vacuum processing chambers, each of which is connectable to the transfer chamber via one of the gate valves; and a load lock chamber which is exhaustible and is connectable to a first gas feed line for feeding an oxygen-based gas into the load lock chamber.

In some embodiments, a second gas feed line for feeding an inert gas into the load lock chamber is connectable to the load lock chamber.

The plurality of vacuum processing chambers may include a chemical vapor deposition chamber, a physical vapor deposition chamber, and a heat treatment chamber.

The heat treatment chamber may include a pedestal which can be raised and lowered and has a supporting surface for supporting a wafer. A cover is installed above the pedestal so that a predetermined space between the supporting surface and the cover can be adjusted by raising and lowering the pedestal. A heating apparatus for heating the wafer is installed at the pedestal and the cover.

The plurality of vacuum processing chambers may include a Ti/TiN layer exclusive chamber for forming a Ti layer, a TiN layer, or a mixed layer of Ti and TiN. The plurality of vacuum processing chambers may include an etching chamber. The etching chamber may be a plasma etching chamber using a radio frequency power source. Alternatively, the etching chamber may be an electron cyclotron resonance etching chamber.

In certain embodiments, a wafer processing apparatus according to the invention includes an oxygen atmosphere chamber which can be connected to the transfer chamber via one of the gate valves. In some embodiments, the oxygen atmosphere chamber includes a third gas feed line for feeding an oxygen-based gas into the oxygen atmosphere chamber and a fourth gas feed line for feeding an inert gas into the oxygen atmosphere chamber.

The wafer processing apparatus according to the invention may further include: a degas chamber which is situated between the load lock chamber and the transfer chamber and is used for preheating a wafer received from the load lock chamber and for outgassing; and a cooling chamber which is situated between the load lock chamber and the transfer chamber and is used for cooling the wafer received from the transfer chamber.

According to embodiments of the invention, a wafer processing apparatus includes: a transfer chamber which is exhaustible and has a plurality of gate valves; a plurality of vacuum processing chambers, each of which is connected to the transfer chamber via one of the gate valves; an oxygen atmosphere chamber which can be connected to the transfer chamber via one of the gate valves and is connectable to a first gas feed line for feeding an oxygen-based gas into the oxygen atmosphere chamber; and a load lock chamber which is exhaustible.

According to embodiments of the invention, a transfer chamber is connected to a plurality of processing chambers via a plurality of gate valves. A load lock chamber is connected to the transfer chamber, and a first gas feed line is connected to the load lock chamber for feeding an oxygen-based gas to the load lock chamber. A predetermined layer is formed in one of the plurality of vacuum processing chambers. The predetermined layer is oxidized on the wafer in the load lock chamber. The load lock chamber and the transfer chamber are exhaustible.

The step of oxidizing the predetermined layer on the wafer may be performed in an oxygen-based gas atmosphere including at least one of oxygen (O2), ozone (O3), and dinitrogen monoxide (N2O). The step of oxidizing the predetermined layer on the wafer may be performed in a mixed gas atmosphere of an inert gas and an oxygen-based gas including at least one of oxygen (O2), ozone (O3), and dinitrogen monoxide (N2O). The step of oxidizing the predetermined layer on the wafer may be performed at a temperature between about room temperature and about 200° C.

According to embodiments of the invention, a first layer is formed on a predetermined portion of the wafer to define a contact hole or via hole region before the step of forming the predetermined layer, and the predetermined layer is formed on the first layer such that the predetermined layer does not cover the contact hole region.

According to embodiments of the invention, a transfer chamber is connected to a plurality of vacuum processing chambers via a plurality of gate valves. An oxygen atmosphere chamber is connected to the transfer chamber via one of the plurality of gate valves. A first gas feed line to the oxygen atmosphere chamber for feeding an oxygen-based gas into the oxygen atmosphere chamber. A load lock chamber is connected to the transfer chamber for facilitating the transfer of a wafer to and from the transfer chamber. The transfer chamber and the load lock chamber is exhaustible.

According to certain embodiments of the invention, exposure to the atmosphere during processing and during the formation of metal wiring layers is eliminated. Therefore, contamination of the wafer may be reduced and throughput may be enhanced.

DETAILED DESCRIPTION OF THE INVENTION

The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which various embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the relative sizes of elements may be exaggerated for clarity. It will be understood that when an element is referred to as being “connected” or “connectable to” another element, it can be directly connected to the other element or intervening elements may also be present.

FIG. 1is a schematic diagram illustrating an integrated in situ cluster tool type wafer processing apparatus according to embodiments of the present invention. Referring toFIG. 1, a wafer processing apparatus according to an embodiment of the present invention includes a transfer chamber10having a plurality of gate valves22,32,42,52, and62. A wafer handling robot14is installed in the transfer chamber10. The wafer handling robot14includes a blade12for supporting a wafer. A plurality of vacuum processing chambers20,30, and40are installed around the transfer chamber10, and each of the vacuum processing chambers20,30, and40is connected to the transfer chamber10through one of the gate valves22,32,42,52, and62. InFIG. 1, the vacuum processing chambers20,30, and40are a chemical vapor deposition (CVD) chamber, a physical vapor deposition (PVD) chamber, and a heat treatment chamber, respectively.

The CVD chamber20can be used for forming a metal layer such as an aluminum layer or an aluminum alloy layer. For example, selective metal organic chemical vapor deposition (MOCVD) for forming an aluminum layer can be performed in the CVD chamber20. The CVD chamber20includes a raw material provider (not shown) for providing an aluminum source for providing aluminum as well as processing gases required for deposition of an aluminum layer in the CVD chamber20. A precursor formed of an organometallic compound, such as dimethylaluminum hydride (DMAH), trimethylamine alane (TMAA), dimethylethylamine alane (DMEAA), or methylpyrrolidine alane (MPA), may be used as the aluminum source. A bubbler type raw material provider, a vapor flow controller type raw material provider, or a liquid delivery system type raw material provider may be used for providing the precursor to the CVD chamber20. An inert gas, such as Ar, may be used as a dilution gas. To promote the decomposition of the precursor, a reaction gas, such as a hydrogen (H2) gas, may be added.

The PVD chamber30may be a sputtering chamber which is capable of performing direct current (DC) sputtering, DC magnetron sputtering, alternating current (AC) sputtering, or AC magnetron sputtering. If necessary, a collimator may be installed in the PVD chamber30for performing sputtering. The PVD chamber30can be used for forming a wiring layer, which includes an aluminum layer or an aluminum alloy layer.

The wiring layer is thermally treated in an inert atmosphere, such as an Ar atmosphere, at a temperature of 350° C. or greater for several minutes and then is reflowed to fill a contact hole or via hole and planarize the wiring layer. The heat treatment chamber40is used to perform the reflowing process. Heat treatment for reflowing the aluminum layer or aluminum alloy layer should be performed in a state when the surface of the aluminum layer or aluminum alloy layer is difficult to oxidize. Thus, it is preferable that the pressure of the heat treatment chamber40is low. Preferably, the heat treatment chamber is maintained to be in a highly vacuum state having a pressure of 10−6Torr or less.

FIGS. 2A and 2Bare schematic diagrams illustrating the structure of the heat treatment chamber40of FIG.1. Referring toFIGS. 2A and 2B, the heat treatment chamber40includes a pedestal44having a supporting surface44afor supporting a wafer W. The pedestal44can be raised and lowered by an elevating apparatus140.FIG. 2Aillustrates the case of the pedestal44in a lowered position, andFIG. 2Billustrates the case of the pedestal44in a raised position. The heat treatment chamber40includes a cover46which is installed above the pedestal44so that a predetermined space between the supporting surface44aand the cover46can be adjusted depending on whether the pedestal44is lowered or raised, respectively. A first heater142and a second heater144are installed in the pedestal44and the cover46, respectively. The first and second heaters142and144may include a resistant coil. The heat treatment chamber40can be exhausted using an exhaust system49including an exhaust pump48.

When the wafer W is put into or taken out of the heat treatment chamber40, the pedestal44is at the lowered position. When the wafer W is thermally treated, the pedestal44is at the raised position. Therefore, the predetermined space between the supporting surface44aand the cover46is closed by the pedestal44when the wafer W is thermally treated, and thus the temperature around the pedestal44is uniformly maintained.

In addition, the wafer processing apparatus according to the present invention includes a load lock chamber50as shown in FIG.3. In certain embodiments of the present invention, the load lock chamber50is used for preparing a space through which a wafer can be moved between the inside and outside of the wafer processing apparatus. The load lock chamber50may also be used for oxidizing the wafer.

FIG. 3is a schematic diagram illustrating the structure of the load lock chamber50. As shown inFIG. 3, the load lock chamber50can be exhausted using an exhaust system54, which includes an exhaust pump53. A first gas feed line56for feeding an oxygen-based gas156to the load lock chamber50and a second gas feed line58for feeding an inert gas158into the load lock chamber50are connected to the load lock chamber50. O2, O3, or N2O may be used as the oxygen-based gas156supplied through the first gas feed line56. The flow rate of gas supplied via the first and second gas feed lines56and58can be controlled by flow regulators151and153, respectively, and valves152and154, respectively. Mounted on a wafer carrier150, a wafer can be easily put into or taken out of the load lock chamber50. A process for oxidizing the wafer is performed using the oxygen-based gas156supplied via the first gas feed line56in the load lock chamber50maintained in a vacuum state by the exhaust system54. At this time, it is possible to perform the oxidation of the wafers mounted on the wafer carrier150in a batch process. The degree to which the wafer is oxidized can be controlled by regulating the flow rate of the oxygen-based gas156, that is, by controlling the partial pressure of the oxygen-based gas and the exposure time.

Referring toFIG. 1, a degas chamber70is installed between the transfer chamber10and the load lock chamber50for the purpose of preheating the wafer received from the load lock chamber50before moving the wafer to the transfer chamber10. The degas chamber70is also used for outgassing the wafer. A cooling chamber80is installed between the transfer chamber10and the load lock chamber50for the purpose of cooling the wafer before moving the wafer to the load lock chamber50. Load chambers90are buffer chambers situated between the degas chamber70and the load lock chamber50and between the cooling chamber80and the load lock chamber50. The wafer processing apparatus is controlled by a controller92.

The wafer processing apparatus shown inFIG. 1, which includes three vacuum processing chambers: the CVD chamber20, the PVD chamber30, and the heat treatment chamber40, can be efficiently used in various processes for forming metal wiring layers such as filling a contact hole or via hole. Also, the wafer processing apparatus shown inFIG. 1can be used in a blanket aluminum deposition process in which an aluminum layer is formed on a wafer using chemical vapor deposition.

FIG. 4is a schematic diagram illustrating the structure of an integrated cluster tool type wafer processing apparatus according to further embodiments of the present invention. The same reference numerals inFIGS. 1 and 4represent the same elements, and thus their description will be omitted.

Referring toFIG. 4, a wafer processing apparatus according to the invention includes the CVD chamber20, the PVD chamber30, the heat treatment chamber40, a Ti/TiN layer exclusive chamber250for forming a Ti layer, a TiN layer, or a mixed layer of Ti and TiN, and an etching chamber260. The Ti/TiN exclusive chamber250and the etching chamber260are connected to the transfer chamber10via gate valves252and262, respectively. The Ti/TiN layer exclusive chamber250may include a CVD chamber or a PVD chamber. The etching chamber260may include a plasma etching chamber using a radio frequency (RF) power source, or an electron cyclotron resonance (ECR) etching chamber. The etching chamber260can be used for removing a surface oxide layer formed in a contact hole or via hole.

FIG. 5is a schematic diagram illustrating the structure of an integrated cluster tool type wafer processing apparatus according to embodiments of the present invention. The same reference numerals inFIGS. 1,4, and5represent the same element, and thus their description will not be repeated.

In addition to the vacuum processing chambers, CVD chamber20, PVD chamber30, heat treatment chamber40, Ti/TiN layer exclusive chamber250, and etching chamber260, the wafer processing apparatus depicted inFIG. 5includes an oxygen atmosphere chamber370. The oxygen atmosphere chamber370is connected to the transfer chamber10via a gate valve372.

FIG. 6is a schematic diagram illustrating the oxygen atmosphere chamber370of FIG.5. As shown inFIG. 6, the oxygen atmosphere chamber370can be exhausted by an exhaust system354including an exhaust pump353. A third gas feed line356for feeding an oxygen-based gas456into the oxygen atmosphere chamber370and a fourth gas feed line358for feeding an inert gas458into the oxygen atmosphere chamber370are connected to the oxygen atmosphere chamber370. The oxygen-based gas456is supplied via the third gas feed line356may be O2, O3, or N2O. The flow rate of gas supplied via the third and fourth feed lines356and358can be controlled by flow regulators451and453, respectively, and valves452and454, respectively. A process of oxidizing a wafer may be performed using the oxygen-based gas456supplied via the third gas feed line356in the oxygen atmosphere chamber370maintained in a vacuum state by the exhaust system354. The degree to which the wafer is oxidized can be controlled by the flow rate of the oxygen-based gas456, that is, the partial pressure of the oxygen gas and the exposure time.

FIG. 7is a flowchart illustrating a wafer processing method according to an embodiment of the present invention. The process may be used for forming a contact hole or a via hole. For clarity and ease of presentation, a contact hole is referred to in the following example with reference toFIG. 7. Afirst layer is formed on a predetermined portion of a wafer to define a contact hole region in step510. The first layer may be an interlayer dielectric layer, a monolayer formed of a TiN layer, or a mixed layer including a TiN layer. In the case of the first layer being a monolayer of a TiN layer or a mixed layer including a TiN layer, the first layer can be formed in the Ti/TiN layer exclusive chamber250of the wafer processing apparatus described with reference to FIG.4.

Next, in step520, a predetermined layer, for example, an aluminum layer or a titanium layer, is formed on the first layer using vacuum processing chambers CVD chamber20or PVD chamber30, with reference to FIG.1. Next, in step530, the predetermined layer is oxidized in the load lock chamber50described with reference toFIGS. 1 and 3. To oxidize the predetermined layer, an oxygen-based gas, such as O2, O3, or N2O, or a mixed gas consisting of the oxygen-based gas and an inert gas is supplied to the load lock chamber50so that the load lock chamber50is maintained at an oxygen atmosphere. The step of oxidizing the predetermined layer may be performed at a temperature between about room temperature and about 200° C. If necessary, the step of forming an aluminum layer using the CVD chamber20or the PVD chamber30and the step of reflowing a semiconductor substrate using the heat treatment chamber40may be additionally performed.

FIG. 8is a flowchart illustrating a wafer processing method according to an embodiment of the present invention. The process may be used for forming a contact hole or a via hole. For clarity and ease of presentation, a contact hole is referred to in the following example with reference toFIG. 8. Afirst layer is formed on a predetermined portion of a wafer so as to define a contact hole region in step610. As described with reference toFIG. 7, the first layer may be an interlayer dielectric layer, a monolayer formed of a TiN layer, or a mixed layer including a TiN layer.

Next, in step620, a predetermined layer, for example, an aluminum layer or a titanium layer, is formed on the first layer using the CVD chamber20or the PVD chamber30installed in the wafer processing apparatus, described with reference to FIG.5. Next, in step630, the predetermined layer is oxidized in the oxygen atmosphere chamber370, described with reference toFIGS. 5 and 6. To oxidize the predetermined layer, an oxygen-based gas or a mixed gas consisting of an oxygen-based gas and an inert gas is fed into the oxygen atmosphere chamber370so that the oxygen atmosphere chamber370is maintained at an oxygen atmosphere. The step of oxidizing the predetermined layer may be performed at a temperature between about room temperature and about 200° C. If necessary, the step of forming an aluminum layer using the CVD chamber20or the PVD chamber30and the step of reflowing the semiconductor substrate using the heat treatment chamber40may be additionally performed.

According to some embodiments of the present invention, a wafer processing apparatus according to the present invention includes a load lock chamber or an oxygen atmosphere chamber which can be maintained at an oxygen-based atmosphere required for performing an oxidation process. Therefore, the wafer is not exposed to atmosphere when transferred to an oxidation apparatus. The probability of the wafer being polluted is therefore reduced and throughput may be enhanced.