TWI223341B - Method of etching porous insulating film, dual damascene process, and semiconductor device - Google Patents

Abstract

This invention discloses a method of etching a porous insulating film with a plasma which comprises using as a treating gas a gas mixture comprising a fluorocarbon gas, e.g., CF4, and an inert gas, e.g., argon, and regulating the pressure to a value of 150 to 300 mTorr to thereby inhibit spike generation during the etching. The RF power density is preferably 0.25 to 0.50 W/cm<2>.

Description

1223341 A7 __B7 V. Description of the Invention (彳) Technical Field of the Invention The present invention relates to a method for engraving a porous insulating film, a method for manufacturing a two-pass metal insert, and a semiconductor device. Background Art In recent years, with the increase in the density of semiconductor integrated circuits, the delay in the transmission of wiring has gradually become an important factor that determines the operating speed. Therefore, a low-dielectric-constant film is used for the interlayer insulating film to suppress the propagation delay. As a method for reducing the specific dielectric constant of the interlayer insulating film, there is a method of making the interlayer insulating film porous. In the case of using a porous insulating film in a semiconductor manufacturing process', in order to form a via, the porous insulating film must be engraved. This porous insulating film etching method is to efficiently etch the porous insulating film while ensuring a certain degree of selection ratio between the porous negative insulating film and the photoresist. Therefore, a C ^ Fs / Ar-based gas, CF4 is used. / Ar gas and so on. In addition, in order to improve the etching rate, it is suitable for etching with a high aspect ratio, and these gases are also mixed with oxygen (02), carbon monoxide (C0), or nitrogen (n2). In addition, when these etching gases are plasmatized and etched, the average free path of the ions is increased so that the ions easily enter the contact holes. At the same time, in order to maintain the in-plane uniformity during etching, worm etching is performed at low pressure and high output. However, when the etching gas is mixed with a 02 gas and the porous insulating film is etched under low pressure and high output conditions, the porous insulating film may have a problem of protrusion. In particular, the generation of this protrusion will become a more serious problem in the two-channel metal damascene manufacturing method. In addition, the so-called protrusions are undulations on the bottom surface of the porous insulating film to be etched. Figure 8 shows the dual-channel metal inlay manufacturing using the previous porous insulating film-4-I paper size SS Home Standard (CNS) A4 specification (210X297 male Θ &quot; ---------- 1223341 2 V. Description of the invention (Sectional view of the method. As shown in FIG. 8 (a), a porous insulating film 42 and a silicon nitride film 43 are formed in the lower layer area 41. By using photolithography technology and etching technology, The film 43 forms an opening portion suitable for the via 32. In addition, the lower layer area 41 is a lower wiring layer such as a silicon substrate, copper (Cu), or aluminum (A1). Next, on the silicon nitride film 43 A porous insulating film 44 is formed, and a photoresist film 45 is formed over the entire surface. Then, by using photolithography technology, an opening portion H4 suitable for the wiring trench 2 is formed in the photoresist film 45. Next, as shown in FIG. 8 (b) As shown in the figure, the photoresist film 45 serves as a mask, and a wiring trench T2 is formed in the porous insulating film 44 by etching E3 such as reactive ion etching RIE. Here, an etching gas for etching E3 is used to ensure porosity. The selection ratio of the insulating film 44 and the silicon nitride film 43 is based on the use of a C4F8 gas. In addition, the etching rate is improved while maintaining the etching In-plane uniformity at this time, the pressure is set to a low pressure of less than 50 mTorr, and the RF power density is set to a high output of more than 0.5 W / cm2. Under this condition, when the E3 of the porous insulating film 44 is etched, the The solid insulating film 44 will generate protrusions SP. Therefore, when the etching E3 is stopped during the etching of the porous insulating film material, the remaining protrusions SP will be left on the step D2 of the wiring trench T2, as shown in FIG. 8 (c), The silicon nitride film 43 is used as a mask, and then E3 is continuously etched to form a via hole b2 in the porous insulating film 42. Here, the porous insulating film 44 is over-etched on the step D2 of the nitride broken film 43. The protrusions SP on the step D2 are removed. In addition, the protrusions generated in the porous insulating film 42 when the via hole B2 is formed can also be removed by etching the porous insulating film 42. Next, as shown in FIG. 8 (d), Remove the photoresist 45, fully deposit Cu or A1, etc.-5- This paper size is applicable to China National Standard (CNS) A4 specification (210 X 297 mm)

1223341 A7 ______B7 V. Description of the invention (4) It means “Extreme load”, which is expressed by (narrow groove etch rate) / (wide groove etch rate) X 1⑻%. The method for etching a porous insulating film according to the present invention is based on the method described above, and is characterized in that the RF power density is 0.25 W / cm2 or more and 0.50 W / cm2 or less. In the case of the insulating film, the film is softer than the non-porous insulating film, so even when the RF power density is reduced, it does not significantly hinder the progress of etching. Therefore, on the one hand, it is possible to prevent the etching characteristics of the porous insulating film from being severely lowered. On the other hand, it is possible to suppress the occurrence of protrusions of the porous insulating film. The method for etching a porous insulating film according to the present invention is based on the method described above, wherein the fluorocarbon-based gas is CL and the inert gas is Ar. By using a gas with a large F / C ratio, it is possible to suppress the accumulation of carbon-based polymers on the one hand due to the low etching speed, and on the other hand, it is possible to perform etching of a porous insulating film. rate. The method for etching a porous insulating film according to the present invention is based on the method described above, and it is specifically intended that the flow rate of the fluorocarbon-based gas further includes oxygen of 0.25 or less. By reducing the flow rate of oxygen (〇2), the carbon component suppresses the reaction with oxygen (〇2) even when the porous insulating film contains a carbon component, because it can inhibit the carbon component from detaching from the porous insulating film. Therefore, it is possible to suppress protrusions during etching of the porous insulating film. In addition, the semiconductor device of the present invention is a semiconductor device formed in a wiring trench and a via hole according to a two-channel metal damascene manufacturing method, and is characterized in that the paper size is in accordance with the Chinese National Standard (CNS) A4 specification (210X297 mm)

Describe the formation of the wiring trench .. _ 々 Xi Porous Insulation Film and the porous shell insulation film formed by the aforementioned vias are formed without interfering with the barrier layer ^ 4 ^ The porous insulation film is substantially enlarged when it is diagonally engraved. Does not exist. According to the present semiconductor device, even if the barrier layer is not shaped and has the same ratio between the porous insulating films, it can be generated in the wiring groove portion of the porous insulating film, and the transmission delay of the wiring can be suppressed while improving. Reliability of wiring buried in wiring trenches. This: 'The dual-channel metal damascene manufacturing method of the present invention is characterized by having a step of forming a first photoresist film formed on the edge film by applying a pattern of suitable via holes; and, cutting the first photoresist The film is used as a cover, and the step of forming the through hole of the porous insulating film is performed by the aforementioned porous insulating film; and the step of removing the first photoresist film; and # forming an applicable wiring on the porous insulating film. A step of forming a second photoresist film with a groove pattern; and under the conditions that the RF power density is 0.25 w / cm2 or more and 500 w / cm2 or less, and the pressure is mTorr or more and 300 mTorr or less, the aforementioned second photoresist film is used as The mask step is to perform the aforementioned step of etching the porous insulating film to form a wiring groove in the porous negative &amp; edge film; and a step of removing the second photoresist film; and in the via hole and the wiring groove. Step of embedding conductive material. — According to the two-channel metal damascene manufacturing method of the present invention, through holes and wiring trenches can be formed in the porous insulating film without using a barrier layer such as a nitrided broken film. At the same time, the protrusion during the etching of the porous insulating film can be suppressed, and it can be simple. Shuangdao Metal -8- This paper size applies to China National Standard (CNS) A4 (210X297 mm)

Inlay manufacturing method. In addition, the method for manufacturing a two-channel metal inlay according to the present invention is characterized in that the processing gas for the step of forming a wiring trench in the epithelial sacral shell insulation film is a mixed gas of a fluorocarbon-based gas and an inert gas, and a fluorocarbon-based The gas is CF4 and the inert gas is Ar. According to the two-channel metal damascene manufacturing method of the present invention, because there is no barrier film such as a nitrided shatter film, there is no need to consider the selection ratio between the barrier film and the porous insulating film, so a larger F / C ratio (:: 174 Instead of C4F8 type gas, the gas-like gas is used to etch the porous insulating film, and the etching rate can be improved when the porous insulating film is etched. Fig. 2 A ~ D are cross-sectional views showing a comparison of the results of the engraving of the embodiment of the present invention with the previous examples. Figs. 3A and B are pressure dependence diagrams showing the etching characteristics of the embodiment of the present invention. Fig. 4A , B is a rf power density dependency graph showing an etching characteristic related to the embodiment of the present invention. FIG. 5A, B is a 02 flow dependence graph showing an etching characteristic related to the priming example. FIG. 6A, B is A graph showing the temperature dependence of the bottom end of the etching characteristics of the embodiment of the present invention is shown in Figs. 7A to 7D are diagrams showing a two-lane metal inlay of the embodiment of the present invention. Standard (CNS) A4 size (210 X 297 male directors) A7 B7

1223341 V. Description of the invention A sectional view of a manufacturing method. 8A to 8D are plan views showing a conventional two-channel metal damascene manufacturing method. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the method for implementing the embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a sectional view showing a schematic configuration of an etching apparatus according to an embodiment of the present invention. In addition, this embodiment is described with the case of &quot; gas as the last name gas. a. In FIG. 1, an upper electrode 2 and a crystal base 3 are provided in the processing chamber 1. This crystal base 3 also serves as a lower electrode. The upper electrode 2 is provided with a gas ejection hole 2a for introducing an etching gas into the processing chamber. In addition, the crystal base 3 is supported by four crystal base supporting tables, and the crystal base supporting table 4 is fixed in the processing chamber 丨 via the insulating plate 5. Plasma crystal seat 3. A refrigerant chamber 10 is provided on the support stand 4 and a refrigerant such as liquid nitrogen passes through the refrigerant supply pipe 10a and the refrigerant discharge pipe 10b to circulate inside the refrigerant chamber 10. In addition, the wafer W can be cooled by the heat and cold transmitted to the wafer w through the wafer support table 4 and the wafer holder 3 '. An electrostatic suction base 6 is provided on the pedestal 3, and the electrostatic suction base 6 has a structure in which a conductive layer 7 is sandwiched between polyimide films 8a and 8b. Here, the conductive layer 7 is connected to a DC high-voltage power source 12 ′. By supplying a DC high voltage to the conductive layer 7, a Coulomb force is applied to the wafer boundary, and the wafer w can be fixed on the wafer base 3. In addition, a gas passage 9 filled with helium (He) gas is provided on the crystal base 3 and the electrostatic suction base 6. 'The helium (He) gas is sprayed to the back surface of the wafer W through this gas passage 9-10- Chinese National Standard (5 ^ ϋ ^ 10χ 297 mm)

Binding

1223341 A7

The wafer W placed on the seat 3 can be placed on the next day. Here, the gas passage 9 is connected to the helium (He) gas supply source 16 through the flow I reforming valve 16a and the on-off valve 16b, and can control the pressure of the helium (He) gas on the back of the wafer ... "" In processing 罜 1, a gas supply pipe la and an exhaust pipe lb are provided. The gas supply pipe la is connected to the CF4 gas supply source 14 and the gas supply source 15 through the flow adjustment valves 14a and 15a and the switches 仙 and i5b. The exhaust pipe is connected to a vacuum pump. With this vacuum pump, the gas in the processing chamber 丨 can be removed, and the pressure in the processing chamber and the process can be adjusted. A horizontal magnetic field forming magnet 13 is set around the processing chamber 1 and is applied in the processing chamber 1. Magnetic field can increase the density of plasma to efficiently carry out worm engraving. When the porous insulating film is etched, the wafer W formed by the porous insulating film is placed on the crystal base 3, and the electrostatic absorption base 6 is used. Secondly, remove the gas from the processing chamber, adjust the pressure in the processing chamber, and open the f-close valves i4b, 15b at the same time, fill the processing chamber with 4 gas and ^ gas. Fine flow control valves 14a, 15a The flow rate ratio of CF4 gas to M gas can be adjusted. It supplies the rf power from high-frequency power source 11 to sun seat 3 for a long time, and the plasma etching gas is used to etch the porous insulating film. At this time, open the on-off valve 1 / \ Put helium gas into the gas path 9 by This helium gas is ejected from the body passage 9: to cool the wafer w. In addition, the flow temperature adjustment valve i can be used to adjust the pressure of the helium gas to control the cooling temperature of the wafer W. When the porous insulating film is etched Under the conditions, the RF power density is 0.25 0 · 50 W / cm 'in the processing chamber! The pressure in the processing chamber is 150 ~ 300 mT0rr. As mentioned above, the occurrence of protrusions can be suppressed, and on the one hand, it can be performed at any depth. Eclipse-11- 1223341 A7 ___B7 V. Description of the invention (9) A porous insulating film is etched. In addition, a porous insulating film refers to, for example, porous hydrogen silsesquioxane (HSQ), porous methyl silsesquioxane MSQ (methyl silsesquioxane), porous organic material, or porous dioxide (SiO2), and its density is 1.3 g / cm3 or less. In addition, the above embodiment is performed using a magnetron RIE device. The method of engraving is described, and it can also be applied to ECR (electron cyclotron resonance) plasma etching device, HEP (spiral wave excited plasma) etching device, ICCP (inductive plasma mixing) etching device, TCP (variable pressure extraction) Type plasma) etching device, etc. The following is a reference The experimental data related to the embodiment of the present invention will be described below. In addition, the following embodiment uses the sample of FIG. 2 (a) to etch using the etching apparatus of FIG. 1. In FIG. 2 (a), the silicon nitride film is used. 21. The porous MSQ film 22 and the anti-reflection film 23 are laminated in this order. On the anti-reflection film 23, a photoresist film 24 is formed between the laminated wire and Shiba. The film thickness of the silicon nitride film 21 is 300 nm. The thickness of the porous MSQ film 22 is 600 nm, the thickness of the antireflection film 23 is 75 nm, and the thickness of the photoresist film 24 is 540 nm. Figs. 2 (b) to (d) are cross-sectional views showing the results of etching according to an embodiment of the present invention compared with the conventional example. Here, the condition of the last name of the previous example 1 is a mixed gas with a flow rate of 10/50/200/200 seem to be 0? 8, N2, C0, and Ar. In addition, the RF power is set to 1500 W, the waste force is 35 mTorr, the He pressure on the back of the wafer is 7 Torr at the center, 40 Torr at the edges, the top and wall temperatures are 60 ° C, and the bottom temperature is 40 ° C. Etch for 20 seconds. In addition, the distance between the electrodes is 37 mm, and the anode diameter is 260 mm. In this case, in a pattern with a line and space of 0.25 μιη / 0 · 25 / xm, porous -12- This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) 1223341 A7 B7 V. Description of the invention ( 10) The MSQ film 22 is only etched in a depth direction of 395.8 nm, and the pattern is 0.25 μm / 1.25 μm in the line and space. The porous MSQ film 22 is only etched in a depth direction of 458.3 nm. At this time, the surname engraving rate is 1 1 87.4 nm / sec for the pattern of line and space of 0.25 μηι / 0.25 μm, and the pattern for line and space of 0.25 μm / 1.25 μm is 1 3 75 nm / sec. In addition, as shown in Fig. 2 (b), any line and space will have a protrusion on the facet of the surname. In addition, the etching conditions of the previous example 2 are a mixture of CF4, Ar, and 02 with a flow ratio of 80/160/20 seem. In addition, set the RF power to 500 W, the pressure to 40 mTorr, the He dust on the back of the wafer: 7 Torr at the center, 40 Torr at the edges, the top and wall temperatures of 60 ° C, and the bottom temperature of 40 ° C , Etch for 20 seconds. In this case, in a pattern with a line and space of 0.25 μm / 0 · 25 μηι, the porous MSQ film 22 etches only 270.8 nm in the depth direction, and in a pattern with a line and space of 0.25 // m / 1.2 5 / xm, the porous MSQ film 22 Only the depth of 302 nir ^ is etched at this time. The pattern of 0.25 /xm/0.25 μηι in line and space is 812.4 nm / sec, and the pattern of 0.25 μm / 1 · 25 / xm in line and space is 906 nm / sec. . In addition, as shown in FIG. 2 (c), any line and space will have protrusions on the etched surface. In addition, the etching conditions in this example are a mixed gas of CF4 and Ar with a flow rate ratio of 80/1 60 seem. In addition, the RF power is set to 500 W, the pressure is 150 mTorr, the He pressure on the back of wafer W is 7 Torr at the center, 40 Torr at the edges, the top and wall temperatures are 60 ° C, and the bottom temperature is 40 ° C. Etch for 35 seconds. In this case, the pattern with lines and spaces of 0 · 25 μιη / 0 · 25 μιη is porous. -13- This paper size applies to China National Standard (CNS) Α4 (210X 297 mm)

Binding

1223341 Α7 Β7 V. Description of the invention (η MSQ film 22 only etches 2 70 · 8 nm in the depth direction, and the pattern in the line and space is 0 2 5 / xm / l · 0 μηι. At this time, the insect engraving rate is in the line The pattern with space 〇μπι / 0 · 25 / zm is 464.2 nm / second, and the pattern with line and space 〇25 # m / i 〇 / xm is 482 · ι nm / second. In addition, as shown in Figure 2 (d) It is shown that any line and space can suppress the protrusion of the etching surface. In this way, when the porous MSQ film 22 is etched, the 02 gas is removed from the etching gas, and at the same time, by increasing the pressure, the etching rate is prevented from falling below the practical level. On the one hand, the protrusion on the etched surface can be suppressed. In addition, when the size of the protrusion is quantitatively expressed, it can be calculated by (the height of the upper part and the height of the bottom part) / (etching depth). Figure. In this example, the pressure is changed by 50, U0, and 300 mT0rr, and other conditions are the same as in Figure 2 (c). In Figure 3 (a), although the cd displacement increases when the pressure rises, The protrusion is reduced. In addition, as shown in FIG. 3 (b), when the pressure is increased, the micro load is deteriorated. However, even if When the pressure rises, even in the case of a porous MSQ membrane, even in any pattern with a line and space of 0.25 μm / 0 · 25 μm and 0.2 5 /xm/0.75 μm, the worming rate hardly changes. Therefore, by increasing the pressure On the one hand, the decrease in the surname engraving rate can be suppressed, and on the other hand, the protrusion of the surname facet can be reduced. Here, from the viewpoint of suppressing the protrusion, the pressure is preferably 50 mTorr or more, and the higher the better. When the pressure is 500 mTorr or more It is best not to exceed this pressure because the etched shape becomes bow-shaped. In addition, when considering the adverse effects on the amount of CD displacement and micro load, the pressure is preferably in the range of 1 50 mTorr to 300 mTorr. -14- This paper scale applies to China National Standard (CNS) A4 (210 X 297 mm) 1223341

In addition, when the pressure is increased, the protrusions are reduced. This is because the average free step of the ions is reduced when the pressure is increased, and the energy obtained by the ions is reduced, resulting in a decrease in the sputtering power of the ions. Fig. 4 is a graph showing a power density dependency of an etching characteristic according to an embodiment of the present invention. In this embodiment, the RF power density is cultured at 0.15, 0, and 5 W / cm, and other conditions are the same as those in FIG. 2 (c). In addition, the diameter of the 'anode is 260 mm. As shown in FIG. 4 (a), when the RF power density is reduced, although the protrusion is reduced, [ο the amount of displacement has almost no effect. Because &amp; reduces the power density, the protrusion on the etched surface can be reduced. In addition, as shown in Fig. 4 (b), when the RF power density decreases, even if the line-and-space pattern is any one of 0.25 Mm / 0.25 μm & 0.25 μm / 〇75 μm, the etching rate will decrease. Here, from the viewpoint of suppressing protrusions, the RF power density is preferably 0.50 W / cm2 or less, but when the etching rate is reduced, the power density is preferably in the range of 0.25 to 0.50 W / cm2. In addition, when the RF power density is reduced, the protrusions are reduced because the energy obtained by the ions is reduced when the RF power density is decreased, and the sputtering power of the ions is reduced. Fig. 5 is a graph showing the dependence of the flow rate of θ2 on the etching characteristics of the embodiment of the present invention. In this embodiment, 0: The flow rate is changed by 0, 10, 20, and 40 SCcm, and other conditions are the same as those in FIG. 2 (c). In Fig. 5 (a), when the flow rate of 〇2 decreases, both the amount of cD displacement and the protrusion decrease. In addition, in Fig. 5 (b), when there is no mixing, it is compared with that when mixing, even if the line-to-line distance is 0.25 μπι / 0 · 25 // ηι &amp; 0 · 25 μηι / 0 · 75 to 111. Any pattern, -15- This paper size applies Chinese National Standard (CNS) A4 specification (210 X 297 mm) 1223341 A7 B7 V. Description of the invention (13) Although the etching rate is reduced, the micro load will be improved. Therefore, by reducing the flow rate of 0, it is possible to reduce the etching rate to a certain extent and to reduce the protrusion on the etched surface. Therefore, from the viewpoint of suppressing protrusions, the flow rate of 0 is preferably 0, and the flow rate of CD and the micro load can also be improved by the flow rate of 0. However, the 02 flow rate is not necessarily 0, and even if a certain degree of 〇2 is mixed, the protrusion can be suppressed to a practically problem-free level. Therefore, when mixing 02, the flow rate ratio of 02 gas to CF4 gas is preferably 0.25 or less. In addition, it is also possible to set a flow rate ratio of 〇2 gas for the flow rate of the entire gas. In this case, the flow rate ratio of 〇2 gas is preferably 0.08 or less. In addition, as the flow rate of 02 increases, protrusions increase. Because of the porous MSQ, an organic group (mainly, CH3 ') is bonded to the side chain of the main chain of' -O-Si-O- '. That is, when 02 gas is present in the etching gas, the carbon component contained in the organic group reacts with the 02 gas to generate f C-CT with high binding energy, which is caused by the release of the carbon component from the porous MSQ. Fig. 6 is a graph showing the bottom temperature dependence of the etching characteristics in accordance with an embodiment of the present invention. In this embodiment, the temperature of the bottom end of the wafer W is changed at 0, 40, and 80 ° C. Other conditions are the same as those in FIG. 2 (c). As shown in Fig. 6 (a), when the temperature at the bottom end rises, the amount of CD displacement increases, but it has little effect on the protrusions. In addition, in Fig. 6 (b), the bottom temperature has almost no effect on the micro load and the etching rate. Therefore, from the viewpoint of suppressing protrusions, the bottom temperature can be set to any temperature, but from the viewpoint of suppressing the amount of CD displacement, the bottom temperature is preferably low. In this case, the bottom temperature is preferably below 40 ° C. In addition, in the above-mentioned embodiment, the use of CF4 gas is described. -16- This paper size is applicable to China National Standard (CNS) A4 (210 X 297 mm) 1223341

As long as it is a fluorocarbon-based gas, it may be used. For example, C2F6 type gas, c3f6 type gas, dagger type gas, C4F8 type gas, dagger type gas, CHF3 type gas, or similar gas may also be used. In addition, these gases may be mixed with CO or%. Alternatively, other inert gases such as He may be used instead of Ba &lt; 1 &gt;. For example, 〇 ^ 8 gas and 11 * and ^ are mixed at a flow rate ratio of 5: 1000: 150, and RF power density is 0.25 to 0500w / cm2, and pressure is 15 to 300mTon :, which can suppress porosity. Protrusion of insulating film.

Fig. 7 is a sectional view showing a method of manufacturing a two-lane metal damascene according to an embodiment of the present invention. In FIG. 7 (a), a porous insulating film 32 and a photoresist film 33 are formed on the lower layer area 31, and an opening portion 适用 is formed in the photoresist film 33 for the via hole B1 by a photolithography technique. In addition, a lower-layer wiring layer such as the lower-layer area 31 or A1. ^ CU Next, as shown in FIG. 7 (b), the photoresist film 33 is used as a mask, and E1 is etched by RIE or the like to form a through hole B1 in the porous insulating film 32 to the surface of the lower layer. Next, as shown in FIG. 7 (c), the photoresist film 33 is removed, and the photoresist film 34 is completely coated. After that, through the photolithography technique, an opening H2 is formed in the photoresist film 34 for the wiring trench T1. Next, as shown in FIG. 7 (d), the photoresist film 34 serves as a mask, and RIE and iso-etching e2 are performed in the middle of the porous insulating film 32 to form a wiring trench T1 in the porous insulating 2 32. Here, the etching conditions for etching E2 are based on the use of a mixed gas of 0; 4 gas and Ar ', and the RF power is set at a degree of 0.25 to 0.50 W / cm2 and a pressure of 15 to 300 mTorr. As mentioned above, even if the porous insulation film is finished on the way -17 · This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) &quot; —----- 1223341

In the case of etching E2, the step D1 can prevent the generation of protrusions. Next, the photoresist 34 is removed, and a conductive material such as yttrium is fully deposited. After that, the surface of the conductive material is planarized by CMP (chemical mechanical polishing) and the like, and vias and wirings are simultaneously formed. Since there are no protrusions on the step difference m, the adhesion of the wiring formed on the step difference D1 can be improved, and particles and the like generated by the protrusions can be suppressed. Thus, according to the above-mentioned two-channel metal damascene manufacturing method, even if nitrogen is removed In the case of a barrier film such as a silicon film, on the one hand, protrusions during etching of the porous insulating film 32 can be suppressed, and on the other hand, via holes B 丨 and wiring trenches T1 can be formed in the porous insulating film 32. Therefore, the porous insulating film 32 The specific permittivity is reduced, and the transmission delay of the wiring can be suppressed. In addition, since a barrier film such as a silicon nitride film does not exist between the porous insulating films 32, it is not necessary to consider the barrier film and the porous film when etching the porous insulating film 32. The selection ratio of the quality insulating film 32. Therefore, using a CF4 type gas with a larger ρ / 匸 ratio instead of the type gas will etch the porous insulating film 32 ′ and increase the etching rate when the porous insulating film 32 is etched. According to the present invention, it is possible to suppress the generation of protrusions of the porous insulating film. Industrial Applicability The etching method, the two-layer metal inlay manufacturing method, and the semiconductor device of the porous insulating film of the present invention can be used for Semiconductor manufacturing industry for semiconductor device manufacturing, etc. Therefore, it has industrial use possibilities. Explanation of component symbols 1 Processing chamber lb Exhaust pipe la Gas supply pipe 2 Upper electrode -18- This paper size applies to China National Standard (CNS) A4 Specifications (210 X 297 mm) 1223341 A7 B7 V. Description of the invention (16) 2a Ejection hole 22 Porous MSQ film 3 Crystal holder 23 Anti-reflection film 4 Crystal holder support 24 Photoresistive film 5 Insulating plate 31 Lower area 6 Electrostatic absorption Block 32 Porous insulating film 7 Conductive layer 33 Photoresist film 8a Polyimide film 34 Photoresist film 8b Polyimide film 41 Lower layer area 9 Gas communication 42 Porous insulation film 10 Refrigerant chamber 43 Silicon nitride film 10a Refrigerant supply tube 44 Porous edge film 10b Refrigerant discharge tube 45 Photoresist film 11 South frequency power supply 46 Via hole 13 Horizontal magnetic field forming magnet 47 Wiring 14 cf4 gas Feed source B1, through-hole 14a, flow adjustment valve B2, through-hole 14b, flow adjustment valve D1, step 15 Ar gas supply source D2, step 15a, flow adjustment valve E1, insect cut 15b, on-off valve E2 1 insect cut 16 He gas supply source E3 I insect cut 16a Flow regulating valve H1 opening portion 16b On-off valve H2 opening portion 21 Silicon nitride film H3 opening portion -19- This paper size applies to China National Standard (CNS) A4 specification (210X 297 mm) 1223341 A7 B7 V. Description of the invention (17) H4 cutout SP protrusion T1 wiring groove W wafer T2 wiring groove -20- This paper size applies to China National Standard (CNS) A4 specification (210 x 297 mm)

Claims (1)

1223341 A8 B8 C8 ___ —__ D8 X. Patent application scope 1. An etching method for a porous insulating film, which is applied in a processing chamber set at a specific pressure in a processing gas atmosphere, and applies RF power to generate a plasma. The porous insulating film is etched, characterized in that: the processing gas is a mixed gas of a fluorocarbon-based gas and an inert gas; and the pressure is 1 50 mTorr or more and 300 mTorr or less. 2. The method for etching a porous insulating film according to item 1 of the scope of patent application, wherein the RF power density is 0.25 w / cm2 or more and 0.50 w / cm2 or less. 3. For the porous insulating film etching method according to item 1 or 2 of the patent application scope, wherein the aforementioned fluorocarbon-based gas is CF4 and the aforementioned inert gas is Ar. 4. The porous insulating film etching method according to item 1 or 2 of the patent application scope, which further includes a gas with a flow ratio of fluorocarbon-based gas of 0.25 or less. 5. The method for etching a porous insulating film according to item 3 of the scope of application for a patent, which further includes a gas with a flow ratio of fluorocarbon-based gas of 0.25 or less. 6. · A semiconductor device formed by a two-channel metal damascene manufacturing method in which a conductive material is buried in these wiring trenches and vias after forming the wiring trenches and vias; characterized in that: the aforementioned wiring trenches are formed The porous insulating film and the porous insulating film formed with the aforementioned through-holes are formed without interposing a barrier layer; they are formed by using a σ gas xiaodou, which is a mixture of an oxygen-containing carbon compound-based gas and an inert gas, as the processing gas. And the pressure is above 150niT0rr. This paper size is applicable to China National Standard (CNS) A4 specification (21〇χ 297 mm) 1223341 A8 B8 C8 D8 In a processing chamber of 300 mT0rr or less, the above-mentioned porous insulating film is etched by a plasma etching method in which rF power is applied to generate a plasma to form the wiring trench. 7. The semiconductor device according to item 6 of the patent application, wherein the RF power density is 0.25 w / cm2 or more and 0.50 w / cm2 or less. 8. The semiconductor device according to item 6 of the application, wherein the fluorocarbon-based gas is cF4, and the aforementioned inert gas is Ar. '9. The semiconductor device according to item 6 of the scope of patent application, further comprising a gas having a flow ratio of fluorocarbon-based gas of 0.25 or less. 10 · A method for manufacturing a two-channel metal damascene, comprising: forming a first photoresist film having a pattern corresponding to a via thereon on an insulating film of a hole g; and using the first photoresist A step of etching the porous insulating film, forming a via hole in the porous insulating film; and a step of removing the first photoresist film; and forming a negative insulating film thereon A step of forming a second photoresist film corresponding to the pattern of the wiring trench; and under the conditions of RF power density of 0.25 W / Cm2 or more and 0.50 w / cm2 or less, and a pressure of 150 mTorr or more and 300 mTorr or less, The second photoresist film = a step of forming a wiring groove for the mask by performing the aforementioned porous f insulation money, and then the step of removing the aforementioned second photoresist film; and -2-this Paper size suitable financial @ S 家 标准 (CNS) A4 specification (210X297 public director) 1223341 A step of burying a conductive material in the aforementioned via hole and the aforementioned wiring trench. 11. The method for manufacturing a two-channel metal damascene according to item 10 of the application, wherein the processing gas for the step of forming wiring grooves in the porous insulating film is a mixed gas of a fluorocarbon-based gas and an inert gas. 12. According to the method for manufacturing a two-channel metal inlay in the scope of application for a patent, wherein the aforementioned fluorocarbon-based gas is CF4, and the aforementioned inert gas is Ar. 13. — Caste engraving device, which is in a processing chamber set to a specific pressure processing gas atmosphere, applies RF power to generate a plasma, and uses the plasma to etch a porous insulating film, characterized in that the processing gas is fluorine-containing A mixed gas of a carbon compound-based gas and an inert gas; the above pressure is 150 mTorr or more and 300 mTorr or less. 14. The etching device according to item 13 of the scope of patent application, wherein the RF power density is 0.25 W / cm2 or more and 0.50 W / cm2 or less. 15. The etching device according to item 13 of the application, wherein the aforementioned fluorocarbon-based gas is CF4 and the aforementioned inert gas is Ar. 16. The etching device according to item 13 of the patent application scope, which further includes a gas having a flow ratio of fluorocarbon-based gas of 0.25 or less. -3-The wave scale applies the Chinese National Standard (CNS) Α4 specification (210 X 297 male #) Order