TW447075B - Method for forming dielectric layer with low dielectric constant - Google Patents

Abstract

The present invention discloses a method for forming a dielectric layer with a low permittivity, which comprises providing a semiconductor substrate completed with a front stage process of an integrated circuit; forming a first silicon nitride layer with a high compression stress; using three steps to form a first black diamond film, which comprises using N2O, O2 and methylsilane as the reaction gases and a high power radio frequency (RF) to perform a deposition of a film rich in oxygen; using N2O and methylsilane as the reaction gases and a high power RF to deposite a first black diamond film; using NH3 to perform an ion bombardment; forming a second silicon nitride layer with a high compression stress; using N2O, O2 and methylsilane as the reaction gases and a high power RF to perform a deposition of a film rich in oxygen; using N2O and methylsilane as the reaction gases and a high power RF to perform a deposition of a second black diamond film to complete the deposition of a dielectric layer with a low permittivity.

Description

447075 V. Description of the invention (1) Detailed description: Technical field: The present invention relates to a method for forming a dielectric layer with a low dielectric constant in an integrated circuit, in particular to a method for forming a silicon nitride layer / low dielectric constant. Method of multilayer structure of dielectric layer / silicon nitride layer / low dielectric constant dielectric layer ° Background of the invention: Research units and manufacturers of integrated circuits in order to pursue faster operating speeds and greater integrated density Work hard to design and manufacture smaller critical dimension (CD) components. According to experiments, when the integrated circuit manufacturing process enters the technical field of 0.18 microns or even 0.13 microns, the key factor affecting the operating speed of the component has been changed from the width of the gate to the resistance of the metal interconnection. RC delay effect. As the product density of the wire increases, its resistance value increases with the degree, and the light micron field between the wires also affects the integration of the integrated circuit. Increasing the metal capacitance, the density of the metal body circuit, and the internal wiring, its cross-sectional area is connected; especially the internal wiring is high. Therefore, the calculation speed of the interconnect is inversely proportional to the line width and the interlayer metal material. As the integrated line width and thickness of the integrated circuit are reduced, the 'closed line distance of the integrated circuit is reduced. As a result, the manufacturing process of the integrated circuit goes deep + resistance-capacitance hysteresis is greatly improved, and the human rate and access rate are greatly increased. In order to connect + generation 1 ¾ line conditions should not be improved t ^ the material of the electrical layer is the best from the original Mingmeng indium alloy $ A Aming steel

Page 4 447075 V. Description of the invention (2)-In addition to the characteristics of low resistance, the alloy is replaced with copper metal, which also has good resistance to electron migration and good stress resistance, in addition to increasing the operating speed of the component ' At the same time, the reliability of the component can be improved; on the other hand, the interlayer dielectric layer must be selected from a low dielectric constant material to replace the original silicon dioxide to reduce the coupling capacitance between the metal interconnects. "The dielectric constant of silicon dioxide is about 39, so a dielectric with a dielectric constant less than 3.9 must be selected as the interlayer dielectric layer to achieve the effect of reducing the resistance-capacitance hysteresis, such as fluorine doping Silicon dioxide (Si 0F), organic spin-on glass (KSq), etc. Another effective material with a low dielectric constant is black diamond, which is formed by methyl silane (11 ^ 1;? 171311 & 116). Its composition is 20% silicon, 30% oxygen, and 9 carbon. %, Hydrogen 36%, and other elements. Because about 36% of the volume of black diamonds is holes ’, its dielectric constant is only about 2.9, which is a low-dielectric constant material with great potential. In copper process technology, because copper metal cannot be engraved with gas like aluminum alloy, so the industry has developed a damascene process method. For beta process technology, please refer to Motorola's Boeck; Bruce Allen, etc. "Method for manufacturing a low dielectric constant inter-level integrated circuit structure" disclosed in U.S. Patent No. 588001 8. Please refer to FIG. 1, a first silicon nitride layer 11, a first low-k dielectric layer 12, a second silicon nitride layer 13, and a second low-silicon layer are successively formed on a semiconductor substrate 10 that has completed the previous process. The dielectric constant dielectric layer 14 'is formed by two successive lithography and etching techniques as shown in the opening 15 of Fig. 1A. among them

Page 5 447075 V. Description of the invention (3) The deposition of silicon nitride layer 1 1, 13 is based on Si i Η and NH as the reaction gas. Plasma enhanced chemical vapor deposition (PEC VD) A thin film of about 500 angstroms (Angstrom) is deposited under a thallium environment, and the required RF power is about 400 watts. The silicon nitride layer formed under normal process conditions has a compressive stress of about 9 dyne / cm 2. In the deposition steps of the first low-k dielectric layer 12 and the second low-k dielectric layer 14, N 20 and methylsi lane are used as reaction gases, and a plasma-enhanced chemical vapor phase is used. Deposition (PECVD) deposition, in which the required RF power is about 70 watts, the flow rate of N2 0 is about 370 sccm, the flow rate of methyl silane is about 68 sccm, and the reaction time is about 60 seconds to form about 50 0 0 Angstrom Black Diamond Film. Next, referring to FIG. 1B, a copper thin film 16 is formed by PVD, CVD, or electroplating. Finally, as shown in FIG. 1C, the copper thin film 16 is polished by chemical mechanical polishing (CMP) to form a copper wire 17. However, there is always an annoying problem in the traditional copper wire / low-k dielectric integration process, because the tensile stress of the low-k dielectric layer is extremely large, which causes a great warpage of the substrate. When chemical mechanical polishing is used to polish a copper thin film, it is easy to cause delamination of the substrate edge, so that the alignment mark of the substrate is blurred, and even the substrate edge (about 0.5 to 2 cm) is abraded. It seriously affects the yield of the process. "Therefore, in order to improve the yield of the product, the development of a stable copper wire / low dielectric constant dielectric layer integrated process to solve the above-mentioned peeling problems has become a very important part of the semiconductor industry. Subject.

447075 V. Description of the invention (4) Summary of the invention: The main object of the present invention is to provide a method for forming a dielectric layer with a low dielectric constant. A secondary object of the present invention is to provide a method for forming a multi-layer structure of a silicon nitride layer / low dielectric constant dielectric layer / silicon nitride layer / low dielectric constant dielectric layer. The invention discloses a method for forming a dielectric layer with a low dielectric constant. The steps are as follows: firstly providing a semiconductor substrate that has completed the pre-process of the integrated circuit and forming a first nitride layer with high compressive stress on the semiconductor substrate; Silicon layer. The next step is to form the first black diamond film in three steps. First, using N2O, 0 and fluorenylsilane as the reaction gases, the high-power radio frequency is used to deposit an oxygen-rich (02-rich) film; then N 20 The first black diamond film was deposited with high-power radio frequency RF with methylsilane as the reaction gas; finally, it was bombarded with NH locust ion. Next, a second gasified rock layer with high compressive stress is formed, and then N 2 0, 0 and methyl silane are used as reaction gases, and high-power radio frequency RF is used to deposit an oxygen-rich (0 2_ri ch) film; finally, Use] \ f20 and methyllithoxane as reaction gases to 'deposit the second black diamond film with high power radio frequency RF' to complete the silicon nitride layer / low dielectric constant dielectric layer / silicon nitride layer / low Deposition of a multi-layer structure of a dielectric constant dielectric layer. The multilayer structure of the silicon nitride layer / low dielectric constant dielectric layer / nitride nitride layer / low dielectric constant dielectric layer formed by the method of the present invention has the following advantages: 1. The present invention combines the silicon nitride layer with The compressive stress is increased to balance the tensile stress of the low dielectric constant dielectric layer, which greatly reduces the strain of the substrate, which can

Page 7 447 075 -r ^ -T * ....... _ 丨 ·-r ------------------- -___ ^ V. Description of the invention (5 ) To avoid the occurrence of peeling phenomenon when the copper film is polished by the chemical mechanical polishing method, which will cause the alignment marks of the wafer to be blurred, and even cause the wear of the wafer edge (about 0.5 to 2 cm). 2. The present invention uses ν 20, 0 and methyl dreamane as reaction gases to deposit an oxygen-rich film with high power radio frequency RF before the black diamond film is deposited to improve the interface between the silicon nitride layer and the black diamond film. Strength to avoid the occurrence of peeling. 3. In the present invention, 'the black diamond film deposition process will increase the power of the RF core from the traditional 70 watts to between 80 watts and ι40 watts, and the optimal RF rf power is 110 watts', which can improve the chip packaging wiring. The stupid resistance of the process. 4. After the black diamond film is deposited, the present invention promotes ion bombardment with NH to increase the strength of the interface between the first black diamond film and the second silicon nitride layer formed later, and further avoid the occurrence of peeling. Brief description of the drawings: Figure 1A is a conventional dual-damascene process in which a first nitride layer, a first low-k dielectric layer, and a second gasified stone are continuously formed on a semiconductor substrate that has completed the previous process. Layer, and a second low-k dielectric layer, and then a schematic cross-sectional view of a process of forming an opening by two successive lithography and post-etching techniques. FIG. 1B is a schematic cross-sectional view of a process for forming a copper film in a conventional dual damascene process. FIG. 1C is a schematic cross-sectional view of a process of grinding the copper thin film to form a copper wire in a conventional dual-damascene process by using a chemical mechanical polishing method. FIG. 2 shows the formation of a silicon nitride layer / low dielectric constant dielectric layer / t / of the present invention.

Page 8 447 0 75 V. Description of the invention (6) Process flow chart of multi-layer structure of silicon layer / low dielectric constant dielectric layer. FIG. 3A is the first silicon nitride layer, the first low-k dielectric layer, the second silicon nitride layer, and the second low-dielectric layer are continuously formed on a semiconductor substrate that has completed the previous process in the process of the present invention. A schematic cross-sectional view of a process for manufacturing a constant dielectric layer. Fig. 3B is a schematic cross-sectional view of a process for forming an opening by two successive lithography and etching techniques in the process of the present invention. FIG. 3C is a schematic cross-sectional view of a process of forming a copper thin film in the process of the present invention. FIG. 3D is a schematic cross-sectional view of a process of polishing the copper film to form a copper wire by using a chemical mechanical polishing method in the process of the present invention. 11-First silicon nitride layer 1 3- Second silicon nitride layer 1 5-Opening 17-Copper wire 3 1-First nitride layer 3 3- Second vaporized silicon layer 3 5- Description of opening number 1 0-semiconductor substrate 1 2-first low dielectric constant dielectric layer 14-second low dielectric constant dielectric layer 16-copper thin film 3 0-semiconductor substrate 32-first low dielectric constant dielectric layer 34 -Second low dielectric constant dielectric layer 3 6 _copper film 3 7-copper wire

447075 V. Description of the invention (7) This invention # discloses a method for forming a dielectric layer with a low dielectric constant, in particular, a method for forming a silicon nitride layer / low dielectric constant dielectric layer / stone nitride layer / low dielectric The multi-layer structure method of the dielectric constant dielectric layer is suitable for the dual damascene process of the copper process. The invention can be applied to the integration process of copper wires / low dielectric constant dielectric layers of various types of logic elements and memory elements. Please refer to FIG. 2 for the process flow chart of the present invention. First, a semiconductor substrate 21 having completed the previous process of the integrated circuit is provided, and a first nitrided layer 22 with compressive stress is formed by chemical vapor deposition method. The next step is to form the first black diamond film in three steps. First, use ~ 2, 0 and methyl silane as the reaction gas to perform a high-powered cheek evaluation for oxygen-rich ⑺ ⑺ ㈣ ㈣ film deposition 23; Next, Nz0 and fluorenylsilane are used as reaction gases, and a first black diamond film 24 is deposited with high-power radio frequency RF; finally, NH is used to bombard 25. Then, a second vaporized silicon layer 26 'having a high compressive stress is formed again by chemical vapor deposition method, and then n 2 0, 0, and fluorene-based silane are used as reaction gases, and high-power radio frequency RF is used to deposit an oxygen-rich film. 27; Finally, the second black diamond film was deposited with high power RF RF using N20 and methyl sinter as reaction gases to complete the silicon nitride layer / low dielectric constant dielectric layer / nitride. Deposition of a multi-layer structure of a wicker / low-k dielectric layer. Please refer to FIG. 3A together, in which step 2 2 uses S i Η and NH as reaction gases to form a first semiconductor substrate 3 0 by using plasma enhanced chemical vapor deposition (PECVD) under the NH environment. A silicon nitride film 31 has a thickness between 300 angstroms and 1,000 angstroms. What is different from the conventional process is that the present invention changes the process parameters, especially the power of the radio frequency (RF) is changed to between 450 watts and 650 watts, so that the first silicon nitride layer 31 is formed.

447075 V. Description of the invention (8) There is a compressive stress between 5 E 9 and 1.5 E1 0 dyne / cm 2. Because the subsequently deposited low dielectric constant dielectric layer has a great tensile stress, the present invention intentionally increases the compressive stress of the silicon nitride layer to balance the tensile stress of the low dielectric constant dielectric layer, so that the semiconductor substrate The strain is greatly reduced to avoid the peeling phenomenon that occurs when the copper film is polished by chemical mechanical polishing method, which causes the semiconductor substrate alignment mark (ali gnment mark) to be blurred, and even causes the substrate edge (about 0.5 to 2 In addition to the black diamond film, other types of low dielectric constant dielectric layers (such as fluorine-doped silicon dioxide (Si 0F), organic spin-on glass (HSQ), etc.) also have Extremely high tensile stress "In another embodiment of the present invention, the above-mentioned process for forming a silicon nitride layer with large compressive stress can be applied to any other process with a low dielectric constant dielectric layer to balance low The great tensile stress of the dielectric constant dielectric layer greatly reduces the strain of the semiconductor substrate. Next, in this embodiment, the first black diamond film is formed in three steps. First, as shown in step 23, using the N 2 0, 0, and methyl silane as the reaction gas, the high-power radio frequency RF is used to perform the oxygen-rich film. Deposition to increase the strength of the interface between the silicon nitride layer and the black diamond film. Wherein, the flow rate of N 2〇 is between 350 and 40 SCCm, and the optimal flow rate is 37 ° sccm; and the fishing flow rate is between 10 and 50 sccm, and the optimal flow rate is 30 sccm; 曱The flow rate of the silane is between 50 and 100 sccm, and the optimal flow rate is 68 sccm. The power of the RF radio frequency is between 120 and 250 watts, and the optimal power is 200 watts. The time of this step is between 0.5 and 5 Between 5 and 5 seconds, the optimal time is 2 seconds. This step can increase the strength of the interface between the silicon nitride layer and the black diamond film, and can avoid peeling.

Page 11 447075 V. Description of Invention (9) Happened. Next, as shown in step 2, using N 20 and methyl silicon as a reaction gas, 'depositing a black diamond thin film with high power radio frequency RF using plasma enhanced chemical vapor deposition method' to form about 5000 〇Angel's first black diamond film 3 2. Wherein, the flow rate of N 2〇 is between 350 and 400 sccm, and the optimal flow rate is 3 70 sccm; the flow rate of methyl silane is between 50 and 100 seem, and the optimal flow rate is 6 8 sccm; The reaction time is between 30 seconds and 100 seconds, and the optimal reaction time is about 60 seconds. It is particularly important that the present invention increases the power of RF rj? From the traditional 70 watts to between 80 watts and 140 watts, and the optimal RF Rf power is 110 watts, which can improve the wi re bonding process for chip packaging. Cracking resistance. Finally, as shown in step 25, ion bombardment with NH is performed to increase the strength of the interface between the first black alumina film 32 and the second silicon nitride layer 33 formed subsequently. The RF power is between watts and 200 watts, and the optimal RF power is 50 watts. Then, as shown in step 26, a second silicon nitride layer 33 with high compressive stress is formed again by the chemical vapor deposition method, and then NaO, 〇, and methylsilane are used as the reaction gases as shown in step 27. High power radio frequency is used for the deposition of oxygen-rich films; finally, as shown in step 2 8 using N 20 and methyl silane as the reaction gas 'deposit the second black diamond thin 臈 34 with high power radio frequency RF' to complete the low Deposition of a dielectric layer with a dielectric constant. The process conditions of steps 26 to 28 are exactly the same as the process conditions of steps 22 to 24, and details are not described again. Similarly, when the second nitride stone layer 33 is formed, the power of the radio frequency RF is changed to between 450 watts and 650 watts, so that the formed second

Page 12 447 0 75 V. Description of the invention (ίο) The silicon nitride layer 3 3 has a compressive stress between 5 E 9 and 1.5 E1 0 dyne / cm² to balance the low dielectric constant dielectric The tensile stress of the layer greatly reduces the strain of the substrate. Referring next to FIG. 3B, the opening 35 is formed by two successive lithography and etching techniques. Next, please refer to FIG. 30 to form a thin copper layer 36 by PVD, CVD, or electroplating. Finally, as shown in FIG. 3D, the copper thin film 36 is polished by a chemical mechanical polishing method to form a copper wire 37β. The silicon nitride layer / low dielectric constant dielectric layer / nitridation formed by the method of the present invention The multilayer / low-k dielectric layer has the following advantages:

1. The present invention increases the compressive stress of the tritiated silicon layer to balance the tensile stress of the low dielectric constant dielectric layer, so that the strain of the substrate is greatly reduced, which can avoid the subsequent polishing of the copper thin film by chemical mechanical polishing. The peeling-off phenomenon occurs and the alignment mark of the substrate is blurred, and even the edge of the substrate (about 0.5 to 2 cm) is worn. -2. Before the black diamond film is deposited, the present invention uses ν 2〇, 0 and methyl silicon as a reaction gas to perform a crystallization process with a high-power radio frequency to improve the interface between the silicon nitride layer and the black diamond thin film. 'Strength' can prevent the occurrence of peeling.

3. In the present invention, the 'black diamond film deposition process increases the RF RF power from the traditional 70 watts to between 80 watts and ι40 watts, and the optimal RF "power is 110 watts" can lift the wafer. The crack resistance value of the packaged wire bonding process. 4. After the black diamond film is deposited in the present invention, the ion bombardment with NH can improve the first black diamond film and the second silicon nitride formed subsequently.

Page 13 447075 V. Description of the invention (11) The strength of the interface of the layer can further avoid the occurrence of peeling. The above description uses the preferred embodiments to explain the present invention in detail, but not to limit the scope of the present invention, and those skilled in the art will also understand that making small changes and adjustments appropriately will still lose the essence of the present invention. Without departing from the spirit and scope of the invention.

Page 14 447075 Simple description of the schematic diagram Brief description of the diagram: Figure 1A is a conventional dual damascene process _ a first silicon nitride layer and a first low dielectric constant are continuously formed on a semiconductor substrate that has completed the previous process A schematic cross-sectional view of a process in which a dielectric layer, a second silicon nitride layer, and a second low-k dielectric layer are formed by two successive lithography and etching techniques. FIG. 1B is a schematic cross-sectional view of a process for forming a copper film in a conventional dual damascene process. FIG. 1C is a schematic cross-sectional view of a process for forming a copper wire by grinding the copper thin film by a chemical mechanical polishing method in a conventional dual damascene process. Β FIG. 2 is a silicon nitride layer / low dielectric constant dielectric according to the present invention. Process flow chart of the multilayer structure of the layer / nitride layer / low dielectric constant dielectric layer. Second nitride dream layer, intention. FIG. 3A is a diagram showing a process of continuously forming a first silicon nitride layer and a first low-dielectric constant second dielectric layer on a half-J plate f that has completed the previous process in the process of the present invention. Open π circle three B is a schematic cross-sectional view of the process in the process of the present invention. The wind is treacherous and the technology is opened. C is a sectional view of the process of forming a layer of steel film in the process of the present invention. FIG. 3D is a process in the process of the present invention using a chemical pusher, mechanical grinding method, and grinding to form a copper wire. The cross section of 枉 is not intended.

Claims (1)

447075-7 ~ 6. Patent application scope 1. A method for forming a dielectric layer with a low dielectric constant, the process steps include: a. Providing a semiconductor substrate that has completed the previous stage of the integrated circuit; b. Forming a first silicon nitride layer on the semiconductor substrate, the compressive stress of which is greater than 5 E 9 dyne / cm 2; c. Using Fu 20, 0 and methyl silane as a reactive gas, and using radio frequency RF to deposit an oxygen-rich film D. Depositing a first black diamond film; e. Subjecting the first black diamond film to ion bombardment; f. Forming a second silicon nitride layer on the first black diamond film with a compressive stress greater than 5 E 9 Dyne / cm 2; g. Deposition of an oxygen-rich film using N 20, 0 and methyl silane as a reaction gas and radio frequency RF; and h. Deposition of a second black diamond thin film. 2. The method for forming a low dielectric constant dielectric layer as described in item 1 of the scope of the patent application, wherein the first silicon nitride layer described in step (b) is a plasma enhanced chemical vapor deposition method. The power of the radio frequency RF is set to be between 45 and 650 watts' so that the first silicon nitride layer formed has a compressive stress between 5E9 and 1.5E10 dyne / cm 2. 3. The method of forming a dielectric layer with a low dielectric constant as described in item 1 of the scope of the patent application, wherein the flow of n 2 in the oxygen-rich film deposition in step (c) is between 35 0 and 400 seem ; The flow rate of 0 is between 10 and 50 sccm, the flow rate of sillstone sintering is between 50 and loosccm; the power of radio frequency r ρ is between 120 and 250 watts. Page 16 4 47 0 75 VI. Patent Application Range 4. The method for forming a dielectric layer with a low dielectric constant as described in item 1 of the patent application range, wherein the first black diamond thin film is made of N 2 0 and The fluorenyl silane is a reactive gas. The black diamond film is deposited using RF-RF between 80 watts and 140 watts using plasma enhanced chemical vapor deposition. 5. The method of forming a dielectric layer with a low dielectric constant as described in item 4 of the scope of the patent application, wherein the flow rate of N 2 0 is between 3 50 and 400 sccm, and the flow rate of methyl silane is 50 To 100 ohm. 6. The method of forming a dielectric layer with a low dielectric constant as described in item 1 of the scope of the patent application, wherein the ion bombardment described in step (e) is performed with NH3 ions, and the power of the radio frequency RF is between 10 () watts Β 7 to 200 watts as described in item 1 of the patent application for a method for forming a dielectric layer with a low dielectric constant ', wherein the second silicon nitride layer described in step (f) is a plasma The enhanced chemical vapor deposition method sets the power of the RF evaluation to between 450 and 650 watts, so that the formed second silicon nitride layer has a distance between 5E9 and 1.5 E 1 0 达Due to compressive stress per square centimeter. 8'The method for forming a low-dielectric-constant dielectric layer as described in item 1 of the scope of the patent application ', wherein the flow rate of the N 2 0 deposited in the step (g) rich in oxygen is between 350 and 400 sccm. 0; the flow rate is between 10 and 50 sccm; the flow rate of methyl silane is between 50 and 100 seem; the power of the RF radio frequency is between 120 and 250 watts. • The method for forming a low-dielectric-constant dielectric layer as described in item 1 of the scope of the patent application, wherein the second black diamond film is made of N 2 0 and fluorenyl silane as a reaction gas' using a plasma enhanced chemistry Vapor phase deposition uses radio frequency (RF) power between 80 watts and 140 watts to deposit black diamond films. Page 17 447075 6. Application for patent scope 10. The method for forming a dielectric layer with a low dielectric constant as described in item 9 of the scope of patent application, wherein the flow rate of N20 is between 350 and 400 sccm. The flow of silanes is between 50 and 100 sccm. 11. A method for forming a dielectric layer with a low dielectric constant, the process steps of which include: a. Providing a semiconductor substrate that has completed the previous process of the integrated circuit; b. Forming a first nitride on the semiconductor substrate Silicon layer with compressive stress between 5E9 and 1.5E10 dyne / cm 2; c. Crystallization process using N 20, 0 and methyl silane as the reaction gas and RF; d. N20 ^ form Silane is a reactive gas, and a plasma enhanced chemical vapor deposition method is used to deposit a first black diamond film with a radio frequency rf between 80 watts and 140 watts; e. Ionizing the first black diamond film Bombarding; f. Forming a second silicon nitride layer on said first black diamond film, the compressive stress of which is between 5 E 9 and 1.5 E 1 0 dyne / cm 2; g · N2〇, 0 and methyllithium sintering as the reaction gas 'Crystalization process with radio frequency rf: and h. Using N 2 0 and methyl silane as the reaction gas' using plasma tough chemical vapor deposition with a power between 80 watt A second black diamond film is deposited with radio frequency RF between 1 and 40 watts. 12. The method for forming a low-dielectric-constant dielectric layer according to item 11 of the scope of the patent application, wherein the first silicon nitride layer described in step (b) uses an electro-enhanced chemical vapor deposition method, Set the RF RF power to between $ § 〇 Page 18 447075 VI. The scope of the patent application is between watts and 650 watts, so that the first nitride layer formed has a compressive stress between 5 E 9 and 1.5 E10 0 dyne / cm 2. 1 3. The method for forming a dielectric layer with a low dielectric constant as described in item 11 of the scope of patent application, wherein the flow rate of the N20 deposited in the oxygen-rich film in step (c) is between 350 and 400 sccm ; The flow rate of 0 is between 10 and 50 sccm; the flow rate of methyl silane is between 50 and 100 sccm; the power of the RF radio frequency is between 120 and 250 watts. 1 4. The method for forming a dielectric layer with a low dielectric constant as described in item 11 of the scope of the patent application, wherein in the step (0, the flow rate of N20 is between 350 and 400 sccm, and the flow rate of methyl hard burn Between 50 and 100 sccm ° 15. The method for forming a dielectric layer with a low dielectric constant as described in item 11 of the scope of patent application, wherein the ion bombardment described in step (e) is performed with NH heterodons, The power of radio frequency RF is between 100 watts and 200 watts. Β 16. The method for forming a low dielectric constant dielectric layer as described in item 11 of the scope of patent application, wherein The second silicon nitride layer uses a plasma-enhanced chemical vapor deposition method to set the power of the radio frequency RF to between 450 watts and 650 watts, so that the second silicon nitride layer formed has an interval between 5E9 to 1. 5E10 dyne / cm 2 compressive stress. 17. The method for forming a low dielectric constant dielectric layer as described in item 11 of the scope of patent application, wherein the step (g) is an oxygen-rich film deposition The flow rate of N 2〇 is between 35 0 and 400 sccm; the flow rate of 0 妁 is between 10 and 50 sccin; the flow rate of methyl silane is 50 Between 1 billion Osccm;. Radiofrequency rf power ranged between 120 and 250 watts 18. Item 11 is formed of the patent application range of the low-k dielectric Page 19, 447075 ΐ ~~ ^-6. The method of applying for a patent scope layer, wherein the flow rate of N20 in step (h) is between 350 and 400 sccm, and the flow rate of fluorenylsilane is between 50 and 10 〇sccm. 19 · —A method of forming a dielectric layer with a low dielectric constant, forming a silicon nitride layer / low dielectric constant dielectric layer / silicon nitride layer / low dielectric on a semiconductor substrate that has completed the pre-process of a circuit The multi-layer structure of the dielectric constant dielectric layer is used to facilitate the use of the dual damascene process; it is characterized in that the silicon nitride M formed has a compressive stress between -5E & uuo dyne / cm2. The dielectric deposition + method for forming a low dielectric constant as described in item 19 of the patent application range of the layer, wherein the silicon nitride layer uses a plasma-enhanced chemical vapor phase 'radio cheek RF power setting is between Between 450 watts and 650 watts. 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