JPH08115903A - Method for manufacturing semiconductor device and plasma etching apparatus - Google Patents

Abstract

PURPOSE: To keep dust particles away from the surface of a semiconductor substrate by covering the surface of an electrode opposed to a substrate with such a material as to produce volatile product, reacting with a fluoride of W, and further, deflecting the flow of gas flowing toward the substrate at the time of plasma etching. CONSTITUTION: A cover 3f of quartz glass, which forms a volatile product, reacting with WFx molecules produced by the reactive ion etching of the W layer within a substrate 4, is provided on the surface opposed to an electrode 2 of an electrode 3. Furthermore, the cover 3f has apertures 3e drawn up in the passage 3d of etching gas 3d, and the gas introduced into a processing chamber 1 from there never reaches the electrode 2 and the substrate 4 retained thereon, being deflected in the direction of an arrow X by quartz glass disc 3g. Hereby, dust particles are kept away from the surface of the substrate, and reliable products can be mass-produced at low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to semiconductor devices, and more particularly to a plasma etching apparatus used for manufacturing a semiconductor device and a method for manufacturing a semiconductor device using such a plasma etching apparatus. With the increase in the integration density of integrated circuits, there is a demand for a fine processing technique capable of forming a finer pattern on a semiconductor substrate. On the other hand, such miniaturization of the pattern tends to cause problems such as stress migration or electromigration in the fine wiring pattern particularly in the conventional wiring structure using Al or Al alloy.

Therefore, in particular, the first in the multilayer wiring structure
It has been proposed to use tungsten (W), which has excellent resistance to stress migration or electromiculation, in place of conventional Al or Al alloy for a wiring layer at a layer level. W like this
In order to form the wiring, an etching apparatus capable of etching W is necessary. In order to manufacture a semiconductor device at low cost, such an etching device is required to be able to provide high throughput and high yield.

[0003]

2. Description of the Related Art FIG. 7 shows the structure of a plasma etching apparatus conventionally used for W reactive ion etching. Referring to FIG. 7, the plasma etching apparatus is
A vacuum processing chamber 1 exhausted through an exhaust port 1a and a pair of Al electrodes 2 and 3 formed in the vacuum processing chamber 1 so as to face each other, and a substrate 4 is held on the electrode 2. The electrostatic chuck 2a is formed. The electrode 2 is insulated from the plasma etching apparatus main body 5 by an insulating layer 6 made of fluororesin or the like, and is supplied with high frequency power from a high frequency power source 7 to form plasma between itself and the counter electrode 3. The surface of the electrode 2 is protected by the quartz cover 2b except for the area where the electrostatic chuck 2a is formed.

On the other hand, the electrode 3 is formed on the grounded Al pipe 3a and held at the ground potential. The surface of the electrode 3 has an Al cover 3b having a large number of openings 3c having a diameter of 0.8 to 1.0 mm, and the cover 3b is a vacuum processing chamber for etching gas supplied through a pipe 3a. 1. Shower nozzle for supplying No. 1 is formed. However, a passage 3d for passing the etching gas is formed in the pipe 3a. The side wall of the vacuum processing chamber 1 is protected by a quartz liner. In a typical example, the vacuum processing chamber 1 is about 30 cm.
And the electrode 2 has a diameter substantially equal to that of the electrode 3. However, in FIG. 7, among the electrodes 3, the quartz cover 2 is used.
The area of the portion covered by b is exaggerated.

When performing the etching of W by the plasma etching apparatus of FIG. 7, while the vacuum processing chamber 1 is exhausted through the exhaust port 1a, N is exhausted through the passage 3d in the pipe 3a.
An etching gas such as F ₃ is introduced. At that time, the internal pressure of the vacuum processing chamber 1 was maintained at about 0.2 Torr, and the high frequency power supply 7
To supply a power of about 200 W to form plasma. Volatile reactive products are produced by the reaction of the F atoms forming the plasma with the surface of the W layer on the substrate 4, and the reaction products further accelerate the etching.
That is, the plasma etching apparatus of FIG. 7 performs reactive ion etching.

FIGS. 8A to 8D show a patterning process of a W layer using such reactive ion etching of W. Referring to FIG. 8A, TiN is formed on the surface of the substrate 4.
A W layer 42 to be patterned is formed via a barrier metal layer 41 made of, for example, and a resist pattern 44 is formed on the W layer 42 via an antireflection film 43 such as amorphous carbon. However, the barrier metal layer 41 is provided to prevent W in the W layer 42 from diffusing into the substrate 4. Further, the antireflection film 43 is for suppressing interference of light used for exposure and minimizing the spread of the pattern when the resist layer is patterned by photolithography to form the resist pattern 44.

More specifically, SiO _{2 is} formed on the surface of the substrate 4.
A film (not shown) is formed as an interlayer insulating film, and the TiN layer 41 is formed as a barrier metal on the interlayer insulating film by sputtering to have a thickness of about 50 nm. Typically, the sputtering is performed by using Ti as a target and inducing a discharge with a DC power of 7 kW in a mixed gas of Ar gas and N ₂ gas having a pressure of 4 mTorr. Further, the formed TiN layer 41 is 400 to 5
Annealing is performed at a temperature of 00 ° C. to improve the characteristics as a barrier metal layer. Furthermore, the T formed in this way
A W layer 42 is formed on the iN layer 41 by the CVD method to a thickness of about 350.
It is formed to a thickness of nm. In this case, WF ₆ is used as a source gas, and a CVD process in which the substrate 4 having the TiN layer 41 formed thereon is set together with a carrier gas made of H _2.
Supply to the reaction chamber of the device. The W layer 42 is typically deposited under a pressure of 80 Torr while maintaining the substrate temperature in the range of 400 ° C to 500 ° C, typically 475 ° C.

Further, an antireflection layer 43 is formed on the formed W layer 42 by depositing an amorphous carbon layer of 54 nm, and a photoresist layer having a thickness of 1.4 μm is further formed on the antireflection layer 43. Then, the resist pattern 44 is formed by exposing it to light and then developing it with an alkali developing solution. Further, the exposed antireflection layer 43 is removed by reactive ion etching using O ₂ plasma, and the structure of FIG. 8A is obtained.

Next, in the step of FIG.
The substrate 4 having the structure shown in (A) is placed in the vacuum processing chamber 1 of the plasma etching apparatus shown in FIG.
4 is used as a mask to carry out reactive ion etching of the W layer 43. More specifically, using NF ₃ as an etching gas, the process chamber 1 of the apparatus shown in FIG.
Supply at a volumetric flow rate of / min. The internal pressure of the processing chamber 1 is 20
By setting the power density of the high frequency power applied between the electrodes 2 and 3 to 0 mTorr and 0.53 W / cm ² ,
An etching rate of 10 nm / min and a selectivity to resist of 1.7 are obtained. By continuing the etching further, the W layer 42 is completely etched in the thickness direction,
As shown in FIG. 8C, a structure in which the barrier layer 41 is exposed is obtained. Further, by patterning the barrier layer 41 by reactive ion etching with plasma using chlorine-based gas, the structure shown in FIG. 8D is obtained. As described above, by using W, it is possible to form a wiring pattern having high resistance to stress migration and electromigration even in a large aspect ratio.

[0010]

By the way, in the manufacture of semiconductor devices, high integration density as well as high throughput and high yield are required. In order to improve throughput at the time of manufacturing, in recent years, a so-called single-wafer processing apparatus that sequentially processes substrates one by one in cooperation with other processes has been replaced by a batch processing apparatus that collectively processes a large number of substrates. in use.

In such a single-wafer processing apparatus, it is necessary to shorten the takt time required for processing one substrate in order to improve the throughput, but when the conventional plasma etching apparatus shown in FIG. 7 is used. It has been discovered that as the number of processed substrates increases with the progress of single-wafer processing, the number of particles adhering to the substrates gradually increases. The adhesion of such particles reduces the yield of semiconductor device manufacturing.

FIG. 9 is a graph showing the adhesion of particles on the substrate as the single wafer processing proceeds. However, in this experiment, we used a 22 cm diameter substrate,
The substrates were processed one after another with a takt time of 90 seconds. Further, the number of particles on the substrate surface was determined by scanning the treated substrate surface with a laser beam and observing the obtained scattered light. In FIG. 9, the vertical axis represents the number of particles generated, and the horizontal axis represents the cumulative number of substrate processings in the single-wafer processing.

As can be seen from FIG. 9, the number of particles on the surface of the substrate is 100 or less at the start of the process, while it exceeds 300 at the time of processing 22 substrates and becomes close to 400. I can see that To generate such particles, simply load the substrate in the vacuum processing chamber 1,
If you take out the board without any processing,
It is not seen when only the gas is introduced into the vacuum processing chamber 1 loaded with the substrate without forming plasma. Further, even when a Si substrate not containing a W layer or a Si substrate having only a SiO ₂ layer is processed by reactive ion etching, such generation of particles is not observed. That is, it can be concluded that such particles are generated as a result of reactive ion etching of the substrate 4 including the W layer in the vacuum processing chamber 1 of the plasma etching apparatus.

FIGS. 10A to 10C are views showing a pattern defect generated by particles attached on such a substrate. Referring to FIG. 10A, when the particles 50 are attached so as to bridge between the pair of resist patterns 44, the particles 50 are generated as shown in FIG.
As shown in (B) and (C), it acts as a mask in the subsequent patterning, and W which should be originally patterned.
This causes problems such as the layer 42 not being patterned. Along with this, the yield of semiconductor devices is also as shown in FIG.
It gradually decreases with the cumulative number of substrate processes. However, in FIG. 11, a wiring pattern is formed by reactive ion etching using the apparatus of FIG. 7 according to the steps of FIGS. 8A to 8D, and the yield is obtained. However, the yield value indicates a relative value normalized by the yield of the first substrate. It can be seen from FIG. 11 that when the number of processed substrates reaches 23, the yield becomes almost half of that at the start of processing.
Most of the particles have a size of about 1 μm.

The origin of such particles is
There are various possibilities. The first reason is due to Al sputtered from the inner wall of the vacuum processing chamber 1 or the counter electrode 3. However, this mechanism cannot explain the tendency that the number of particles generated increases as the number of processed sheets increases when the single-wafer processing is performed.

FIG. 12 shows an inductively coupled plasma mass spectrometric analysis (ICP-MS) of a substance deposited on a substrate in consideration of the possibility that such particles are generated by the sputtering from the chamber wall or the counter electrode. The results of analysis by are shown.
However, the vertical axis represents the Al atom density on the substrate surface, and the horizontal axis represents the cumulative number of times of substrate processing. As you can see from this figure,
It was confirmed that the Al atom density on the substrate is substantially independent of the cumulative number of substrate treatments.

Further, such adhesion of particles on a substrate, even in the single-wafer processing, lengthens the interval between the processing of one substrate and the processing of the next substrate to about 1 hour. However, it does not appear when the vacuum processing chamber 1 is continuously evacuated during that time. That is, in the conventional batch type processing,
Particles were generated by a similar mechanism,
It is considered that such a problem did not become apparent because the interval between the treatments was very long and the vacuum treatment chamber was efficiently evacuated during that time.

The inventor of the present invention has considered the following mechanism as a mechanism for generating particles generated when plasma-etching the W layer by single-wafer processing.
In the etching of W, fluorides such as NF ₃ are used as the etching gas as described above. However, when these fluorine-based etching gases are used, the radicals of F penetrate into the lattice of W, To form volatile tungsten fluoride WFx as a reaction product. However,
In the formula WFx, x takes a value in the range of 1 to 6 (x <
6). The reaction product WFx has a structure in which F atoms are coordinated around W atoms, and especially low-order tungsten fluoride compounds having an x value of 5 or less have an unpaired electron, and thus easily react with other molecules. React to. In the reactive ion etching of W, the WFx thus formed is chemically sputtered by ion irradiation, and the etching proceeds.

Considering the mechanism of such sputter etching, the mechanism by which the reaction product WFx adheres to the vacuum processing chamber 1 and the counter electrode 3 and combines with other atoms to form a nucleus of particles is rational. It is believed that there is. In fact, it is conventionally known that when such WFx adheres to the counter electrode 3, a large amount of particles are generated by reacting with the material forming the electrode. Therefore, it is considered that the above-described pattern defect is caused by the particles on the counter electrode 3 being separated from the counter electrode 3 by some mechanism and transported to the surface of the semiconductor substrate 4. Assuming the above mechanism, the tendency shown in FIG. 9 or FIG. 11, which appears when the single-wafer processing is performed, can be reasonably explained.

FIGS. 13A to 13D are views for explaining the mechanism of particle generation. However, in the figure, the portions corresponding to the portions described above are designated by the same reference numerals and the description thereof will be omitted. In FIGS. 13A to 13D,
The substrate 4 is shown mounted on the electrode 2, and therefore is apparently turned upside down with respect to FIGS. 8A to 8D or 10A to 10C.

Referring to FIG. 13 (A), when the W layer 42 is subjected to reactive ion etching with a fluoride gas, a reaction product WFx is generated, and the generated WFx reaches the electrode 3, and the nuclei on the electrode 3 Agglomerates around. By repeating the etching, the nuclei grow as shown in FIG. 13B, and the particles 50 are formed. In addition, particles 50
When the particles are separated from the surface of the electrode 3, the particles 50 become particles in FIG.
As shown in FIG. 5, the etching gas flows from the electrode 3 to the electrode 2 and reaches the substrate 4 to cause a defect. The number of particles on the substrate 4 continues to increase as shown in FIG. 13D by continuing the etching.

Therefore, it is a general object of the present invention to provide a new and useful method and apparatus for manufacturing a semiconductor device, which solves the above problems. A more specific object of the present invention is to provide a method for manufacturing a semiconductor device including a step of treating a W layer by reactive ion etching, to minimize accumulation of particles on an electrode surface facing a semiconductor substrate, It is an object of the present invention to provide a method for manufacturing a semiconductor device in which the adhesion of particles is minimized.

Another object of the present invention is, in a method of manufacturing a semiconductor device, including a step of treating a W layer by reactive ion etching, to transport particles accumulated on an electrode facing a substrate to a substrate surface. It is an object of the present invention to provide a semiconductor device manufacturing method and manufacturing apparatus that minimize the above.

[0024]

According to the present invention, there is provided a processing chamber as set forth in claim 1 and a processing chamber, which is provided in the processing chamber and configured to hold the substrate. In a plasma etching apparatus provided with a first electrode plate and a second electrode plate provided in the reaction chamber so as to face the electrode plate, a substrate having a W layer deposited on the surface thereof is subjected to reactive ion etching. In a method of manufacturing a semiconductor device including a step of patterning by etching, a step of holding a substrate having a W layer deposited on the surface thereof on the first electrode plate; and introducing an etching gas into the processing chamber, Forming a plasma between the first and second electrode plates and carrying out reactive ion etching of the W layer, and prior to the reactive ion etching process, the surface of the second electrode plate is The above It reacted with halogen compounds of the resulting W reactive ion etching in the Rishitsu,
Including a step of covering with a material that forms a volatile product, the reactive ion etching step in the processing chamber,
The method further includes the step of setting the flow of the etching gas from a first direction from the second electrode plate toward the first electrode plate to another direction that avoids the first electrode plate. According to a method for manufacturing a semiconductor device or as set forth in claim 2, the step of setting the flow of the etching gas is performed by introducing the etching gas from an inlet formed in the second electrode plate into the processing chamber. The process of introducing
Including a step of flowing the etching gas introduced into the processing chamber in the first direction, and a step of deflecting the flow of the etching gas flowing in the first direction to another direction. According to the method of manufacturing a semiconductor device according to claim 1, or as described in claim 3,
In the step of setting the flow of the etching gas, the etching gas may be a first surface of the pair of main surfaces defining the second electrode plate facing the first electrode plate in the processing chamber. 2. The semiconductor device according to claim 1, further comprising a step of introducing the gas into the processing chamber from an introduction port located on the side of the second main surface opposite to the main surface and flowing along the second main surface. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the reactive ion etching step is performed by using NF ₃ as an etching gas, as described in claim 4. Alternatively, as described in claim 5, the reactive ion etching process is performed using NF.
_The method of manufacturing a semiconductor device according to claim 1, wherein a mixed gas of ₃ and Ar is used as an etching gas, or the reactive ion etching step is performed in 400 times. ° C to 500 °
2. Carrying out at a temperature in the range C. 1.
According to the method for manufacturing a semiconductor device described above or as described in claim 7, the surface of the second electrode plate is covered with SiO ₂ , Si before the reactive ion etching step.
9. The method of manufacturing a semiconductor device according to claim 1, further comprising a step of covering with a material selected from the group consisting of C, C, Si, SiN, and a mixture thereof, or as described in claim 8. A processing chamber; a first electrode plate provided in the processing chamber for holding a substrate; and an etching gas provided in the processing chamber so as to face the first electrode plate. A second electrode plate having an introduction port formed therein, which is connected to the second electrode plate and has an etching gas passage formed therein which communicates with the introduction port. In a plasma etching apparatus comprising a pipe introduced into the processing chamber through an introduction port, the second electrode plate, on the main surface facing the first electrode, is introduced from the introduction port, Inside the processing chamber, the second 10. A plasma etching apparatus characterized in that a flow channel deflecting structure for changing a flow channel of an etching gas flowing toward an electrode is formed, or as described in claim 9, the flow channel deflecting structure includes the second channel. 9. The plasma etching apparatus according to claim 8, wherein the plate is formed on the substrate at a position so as to close the inlet, and is separated from the main surface of the second substrate. A processing chamber; a first electrode plate provided in the processing chamber for holding a substrate; and a second electrode plate provided in the processing chamber so as to face the first electrode plate. A plasma etching apparatus comprising: an electrode plate; a pipe connected to the second electrode plate, having a passage for an etching gas formed therein, and supplying an etching gas to the processing chamber, wherein An inlet for introducing the etching gas into the processing chamber is formed on the side opposite to the first electrode plate with respect to the electrode plate, in communication with the passage of the etching gas. The main surface of the second electrode plate facing the first electrode plate may be formed by a plasma etching apparatus or as described in claim 11, in which W generated as a result of the reactive ion etching in the processing chamber. 11. A plasma etching apparatus according to claim 8 or 10, characterized in that it is covered with a material that reacts with halogen compounds to form volatile products, or as described in claim 12. The main surface of the second electrode plate facing the first electrode plate is Si
_{O 2, SiC, C, Si} , SiN and it is solved by a plasma etching apparatus according to claim 8 or 10, wherein the covered with a material selected from the group consisting of mixtures.

[0025]

The principle of the present invention will be described below with reference to FIGS. Referring to FIG. 1 (A), in the present invention, the surface of the counter electrode 3 is covered with a material such as SiO ₂ which reacts with a halogen compound of W to generate a volatile product. As a result, as shown in FIG.
When the reaction product WFx is generated by the reactive ion etching with NF ₃ , the reaction product reacts with the SiO ₂ covering the surface of the electrode 3 and is immediately removed from the processing chamber. Further, as shown in FIG. 1A, even if the particles 50 are already formed on the surface of the electrode 3, WFx lifts off the particles, so that the particles do not substantially grow, and the particles are efficiently grown from the substrate surface. Will be removed. That is, particles do not accumulate on the surface of the electrode 3. Further, as shown in FIGS. 1C and 1D, particles are not accumulated on the surface of the electrode 3 even if etching is repeated.

Claims 4 and 5 or claims 9 and 10 are based on such a principle, and the counter electrode 3
Minimize the accumulation of particles on top. Further, in the present invention, in order to prevent the particles lifted off from the surface of the electrode 3 from reaching the substrate 4 held on the electrode 2 together with the flow of the etching gas, the etching gas of the etching chamber The flow path is changed from the conventional one.

Generally, in the plasma etching apparatus having the structure shown in FIG. 7, whether or not the particles on the electrode 3 reach the substrate 4 depends on the sedimentation speed of the particles due to gravity and the etching gas flowing from the electrode 3 to the electrode 2. It depends on the difference in the flow velocity of. If the flow velocity of the etching gas is higher than the sedimentation velocity of particles, some of the particles may reach the substrate 4 on the electrode 2 even if the generation of particles is suppressed.

The gravitational sedimentation velocity v _g of the particles is: v _g = ρ _p C _c d _p ² g / 18 η (1) C _c = 1 + (2 / Pd _p ) [6.32 + 2.01 exp (-0.1095Pd _p )] (2) (RP Donovan et. Al., J. Electroche
m Soc. vol.140, 1993, pp2917). Here, P is the internal pressure of the processing chamber in units of cmHg, d _p is the particle diameter, ρ _p is the particle density, g is the gravitational acceleration, and η is the viscosity coefficient of the etching gas.

On the other hand, the gas flow velocity v in the processing chamber
_fLet v be the diameter of the gas introduction pipe and F be the gas flow rate, then_f= F / (D / 2)²It is given by π (3). Therefore, the pressure P is 0.2 Torr and the particle size is
d_p1 μm, density ρ_p1 g / cm ², Gravity acceleration g
To 980 cm / s², Viscosity coefficient η is 20 × 10 -5 g / c
Gravity sedimentation velocity v_gIs 2.27 cm / s
Is required. On the other hand, the flow rate F is 200 SCCM,
If the pipe diameter D is 1.2 cm, the etch in the processing chamber will be
Velocity of the ching gas v_fIs 3.00 cm / s. this
The result is that the particles on the electrode 3 reach the surface of the substrate 4.
It means that it will end up.

In order to prevent the particles from being transported by the etching gas, the flow path of the etching gas in the processing chamber 1 is changed so as not to directly reach the electrode 3 and the substrate 4 thereon from the electrode 3 in the present invention. According to claims 1 and 2, or 6 and 7, such a change of the flow path is performed by providing a disk on the electrode 3 which acts as a deflecting plate on the gas inlet, and the gas introduced from the gas inlet directly enters the electrode 2. Avoid reaching. Further, in the first and third aspects or the eighth aspect, the gas introduction port is formed behind the electrode 3 to prevent the etching gas introduced into the processing chamber from directly reaching the substrate 4.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIG. FIG. 2 is a diagram showing the configuration of the plasma etching apparatus according to the first embodiment of the present invention. However, in FIG. 2, the same parts as those of FIG. 7 described above are designated by the same reference numerals,
Description is omitted.

Referring to FIG. 2, the shower nozzle 3c used in the apparatus of FIG. 7 is removed, and a quartz glass cover 3f is formed on the surface of the electrode 3 facing the electrode 2. The quartz glass cover 3f has an opening 3e aligned with the passage 3d for the etching gas, and the etching gas is introduced into the processing chamber 1 through the opening 3e. Cover 3f
Has a shape and size corresponding to the outer shape of the electrode 3, and continuously covers the surface of the electrode except the opening 3e. Further, a quartz glass disk 3g is provided on the cover 3f so as to cover the opening 3e, and is separated from the surface of the quartz glass cover 3f.

FIG. 3 is an enlarged view of a portion of the electrode 3 including the quartz glass disk 3g. As can be seen from FIG. 3, the quartz glass disk 3g is formed corresponding to the opening 3e of the quartz glass cover 3f, and the quartz glass rod 3g is formed.
The flow of the etching gas, which is supported by _{1 to 3} g ₃ and is introduced into the processing chamber 1 through the opening 3e, is deflected so as not to go directly to the electrode 2 but to the side.

In operation, the processing chamber 1 is evacuated through the exhaust port 1a, and NF ₃ is discharged through the passage 3d and the opening 3e.
A halogen-based etching gas such as is introduced into the processing chamber 1. Similar to the case described with reference to FIG. 7, a high frequency power of about 200 W is supplied from the high frequency power supply 7 to the electrode 2, plasma consisting of halogen ions is formed between the electrodes 2 and 3, and the W layer on the substrate 4 is formed. Reactive ion etching occurs.

In the structure of FIG. 2, since the surface of the electrode 3 is covered with the quartz glass cover 3f, that is, SiO ₂ , the WFx molecules generated by the reactive ion etching of the W layer in the substrate 4 are shown in FIG. 1 (A). By the mechanism shown in to (D), it immediately reacts with SiO _{2 on the} surface of the cover 3f,
The reaction chamber 1 is immediately exhausted as a volatile product. Further, the flow of the etching gas supplied through the passage 3d and introduced into the processing chamber 1 through the opening 3e is deflected laterally in the quartz glass disk 3g as indicated by an arrow X in FIG. And the substrate 4 held on it will not be reached directly. Therefore, even if particles are present on the quartz glass cover 3f, it is possible to prevent these particles from reaching the substrate 4 against the sedimentation due to gravity due to the flow of the etching gas.

FIG. 4 corresponds to FIG. 9 described above and shows the generation of particles on a Si substrate when a single wafer processing is performed using the apparatus of FIG. 2 as a function of the number of processed substrates. . However, the experimental conditions were set to be the same as in the case of FIG. That is, the W layer 42 was patterned by the steps of FIGS. As can be seen from FIG. 4, the tendency that the number of particles generated on the substrate increases as the single-wafer processing progresses disappears, and it can be seen that the number of particles generated is 100 or less even in the 22nd substrate.

FIG. 5 corresponds to FIG. 11 described above, and FIG.
2 shows a change in the yield of semiconductor devices with the progress of processing when single-wafer processing is performed using this apparatus. Similar to the case of FIG. 11, the experiment of FIG. 5 also shows the relative value normalized by the maximum yield. As can be seen from FIG. 5, when a semiconductor device is formed using the device of FIG. 2, the yield does not depend on the number of processed substrates.

FIG. 6 shows the structure of the plasma etching apparatus according to the second embodiment of the present invention. However, in FIG. 6, the parts described previously are designated by the corresponding reference numerals, and the description thereof will be omitted. Referring to FIG. 6, in the present embodiment, the opening 3f formed in the electrode 3 in the apparatus of FIG. 2 is removed, and instead an opening 3h is formed at a position behind the electrode 3 on the pipe 3a. . Along with this, the entire surface of the electrode 3 is covered with the quartz glass cover 3f.

In the structure of FIG. 6, the etching gas supplied through the passage 3d is discharged from the opening 3h, and the electrode 3
Flows sideways along the back surface of the, as indicated by arrow X.
As a result, particles on the quartz glass cover 3f are prevented from reaching the substrate 4. Moreover, since the entire surface of the electrode 3 on the side facing the electrode 2 is covered with the quartz glass cover 3f, particles do not accumulate on the cover 3f.

2 and 6, the cover provided on the electrode 3 is not limited to quartz glass, and may be SiC, C, Si, SiN or a mixture thereof. Further, in carrying out the present invention using the plasma etching apparatus of FIG. 2 or 6, the etching gas is not limited to NF ₃ , and other halogen gas may be used.

The present invention is not limited to the embodiments described above, and various modifications and changes can be made within the scope of the present invention.

[0042]

According to the features of the present invention as set forth in claim 1 or 11, the flow path of the etching gas is set so as to avoid the first electrode plate holding the substrate, The particles formed by the agglomeration of WFx on the second main surface are not transported to the substrate, and the adhesion of the particles to the substrate surface can be minimized. As a result, semiconductor devices having a highly reliable W wiring pattern can be mass-produced at low cost by single-wafer processing. Further, by covering the surface of the second electrode facing the substrate in the plasma etching apparatus with a material that reacts with the halogen compound of W to generate a volatile product, the halogen compound of W is generated as a result of etching. Even if generated as a substance, such a product reacts with the material covering the surface of the second electrode and changes into a volatile product, so that the accumulation of particles on the surface of the second electrode does not substantially occur. .

In particular, according to the features of the present invention as set forth in claim 2, 8 or 9, in the conventionally used plasma etching apparatus, the flow of the etching gas introduced from the second electrode plate into the processing chamber is deflected. It is only necessary to provide the structure on the second electrode plate, and it is not necessary to use or manufacture a plasma etching apparatus having a special structure.

According to the features of the present invention described in claim 3 or 10, the desired flow path of the etching gas can be deflected without providing a special structure on the surface of the second electrode plate. A stable plasma can be formed between the first electrode and the second electrode when performing the ion etching. According to the features of the present invention described in claims 4 to 6, by using an etching gas containing NF ₃ , reactive WFx is formed by the etching of W, and particles deposited on the counter electrode are immediately lifted off. To be done.

According to a seventh aspect of the present invention, the surface of the second electrode is formed of SiO ₂ , SiC,
By covering with a material selected from the group consisting of C, Si, SiN, and a mixture thereof, accumulation of particles on the surface of the second electrode can be substantially removed.

[Brief description of drawings]

FIG. 1A to FIG. 1D are views for explaining the mechanism of reactive ion etching according to the present invention.

FIG. 2 is a diagram showing a configuration of a plasma etching apparatus according to a first embodiment of the present invention.

FIG. 3 is a diagram illustrating a main part of the apparatus of FIG.

4 is a diagram showing the number of particles generated on a substrate in a single-wafer processing using the apparatus of FIG.

5 is a diagram showing a relative yield on a substrate in a single wafer processing using the apparatus of FIG.

FIG. 6 is a diagram showing a configuration of a plasma etching apparatus according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a conventional plasma etching apparatus.

8A to 8D are diagrams illustrating patterning of a W layer in the etching apparatus of FIG.

9 is a diagram showing generation of particles on a substrate when a single wafer processing is performed in the plasma etching apparatus of FIG.

10A to 10C are diagrams illustrating a defect formation mechanism of a semiconductor device due to particles.

11 is a diagram showing a decrease in relative yield of semiconductor devices when a single wafer processing is performed in the plasma etching apparatus of FIG.

12 is a diagram showing a result of measuring Al atom density detected on a substrate in the plasma etching apparatus of FIG.

13 (A) to 13 (D) are views for explaining a mechanism of particle generation accompanying reactive ion etching of W in a plasma etching apparatus, which is proposed by the inventor of the present invention.

[Explanation of symbols]

1 Vacuum Processing Chamber 1a Exhaust Port 2 Upper Electrode 2a Electrostatic Chuck 2b Quartz Cover 3 Lower Electrode 3a Piping 3b Shower Nozzle 3c Opening 3d Etching Gas Passage 3e, 3h Gas Outlet 3f Quartz Cover 3g Deflection Plate 3g _{1 to} 3g ₃ Strut 4 Substrate 5 Plasma etching apparatus body 6 Insulation part 7 High frequency power supply 8 Quartz liner 41 TiN barrier layer 42 W layer 43 Antireflection film 44 Resist pattern 50 Particles

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Daisuke Matsunaga 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (12)

[Claims] 1. A processing chamber, a first electrode plate provided in the processing chamber and configured to hold the substrate, and provided in the reaction chamber so as to face the electrode plate. A plasma etching apparatus including a second electrode plate, and a step of patterning a substrate having a W layer deposited on its surface by reactive ion etching. A step of holding a substrate having a W layer deposited on the surface thereof; introducing an etching gas into the processing chamber to form plasma between the first and second electrode plates, and reactive ion etching of the W layer. Prior to the reactive ion etching step, the second step is performed.
The step of covering the surface of the electrode plate with a material that forms a volatile product by reacting with a halogen compound of W generated as a result of the reactive ion etching in the processing chamber, wherein the reactive ion etching step comprises: A step of setting the flow of the etching gas in the processing chamber from a first direction from the second electrode plate toward the first electrode plate to another direction avoiding the first electrode plate; A method of manufacturing a semiconductor device, comprising: 2. The step of setting the flow of the etching gas, the step of introducing the etching gas into the processing chamber from an inlet formed in the second electrode plate, and the step of introducing the etching gas into the processing chamber. The method includes the steps of flowing the introduced etching gas in the first direction and deflecting the flow of the etching gas flowing in the first direction in another direction. Item 2. A method of manufacturing a semiconductor device according to item 1. 3. The step of setting the flow of the etching gas, the etching gas in the processing chamber,
Of the pair of main surfaces defining the second electrode plate, the introduction port is located on the side of the second main surface opposite to the first main surface facing the first electrode plate. 2. The method of manufacturing a semiconductor device according to claim 1, further comprising the step of introducing it into a processing chamber and flowing it along the second main surface. 4. The reactive ion etching step comprises N
2. The method for manufacturing a semiconductor device according to claim 1, wherein F ₃ is used as an etching gas and the etching is performed. 5. The reactive ion etching step comprises N
2. The method of manufacturing a semiconductor device according to claim 1, wherein a mixed gas of F ₃ and Ar is used as an etching gas and the etching is performed. 6. The reactive ion etching process comprises 4 steps.
The method for manufacturing a semiconductor device according to claim 1, wherein the method is performed at a temperature in the range of 00 ° C to 500 ° C. 7. Prior to the reactive ion etching step, the surface of the second electrode plate is covered with SiO ₂ , C, S.
A step of coating with a material selected from the group consisting of i, SiN, and mixtures thereof.
The manufacturing method of the semiconductor device described in the above. 8. A processing chamber; a first electrode plate provided in the processing chamber for holding a substrate; and a first electrode plate in the processing chamber.
A second electrode plate that is provided so as to face the electrode plate and that has an introduction port for introducing an etching gas into the processing chamber; etching that is connected to the second electrode plate and communicates with the introduction port. A plasma etching apparatus comprising a pipe having a gas passage formed therein and introducing the etching gas in the passage into the processing chamber through the introduction port, wherein the first electrode of the second electrode plate is provided. On the main surface facing the electrode, it is introduced from the introduction port, and the second inside of the processing chamber is introduced.
A plasma etching apparatus having a flow path deflecting structure for changing a flow path of etching gas flowing toward the electrode. 9. The flow path deflecting structure comprises a plate formed at a position on the second substrate that closes the introduction port and spaced from the main surface of the second substrate. The plasma etching apparatus according to claim 8. 10. A processing chamber; provided in the processing chamber,
A first electrode plate for holding the substrate; a second electrode plate provided in the processing chamber so as to face the first electrode plate; and a second electrode plate connected to the second electrode plate for etching gas. A plasma etching apparatus comprising a pipe having a passage formed therein and supplying an etching gas to the processing chamber, wherein the pipe is provided on a side opposite to the first electrode plate with respect to the second electrode plate. A plasma etching apparatus, wherein an introduction port for introducing the etching gas into the processing chamber is formed in communication with a passage of the etching gas. 11. The main surface of the second electrode plate facing the first electrode plate reacts with a halogen compound of W generated as a result of reactive ion etching in the processing chamber to generate a volatile product. The plasma etching apparatus according to claim 8 or 10, wherein the plasma etching apparatus is covered with a material that forms a film. 12. The main surface of the _second electrode plate facing the first electrode plate is made of SiO ₂ , SiC, C, Si, Si.
11. Covered with a material selected from the group consisting of N and mixtures thereof.
The plasma etching apparatus described.