TWI423333B - Method and apparatus for fabricating a high dielectric constant transistor gate using a low energy plasma system - Google Patents

Description

Method and device for manufacturing high dielectric constant crystal gate by using low energy plasma system

Embodiments of the present invention are generally directed to methods and apparatus for forming high k (dielectric constant) dielectric layers. In particular, embodiments of the present invention are directed to methods of forming a gate dielectric layer.

An integrated circuit is made up of millions of components, such as transistors, capacitors, and resistors. A transistor, such as a field effect transistor, typically includes a source, drain and gate stack structure. The gate stack structure generally includes a substrate (eg, a germanium substrate), a gate dielectric layer, and a gate electrode (eg, a polysilicon) on the gate dielectric layer. The gate dielectric layer is composed of a dielectric material such as hafnium oxide (SiO ₂ ) or a high-k dielectric material having a dielectric constant greater than 4.0, such as niobium oxynitride (SiON), tantalum nitride (SiN), oxidation. HfO ₂ , HfSiO ₂ , HfSiON, ZrO ₂ , ZrSiO ₂ , Barium titanate (BaSrTiO 3 or BST), Titanium zirconate Lead (Pb(ZrTi)O ₃ or PZT) and the like. It should be noted, however, that the film stack structure may comprise a film layer of other materials.

FIG. 1A illustrates a cross section of a field effect transistor (FET) 10 including a gate dielectric layer 14. As shown, the substrate 12 is provided with a gate dielectric layer 14 and a gate electrode 16. The sidewall spacers 18 abut the vertical sidewalls of the gate dielectric layer 14 and the gate electrode 16. The source/drain junctions 13 are formed in a substrate 12 that substantially abuts the opposite vertical sidewalls of the gate electrode 16.

As the size of the integrated circuit and the size of the transistor thereon are reduced, the gate drive current required to increase the speed of the transistor also increases. The drive current increases as the gate capacitance increases, and the capacitance = kA/d, where k is the dielectric constant of the gate, d is the thickness of the dielectric layer, and A is the area of the component. Reducing the thickness of the dielectric layer and increasing the dielectric constant of the gate dielectric layer are methods for increasing gate capacitance and drive current.

The thickness of the SiO ₂ gate dielectric layer has been attempted to fall below 20 angstroms (Å). However, the use of a SiO ₂ gate dielectric layer of less than 20 Å has been found to have an adverse effect on the performance and durability of the gate. For example, boron of a boron-doped gate electrode will pass through a thin SiO ₂ gate dielectric layer to reach the underlying germanium substrate. And the thin dielectric layer increases the power consumed by the gate, thereby increasing the gate leakage current (ie, the tunneling current). The thin SiO ₂ gate dielectric layer is susceptible to cracking by the NMOS hot carrier, where high energy carriers that traverse the dielectric layer can damage or destroy the channel. The thin SiO ₂ gate dielectric layer is also susceptible to PMOS negative bias temperature instability (NBTI), where the threshold voltage or drive current drifts with gate operation.

A method of forming a gate dielectric layer suitable for a metal oxide half field effect transistor (MOSFET) includes nitriding a hafnium oxide film in a nitrogen-containing plasma. The increase in dielectric constant by increasing the net nitrogen content of the gate oxide layer is based on several reasons. For example, the oxide dielectric layer block may be slightly added with nitrogen during the plasma nitridation process to reduce the equivalent oxide thickness (EOT) on the original oxide layer. Due to the pinning effect of the FET during operation, it has the same EOT as the unnitrided oxide dielectric layer, which reduces the gate leakage current. At the same time, increasing the nitrogen content can also reduce the damage caused by the F-N tunneling current if the thickness of the dielectric layer falls within the Fowler-Nordheim (F-N) tunneling current during subsequent processing operations. Another benefit of increasing the net nitrogen content of the gate oxide layer is that the nitrided gate dielectric layer is more resistant to gate undercut problems, thereby reducing gate edge defects and reducing leakage current.

Issued in the US Patent No. 6,610,615 of August 26, 2003, and the patent name is "Plasma Nitridation For Reduced Leakage Gate Dielectric Layers" McFadden et al. compared the nitrogen distribution of the yttrium oxide film in the thermal nitridation process and the plasma nitridation process (see Figure 1B). The nitrided oxide layer is on the tantalum substrate. Figure 1B shows the distribution of nitrogen in the crystalline enthalpy below the oxide film. The nitrogen distribution curve 22 obtained by the thermal nitridation process shows: the first nitrogen concentration on the top surface of the oxide layer, the nitrogen concentration which generally decreases with the deep oxide layer, the cumulative nitrogen concentration at the interface of the oxide layer/矽 layer interface, and finally the usual The nitrogen concentration gradient gradually decreases as it penetrates the substrate. On the contrary, the nitrogen distribution curve 24 obtained by the plasma nitridation process shows that the nitrogen concentration is substantially reduced from the top surface of the oxide layer to the substrate through the oxide/germanium layer interface. Ion bombardment with nitrogen plasma does not produce an accumulation of nitrogen concentration at the improper interface formed by the thermal nitridation process. Furthermore, the nitrogen concentration in all depths of the substrate in the plasma nitridation process is lower than that in the thermal nitridation process.

As mentioned above, the advantage of increasing the nitrogen concentration at the gate electrode/gate oxide interface reduces the diffusion of dopants (e.g., boron) from the polysilicon gate electrode to the gate oxide layer or through the gate oxide layer. This can reduce, for example, defects in the gate oxide layer due to boron in-diffused in the boron-doped polysilicon gate electrode, thereby improving the reliability of the device. Another advantage of reducing the nitrogen content at the gate oxide/germanium channel interface is to reduce the fixed charge and reduce the interface morphology density. This improves channel mobility and transconductance. Therefore, the plasma nitridation process is superior to the thermal nitridation process.

As the semiconductor components become smaller and smaller, the size of the nitrided gate oxide layer has reached its limit. However, when further reducing the thickness of the nitriding gate cerium oxide layer (from 10 As a result, the gate leakage has increased to the extent that components cannot be applied. In order to meet the requirements for continued shrinkage of component sizes, new gate dielectric materials and/or processes are required.

The replacement of cerium oxide (SiO ₂ ) with high-k dielectric materials has faced several challenges. For example, deposition methods of high-k dielectric materials generally employ chemical vapor deposition (CVD) or atomic layer deposition (ALD), which tends to cause carbon-containing precursor materials to be mixed with other contaminants into the deposited film layer. Carbon and other contaminants can deteriorate the dielectric properties of the gate dielectric layer. In addition, the interfacial properties of the high-k film and channel regions of CVD or ALD deposition are not as good as those of the ceria layer.

Therefore, this art requires a method and apparatus for forming a gate dielectric layer having a preferred dielectric property and a small EOT.

The present invention generally provides a method of forming a semiconductor device comprising: forming a dielectric layer having a predetermined thickness on a surface of a substrate; using a low energy sputtering process to implant a level of the first material into the dielectric layer to form a through a concentration gradient of at least a portion of the formed dielectric layer thickness, wherein the low energy sputtering process includes applying a RF energy to the processing region of the low energy sputtering chamber at a first RF frequency and a first RF power to cause the first target The material is placed in the dielectric layer; and the second material is deposited on the dielectric layer.

Embodiments of the present invention further provide an apparatus for forming a high-k dielectric layer, comprising: a transfer chamber having one or more wall surfaces constituting a transfer area and a transfer robot disposed in the transfer area; a plasma nitridation chamber connected to a transfer chamber and disposed to form a nitride on a surface of the substrate of the first processing region in the nitridation chamber, wherein the plasma nitridation chamber includes an RF source in electrical communication with the first processing region, and is selected with the first processing region a substantially nitrogen-containing gas; and a first low-energy plasma processing chamber coupled to the transfer chamber and transferable to the robotic arm, wherein the first low-energy plasma processing chamber comprises one or more a wall constituting the second treatment region, the surface being exposed to the target of the second treatment region, wherein the target comprises the first material, and the first RF generator is adapted to supply energy to the second treatment region at the first RF frequency And a substrate support disposed in the second processing region.

Embodiments of the present invention further provide an apparatus for forming a high-k dielectric layer comprising: one or more walls constituting a processing region; a surface exposed to a target of the processing region; at least one surface being a substrate support facing the processing region Wherein the substrate support is adapted to support a substrate having a dielectric layer formed on the surface of the substrate; the first generator being in electrical communication with the target and disposed to transmit at a frequency of from about 1 MHz to about 200 MHz An energy to target to maintain a capacitively coupled plasma in the processing region, wherein the first generator is configured to generate a bias on the target surface to sputter the target from the target; and the controller is configured to The frequency at which the first generator is delivered to the target is controlled.

Embodiments of the present invention further provide an apparatus for forming a high-k dielectric layer comprising: one or more walls constituting a processing region; a surface exposed to a target of the processing region, and the target and the direct current (DC) power supply are electrically Communicating; a first coil in electrical communication with the processing region and the first generator, wherein the first coil and the first generator are adapted to generate plasma at a processing region adjacent the target surface; and a substrate support at the processing region Pieces.

Embodiments of the present invention further provide a method of forming a high-k dielectric layer, comprising: placing a substrate having a dielectric layer formed thereon in a processing region of a plasma processing chamber; and placing the first energy using a low energy sputtering process a material into the dielectric layer, wherein the low energy sputtering process comprises delivering a plurality of RF energy pulses from the first RF generator to a target containing the first material, and each RF energy pulse is delivered at a first RF frequency And delivering a plurality of DC pulses from the DC source component to the target, wherein the RF energy pulse and the DC pulse are synchronized.

Embodiments of the present invention further provide a method of forming a high-k dielectric layer, comprising: placing a substrate having a dielectric layer formed thereon in a processing region of a plasma processing chamber; and placing the first energy using a low energy sputtering process a material into the dielectric layer, wherein the low energy sputtering process includes delivering a plurality of RF energy pulses from the first RF generator to a coil in electrical communication with the processing region, and the RF energy is at a first RF frequency and a power delivery; and delivering a plurality of DC pulses from the DC source assembly to the target containing the first material, wherein the RF energy pulses and the DC pulses are synchronized.

Embodiments of the present invention further provide a method of forming a high-k dielectric layer, comprising: placing a substrate having a dielectric layer formed thereon in a processing region of a plasma processing chamber; and placing the first energy using a low energy sputtering process a material into the dielectric layer, wherein the low energy sputtering process includes delivering a plurality of first RF energy pulses from the first RF generator at a first RF frequency to a coil in electrical communication with the processing region; and A plurality of second RF energy pulses of the two RF generators are delivered at a second RF frequency to a target in electrical communication with the processing region, wherein the plurality of first RF energy pulses and the plurality of second RF energy pulses are synchronized.

SUMMARY OF THE INVENTION The present invention generally provides methods and apparatus for forming a high quality gate dielectric layer on a substrate. Embodiments include a method in which a metal plasma processing process is employed instead of a standard nitridation process to form a high dielectric constant layer on a substrate. Embodiments further include apparatus for "implanting" lower energy metal ions to reduce ion bombardment damage to the gate dielectric layer (such as the cerium oxide layer) and to avoid metal atoms from bonding to the underlying germanium. Embodiments of the invention may be used to form semiconductor components, such as logic or memory components.

Method for fabricating a high dielectric constant transistor gate

Today's component manufacturing process is difficult to manufacture 5-10 The equivalent oxide layer thickness (EOT) and gate dielectric layer with low leakage current. Currently used for 10-16 in the crystal node from 65 nm to 90 nm The EOT is a plasma nitridation process. However, when the nitrided erbium gate dielectric layer becomes thinner (eg 10 ), the gate leakage may increase to the extent that it cannot be actually used for components. In order to solve the gate leakage problem of a thin dielectric layer, the following processes can be utilized to form, for example, hafnium (Hf), hafnium (La), aluminum (Al), titanium (Ti), zirconium (Zr), and antimony (Sr). A deposition process of high-k dielectric oxide or telluride material of lead (Pb), yttrium (Y), or yttrium (Ba) in place of the plasma nitridation process.

The present invention comprises a method of fabricating a gate dielectric layer of a field effect transistor for a gate dielectric layer of about 5-10 A logical type application of the equivalent (electrical) oxide thickness (EOT). The invention also includes a method of fabricating a gate dielectric layer of a field effect transistor for a gate dielectric layer of about 10-30 The equivalent (electrical) oxide thickness (EOT) memory type application. This process can be used to fabricate integrated semiconductor components and circuits.

Method and apparatus for forming a gate oxide layer

In order to solve the problem of common gate performance seen in the 45 nanometer (nm) process and smaller MOS type components, novel processes have been developed to reduce and/or eliminate defects such as Fermi-level pinning. Or critical voltage pinning. In general, the process includes forming a high-k dielectric layer followed by termination of the deposited high-k material surface to form a good interface between the gate electrode and the high-k dielectric material. Embodiments of the present invention also provide a cluster tool for forming a high-k dielectric material, terminating a surface of a high-k dielectric material, performing one or more post-processing steps, and forming a polysilicon and/or a metal gate Floor.

FIG. 2A illustrates a process 251 of an embodiment of the present invention, including a series of steps for fabricating a gate dielectric layer of a field effect transistor in accordance with an embodiment of the present invention. The processing program 251 generally includes a processing step performed on the substrate to form a gate structure of a MOS type element example. The region of the substrate 401 shown in FIGS. 3A-3F is a gate oxide layer and a gate formed by the processing procedure 251 of FIG. 2A. Figures 3A-3F are not drawn to scale and have been simplified. At least a portion of the processing program 251 can be performed using a processing reactor (shown in Figure 7) of an integrated semiconductor substrate processing system (i.e., a cluster tool).

The process 251 begins in step 252 and proceeds to step 268. Step 252 is to provide a bismuth (Si) substrate 401 (eg, a 200 mm wafer, a 300 mm semiconductor wafer) that is exposed to the cleaning solution to remove the native oxide layer 401A on the surface of the substrate (eg, dioxide)矽 (SiO ₂ )) (Fig. 3A). In one embodiment, the removal of the native oxide layer 401A is a cleaning solution using hydrogen fluoride (HF) and deionized (DI) water. In one embodiment, the cleaning fluid is an aqueous solution containing from about 0.1% to about 10% by weight of HF maintained at from about 20 °C to about 30 °C. In one embodiment, the cleaning fluid comprises about 0.5 wt% HF and is maintained at about 25 °C. In step 252, substrate 401 can be immersed in a cleaning solution and then washed with deionized water. Step 252 can be performed in a single substrate processing chamber or a plurality of batch type substrate processing chambers, which can include the delivery of ultrasonic energy during processing. Alternatively, step 252 can be performed on a single substrate wet cleaning reaction chamber in integrated processing system 600 (Fig. 7). In another embodiment, the removal of the native oxide layer 401A may employ an RCA cleaning process. After completion of step 252, the substrate 401 is placed in a vacuum-loaded lock chamber or an environment in which nitrogen (N ₂ ) is introduced. Alternatively, step 252 can be performed on a single substrate wet cleaning reaction chamber in integrated processing system 600 (Fig. 7).

In step 254, a thermal oxide layer (SiO ₂ ) 402 is formed on the surface 401B of the cleaned substrate 401 (Fig. 3B). Thermal oxide layer 402 typically has a thickness of from about 3 angstroms to about 35 angstroms. In the case of a logic type application, the thickness of the thermal oxide layer 402 is from about 6 angstroms to about 15 angstroms; for example, in the memory type application, the thickness of the thermal oxide layer 402 is from about 15 angstroms to about 40 angstroms. Embodiments of the invention may also be applied to the thermal oxide layer 402 having a thickness greater than 35 angstroms. The thermal oxidation step 254 can form a cerium oxide (SiO ₂ ) sub-layer on the interface of the tantalum dielectric layer. Step 254 can improve the quality and reliability of the dielectric material/germanium interface on the deposited dielectric layer (such as the high-k dielectric layer 404 of FIG. 3D), and can also enhance the charge carrier on the channel region below the surface 401B. Mobility. Step 254 can be performed in a rapid thermal processing (RTP) reactor located in one of the substrate processing chambers 614A-614F of integrated processing system 600 (Fig. 7). A suitable RTP chamber is available under the trade name RADIANCE from Applied Materials, Inc. of Santa Clara, California. RTP room. In an embodiment, 6 The cerium oxide (SiO ₂ ) layer was formed on the surface 401B of the substrate 401 by a process of 18 seconds, 750 ° C, 2 Torr, and an oxygen (O ₂ ) flow rate of 2 slm. In this embodiment, oxygen is the reactive gas injected into the processing chamber when the thermal oxide layer 402 is formed; in some cases, an inert carrier gas may be added to the processing chamber to achieve a predetermined chamber pressure. Or in some cases, step 254 may use a reactive gas such as nitric oxide (NO), nitrous oxide (N ₂ O), or a mixed reactive gas such as hydrogen (H ₂ ) / oxygen (O ₂ ), and Nitrous oxide (N ₂ O) / hydrogen (H ₂ ).

In step 257, the thermal oxide layer 402 is exposed to a metal ion-containing plasma for doping a predetermined material into the thermal oxide layer to form a high-k dielectric layer 403. The high-k dielectric layer 403 formed in step 257 may be a hafnium oxide layer doped with hafnium (Hf), hafnium (La) or the like. In one embodiment, the low energy deposition process is performed in a processing chamber similar to that described with reference to Figures 4A-4C and 4F. In one embodiment, transporting the dopant material to the thermal oxide layer 402 is desirably generated by using RF energy delivered to the processing region 522, followed by formation of a cathode bias to the target (eg, symbol 505 of Figure 4A). Or on the symbol 571) of Figure 4B, to sputter material from it. In one aspect, it is also desirable to RF bias, DC bias, or ground the substrate support 562 such that the sputtered and ionized material is implanted within a predetermined depth of the thermal oxide layer 402. In another aspect, it is also desirable to electrically "float" the substrate support 562 and cause a low voltage between the substrate support 562 and the plasma due to self-biasing. The voltage is to reduce the energy of the ionized material striking the thermal oxide layer 402. Various methods of transferring the low energy material to dope the thermal oxide layer 402 will be described below with reference to Figures 4A-4F and 5A-5C. By carefully controlling the chamber pressure, RF power, pulsed DC power, bias applied to the substrate support 562, and/or processing time, the doping amount and concentration corresponding to the dopant material in the thermal oxide layer 402 can be controlled. The relationship of depth. In one embodiment, the plasma may comprise argon ions and metal ions such as ruthenium, osmium, aluminum, titanium, zirconium, hafnium, lead, bismuth and antimony, and may also comprise one or more selective inert gases. Typical inert gases may include helium (Ne), helium (He), helium (Kr), helium (Xe), nitrogen (N ₂ ), and the like. In one embodiment, the thermal oxide layer 402 is doped with about 5-30 atomic percent of hafnium (Hf). It is generally desirable to reduce the dopant concentration of the thermal oxide layer 402 such that the concentration drops to near zero at the interface between the thermal oxide layer 402 and the surface of the germanium channel (e.g., surface 401B) or at least a few angstroms. In one embodiment, when an inductively coupled type of processing chamber (element symbol 500 of Figure 4A) is used, it employs a process of 180 seconds and a chamber pressure of 10 millitorr (mT) (e.g., primarily argon). A cerium (Hf) having an average concentration of 10 atomic % was placed in the thermal oxide layer 402, and the process applied -150 VDC to the target (component symbol 505) and used a 5% duty cycle and "floating" The base is placed to deliver RF energy to the coil (component symbol 509) at a frequency of 13.56 MHz and a power of 50 watts (W). In another embodiment, when a fabrication configuration similar to that of Figure 4G is used, it employs a process of 180 seconds and a chamber pressure of 10 millitorr (e.g., primarily argon) to bring an average concentration of 7 atomic percent of germanium. (Hf) is placed in the thermal oxide layer 402, and the process applies an average of about 100 watts of RF power (ie, an energy cycle of about 5% and a maximum RF power of about 2000 watts) to the target 505 containing germanium, and uses "floating" The pedestal is applied with an average of about 100 watts of RF power (i.e., an energy cycle of about 5% and a maximum RF power of about 2000 watts) to the coil 509 at a frequency of 13.56 MHz. In one embodiment, to avoid damaging the thermal oxide layer 402 during step 257, the average RF power is maintained less than about 1000 watts. In another embodiment, the average RF power used in performing step 257 is less than about 200 watts. In yet another embodiment, the average RF power used in performing step 257 is less than about 50 watts. In one embodiment, step 257 is performed in a low energy plasma processing chamber (such as processing chamber 500 or processing chamber 501) located in one of substrate processing chambers 614A-614F of integrated processing system 600 (Fig. 7) ).

In one embodiment, as shown in FIGS. 2A and 3D, step 256 is performed to deposit a high-k dielectric using a metal organic chemical vapor deposition (MoCVD) process, an atomic layer deposition (ALD) process, or other similar deposition process. The electric layer 404 is applied to the surface 401B of the substrate 401 instead of performing steps 254 and 257 to form the high-k dielectric layer 403 from the thermal oxide layer 402. The high-k dielectric layer 404 may include zirconium oxide (zrO ₂ ), hafnium oxide (Hf _x O _y ), hafnium niobate oxide (Hf _x Si _1-x O _y ), hafnium oxide (La ₂ O ₃ ), and / or alumina (Al ₂ O ₃ ), but not limited to this. Step 256 can be performed on an atomic layer deposition system, such as the Centura ALD High-K system available from Applied Materials. The ALD type reactor may also be located in one of the substrate processing chambers 614A-614F of the integrated processing system 600 (Fig. 7).

In step 259, the surface of high-k dielectric layer 403 or high-k dielectric layer 404 is terminated using a plasma deposition process to form termination region 405. The termination region 405 is typically formed by depositing a layer of material and/or a region doped with a high-k dielectric layer 403 or a high-k dielectric layer 404. Increasing the termination region 405 containing a passive material such as lanthanum oxide (La ₂ O ₃ ) or aluminum oxide (Al ₂ O ₃ ) is believed to render the surface passive and solve the common cost of conventional ALD or MoCVD high-k layers. The meter can be pinned or the critical voltage drift problem. In one embodiment, the high-k dielectric layer 403 or the high-k dielectric layer 404 is doped with about 0.1-10 atomic percent of lanthanum (La) and/or about 0.1-10 atomic percent of aluminum (Al). In another embodiment, the high-k dielectric layer 403 or high-k dielectric layer 404 is doped with about 0.25-5 atomic percent lanthanum (La) and/or about 1-10 atomic percent aluminum (Al). It is desirable to reduce the dopant concentration of the high-k dielectric layer 403 or the high-k dielectric layer 404 such that the concentration extends only to a depth of several angstroms of the high-k dielectric layer 403 or the high-k dielectric layer 404. In one embodiment, the lanthanum (La) dopant is driven into the high-k dielectric layer 403 using the process chamber of Figures 4A-4C below. In one embodiment, a process of 120 seconds and a chamber pressure of 10 millitorr (eg, primarily argon) is used to drive a high concentration of 0.5 atomic percent of lanthanum (La) into a high doping of 10 atomic percent. Within k dielectric layer 403, and the process applies -100 VDC to the target (such as symbol 505 of Figure 4A) and uses a 5% energy cycle and a "floating" pedestal, at a frequency of 13.56 MHz and 50 The power of the watts is used to deliver RF energy to the coil (e.g., symbol 509 of Figure 4A).

In one embodiment, step 259 can be performed in a processing chamber similar to processing chamber 500 or processing chamber 501 of Figures 4A-4C. In this configuration, the termination region 405 is formed by a low energy implantation process similar to the above step 257. In one aspect, the uppermost region of the high-k dielectric layer 403 is transported by the dopant material to generate plasma by using RF energy delivered to the processing region 522, followed by forming a cathode bias to the target 505 to Sputter out the material. The substrate support 562 can be RF biased, DC biased, grounded, or floated to implant the sputtered and ionized material into the high k dielectric layer 403. Various methods of transferring the low energy material to dope the high-k dielectric layer 403 will be described below with reference to Figures 4A-4F and 5A-5C. By carefully controlling the chamber pressure, RF power, pulsed DC bias, random bias applied to the substrate support 562, and/or processing time, the doping amount and concentration can be controlled to correspond to the dopant material in the high-k dielectric. The relationship of depth within layer 403. In one embodiment, the dopant is an aluminum-containing material, a cerium-containing material, or other similar material.

In one embodiment, step 259 can be performed in process chamber 500, which is located in one of substrate processing chambers 614A-614F of integrated processing system 600 (Fig. 7). In one aspect, the processing chamber 500 used to perform step 259 is different from the processing chamber used to perform step 257. In another embodiment, the single processing chamber 500 of the slave integrated processing system 600 is used to perform steps 257 and 259, but each step uses a different target that is placed in the processing region 522 of the processing chamber 500.

According to another embodiment of step 259, termination region 405 is an additional layer of material deposited onto the surface of high-k dielectric layer 403 using a sputtering process. In one aspect, the sputtering process is performed in a processing chamber similar to processing chamber 500 or processing chamber 501 of Figures 4A-4C. In this configuration, the termination region 405 is formed by using the RF energy delivered to the processing region 522 to generate a plasma, followed by forming a cathode bias to the target 505 to sputter material therefrom to deposit the target to a high k. On the dielectric layer 403. The substrate support 562 can be RF biased, grounded, or electrically floating to control the energy and depth of the sputtered and ionized material that will be implanted into the high-k dielectric layer 403. In an embodiment, the deposited layer contains aluminum (Al), lanthanum (La), or other suitable material.

In one embodiment, the optional step 260 employs an oxygenated RF plasma to oxidize the exposed material and convert it to a dielectric material. In one embodiment, the high-k dielectric layer 403, the high-k dielectric layer 404, and/or the termination region 405 are exposed to an oxygen-containing plasma to form aluminum oxide or tantalum oxide. In another embodiment, nitrogen (N ₂₎ of the plasma may also include one or more oxidizing gases, such as oxygen (O _2), nitric oxide (NO), nitrous oxide (N ₂ O). The plasma may also contain one or more selective inert gases such as argon (Ar) and helium (He). Step 260 can be performed, for example, on a decoupled plasma nitriding (DPN) plasma reactor of integrated processing system 600 (Fig. 7). In one embodiment, the thermal oxidation step replaces the plasma oxidation step to oxidize the exposed material and convert it into a dielectric material. In one embodiment, the plasma oxidation step employs a 5% energy cycle with a maximum RF power of 1000 watts (ie, an average power of 50 watts), a frequency of 13.56 MHz for 30 seconds, and a nitrogen flow rate of about 100 sccm. Oxygen at a flow rate of about 100 sccm is used to oxidize the exposed material.

In another embodiment, the optional step 262 is used in place of step 260. In step 262, high-k dielectric layer 403 or high-k dielectric layer 404, and substrate 401 are annealed at about 600 ° C to about 1100 ° C. Annealing at a lower temperature (e.g., an annealing temperature of from about 600 ° C to about 800 ° C) helps prevent crystallization from occurring prior to deposition of the material, such as ruthenium (Si), oxygen (O ₂ ), or both. Step 262 can be performed in a suitable thermal annealing chamber, such as RADIANCE of integrated processing system 600. Reactor or RTP XE ⁺ reactor, or single substrate or batch furnace tube. Step 262 can form a niobic sublayer in the high k dielectric layer 403 or termination region 405. In one embodiment, step 262 can be performed using at least one of about 2-5000 sccm of oxygen (O ₂ ) and about 100-5000 sccm of nitric oxide (NO), or selectively mixed with nitrogen (N ₂ ), and The substrate surface temperature is maintained from about 600 ° C to about 1100 ° C and the process chamber pressure is from about 0.1 to 50 Torr. This process can be performed for about 5-180 seconds. In one embodiment, step 262 is a 15 second, 900 ° C, 1 Torr process using oxygen (O ₂ ) at a flow rate of about 60 sccm and nitrogen (N ₂ ) at a flow rate of about 940 sccm. In another embodiment, the oxygen (O ₂ ) supply is about 200 sccm (eg, an oxygen partial pressure of about 200 mT), the nitrogen (N ₂ ) is about 800 sccm, and the chamber pressure is maintained at about 1000 ° C. The ear is for about 15 seconds. In yet another embodiment, the NO is about 500 sccm and the chamber pressure is maintained at about 0.5 Torr for a period of about 15 seconds at a substrate temperature of about 1000 °C.

In an embodiment, step 260 or step 262 is performed after step 256, step 257, or step 259. According to an embodiment of the procedure 251, an oxidation step similar to step 260 or step 262 can be performed between step 257 and step 259 to re-oxidize the deposition of step 257 prior to deposition of the termination region 405 onto the high-k dielectric layer 403. Admixture material.

In step 264, termination region 405 and high-k dielectric layer 403 or high-k dielectric layer 404 are treated with nitrogen plasma to increase the nitrogen content of these regions. This process may be used DPN reactor and provides about 10-2000 sccm of nitrogen (N _2), a susceptor temperature of about 20-500 deg.] C, and a reaction chamber pressure of about 5-200 mTorr. Radio frequency (RF) plasma supplies energy, for example, at 13.56 MHz or 60 MHz, and up to about 3-5 watts of continuous wave (CW) or pulsed plasma power. When generating pulses, the range of maximum RF power, frequency, and energy cycles is typically about 10-3000 watts, about 10 kHz, and about 2%-100%, respectively. This process can be carried out for about 1 second to about 180 seconds. In one embodiment, the supply of nitrogen (N ₂ ) is about 200 sccm, and the maximum RF power of about 1000 watts is about 10 kHz and about 5% of the energy cycle applied to the inductive plasma source, at a temperature of about 25 ° C. Pulses are generated under conditions such as a pressure of about 10-80 mTorr for a period of about 15 seconds to about 180 seconds. The plasma can be generated using a quasi-remote plasma source, an inductive plasma source, a radial line slotted antenna (RLSA) source, or other plasma source. In another embodiment, a CW and/or pulsed microwave power source can be used to form regions of high nitrogen content.

In step 266, the substrate 401 can be annealed to reduce leakage current between the layers on the substrate 401 and to improve mobility of the charge carriers in the channel region below the surface 401B and to improve reliability of the formed components. Step 266 helps to reduce the number of defects in the film layer formed on the substrate 401. In step 266, the nitride layer formed by the annealing process or passivation step 264 is believed to help promote the formation of an effective barrier layer to block diffusion of boron from the boron-doped polysilicon gate electrode. Step 266 can be performed in a suitable thermal annealing chamber, such as RADIANCE of integrated processing system 600. Reactor or RTP XE ⁺ reactor, or single substrate or batch furnace tube. In an embodiment, the annealing process of step 266 may employ at least one of oxygen (O ₂ ) having a flow rate of about ₂ to 5000 sccm and nitric oxide (NO) having a flow rate of about 100 to 5000 sccm, or may be selectively mixed. Nitrogen (N ₂ ), and maintaining a substrate surface temperature of from about 800 ° C to about 1100 ° C, and a process chamber pressure of from about 0.1 to 50 Torr. This process can be performed for about 5-180 seconds. In one embodiment, the oxygen (O ₂ ) supply is about 500 sccm and the chamber pressure is maintained at about 1000 ° C for about 15 Torr for a period of about 15 seconds. In one embodiment, step 266 uses a process recipe similar to step 262 above.

Once steps 260, 262, 264, or 266 are completed, step 268 is performed to deposit one or more layers of the film onto the formed film layer to form the gate region or gate electrode of the MOS device. According to an embodiment of step 268, a polysilicon layer is deposited into the gate region above the film layer to provide a gate electrode. In one embodiment, the deposition of the polysilicon layer is performed using a conventional polysilicon deposition process. In one embodiment, a polysilicon deposition chamber (not shown) is part of integrated processing system 600. In one embodiment, the polysilicon is deposited over the film layer formed by the process 251 using a CVD or ALD reactor, such as the Centura CVD reactor available from Applied Materials, which includes the substrate of the integrated processing system 600. One of the processing chambers 614A-614F (Fig. 7).

According to another embodiment of step 268, as shown in FIG. 3F, the gate region 408 includes a plurality of conductor layers, such as a thin metal layer 407 and a polysilicon layer 406. In one embodiment, the gate region 408 includes a thin metal layer 407 deposited on the film layer formed by the process 251 to provide a gate material having a higher carrier concentration than conventional polysilicon gate materials. The thickness of the thin metal layer 407 is about 5-200 Preferably less than about 30 . In an embodiment, the thin metal layer 407 comprises a metal such as tantalum (Ta), tantalum nitride (TaN), tantalum carbide (TaC), tungsten (W), tungsten nitride (WN), tantalum nitride (TaSiN). ), hafnium (Hf), aluminum (Al), ruthenium (Ru), cobalt (Co), titanium (Ti), nickel (Ni), titanium aluminum nitride (TiAlN), tantalum nitride (RuN), tantalum nitride (HfN), nickel telluride (NiSi), titanium nitride (TiN), or other suitable materials. The formation of the thin metal layer 407 is preferably by using a processing chamber 500 (Fig. 4A) or a processing chamber 501 (Fig. 4B-4C), which is dependent on the integrated processing system 600 (Fig. 7). In this configuration, the thin metal layer 407 is formed by depositing a target onto the film formed by the process 251, which uses RF energy to generate a plasma and bias the target to sputter metal therefrom, followed by The substrate support 562 (Fig. 4A-4B) is selectively biased to deposit a sputtered and ionized metal material onto the previously formed film layer. The use of RF energy to drive the sputter deposition process is allowing a small amount of material to be reliably deposited on the surface of the substrate. Conversely, conventional physical vapor deposition or sputtering techniques are strictly limited by the fact that the sputtering (DC) voltage required to form a thin metal layer to a low degree of deposition typically does not sustain the sputtering plasma. It does have the ability to deposit small amounts of material. In other embodiments, the thin metal layer 407 can be formed using conventional CVD, PECVD, or ALD processes.

FIG. 2B illustrates another embodiment of the processing program 251. The process 251 of FIG. 2B is the same as the step described in FIG. 2A except that at least one of the two selective steps 258A and/or step 258B is added to either step 257 or step 256 and step 259. In one embodiment, the plasma nitridation step is added to the process 251 for nitriding one of the high-k dielectric layer 403 or the high-k dielectric layer 404 formed by one of the steps 254, 256 or 257. A variety of materials. In one embodiment, it is desirable to form a tantalum nitride-containing film layer using a plasma nitridation process to prevent the germanium material in the high-k dielectric layer 403 or the high-k dielectric layer 404 from undergoing subsequent annealing steps (eg, step 258B). Crystallized in 262 or 266). In one embodiment, step 258A is the process described in step 264.

In one embodiment, a selective thermal annealing step (step 258B) is added to the processing sequence 251 to reduce defects and stresses in the formed high-k dielectric layer 403 or high-k dielectric layer 404, thereby improving formation. The reliability of the component. In one embodiment, step 258B is the process described in step 262 and/or step 264. In one embodiment, step 258B is performed after completion of step 258A above. In one embodiment, step 258B is a 15 second, 900 ° C, 1 Torr process using oxygen (O ₂ ) at a flow rate of about 60 sccm and nitrogen (N ₂ ) at a flow rate of about 940 sccm.

FIG. 2C illustrates still another embodiment of the processing program 251. The processing program 251 of FIG. 2C is the same as the step described in FIG. 2A except that step 253 is added between step 252 and step 254, and step 256 is performed after step 254 is completed. In this embodiment, the plasma nitridation step (step 253) is followed by the removal of the native oxide layer step 252 of the process 251 to nitride the surface of the substrate prior to performing step 254 or 256. The nitrided tantalum substrate surface is believed to contribute to the formation of the desired silicon oxynitride (SiON) layer which remains on or near the surface of the tantalum oxide layer formed by the subsequent thermal oxidation step (step 254). Forming a SiON layer on or near the surface of the ruthenium dioxide layer helps to reduce the diffusion of the gate electrode material (step 268) into the gate dielectric layer during successive processing steps. The sequence of steps 256 and 254 in this embodiment is modified to form a hafnium oxynitride (SiON) interfacial layer prior to the deposition of the high-k dielectric layer step 256, which will help improve the high-k dielectric layer and the component channel. The interface nature of the area. Step 253 can be performed on a DPN reactor available from Applied Materials, Inc. of Santa Clara, California. In one embodiment, step 253 is 10 seconds, 70 mTorr of process, using 25 watts average RF power (5% of the rate of energy cycle with 500 watts maximum RF power), 200 sccm of nitrogen (N ₂₎ Airflow and substrate temperature of about 25 °C. And in accordance with an embodiment of the processing program 251, step 254 is modified to ensure that the nitrided tantalum surface obtained in step 253 still retains predetermined properties. In this case, the reaction is also desirable to inject other gases performing step 254 (e.g. nitrogen (N ₂₎₎ and oxygen gas to the chamber, to ensure a high-quality dielectric layer. In one embodiment, the yttrium oxynitride (SiON) layer is formed on the surface 401B by a process of 30 seconds, 1050 ° C, and 5 Torr (ie, a partial pressure of oxygen of about 15 mT) using oxygen at a flow rate of about 15 sccm. (O ₂ ) with a flow rate of about 5 slm of nitrogen (N ₂ ), followed by a flow rate adjustment of 0.5 slm of oxygen (O ₂ ) and about 4.5 slm of nitrogen (N ₂ ) for 15 seconds.

FIG. 2D illustrates still another embodiment of the processing program 251. The processing program 251 of Fig. 2D is the same as the step described in Fig. 2A except that the two selective step 255A or step 255B is added between step 254 and step 257. In one embodiment, the selective plasma nitridation step (step 255A) is added between step 254 and step 257 to nitride the upper surface of the thermal oxide layer formed in step 254 to form a SiON layer. The SiON layer acts as a diffusion barrier to prevent the gate electrode material from diffusing into the gate dielectric. In one embodiment, in step 255A is 30 seconds, 10 mTorr of process, using 50 watts average RF power (5% of the rate of energy cycle and 1000 watts maximum RF power), 200 sccm of nitrogen (N ₂₎ And a substrate temperature of about 25 °C.

Referring to FIG. 2D, in an embodiment, a selective thermal annealing step (step 255B) is added to the processing sequence 251 to reduce defects and stresses in the formed high-k dielectric layer 403, thereby improving component formation. Reliability. In an embodiment, the annealing step 255B may employ at least one of oxygen (O ₂ ) having a flow rate of about 15 sccm and nitrogen (N ₂ ) of about 500 sccm, and maintaining the surface temperature of the substrate at about 1050 ° C, the processing chamber. The pressure is about 1-5 Torr. In another embodiment, step 255B is a process as described in step 262 and/or step 266. In an embodiment, step 255B is performed after completion of step 255A above.

FIG. 2E illustrates another embodiment of the processing program 251. Process 251 of Figure 2E is the same as that described in Figure 2A, except that step 254 is removed and step 252 is modified to wet cleaning step 252A to form an yttria-containing interface layer. In this embodiment, the new step 252A utilizes a wet cleaning process to clean and intentionally form an oxide layer on the substrate surface 401B. The new step 252A may be performed in Emersion ^TM reactor taken from the Santa Clara, California, Applied Materials. In one embodiment, step 252A forms an oxide layer of 4-5 angstroms by immersing the substrate in a dilute hydrofluoric acid (HF) bath for 8 minutes, followed by washing the substrate and immersing the substrate at 50 °C. A standard wash (SC1) bath (eg less than 5 vol.% ammonium hydroxide (NH ₄ OH) / less than 3 vol.% hydrogen peroxide (H ₂ O ₂ ) / measured deionized water) for 6 minutes, then The substrate is washed in a megasonic starter tank (ie, 1500 watts) containing deionized water for a period of time. In another embodiment, the oxide layer is formed using ozone-containing (O ₃₎ of the washing liquid formed by wet cleaning process.

FIG. 2F illustrates still another embodiment of the processing program 251. The processing program 251 of Fig. 2F is the same as the step described in Fig. 2A except that step 256 is performed after completion of step 254. In this embodiment, the order of steps 256 and 254 is modified to form a thin layer of cerium oxide (SiO ₂ ) (eg, less than 10) prior to depositing the high-k dielectric layer step 256. ). In one embodiment, the thin high-k dielectric layer 404 is deposited on the thermal oxide layer 402 grown in step 254 using an ALD type deposition process. The reason why this structure is useful is that the thin layer of ruthenium dioxide formed in step 254 provides good dielectric layer/channel region interface properties at the junction of the dielectric layer and the component channel region, while providing the desired intervening of the completed stack structure. Electrical properties.

Design aspect of hardware equipment

As described above, the method of forming the high-k dielectric layer is desirably using a plasma process in combination with the above steps 257 and 259. A plasma processing process using a high plasma potential (e.g., tens of volts) may damage the thin gate dielectric layer and even bond the bombarded metal atoms to the channel region underneath the formed MOS device. Destruction of a dielectric layer (such as a ruthenium dioxide layer) or the incorporation of metal atoms into the underlying regions is undesirable because it reduces component performance and increases leakage current. The various embodiments described below can utilize a plasma processing process to actually form a gate dielectric layer. Examples of equipment that can be used to perform such a metal plasma processing process will be described below in conjunction with Figures 4A-4C and 4F.

Inductively coupled plasma processing chamber

4A depicts a cross section of one embodiment of a plasma processing chamber 500 that can be used to perform step 257 and/or step 259 above. In this configuration, the processing chamber 500 is an inductively coupled plasma processing chamber that can process a substrate 502, such as a substrate 401 (Fig. 3A), located in the processing region 522. In one embodiment, process chamber 500 is a modified decoupled plasma nitriding (DPN) chamber available from Applied Materials, Inc. of Santa Clara, California, USA, and using an inductively coupled RF source.

Processing chamber 500 generally includes an inductive RF source assembly 591, a DC source assembly 592, a target 505, a system controller 602, a process chamber assembly 593, and a substrate support assembly 594. The process chamber assembly 593 generally includes an assembly that can form a vacuum in the processing region 522, allowing the plasma process to proceed there. The process chamber assembly 593 generally includes a chamber bottom 527, a chamber wall 528, and a chamber cover 529 that sealingly surrounds the treatment region 522. The treatment zone 522 can be evacuated to a predetermined vacuum pressure using a vacuum pump 510 that is coupled to the treatment zone 522 via the chamber bottom 527 and/or the chamber wall 528. In general, chamber wall 528 and chamber bottom 527 may be constructed of metal, such as aluminum or other suitable material. In one embodiment, the chamber wall 528 has a removable chamber shield (not shown) to prevent the sputter material from the target 505 from falling on the chamber wall 528.

The inductive RF source assembly 591 generally includes an RF generator 508 and an RF matcher 508A that is coupled to a coil 509 adjacent the chamber cover 529. In an embodiment, RF generator 508 can operate from about 0 to 3000 watts at a frequency of from about 400 kHz to about 20 MHz. In an embodiment, the RF generator 508 operates at a frequency of 13.56 MHz. The chamber cover 529 is typically a dielectric component (e.g., quartz, ceramic material) for causing RF energy of the inductive RF source assembly 591 to form a plasma in the processing region 522. In one embodiment, the coil 509 is located adjacent the target 505 such that when sputtering is performed, the plasma generated in the processing region 522 will be formed adjacent the active surface of the target. Controlling the plasma near the activated surface helps control the plasma density near the target area where the low energy sputter deposition process is sputtered. Since the plasma is generated by the coil 509, this configuration also facilitates the reduction of improper plasma bombardment of the ultra-thin gate dielectric layer.

In an embodiment, the chamber cover 529 is modified such that a vacuum-sealed electrical feed-through 504 contacts the target 505 located in the processing region 522. In this configuration, the coaxial cable 506 is connected to the vacuum-sealed electrical feedthrough 504 to deliver energy from the DC power supply 507, causing ions generated by the plasma to sputter the target 505 material onto the substrate 502. In one aspect, the system controller 602 described below in conjunction with Figures 5A-5C is used to synchronize the output of the RF generator 508 with the DC power delivered from the DC source assembly 592. In an embodiment, the target 505 may be composed of a single material or alloy containing elements selected from the group consisting of hafnium (Hf), lanthanum (La), aluminum (Al), titanium (Ti), zirconium (Zr), and yttrium ( A group consisting of Sr), lead (Pb), yttrium (Y), or yttrium (Ba).

In one aspect, the process chamber assembly 593 also includes a gas delivery system 550 for delivering one or more process gases to the processing region 522 formed by the chamber bottom 527, the chamber wall 528, and the chamber cover 529. The pressure of the treatment zone 522 can be controlled by the system controller 602 for adjusting the flow of gas delivered by the gas delivery system 550 and the pumping speed of the vacuum pump 510, while the pump 510 is regulated by the throttle valve 511. In one aspect, the chamber pressure of the process is from about 5 mTorr to about 100 mTorr.

The substrate support assembly 594 generally includes a substrate support 562 that includes a substrate support member 562A. The substrate support member 562A may be a conventional electrostatic chuck that actively holds the treated substrate, or simply a substrate support. The temperature controller 561 is generally used to heat and/or cool the substrate support member 562A to a predetermined temperature, and the predetermined temperature is set by the temperature controller 561 by conventional means, such as embedding the impedance heating element or coupling to the heat exchange. Fluid cooling channel (not shown). In one aspect, the temperature controller 561 is adapted to operate and heat the substrate 502 placed on the substrate support member 562A to a temperature of between about 20 ° C and about 800 ° C. The substrate support 562 can be coupled to the RF generator 523 as the process proceeds such that RF bias can be applied to portions of the substrate support 562 to drag plasma ions generated in the processing region 522 to the substrate 502. s surface. In one embodiment, the substrate support member 562A is grounded, DC biased, or electrically floated during the plasma process to reduce ion bombardment damage to the substrate 502.

Transferring the RF energy of the RF generator 508 to the processing region 522 will cause ionization of the gas atoms in the processing region. The ionized gas atoms in the plasma are then attracted to the target 505 by the cathode bias applied by the DC source component 592 to the target 505, whereby the material can be sputtered from the target 505 and land on the surface of the substrate 502. In order to reduce the mutual interference and interaction of the RF energy delivered by the inductive RF source component 591 with the DC bias applied by the DC source component 592, it is generally desirable to synchronize the energy pulses delivered from the DC source component 592 and the RF source component 591 to minimize mutual interference. And at the same time maximize deposition rate, film uniformity and film quality. By generating and maintaining a low electron temperature and low ion energy plasma to generate an induced RF source pulse to excite the plasma, the problems associated with high plasma potential disrupting the surface of the substrate can be mitigated. In general, pulsed RF inductive plasma produces ions of low ion energy (eg, less than 10 electron volts (eV)) and therefore does not destroy the substrate located within the plasma. This is more fully described in U.S. Patent No. 6,831,021, filed on June 12, 2003, which is incorporated herein by reference. Theoretical calculations (see Figure 4D) allude to the low ion energy of most inert gases such as argon (Ar), helium (Ne), helium (He), helium (Kr) or helium (Xe). Sufficient energy from the pulsed RF source will not be available to sputter the target atoms, where the target composition is hafnium (Hf), lanthanum (La), or other heavy metals or dielectric materials. For example, in the case of argon plasma, the critical sputtering energy of the Hf and La targets is 42.3 eV and 25.5 eV, respectively, and the safe ion energy of the ion implantation gate oxide layer is usually less than 10 eV. Thus, in the case of RF inductive plasma, the ion energy that is low enough to form the gate dielectric layer is not sufficient to sputter the desired metal off the target from the target. Therefore, a DC source component 592 is required to apply a DC bias to the target for the sputtering process. Various aspects of the pulse deposition process will be described below in conjunction with Figures 5A-5C.

Capacitively coupled plasma processing chamber

4B-4C depicts a cross section of another embodiment of a plasma processing chamber that can be used to perform step 257 and/or step 259 above. In this configuration, the processing chamber 501 is a capacitively coupled plasma processing chamber that can process the substrate 502 located in the processing region 522. Processing chamber 501 typically includes an ultra high frequency (VHF) source assembly 595, a target assembly 573, a system controller 602, a process chamber assembly 596, and a substrate support assembly 594. In this configuration, the capacitively coupled plasma is formed into a processing region 522 between the target 571 and the grounded chamber wall 528 of the processing chamber assembly 596 using a VHF source assembly 595 coupled to the target 571. The process chamber assembly 596 generally includes all of the components of Figure 4A above, except that the chamber cover 529 is replaced by a target assembly 573 that is intimately coupled to the chamber wall 528 and an electrical insulator 572. The components of the process chamber assembly 596 and the substrate support assembly 594 are the same as or similar to the components of the process chamber 500 described above, and thus the same reference numerals will be used and will not be described again.

Referring to FIG. 4B, in one embodiment, VHF source component 595 includes an RF source 524 and a matcher 524A for transmitting RF energy to processing region 522 through one or more components of target component 573. Target assembly 573 generally includes a backing plate assembly 570 and a target 571. The backplane assembly 570 can include a fluid passage (not shown) for cooling the target with a fluid transported by a heat exchanger (not shown) during processing, and including a magnetron assembly (not shown). To promote the full use of the target and improve the uniformity of deposition.

When the processing chamber 501 is in operation, the VHF source assembly 595 is used to bias the target 571 to deposit material atoms of the target 571 on the surface of the substrate 502. In one embodiment, the RF source 524 of the VHF source component 595 transmits power to the processing region 522 through the target component 573 at an RF frequency of about 1-200 MHz and a power of about 0.01-5 kW. In one embodiment, the VHF source component 595 is used on the capacitively coupled target 571 due to the pressure drop across the plasma sheath causing ions generated by the plasma to sputter material out of the surface of the target 571. Self-biasing is generated to provide sufficient energy. Because of the difference in surface area between the anode and the cathode (e.g., target 571), the capacitively coupled electrode or target 571 biased with the VHF source will typically reach a self-bias voltage. The self-bias voltage achieved by the target 571 during processing can be adjusted to optimize the sputtering rate of the target 571. Figure 4E is a plot of the self-bias voltage (V _DC ) versus frequency. This figure generally shows the effect of the frequency on the self-bias voltage of the electrode when biased at a higher and higher frequency. It will be noted that the self-bias voltage decreases as the frequency increases, so the ion energy of the impact target can be reduced by increasing the frequency of the VHF source component 595. For example, at a pressure of 50 mTorr and using argon and 300 watts of RF power, the target biased with an RF signal at a frequency of 27 MHz will have a bias voltage of about -200 V, with a 100 MHz RF signal. The biased target will only have a voltage of about 10V. In another embodiment, using a fixed RF power of about 400 watts to change the RF frequency to about 60-100 MHz, the DC bias on the target can be varied from about -50 volts to about -20 volts.

Transmitting energy to the target 571 at an RF frequency in the VHF range may improve the process results of step 257 and/or step 259, which is superior to the process results at lower RF frequencies due to the target The DC bias change becomes smaller, and the DC bias is a function of the frequency variation and the RF power variation delivered to the target 571. Reducing the variation in DC bias is important for low energy sputtering processes. Thus, by controlling the frequency and power of the RF energy, such as delivering power to the target 571 at a predetermined energy rate period (described below), the DC bias on the target can be controlled correctly and repeatedly. Precise control of the DC bias ensures that the process of doping the ultrathin gate dielectric layer is performed correctly and repeatedly.

Referring to Figure 4D, in one embodiment, if the sputtering gas is primarily argon (Ar) and the target is composed of lanthanum (La), the energy required to sputter the ruthenium atoms on the surface of the target is at least 25.5 eV. That is, the self-bias voltage formed on the target needs to be high enough to generate an ion energy of about 25.5 eV to ensure that some of the germanium atoms will be sputtered from the target surface. Thus, by controlling the frequency and power (e.g., watts) delivered to target 571, the sputtering rate, the ion energy of the gas atoms, the ion energy of the sputtered atoms, and the atomic energy deposited on the substrate can be controlled. And during the process, the bias on the substrate support 562 can be adjusted to further control the energy of the sputtered atoms deposited on the gate dielectric layer or implanted in the gate dielectric layer.

The sputtering process is generally carried out in the processing chamber 501 under conditions of a chamber pressure of about 1-100 mTorr, an argon flow rate of about 1-500 sccm, and a heater temperature of about 20 ° C to about 800 ° C. Preferably, the substrate temperature is from about 200 ° C to about 300 ° C. The excitation frequency of the RF source 524 can be adjusted from about 1 MHz to about 200 MHz to obtain the correct self-biased DC voltage to cause the target to be sputtered into the plasma and onto the surface of the substrate. Preferably, the excitation frequency of the RF source 524 can be adjusted to between about 27 MHz and about 100 MHz; more preferably, the frequency can be adjusted to between about 30 MHz and about 60 MHz. In one embodiment, taking the target as an example, a frequency of 60 MHz can be used to supply the desired sputtering energy and maintain a low energy plasma. In one embodiment, it is desirable to vary the distance between the surface of substrate 502 and the surface of target 571 to adjust the uniformity and energy of the sputtered atoms deposited on the surface of the substrate. In one aspect, it is desirable to vary the spacing of the substrate 502 relative to the surface of the target 571 during deposition to adjust the depth and/or deposition uniformity of the sputter material within the gate oxide layer.

Figure 4C depicts a second embodiment of a processing chamber 501 in which the VHF source assembly 595 of Figure 4B is replaced by a dual VHF source assembly 597 having two RF sources 524, 525, respectively, at different frequencies. And/or power to transfer energy to the processing region 522 of the processing chamber 501 to provide different sputtering properties for different processing times. The processing chamber 501 of FIG. 4C generally includes an RF source 524, a second RF source 525, an RF switch 526, and a matcher 524A coupled to the target assembly 573. In this configuration, the energy transferred from the dual VHF source component 597 to the target component 573 can be switched between the RF source 524 and the second RF source 525 by the RF switch 526. The state of the switch 526 is controlled by the system controller 602. This embodiment can be used for targets that require rapid initial modulation to remove oxides that may form on the target surface when initially installed or after long periods of inactivity. The ability to switch to a lower frequency source (e.g., about 27 MHz or less) can form a high self-biased DC voltage on target 571, resulting in a faster target sputtering rate. Therefore, after the initial processing, the output of the dual VHF source component 597 can be changed by switching to a higher frequency source (for example, 60 MHz) to slow down the sputtering rate and reduce the ion energy of the sputtered atoms, thereby reducing the potential breakdown substrate. A gate dielectric layer on the surface. In one embodiment, RF source 524 can transmit RF energy at a power of about 0-2000 watts at a frequency of about 27 MHz, while second RF source 525 can transmit about 0-500 watts at a frequency of about 40-200 MHz. The RF energy of the power.

In one embodiment, DC source component 592 is selectively coupled to target component 573 to deliver one or more pulses of DC energy in a plasma processing step. The DC bias can be superimposed on the VHF signal delivered by the VHF source components (e.g., component symbols 595 and 597). The DC voltage applied to target 571 can be used to more directly control the energy of the gas atoms that are ionized to strike target 571 during the sputtering process.

In one embodiment, as described above, the substrate support 562 can be coupled to the RF generator 523 during processing, with RF or VHF bias applied to a portion of the substrate support 562 to ionize the plasma. Drag onto the surface of the substrate 502. In one embodiment, the substrate support member 562A is grounded, DC biased, or electrically floated during the plasma process to minimize ion bombardment damage to the substrate 502.

Pulsed plasma treatment process

5A-5C are schematic views of various pulsed plasma processes, which may be deposited in the above step 257 and/or step 259 to deposit the target 505 of FIG. 4A or the target 571 of the 4B and 4C drawings. The material is to the surface of the substrate 502. The pulsed plasma process of Figures 5A-5C is typically a series of continuous energy pulses and DC energy pulses, wherein the continuous energy pulses utilize an inductive RF source component 591 or a VHF source component (i.e., VHF source component 595 or dual VHF source component 597). Delivery to processing region 522 is a function of time, while DC energy pulses are delivered from DC source assembly 592 to the target. FIG. 5A is a diagram showing the RF energy 531 delivered by the inductive RF source component 591 or the VHF source component and the DC voltage 535 delivered by the DC source component 592 as a function of time. FIG. 5A is a diagram showing the RF energy 531 delivered by the inductive RF source component 591 or the VHF source component 595 and the DC voltage 535 delivered to the target as a function of time. In this manner, the DC of one embodiment is illustrated. And RF or VHF (hereinafter referred to as RF/VHF) pulses are synchronized. In this embodiment, the pulses of RF energy 531 and DC voltage 535 are synchronized so that they are not applied simultaneously. The DC pulse 532 typically provides a brief attraction to attract RF/VHF excitation ions in the plasma, allowing the ions to have sufficient energy to accelerate toward the target 505 to sputter the target into the plasma. The sputter material that excites the target surface enters the plasma in the processing region 522 during the generation of the RF/VHF pulse 533, where it can then be ionized. Depending on whether the substrate support member 562A is biased, grounded or floated by RF/VHF, the ionized sputtered atoms can be delivered to the surface of the substrate by the energy set by the plasma sheath produced near the surface of the substrate. In most cases, when a low energy bias is used to deliver a DC voltage pulse (or DC current pulse) to ensure that a predetermined ion density and sputtering rate are achieved, it is desirable to synchronize the RF/VHF pulse 533 end. Sufficient plasma is produced in the processing chamber.

With continued reference to Figure 5A, it is generally desirable to use an inductively coupled plasma chamber design to generate ions during RF/VHF pulse 533 (RF/VHF pulse 533 does not have sufficient energy to sputter target atoms), thus sputtering atoms The energy is more easily controlled by the DC bias applied to the target. In some instances, it is desirable to use RF/VHF pulses to ionize the sputtered target atoms to accelerate and implant the target atoms at low energy using a low potential bias applied to the susceptor on which the substrate is placed. To the surface of the substrate. In one aspect, the DC voltage pulse (or DC current pulse) applied to the target is synchronized with the pulsed RF/VHF off-cycle, making the energy generated by the ions in the plasma easier to use. The application of DC energy to reduce the net increase in plasma energy is controlled. The magnitude of the voltage of the DC pulse provides sufficient energy for the argon ions to sputter the target to the plasma during the doping process.

It should be noted that system controller 602 can be used to synchronize RF/VHF pulse 533 with DC pulse 532 and energy cycle to achieve a desired plasma density, sputter deposition rate, and plasma ion energy. Referring to Figure 5A, the energy cycle represented by the "on" time (t ₁ ) divided by the overall pulse time (t ₃ ) of the RF energy 531 can be optimized to ensure a plasma system having a predetermined average density. Controlled. Note that still need to "start (ON)" time (t ₄₎ divided by the DC voltage 535 of the overall pulse time (t ₆₎ can be represented by the cycle rate may be optimized to ensure a predetermined average deposition rate.

Referring to Figures 4B-4C and 5A-5C, in one embodiment, VHF source component 595 is set to a pulse mode having a pulse frequency of 1 Hz to 50 kHz and an energy period of 0.1% to 99%. In this embodiment, a pulsed VHF source is used to generate and maintain the plasma formed in the processing region 522 and to reduce the average plasma density and ion energy. System controller 602 can be used to adjust the energy cycle, pulse frequency, RF energy (ie, RF power) magnitude, and RF energy frequency to control the energy of the plasma, ions, and sputter materials. In one embodiment, to deliver a low energy sputtered material to the surface of the substrate, system controller 602 can deliver RF energy to coil 509 (Fig. 4A) at an energy cycle of about 1% to 50%. Or in one embodiment, the low energy sputtered material can be delivered to the surface of the substrate by delivering RF energy to target 571 (Fig. 4B) at an energy cycle of between about 1% and 50%. In some examples, it is desirable to maintain an energy rate period of about 1%-10% delivered to coil 509 (Fig. 4A) or target 571 (Fig. 4B) to minimize energy delivered to the plasma ions.

FIG. 5B illustrates another embodiment of a pulsed plasma process in which DC pulse 532 is pulsed RF energy 531 delivered by an inductive RF source component 591 or a VHF source component (ie, VHF source component 595 or dual VHF source component 597). Delivered during at least part of the period. In yet another embodiment, as shown in FIG. 5C, RF energy 531 at a time t ₁ remains unchanged, when the RF energy is "start (on)", DC voltage pulses delivered to the 535-based target 505 . It should be noted that it is preferred to reduce the magnitude of the RF energy 531 during the DC pulse 532 to reduce any possible mutual interference between the transmitted signals. In one embodiment, it is desirable to use RF generator 523 (FIG. 4A) to bias substrate support 562 to generate attracting ions during different RF/VHF plasma generation phases and/or pulsed DC sputtering periods. The bias on the substrate.

In another embodiment, it is desirable to generate RF/VHF energy pulses such that ions generated in the plasma will not have sufficient energy to sputter the target. In this case, a DC bias is applied to the target to promote sputtering of the target.

In one embodiment, a pulsed RF/VHF signal is applied to the substrate support 562 to create and maintain a plasma throughout the surface of the substrate. Thus, in one embodiment, the synchronized DC pulses are delivered to the target 571, and the synchronized VHF pulses are delivered to the substrate support 562 to sputter the target into the plasma and dope to the gate dielectric layer. Inside.

Grounded collimator (Collimator) aids design

FIG. 4F is a cross-sectional view showing another embodiment of the plasma processing chamber 500, which can be used for metal plasma processing of the gate dielectric layer, that is, performing a low energy sputtering process to form a doped gate dielectric layer. . In this embodiment, a grounded collimator 540 is disposed between the substrate 502 and the target 505 to extract charged metal ions. The grounded collimator 540 promotes substantially neutral sputtering atoms to the substrate 502 to form a thin layer of metal on the surface of the substrate 502 (possibly as thin as a single layer). The collimator is typically a ground plane or patch net containing a plurality of holes 540A throughout the ground plate such that neutral atoms (and perhaps some ions) are transferred from the processing region near the target to the surface of the substrate. Since the energy of a neutral atom usually accounts for only a small fraction of the energy required to sputter the atoms on the surface of the target and the neutral atom does not affect the plasma potential, the method is used to deposit this layer to the surface of the gate dielectric layer. It will only cause a slight ion bombardment damage. The metal layer can then be combined with a subsequently formed oxide layer to form a high dielectric constant (high-k) dielectric layer without metal or nitrogen ion implantation and related problems such as destruction of the germanium layer and metal over penetration of the substrate. The next layer of enamel. It will be understood by those skilled in the art that the processing chamber 501 of FIGS. 4B and 4C can also be provided with a grounded collimator 540 between the target 571 and the surface of the substrate 502 to have the same function and can be used for charged particles. The surface of the material is used to extract a large amount of charged particles in the plasma to reduce the damage to the gate dielectric layer.

Another design of the processing room

FIG. 4G is a cross-sectional view showing another embodiment of the plasma processing chamber 500, which can be used for metal plasma processing of the gate dielectric layer, that is, performing a low energy sputtering process to form a doped gate dielectric layer. . According to one embodiment of the processing chamber 500, the output of the inductive RF source assembly 591 is coupled to the target 505 such that the coil 509 and the capacitive coupling target 505 can be utilized to generate plasma in the processing region 522. In one embodiment, target 505 is coupled to the output of RF matcher 508A via coil 508B, and when generator 508 delivers power via RF match 508A, coil 508B is resized to achieve resonance. Referring to FIG. 4A, the RF bias applied to target 505 can cause coil 509 to generate and form a plasma, and the RF frequency and RF power delivered to target 505 can control the DC bias and the ion energy of impact target 505. In addition, an inductively coupled plasma generating component and a capacitively coupled plasma generating component that generate pulses at a predetermined energy rate cycle can more easily control DC bias (ie, self-biasing), sputtering rate, and sputtering applied to the target. The ion energy. By carefully controlling the chamber pressure, RF frequency, RF power, energy cycle, bias applied to the substrate support 562, and/or processing time, the amount and concentration of the sputter material can be controlled to correspond to the sputter material in the dielectric layer. The relationship between depths. The use of a single RF generator 508 and RF matcher 508A can also reduce reaction chamber cost and system complexity. In one embodiment, DC source component 592 is coupled to target 505 such that DC pulses can be delivered to target 505 during or between RF pulses generated by RF generator 508.

In another embodiment, as shown in FIG. 4H, it is desirable to have individual RF generators 565 and RF matchers 565A to supply target 505 RF energy, and coils 509 are individually used by RF generator 508 and RF matcher 508A. Is biased by RF. In this configuration, system controller 602 can be utilized to individually control the components of new RF matcher 565A and RF generator 565 and sense RF source component 591. In one aspect, the DC source component 592 is also coupled to the target 505, such that during the component of the inductive RF source component 591 and/or the RF generator 565 to deliver RF pulses or between RF pulses, the DC pulse can be Delivery to target 505.

Plasma processing system

One or more plasma processing chambers (such as the processing chambers of Figures 4A-4C and 4F above) are preferably integrated into a plurality of reaction chambers, a plurality of process substrate processing platforms (e.g., integrated processing system 600 of Figure 7). ). Examples of integrated processing systems that are beneficial to the present invention are described in U.S. Patent No. 5,882,165, filed on March 16, 1999, U.S. Patent No. 5,186,718, filed on February 16, 1993. And the US Patent No. 6,440,261 and the application date of August 27, 2002, which are attached for reference. The integrated processing system 600 can include a working interface 604, load ports 605A-605D, a system controller 602, vacuum load lock chambers 606A, 606B, a transfer chamber 610, and a plurality of substrate processing chambers 614A-614F. The one or more substrate processing chambers 614A-614F can be plasma processing chambers, such as the processing chamber 500 of Figures 2-5 above and/or one or more processing chambers 501 for performing a plasma process. In other embodiments, integrated processing system 600 can include more than six processing chambers.

In accordance with an aspect of the present invention, integrated processing system 600 generally includes a plurality of reaction chambers and robotic arms, and is preferably provided with a system controller 602 that is programmed to control and perform various processing methods and procedures in integrated processing system 600. in. The system controller 602 is generally used to assist in the control and automation of the entire system, and generally includes a central processing unit (CPU) (not shown), a memory (not shown), and a support circuit (or input/output (I/). O)) (not shown). The CPU can be any type of computer processor used in industrial devices to control various system functions, reaction chamber processes and supporting hardware (such as detectors, robot arms, motors, gas source equipment, etc.), and to monitor systems and reactions. Chamber process (such as reaction chamber temperature, processing capacity, reaction chamber processing time, I/O signals, etc.). The robotic arm 613 is positioned in the center of the transfer chamber 610 to transfer the substrate from the load lock chamber 606A or 606B to one of the process chambers 614A-614F. The robot arm 613 generally includes a blade assembly 613A coupled to the robot arm drive assembly 613C, and a robot arm assembly 613B. The robot arm 613 transfers the substrate "W" to each of the processing chambers in accordance with an instruction sent by the system controller 602. A robotic arm assembly useful in the present invention is described in U.S. Patent No. 5,469,035, entitled "Two-axis Magnetically Coupled Robot", and application dated August 30, 1994; U.S. Patent No. 5,447,409, entitled "Robot Assembly", application dated April 11, 1994; and U.S. Patent No. 6,379,095, entitled "Robot For Moving Semiconductor Substrate" (Robot For Handling Semiconductor Substrates), the application date is April 14, 2000, and is attached for reference. A plurality of slit valves (not shown) can be used to selectively separate the processing chambers 614A-614F from the transfer chamber 610 so that each of the reaction chambers can be individually vacuumed for vacuum processing during the processing.

A significant benefit of integrating the plasma chamber into the integrated processing system 600 is that a series of process steps can be performed on the substrate without contact with air. This allows the step of depositing the sputtered atoms, for example, in the above Figures 2-5, onto the surface of the substrate without oxidizing the as-deposited ultra-thin metal layer. Integrating multiple processing chambers into the integrated processing system 600 containing the processing chamber in which the annealing step can be performed also avoids the out-of-control oxidation of the as-deposited material prior to the stable annealing process. The integrated system does not expose the substrate to an oxygen source environment that is unique to the non-integrated process, thereby preventing oxidation of materials (eg, dopant materials) within the high-k dielectric layer 403 or high-k dielectric layer 404. Contaminants seen in non-integrated processes directly affect the reproducibility of the component process and the average performance of the component.

According to one embodiment of integrated processing system 600, substrate processing chamber 614A or a reaction chamber coupled to working interface 604 can be used to perform the RCA cleaning step as described above in step 252. Subsequent to the removal of the native oxide layer 401A (see FIG. 3A), a conventional rapid thermal oxidation (RTO) process, plasma assisted chemical vapor deposition (PECVD), or ALD can be performed in the process chamber 614B to form a dielectric layer. (such as thermal oxide layer 402, high-k dielectric layer 404) on the substrate. The substrate processing chambers 614C and 614D are plasma processing chambers similar to the processing chamber 500 and/or the processing chamber 501 described above for performing steps 257 and 259. Thus, the plasma process can process the substrate in processing chambers 614C and 614D and maintain the substrate in a vacuum environment while avoiding the native oxide layer re-growing the various layers on the substrate. This is especially important when the exposed film layer contains highly oxophilic materials such as ruthenium. In one aspect, step 260 is sequentially applied to the substrate in substrate processing chamber 614E to oxidize the metal surface formed in substrate processing chamber 614D. In another aspect, step 262 can be performed in an RTP chamber located in substrate processing chamber 614E. Next, a plasma nitridation process (step 264) (e.g., a DPN process available from Applied Materials, Inc.) can be performed in the substrate processing chamber 614F. In yet another aspect, step 266 can be performed in an RTP chamber located in substrate processing chamber 614E or substrate processing chamber 614F, if any.

In another embodiment, step 252 (ie, removing the native oxide layer step) and step 254 (ie, depositing the thermal oxide layer step) can be performed in different systems. In this embodiment, substrate processing chambers 614A and 614B can be plasma processing chambers similar to processing chamber 500 and/or processing chamber 501 for performing steps 257 and 259. In one aspect, step 260 is sequentially applied to the substrate in substrate processing chamber 614C to oxidize the metal surface formed in substrate processing chamber 614B. Or in another aspect, step 262 can be performed in RTP processing chamber 614C. Next, a plasma nitridation process (step 264) (e.g., a DPN process available from Applied Materials, Inc.) can be performed in a processing chamber located in substrate processing chamber 614D. In one aspect, step 266 can be performed in RTP processing chamber 614E or substrate processing chamber 614C, if any. In one aspect, after step 260 is completed in substrate processing chamber 614C, the surface nitridation step can be performed on substrate processing chamber 614D without removing the substrate from the vacuum environment to contact the air.

Another method of forming a gate oxide layer

6A is a flow diagram of a method 100 of fabricating a gate dielectric layer of a field effect transistor in accordance with an embodiment of the present invention. The method 100 includes a series of steps performed on a substrate during the fabrication of a gate structure of a complementary metal oxide half (CMOS) field effect transistor paradigm. FIG. 6A illustrates the complete procedure of method 100. At least a portion of the method 100 can be practiced in a process reactor of an integrated semiconductor substrate processing system (ie, a cluster tool). An example of such a processing system is CENTURA obtained from Applied Materials, Inc., Santa Clara, California, USA. Integrated processing system.

Figure 6B-6G is a series of cross-sectional views of the substrate on which the gate structure is fabricated using the method of Figure 6A. The sections of Figures 6B-6G correspond to the individual process steps of fabricating the gate dielectric layer of a larger gate structure (not shown) in the transistor, respectively. Figures 6B-6G are not drawn to scale and have been simplified.

The method 100 begins at step 102 and proceeds to step 118. Referring first to Figures 6A and 6B, in step 104, a bismuth (Si) substrate 200 (e.g., a 200 mm wafer, a 300 mm wafer) is provided and exposed to a solution to remove the surface of the substrate. The native oxide layer (SiO ₂ ) 204. In one embodiment, the native oxide layer 204 is removed using a cleaning fluid (ie, a hydrofluoric acid solution) containing hydrogen fluoride (HF) and deionized (DI) water. In one embodiment, the cleaning fluid is an aqueous solution containing from about 0.1% to about 10% by weight of HF maintained at from about 20 °C to about 30 °C. In another embodiment, the cleaning fluid comprises about 0.5 wt% HF and is maintained at about 25 °C. In step 104, substrate 200 can be immersed in a cleaning solution and then washed with deionized water. Step 104 can be performed in a single substrate processing chamber or a plurality of batch type substrate processing chambers, which can include the delivery of ultrasonic energy during processing. Alternatively, step 104 can be performed in a single substrate wet cleaning reaction chamber in integrated processing system 600 (Fig. 7). In another embodiment, the removal of the native oxide layer 204 can employ an RCA cleaning process. After completion of step 104, the substrate 200 is placed in a vacuum loaded lock chamber or an environment in which nitrogen (N ₂ ) is passed.

In step 106, a thermal oxide layer (SiO ₂₎ 206 is formed on a 200 (Fig. 6C) substrate. Thermal oxide layer 206 typically has a thickness of from about 3 angstroms to about 35 angstroms. In one embodiment, the thermal oxide layer 206 has a thickness of from about 6 angstroms to about 15 angstroms. The step of depositing a thermal oxide layer 106 can be performed on an RTP reactor, such as RADIANCE in integrated processing system 600 (Fig. 7). RTP reactor. RADIANCE The RTP reactor was obtained from Applied Materials, Inc. of Santa Clara, California.

In step 108, the thermal oxide layer 206 is exposed to a plasma containing metal ions. For example, step 108 forms a metal oxide layer 209 or a metal sublayer 209 of a metal ruthenate layer or a ruthenium oxynitride metal layer on the substrate 200 (Fig. 6D). In one embodiment, preferably, the metal layer 208 of about 1 angstrom to about 5 angstroms is formed on the surface of the thermal oxide layer 206 when the step 108 is performed. In one embodiment, the metal ion-containing plasma comprises an inert gas and at least one metal ion, such as ruthenium or osmium. The inert gas may comprise argon, and one or more selective inert gases such as helium (Ne), helium (He), helium (Kr), or helium (Xe). In one aspect, the metal ion-containing plasma can comprise nitrogen (N ₂ ).

In step 110, thermal oxide layer 206 is oxidized to metal oxide layer 209 by exposure to an oxygen-containing plasma and metal layer 208 (when such layer is applied) to dielectric region 210 (FIG. 6E). In another embodiment, the plasma may comprise nitrogen (N ₂ ), and one or more oxidizing gases such as oxygen (O ₂ ), nitrogen monoxide (NO), and nitrous oxide (N ₂ O). The plasma may also contain one or more inert gases such as argon (Ar), helium (Ne), helium (He), helium (Kr), or helium (Xe). Step 110 can be performed, for example, on a decoupled plasma nitriding (DPN) plasma reactor of integrated processing system 600 (Fig. 7).

In another embodiment, step 112 is used to replace step 110 to anneal substrate 200 at about 800 ° C to about 1100 ° C. Step 112 can be performed in a suitable thermal annealing chamber, such as RADIANCE of integrated processing system 600. Reactor or RTP XE ⁺ reactor, or single substrate or batch furnace tube. Thermal oxidation step 112 forms a dielectric region 210 containing a dielectric material. In one aspect, dielectric region 210 can comprise a phthalate material. In one embodiment, the annealing step 112 may employ oxygen (O ₂ ) at a flow rate of about 2 to 5000 sccm and nitric oxide (NO) at about 100 to 5000 sccm, or selectively mix nitrogen (N ₂ ), and maintain The substrate surface temperature is from about 800 ° C to about 1100 ° C and the process chamber pressure is from about 0.1 to 50 Torr. This annealing process can be carried out for about 5-180 seconds. In one embodiment, the oxygen (O ₂ ) is supplied at a flow rate of about 500 sccm and the chamber pressure is maintained at about 1000 ° C for about 15 Torr for a period of about 15 seconds. In another embodiment, the nitrogen monoxide (NO) is supplied at a flow rate of about 500 sccm and maintains a chamber pressure of about 0.5 Torr at about 1000 ° C for a period of about 15 seconds.

In step 114, the surface of the substrate 200 is exposed to the nitrogen plasma to increase the nitrogen content of the surface constituting the structure, and the nitride layer 214 is formed (Fig. 6F). This process may be used DPN reactor and provides about 10-2000 sccm of nitrogen (N _2), a susceptor temperature of about 20-500 deg.] C, and a reaction chamber pressure of about 5-1000 mTorr. Radio frequency (RF) plasma supplies energy, for example, at 13.56 MH, and up to about 3-5 watts of continuous wave (CW) or pulsed plasma power. When a pulse is generated, the range of maximum RF power, frequency, and energy cycle is typically about 10-3000 watts, about 2-100 kHz, and about 2%-100%, respectively. This process can be carried out for about 1 second to about 180 seconds. In one embodiment, the supply of nitrogen (N ₂ ) is about 200 sccm, and the maximum RF power of about 1000 watts is pulsed at about 10 kHz with an energy rate of about 5% applied to the inductive plasma source, about 25 ° C. The temperature, and a pressure of about 10-80 mTorr, is generated to generate a pulse for a period of about 15 seconds to about 180 seconds. The plasma can be generated using a quasi-remote plasma source, an inductive plasma source, a radiant lined slot antenna (RLSA) source, or other plasma source. In another embodiment, a CW and/or pulsed microwave power source can be used to form the nitride layer 214. A nitride layer 214 may be formed on the upper surface of the dielectric region 210 (FIG. 6E).

In step 116, the gate dielectric layer (oxide layer 206, nitride layer 214, and metal sublayer 209), and substrate 200 may be annealed. Step 116 can reduce the leakage current between the oxide layer 206, the nitride layer 214 and the metal sub-layer 209, and improve the mobility of the charge carriers in the channel region below the SiO ₂ sub-layer 216 and improve the gate dielectric. The reliability of the electrical layer as a whole. Step 116 can be performed in a suitable thermal annealing chamber, such as RADIANCE of integrated processing system 600. Reactor or RTP XE ⁺ reactor, or single substrate or batch furnace tube. The thermal oxidation step 116 can form a cerium oxide (SiO ₂ ) sub-layer 216 at the 矽/dielectric layer interface (Fig. 6G). Step 116 enhances the mobility of the charge carriers in the channel region below the SiO ₂ sub-layer 216 and improves the reliability of the dielectric/germanium interface.

In an embodiment, the annealing process of step 116 may employ at least one of about 2-5000 sccm of oxygen (O ₂ ) and about 100-5000 sccm of nitrogen monoxide (NO), or selectively mix nitrogen (N _{2 ).} And maintaining the substrate surface temperature from about 800 ° C to about 1100 ° C and the process chamber pressure from about 0.1 to 50 Torr. This process can be performed for about 5-180 seconds. In one embodiment, the oxygen (O ₂ ) supply is about 500 sccm and the chamber pressure is maintained at about 1000 ° C for about 15 Torr for a period of about 15 seconds.

After completing step 116, step 118 ends the method 100. In fabricating an integrated circuit, the method 100 facilitates the formation of an ultra-thin gate dielectric layer and reduces leakage current and enhances mobility of the charge carriers in the channel region.

While the present invention has been described above by way of a preferred embodiment, it is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

10. . . Transistor

12. . . Substrate

13. . . Junction

14. . . Dielectric layer

16. . . Gate electrode

18. . . Clearance wall

22, 24. . . curve

100. . . method

200. . . Substrate

204, 206. . . Oxide layer

208. . . Metal layer

209. . . Metal sublayer

210. . . Dielectric area

214. . . Nitride layer

216. . . Secondary layer

251. . . program

401. . . Substrate

401A, 402. . . Oxide layer

401B. . . surface

403, 404. . . Dielectric layer

405. . . region

406. . . Polycrystalline layer

407. . . Metal layer

408. . . Gate region

500, 501. . . Processing room

502. . . Substrate

504. . . Feed port

505, 571. . . Target

506. . . Coaxial cable

507. . . Power Supplier

508, 523, 565. . . Generator

508A, 524A, 565A. . . Matcher

508B, 509. . . Coil

510. . . Pump

511. . . Throttle valve

522. . . Processing area

524, 525. . . RF source

526. . . Switcher

527. . . Room bottom

528. . . Wall

529. . . Room cover

531. . . RF energy

532. . . DC pulse

533. . . RF/VHF pulse

535. . . DC voltage

540. . . Collimator

540A. . . Hole

550. . . Gas delivery system

561. . . Temperature controller

562. . . supporting item

562A. . . Support member

570. . . Backplane assembly

572. . . Insulation

573. . . Target assembly

591. . . RF source component

592. . . DC source component

593, 596. . . Processing chamber component

594. . . Substrate support assembly

595, 597. . . VHF source component

600. . . system

602. . . Controller

604. . . Working interface

605A-605D. . . Load port

606A, 606B. . . Load lock room

610. . . Transmission room

613. . . Mechanical arm

613A. . . Blade assembly

613B. . . Robot arm assembly

613C. . . Drive component

614A-614F. . . Processing room

W. . . Substrate

In order to make the above-mentioned features of the present invention more obvious and understandable, it can be explained with reference to the reference embodiment, and a part thereof is illustrated as a drawing. It is to be understood that the specific embodiments of the invention are not to be construed as limiting the scope of the invention. .

Figure 1A (Prior Art) depicts a cross section of an FET and can be fabricated in accordance with the present invention.

Figure 1B (previous technique) is a nitrogen concentration profile of a conventional thermal nitridation process and a conventional plasma nitridation process based on secondary ion mass spectrometry data.

2A is a flow chart showing the fabrication of a gate dielectric layer of a field effect transistor in accordance with an embodiment of the present invention.

2B is a flow chart showing the fabrication of a gate dielectric layer of a field effect transistor in accordance with an embodiment of the present invention.

2C is a flow chart showing the fabrication of a gate dielectric layer of a field effect transistor in accordance with an embodiment of the present invention.

2D is a flow chart showing the fabrication of a gate dielectric layer of a field effect transistor in accordance with an embodiment of the present invention.

2E is a flow chart showing the fabrication of a gate dielectric layer of a field effect transistor in accordance with an embodiment of the present invention.

2F is a flow chart showing the fabrication of a gate dielectric layer of a field effect transistor in accordance with an embodiment of the present invention.

Figures 3A-3F are a series of substrate cross-sections on which are gate structures fabricated using the method of Figure 2A.

4A is a cross-sectional view of a plasma processing chamber in accordance with another embodiment of the present invention.

Figure 4B is a cross section of a plasma processing chamber in accordance with yet another embodiment of the present invention.

Figure 4C is a cross section of a plasma processing chamber in accordance with still another embodiment of the present invention.

Fig. 4D is a theoretical calculation table illustrating various properties of the target and the target according to an embodiment of the present invention.

Figure 4E is a graph of self-bias voltage versus frequency for a capacitively coupled plasma processing chamber in accordance with an embodiment of the present invention.

Figure 4F is a cross section of a plasma processing chamber in accordance with an embodiment of the present invention.

Figure 4G depicts a cross section of a plasma processing chamber in accordance with an embodiment of the present invention.

Figure 4H depicts a cross section of a plasma processing chamber in accordance with an embodiment of the present invention.

FIG. 5A is a timing diagram showing an interrupted cycle of pulsed RF/VHF excitation energy and pulsed DC voltage applied to a target in accordance with another embodiment of the present invention.

FIG. 5B is a timing diagram showing an interrupted cycle of pulsed RF/VHF excitation energy and pulsed DC voltage applied to the target in accordance with yet another embodiment of the present invention.

FIG. 5C is a timing diagram showing an interrupt cycle of a pulsed DC voltage applied to a target and continuous RF/VHF energy, in accordance with still another embodiment of the present invention.

6A is a flow chart showing a method 100 of fabricating a gate dielectric layer of a field effect transistor, in accordance with an embodiment of the present invention.

Fig. 6B-6G is a series of substrate cross-sections on which the gate structure fabricated by the method of Fig. 6A is used.

FIG. 7 illustrates an integrated processing system in accordance with an embodiment of the present invention.

251. . . program

Claims (23)

A method of forming a semiconductor device, comprising: forming a dielectric layer having a predetermined thickness on a surface of a substrate; using at least one portion of the formed dielectric layer by a low energy sputtering process Forming a concentration gradient of the first material in the thickness, wherein the low energy sputtering process comprises: generating a radio frequency energy by using a radio frequency generator at a first radio frequency (RF) frequency and a first radio frequency power a processing region to a low energy sputtering chamber; the pulse generates a DC (DC) voltage, and the DC voltage is delivered from the DC source assembly to a target placed in the processing region; and the pulse is synchronized The RF energy and the DC voltage of the pulse are such that a quantity of the first material removed from the target can be placed in the dielectric layer; and a second material is deposited on the dielectric layer. The method of claim 1, further comprising exposing the dielectric layer and the first material to a nitrogen-containing radio frequency plasma. The method of claim 1, wherein the thickness of the dielectric layer is less than about 40 angstroms (Angstroms). The method of claim 1, wherein the first material is And, the concentration of the first material in the dielectric layer is less than about 30 atomic percent. The method of claim 1, wherein the first material is selected from the group consisting of zirconium, hafnium, yttrium, lanthanum, lead, lanthanum, and cerium. The method of claim 1, wherein the dielectric layer comprises a material selected from the group consisting of cerium oxide, cerium oxide, zirconium oxide, hafnium silicate oxide, cerium oxide, And a group of alumina. The method of claim 2, further comprising: placing a third content of the third material into the dielectric layer prior to exposing the dielectric layer to the nitrogen-containing radio frequency plasma, wherein The third material comprises an element selected from the group consisting of ruthenium, osmium, aluminum, titanium, zirconium, hafnium, lead, bismuth, and antimony. The method of claim 7, further comprising exposing the dielectric layer, the first material and the third material to an oxidizing environment, wherein the oxidizing environment is oxidized using a thermal oxidation process or a plasma Process. The method of claim 1, wherein the second material comprises a material selected from the group consisting of polycrystalline germanium, germanium, tantalum nitride, tantalum carbide, tungsten, tungsten nitride, tantalum nitride, niobium, Aluminum, bismuth, cobalt, titanium, nickel, and nitrogen A group of titanium. The method of claim 1, further comprising annealing the dielectric layer and the first material disposed on the surface of the substrate at a temperature of from about 800 ° C to about 1100 ° C. The method of claim 1, further comprising exposing the surface of the substrate to a nitrogen-containing radio frequency plasma prior to forming the dielectric layer. A method of forming a high dielectric constant (k) dielectric layer, comprising: placing a substrate having a dielectric layer formed thereon in a processing region of a plasma processing chamber; utilizing a low energy sputtering The process forms a concentration gradient of the first material in the dielectric layer, wherein the low energy sputtering process comprises: transmitting a plurality of RF energy pulses from a first RF generator to a target containing the first material Each of the plurality of RF energy pulses is delivered at a first RF frequency; and a plurality of DC pulses from the DC source component are delivered to the target, wherein the RF energy pulses and the DC pulses are synchronized. The method of claim 12, wherein the first radio frequency is from about 1 MHz to about 200 MHz. The method of claim 12, wherein the first material comprises a material selected from the group consisting of aluminum, titanium, zirconium, hafnium, tantalum, niobium, lead, niobium, and tantalum. The method of claim 12, further comprising transmitting a plurality of second RF energy pulses to the target, wherein the RF energy of the second RF energy pulses is delivered at a second RF frequency, and the The second RF frequency is greater than the first RF frequency. A method of forming a high dielectric constant (k) dielectric layer, comprising: placing a substrate having a dielectric layer formed thereon in a processing region of a plasma processing chamber; utilizing a low energy sputtering The process forms a concentration gradient of the first material in the dielectric layer, wherein the low energy sputtering process includes: transmitting a plurality of RF energy pulses from a first RF generator to a one in electrical communication with the processing region a coil, wherein the RF energy pulses are delivered at a first RF frequency and a first power; and a plurality of DC pulses from the DC source assembly are delivered to a target containing the first material, wherein the RF The energy pulse and the DC pulses are synchronized. The method of claim 16, wherein the dielectric layer The thickness is less than about 30 angstroms. The method of claim 16, wherein the first material comprises a material selected from the group consisting of aluminum, titanium, zirconium, hafnium, niobium, tantalum, lead, niobium, and tantalum. A method of forming a high dielectric constant (k) dielectric layer, comprising: placing a substrate having a dielectric layer formed thereon in a processing region of a plasma processing chamber; utilizing a low energy sputtering The process includes forming a concentration gradient of the first material in the dielectric layer, wherein the low energy sputtering process comprises: transmitting a plurality of first RF energy pulses from a first RF generator to the first RF frequency to The processing region is a coil that is in electrical communication; and the plurality of second RF energy pulses from a second RF generator are delivered at a second RF frequency to a target in electrical communication with the processing region, wherein the The first RF energy pulse and the second RF energy pulses are synchronized. The method of claim 19, wherein the first RF frequency is from about 40 kHz to about 20 MHz and the second RF frequency is from about 1 MHz to about 200 MHz. The method of claim 19, wherein the dielectric layer has a thickness of less than about 30 angstroms. The method of claim 19, wherein the first material comprises a material selected from the group consisting of aluminum, titanium, zirconium, hafnium, tantalum, niobium, lead, niobium, and tantalum. The method of claim 19, wherein the first RF energy pulses and the second RF energy pulses are delivered at a pulse frequency of between about 1 Hz and about 50 kHz.