TWI515801B - Process for fabricating semiconductor device and method of fabricating metal oxide semiconductor device - Google Patents

Description

Semiconductor process method and method of manufacturing metal oxide semiconductor device

The present invention relates to a semiconductor process method and a method of fabricating a metal oxide semiconductor device.

With the development of the ultra-large integrated circuit industry, the component size has been continuously miniaturized, and the gate width and the thickness of the gate dielectric layer have been gradually reduced or thinned. Cerium oxide is the most common type of gate dielectric. However, the pin holes in the ruthenium oxide layer are liable to cause various electrical problems such as direct tunneling current, and therefore, it is difficult to form a thin dielectric layer. At present, a method of implanting nitrogen into yttrium oxide and nitriding it to form bismuth oxynitride has been disclosed to reduce leakage current and improve process reliability. However, in such a manner, when the nitridation process is performed, problems such as easy diffusion of nitrogen atoms to the interface between the ruthenium substrate and the ruthenium oxide layer are easily derived, which affects the efficiency and reliability of the device.

The invention provides a semiconductor manufacturing method, which can make the formed yttria layer have a sufficient nitrogen concentration and a high dielectric constant k value to enhance its electrical performance.

The invention provides a method for manufacturing a gold-oxygen semiconductor device, wherein the formed yttria layer has a sufficient nitrogen concentration and has a high dielectric constant k value, so that the MOS device can have good performance.

The present invention provides a semiconductor processing method comprising forming a ruthenium oxide layer, followed by at least two steps of nitriding, and nitriding the ruthenium oxide layer to form a ruthenium oxynitride layer. The nitridation process sequentially includes a first nitridation step and a second nitridation step, and at least one of the parameters of performing the first nitridation step and the performing the second nitridation step is different.

According to an embodiment of the invention, the first nitriding step and the second nitriding step respectively comprise a decoupling plasma nitridation process, a remote plasma nitridation process or an ammonia gas thermal nitridation process.

According to an embodiment of the invention, the first nitriding step is different from the power of the second nitriding step.

According to an embodiment of the invention, the power of the first nitriding step is greater than the power of the second nitriding step. The second nitridation step is performed for a longer period of time than the first nitridation step. The duty cycle of the first nitridation step is greater than the duty cycle of the second nitridation step.

According to an embodiment of the invention, the power of the first nitriding step is less than the power of the second nitriding step. The first nitridation step is performed for a longer period of time than the second nitridation step. The duty cycle of the second nitridation step is greater than the duty cycle of the first nitridation step.

According to an embodiment of the invention, the method for forming the ruthenium oxide layer includes an on-site vapor generation (ISSG) method, a chemical vapor deposition method, or a decoupling plasma oxidation method.

According to an embodiment of the invention, the semiconductor manufacturing method further includes a post-stage tempering process.

According to an embodiment of the invention, the subsequent tempering process includes a nitrogen tempering process and an oxygen tempering process.

The present invention also provides a method of fabricating a MOS device, comprising forming a yttrium oxide layer on a substrate, and then performing a nitridation process of at least two steps to nitride the ruthenium oxide layer to form a ruthenium oxynitride layer. The nitridation process sequentially includes a first nitridation step and a second nitridation step, and at least one of the parameters of performing the first nitridation step and the performing the second nitridation step is different. Thereafter, a gate conductor layer is formed on the above yttria layer.

According to an embodiment of the invention, the first nitriding step and the second nitriding step respectively comprise a decoupling plasma nitridation process, a remote plasma nitridation process or an ammonia gas thermal nitridation process.

According to an embodiment of the invention, the first nitriding step is different from the power of the second nitriding step.

According to an embodiment of the invention, the power of the first nitriding step is greater than the power of the second nitriding step. The second nitridation step is performed for a longer period of time than the first nitridation step. The duty cycle of the first nitridation step is greater than the duty cycle of the second nitridation step.

According to an embodiment of the invention, the power of the first nitriding step is less than the power of the second nitriding step. The first nitridation step is performed for a longer period of time than the second nitridation step. The duty cycle of the second nitridation step is greater than the duty cycle of the first nitridation step.

According to an embodiment of the invention, the method for forming the ruthenium oxide layer includes an on-site vapor generation (ISSG) method, a chemical vapor deposition method, or a decoupling plasma oxidation method.

According to an embodiment of the invention, the method for fabricating the MOS device further includes a post-stage tempering process.

Based on the above, the semiconductor process method of the present invention nitrides the hafnium oxide layer through a nitridation process of at least two steps, so that the formed hafnium oxynitride layer has a sufficient nitrogen concentration to enhance its electrical performance. When the ruthenium oxynitride layer is applied to the MOS device as a gate dielectric layer, the MOS device can have good performance.

The above described features and advantages of the present invention will be more apparent from the following description.

FIG. 1 is a flow chart of a semiconductor process method according to an embodiment of the invention. 2 is a graph showing the relationship between nitrogen concentration and depth in a ruthenium oxynitride layer according to an example of the present invention.

Referring to FIG. 1, the semiconductor manufacturing method of the present invention includes steps 10, 20 and 30. In step 10, a ruthenium oxide layer is formed on the substrate. The material of the substrate may be a semiconductor such as germanium or a semiconductor compound such as germanium germanium or germanium (SOI) on the insulating layer. Methods of forming a ruthenium oxide layer include an on-site vapor generation (ISSG) method, a chemical vapor deposition method, or a decoupled plasma oxidation method. The thickness of the ruthenium oxide layer is, for example, from 1.68 nm to 1.76 nm. If the thickness of the yttrium oxide layer is too thick, the efficiency thereof will decrease; if the thickness of the yttrium oxide layer is too thin, it will easily have a problem of nitrogen penetration during the subsequent nitriding process.

Referring to FIG. 1, step 20, a nitridation process of at least two steps is performed to nitride the ruthenium oxide layer. In the formed ruthenium oxynitride layer, the atomic content of nitrogen is 20% to 25%. The nitridation process of step 20 includes a first nitridation step 22 and a second nitridation step 24, respectively, and at least one of the parameters of performing the first nitridation step 22 and the performing the second nitridation step 24 is different. The aforementioned different parameters are, for example, power, time, duty cycle, cavity pressure and/or nitrogen flow. The nitridation process is, for example, a decoupled plasma nitridation process, a remote plasma nitridation process, or an ammonia gas thermal nitridation process. The decoupling plasma nitridation process includes a cavity decoupling plasma nitridation process, a remote decoupling plasma nitridation process, or an ammonia gas thermal decoupling plasma nitridation process.

Referring to FIG. 1, in an embodiment, the first nitridation step 22 and the second nitridation step 24 respectively include a decoupling plasma nitridation process, and the first nitridation step 22 and the second nitridation step 24 are used. The power, time or duty cycle is different. More specifically, the power of the first nitridation step 22 is greater than the power of the second nitridation step 24; the second nitridation step 24 is performed for a longer time than the first nitridation step 22; the first nitridation step 22 The duty cycle is greater than the duty cycle of the second nitridation step 24. More specifically, the pressure of the first nitridation step 22 is, for example, 200 mTorr, the power is, for example, 2,200 watts, the duty cycle is, for example, greater than 20%, and the time is, for example, 30 seconds. The pressure of the second nitridation step 24 is, for example, 200 mTorr, the power is, for example, 2000 watts, the duty cycle is, for example, 20%, and the time is, for example, 60 seconds.

In addition to the two-step nitridation, more steps of nitriding can be employed.

From the relationship between the nitrogen concentration and the depth in the yttrium oxynitride layer shown in FIG. 2, the first nitridation step 22 uses a larger energy, and the concentration profile of the nitrogen atom is as shown by the curve 26, and the peak is It is far from the upper surface of the cerium oxide, and because of the short time of nitriding treatment, the problem of nitrogen penetrating the cerium oxide layer can be avoided or slowed down. The second nitridation step 24 uses a nitriding treatment with a lower energy for a longer period of time to provide a more sufficient nitrogen atom near the upper surface of the cerium oxide, the nitrogen atom concentration profile of which is shown by curve 28. The curve after the combination of the first nitridation step 22 and the second nitridation step 24 is as shown by the curve 29.

In another implementation, the first nitridation step 22 and the second nitridation step 24 respectively include a decoupling plasma nitridation process, the power of the first nitridation step 22 is less than the power of the second nitridation step 24; The nitridation step 24 is performed for a shorter period of time than the first nitridation step 22; the duty cycle of the first nitridation step 22 is less than the duty cycle of the second nitridation step 24. In detail, the pressure of the first nitridation step 22 is, for example, 200 mTorr, the power is, for example, 2000 watts, the duty cycle is, for example, 20%, and the time is, for example, 60 seconds. The pressure of the second nitridation step 24 is, for example, 200 mTorr, the power is, for example, 2200 watts, the duty cycle is, for example, greater than 20%, and the time is, for example, 30 seconds.

From the relationship between the nitrogen concentration and the depth in the yttrium oxynitride layer shown in FIG. 2, the first nitridation step 22 uses a nitriding treatment with a smaller energy for a longer period of time, which can provide sufficient surface near the yttrium oxide. The nitrogen atom and its nitrogen atom concentration profile are shown by curve 28. The second nitridation step 24 uses a larger energy whose concentration profile of nitrogen atoms is farther from the upper surface of the yttrium oxide, as shown by curve 26, which avoids or slows down nitrogen due to the shorter time it takes to perform the nitridation treatment. The problem of penetrating the ruthenium oxide layer. The curve after the combination of the first nitridation step 22 and the second nitridation step 24 is as shown by curve 29.

In step 30, a post-stage tempering process is performed. The above-mentioned post-stage tempering process sequentially includes a nitrogen tempering process and an oxygen tempering process. The nitrogen tempering process is, for example, a rapid thermal tempering process, an ultraviolet annealing process, or a laser tempering process. The oxygen tempering process is, for example, a rapid thermal tempering process, an ultraviolet annealing process, or a laser tempering process. In an embodiment, the nitrogen tempering process is, for example, a rapid thermal tempering process, the tempering temperature is, for example, 800 degrees Celsius, and the tempering time is, for example, 10 to 120 seconds; and the oxygen tempering process is, for example, a rapid thermal tempering process. The tempering temperature is, for example, 600 degrees Celsius, and the tempering time is, for example, 10 to 120 seconds.

3 is a flow chart of a method of fabricating a MOS device in accordance with an embodiment of the invention. 4A-4B are cross-sectional views showing a method of fabricating a MOS device in accordance with an embodiment of the present invention.

Referring to FIGS. 3 and 4A, the method of fabricating the MOS device of the present invention includes steps 110, 120, 130, 140, and 150. Steps 110, 120, 122, 124, and 130 respectively form a ruthenium oxynitride layer 202 on the substrate 200 as described in the above steps 10, 20, 22, 24, and 30, the details of which can be referred to the above embodiments, and no longer Narration.

Referring to FIG. 3 and FIG. 4A, in step 140, a conductor layer 204 is deposited on the yttria layer 202. The material of the conductor layer 204 includes doped polysilicon, metal or a combination thereof. The method of forming the conductor layer 204 is, for example, a chemical vapor deposition method. In one embodiment, the conductor layer 204 is made of doped polysilicon, which can be formed by using a CVD ethane as a reactive gas through a chemical vapor deposition process, and the thickness of the deposited doped polysilicon is, for example, 400 Å to 900 Å. Ai.

Referring to FIGS. 3 and 4B, in step 150, the conductor layer 204 and the yttria layer 202 are patterned to form a patterned conductor layer 204a and a patterned yttria layer 202a. The method of patterning the conductor layer 204 and the argon oxynitride layer 202 is, for example, a lithography and etching method. The patterned conductor layer 204a serves as a gate conductor layer, and the patterned yttria layer 202a serves as a gate dielectric layer.

Based on the above, the semiconductor process method of the present invention nitrides the hafnium oxide layer through a nitridation process of at least two steps, so that the formed hafnium oxynitride layer has a sufficient nitrogen concentration to increase its dielectric constant k value and enhance its Electrical performance. When the ruthenium oxynitride layer is applied to the MOS device as a gate dielectric layer, the MOS device can have good performance.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

10, 20, 22, 24, 30, 110, 120, 122, 124, 130, 140. . . step

200. . . Base

202. . . Niobium oxynitride layer

202a. . . Patterned yttria layer

204. . . Conductor layer

204a. . . Patterned conductor layer

FIG. 1 is a flow chart of a semiconductor process method according to an embodiment of the invention.

2 is a graph showing the relationship between nitrogen concentration and depth in a ruthenium oxynitride layer according to an example of the present invention.

3 is a flow chart of a method of fabricating a MOS device in accordance with an embodiment of the invention.

4A-4B are cross-sectional views showing a method of fabricating a MOS device in accordance with an embodiment of the present invention.

10, 20, 22, 24, 30. . . step

Claims (12)

A semiconductor processing method comprising: forming a niobium oxide layer, wherein the method of forming the hafnium oxide layer comprises an on-site vapor generation (ISSG) method or a decoupling plasma oxidation method; and performing at least two steps of a nitridation process to cause the oxidation The ruthenium layer is nitrided to form a ruthenium oxynitride layer, the nitridation process includes a first nitridation step and a second nitridation step, and at least one of the parameters of performing the first nitridation step and the performing the second nitridation step The first nitriding step and the second nitriding step respectively include a far-end plasma nitridation process or an ammonia gas thermal nitridation process, and the power of the first nitridation step is greater than the second nitridation step. The power is such that the peak of the concentration profile of the nitrogen atom of the first nitriding step is farther from the upper surface of the yttrium oxide layer, and the nitrogen atom provided by the second nitriding step is closer to the upper layer of the yttrium oxide layer The surface, and the second nitridation step is performed for a longer time than the first nitridation step to avoid or slow the penetration of nitrogen through the yttrium oxide layer during the first nitridation step. The semiconductor process method of claim 1, wherein the first nitriding step is performed before the second nitriding step. The semiconductor process method of claim 1, wherein the duty cycle of the first nitridation step is greater than the duty cycle of the second nitridation step. The semiconductor process method of claim 1, wherein the first nitriding step is performed after the second nitriding step. For example, the semiconductor process method described in claim 1 further includes a post-stage tempering process. The semiconductor process method of claim 5, wherein the subsequent tempering process comprises a nitrogen tempering process and an oxygen tempering process. A method for fabricating a MOS device, comprising: forming a ruthenium oxide layer on a substrate, wherein the ruthenium oxide layer is formed by an on-site vapor generation (ISSG) method or a decoupled plasma oxidation method; performing at least two steps a nitridation process for nitriding the yttrium oxide layer to form a yttrium oxynitride layer, the nitridation process comprising a first nitridation step and a second nitridation step, and performing the first nitridation step and performing the first At least one of the parameters of the diazotization step, wherein the first nitriding step and the second nitriding step respectively comprise a far end plasma nitridation process or an ammonia gas thermal nitridation process, the power of the first nitridation step The power greater than the second nitriding step is such that the peak of the concentration profile of the nitrogen atom of the first nitriding step is farther from the upper surface of the yttrium oxide layer, and the nitrogen atom provided by the second nitriding step is Adjacent to the upper surface of the yttrium oxide layer, the second nitridation step is performed for a longer period of time than the first nitridation step to avoid or slow nitrogen penetration of the ruthenium oxide layer during the first nitridation step And the nitrogen Forming a conductive layer on the layer of silicon. As claimed in claim 7 of the MOS device A manufacturing method, wherein the first nitriding step is performed before the second nitriding step. The method of manufacturing a MOS device according to claim 7, wherein the duty cycle of the first nitridation step is greater than the duty cycle of the second nitridation step. The method of manufacturing a MOS device according to claim 7, wherein the first nitriding step is performed after the second nitriding step. The method for manufacturing a MOS device according to claim 7, further comprising a post-stage tempering process. The method for manufacturing a MOS device according to claim 11, wherein the subsequent tempering process comprises a nitrogen tempering process and an oxygen tempering process.