Method for reducing K value of low-K silicon oxide material

Abstract

The invention belongs to the field of semiconductors, and particularly relates to a method for reducing the K value of a low-K silicon oxide material. The method comprises the following steps: (1) transferring a wafer deposited with a low-K silicon oxide material to a reaction cavity; (2) preheating the wafer on which the low-K silicon oxide material is deposited; (3) igniting the remote plasma device by using argon; and (4) gradually reducing the flow of the argon and gradually increasing the flow of the hydrogen until the flow of the argon is zero, so that the low-K silicon oxide material is continuously treated by the hydrogen. According to the method, the configuration of carbon in the low-K silicon oxide material is changed through the remote hydrogen plasma, so that the K value of the low-K silicon oxide material is reduced. The remote hydrogen plasma technology is a brand new method for reducing the K value of the low-K silicon oxide material, the method is simple, direct and efficient and does not need chemical additives, new pores cannot be introduced into the low-K silicon oxide material in the process, and the method provides a new solution for solving the problem of the low-K silicon oxide material.

Description

Technical Field

[0001] The invention belongs to the field of semiconductors, and in particular relates to a method for reducing the K value of a low-K silicon oxide material. Background Art

[0002] As the feature size of integrated circuits continues to shrink, interconnection resistance and capacitance delay (RC Delay) has become an important factor restricting the improvement of chip performance. By reducing the K value of low-K silicon oxide materials used in integrated circuits, RC delay can be effectively reduced, circuit leakage current can be reduced, and circuit heating can be alleviated, thereby improving the operation speed of integrated circuits. The low-K dielectric material used in processes below the 130nm technology node is generally SiOCH (carbon-doped silicon oxide), which introduces organic groups such as -CH3 into silicon oxide to dope hydrocarbon elements. The polarizability and density of the film are reduced through the spatial effect of -CH3, thereby reducing the K value of the material. At present, the method of reducing the K value of materials in integrated circuit manufacturing is mainly to increase the free volume or introduce well-controlled nanoscale holes into the film, but this method usually requires the introduction of new chemical reagents, and too many pores will cause the thermal stability and mechanical properties of the material to deteriorate, and it is easy to break during processing. Therefore, there is an urgent need in the art to propose a new method for reducing the K value of materials. Summary of the invention

[0003] The object of the present invention is to provide a method for reducing the K value of low-K silicon oxide material.

[0004] A first aspect of the present invention provides a method for reducing the K value of a low-K silicon oxide material, the method comprising the steps of:

[0005] (1) transferring a wafer with low-K silicon oxide material deposited thereon to a reaction chamber;

[0006] (2) preheating the wafer on which the low-K silicon oxide material is deposited;

[0007] (3) Using argon gas to ignite the remote plasma device;

[0008] (4) gradually reducing the flow rate of argon gas and gradually increasing the flow rate of hydrogen gas until the flow rate of argon gas is zero, so that the hydrogen gas continues to process the low-K silicon oxide material.

[0009] In one or more embodiments, the low-K silicon oxide material includes carbon-doped silicon oxide.

[0010] In one or more embodiments, the low-K silicon oxide material includes a non-porous low-K silicon oxide material and a porous low-K silicon oxide material.

[0011] In one or more embodiments, in step (1), the side of the wafer deposited with the low-K silicon oxide material faces the shower plate in the reaction chamber, and the distance between the shower plate and the wafer is adjusted to 10-20 mm.

[0012] In one or more embodiments, in step (2), the wafer deposited with the low-K silicon oxide material is preheated to 220-260°C.

[0013] In one or more embodiments, in step (3), the flow rate of argon gas is 2000-4000 sccm; and / or, in step (3), the ignition is performed for 1-20 seconds.

[0014] In one or more embodiments, in step (4), the flow rate of hydrogen is gradually increased to 800-1600 sccm.

[0015] In one or more embodiments, in step (3) and step (4), the pressure in the reaction chamber is ≤ 2 Torr.

[0016] In one or more embodiments, the flow rate of argon gas is gradually reduced within 3-20 seconds until the flow rate of argon gas is zero; and / or, the flow rate of hydrogen gas is gradually increased to 800-1600 sccm within 3-20 seconds.

[0017] In one or more embodiments, after the flow rate of argon gas reaches zero, hydrogen gas is continuously passed for 10-60 seconds.

[0018] The second aspect of the present invention provides a wafer deposited with a low-K silicon oxide material, which is prepared using the method described in the first aspect of the present invention.

[0019] A third aspect of the present invention provides an integrated circuit, wherein the integrated circuit comprises the wafer described in the second aspect of the present invention.

[0020] A fourth aspect of the present invention provides an application selected from the group consisting of:

[0021] (1) Application of the wafer according to the second aspect of the present invention in reducing RC delay of an integrated circuit;

[0022] (2) Use of the wafer according to the second aspect of the present invention in reducing circuit leakage current of an integrated circuit;

[0023] (3) Application of the wafer according to the second aspect of the present invention in alleviating circuit heating of an integrated circuit;

[0024] (4) Application of the wafer described in the second aspect of the present invention to improving the operating speed of integrated circuits.

[0025] The present invention has the following beneficial effects:

[0026] (1) The method of the present invention changes the carbon configuration inside the low-K silicon oxide material through remote hydrogen plasma to reduce its K value. The method of the present invention reduces the K value of the material through remote hydrogen plasma technology. Compared with the prior art, remote hydrogen plasma technology is a new method for reducing the K value of low-K silicon oxide materials. This method is simple, direct, efficient, and does not require chemical additives. In addition, the process does not introduce new pores inside the low-K silicon oxide material. The method of the present invention provides a new solution to the problem of low-K silicon oxide materials.

[0027] (2) The method of the present invention can be completed in a chamber having a plasma treatment process. The process is simple and efficient, and no chemical additives need to be introduced.

[0028] (3) The method of the present invention can be used to perform remote hydrogen plasma treatment on other porous low-K silicon oxide materials to further reduce their K values, and has universal applicability in practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a comparison chart of the K value after the low-K silicon oxide material is treated by the method of Example 1 of the present invention (HRPS) and the K value before the treatment (Pre). DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0031] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0032] Herein, “comprising”, “including”, “containing” and similar terms encompass the meanings of “consisting essentially of” and “consisting of”. For example, when “A comprises B and C” is disclosed herein, “A consists essentially of B and C” and “A consists of B and C” should be deemed to be disclosed herein.

[0033] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are only for brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0034] In this document, unless otherwise specified, percentage refers to mass percentage and ratio refers to mass ratio.

[0035] Herein, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all substitutes, improvements and equivalents of the methods and materials described in the present invention can be included in the scope limited by the claims.

[0036] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0037] The present invention provides a method for reducing the K value of a low-K silicon oxide material, the method comprising the steps of:

[0038] (1) transferring a wafer with low-K silicon oxide material deposited thereon to a reaction chamber;

[0039] (2) preheating the wafer on which the low-K silicon oxide material is deposited;

[0040] (3) Using argon gas to ignite the remote plasma device;

[0041] (4) gradually reducing the flow rate of argon gas and gradually increasing the flow rate of hydrogen gas until the flow rate of argon gas is zero, so that the hydrogen gas continues to process the low-K silicon oxide material.

[0042] In some embodiments, the low-K silicon oxide material includes carbon-doped silicon oxide (SiOCH).

[0043] In some embodiments, the low-K silicon oxide material includes a non-porous low-K silicon oxide material and a porous low-K silicon oxide material. The method of the present invention can be applied to both non-porous low-K silicon oxide materials and porous low-K silicon oxide materials to further reduce the K value of the porous low-K silicon oxide material. Specifically, the method of the present invention can be applied to both non-porous SiOCH and porous SiOCH to further reduce the K value of the porous SiOCH. Preferably, the low-K silicon oxide material includes porous carbon-doped silicon oxide and non-porous carbon-doped silicon oxide.

[0044] In step (1), the side of the wafer on which the low-K silicon oxide material is deposited is arranged to face the shower plate in the reaction chamber. The distance between the shower plate and the wafer is adjusted to 10-20 mm, for example, 10 mm, 13 mm, 15 mm, 17 mm, 18 mm, 19 mm, 20 mm, preferably 10-15 mm. By controlling the distance between the shower plate and the wafer within the range specified by the method of the present invention, the K value of the low-K silicon oxide material can be reduced.

[0045] In step (2), the wafer with the low-K silicon oxide material deposited thereon is preheated to 220-260°C, for example, 220°C, 230°C, 240°C, 250°C, 260°C, preferably 220-240°C, 230-250°C or 220-230°C. Herein, the wafer is heated using a heating plate provided in the reaction chamber, which is a component conventionally provided in the reaction chamber for remote plasma processing in the art. Preheating the wafer to within the range specified by the method of the present invention can reduce the K value of the low-K silicon oxide material.

[0046] In step (3), pure argon gas with good ignition effect is used to ignite the plasma device at the beginning. The flow rate of argon gas can be 2000-4000sccm, for example, 2000sccm, 2500sccm, 3000sccm, 3500sccm, 4000sccm, preferably 2000-3000sccm or 2000-2500sccm. Firstly, argon gas is selected to ignite the plasma device, which can reduce the K value of the low-K silicon oxide material. The flow rate of argon gas used for ignition of the plasma device is controlled within the range of the method of the present invention, which can reduce the K value of the low-K silicon oxide material.

[0047] In step (3), the ignition is performed for 1-20 seconds, such as 1 second, 2 seconds, 3 seconds, 5 seconds, 8 seconds, 10 seconds, 12 seconds, 15 seconds, 18 seconds, 20 seconds, preferably 1-5 seconds, 5-10 seconds or 5-20 seconds. Controlling the ignition time of the plasma device within the range specified by the method of the present invention can reduce the K value of the low-K silicon oxide material.

[0048] In step (4), the flow rate of hydrogen is gradually increased to 800-1600sccm, for example, 800sccm, 900sccm, 1000sccm, 1100sccm, 1200sccm, 1300sccm, 1400sccm, 1500sccm, 1600sccm, preferably 800-1400sccm or 1600sccm. Controlling the flow rate of hydrogen within the range specified in the method of the present invention can reduce the K value of the low-K silicon oxide material. Preferably, the flow rate of hydrogen is gradually increased to 800-1600sccm within 3-20s, for example, 3s, 5s, 7s, 8s, 9s, 10s, 12s, 15s, 18s, 20s. Preferably, the flow rate of hydrogen is uniformly increased within 3-20s. Gradually increasing the flow rate of hydrogen to a set value within the time specified in the method of the present invention can reduce the K value of the low-K silicon oxide material.

[0049] In step (4), the flow rate of argon gas is gradually reduced within 3-20 seconds until the flow rate of argon gas is zero. Preferably, the flow rate of argon gas is uniformly reduced within 3-20 seconds until the flow rate of argon gas is zero. Gradually reducing the flow rate of argon gas to zero within the time specified by the method of the present invention can reduce the K value of the low-K silicon oxide material.

[0050] In step (4), within the same time, the flow rate of argon gas is reduced to zero and the flow rate of hydrogen gas is increased to the maximum set value, which can reduce the K value of the low-K silicon oxide material.

[0051] In step (4), after the flow rate of argon gas is zero, hydrogen gas is continuously passed for 10-60s, for example, 10s, 15s, 20s, 25s, 30s, 35s, 40s, 45s, 50s, 55s, 60s, preferably 20-30s, 20-40s or 10-20s. The hydrogen gas passing time after the flow rate of argon gas is controlled to be zero is within the range specified by the method of the present invention, and the K value of the low-K silicon oxide material can be reduced.

[0052] In step (3) and step (4), the pressure in the reaction chamber is ≤ 2 Torr. Controlling the pressure in the reaction chamber in step (3) and step (4) within the range specified by the method of the present invention can reduce the K value of the low-K silicon oxide material.

[0053] In step (4), the treatment is a surface cleaning process.

[0054] The low-K silicon oxide material in the method of the present invention can be applied to the fields of memory chips, logic chips, etc. Therefore, the method of reducing the K value of the low-K silicon oxide material of the present invention has a certain universality to the low-K silicon oxide materials involved in the fields of memory chips, logic chips, etc.

[0055] The method of the present invention uses remote hydrogen plasma technology to perform surface treatment on the surface of a low-K silicon oxide material to reduce its K value. The principle of the method of the present invention includes, but is not limited to, hydrogen doping, and it is also possible that hydrogen atoms enter the surface layer of the low-K silicon oxide material at a high speed, changing the hybrid structure of carbon inside the low-K silicon oxide material, thereby achieving the effect of reducing the K value of the low-K silicon oxide material.

[0056] The method of the present invention uses a substrate having a low-K silicon oxide material, and performs remote hydrogen plasma treatment on the low-K silicon oxide material to reduce its K value. It can be seen from the following Debye equation that the K value is proportional to the number of molecules N and the polarizability. The introduction of hydrogen plasma can change the configuration of carbon inside SiCOH, thereby achieving the purpose of reducing the polarizability and the number of molecules to reduce the K value.

[0057]

[0058] The present invention also provides a wafer deposited with low-K silicon oxide material, which is prepared by the method of the present invention.

[0059] The present invention also provides an integrated circuit comprising the wafer of the present invention.

[0060] The present invention also provides application of the wafer of the present invention in reducing RC delay of an integrated circuit.

[0061] The invention also provides application of the wafer of the invention in reducing circuit leakage current of an integrated circuit.

[0062] The present invention also provides application of the wafer of the present invention in alleviating circuit heating of an integrated circuit.

[0063] The invention also provides application of the wafer of the invention in improving the operation speed of integrated circuits.

[0064] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples without specifying specific conditions are usually based on conventional conditions or the conditions recommended by the manufacturer. Unless otherwise stated, percentages and parts are calculated by weight.

[0065] In this paper, the mercury cv method is used to test the K value of the material.

[0066] Example 1

[0067] (1) The wafer with SiOCH deposited on it is transferred to the reaction chamber, with the side of the wafer with SiOCH deposited on it facing the shower plate, and the distance between the shower plate and the wafer is adjusted to 10 mm.

[0068] (2) Preheat the wafer with SiOCH deposited on it to a process temperature of 240°C.

[0069] (3) Use pure argon gas to ignite the plasma for 5 seconds with an argon flow rate of 2000 sccm; starting from step (3), the pressure in the reaction chamber is controlled not to exceed 2 Torr in subsequent steps.

[0070] (4) Within 5 seconds, the Ar flow rate was gradually reduced to zero, and the H2 flow rate was gradually increased from 800 to 1600 sccm to form an environment composed entirely of hydrogen plasma. The hydrogen was continued to flow for 20 seconds to reduce the K value of the low-K silicon oxide material.

Claims

1. A method for reducing the K value of a low-K silicon oxide material, characterized in that: The method comprises the steps of: (1) transferring a wafer with low-K silicon oxide material deposited thereon to a reaction chamber; (2) preheating the wafer on which the low-K silicon oxide material is deposited; (3) Using argon gas to ignite the remote plasma device; (4) gradually reducing the flow rate of argon gas and gradually increasing the flow rate of hydrogen gas until the flow rate of argon gas is zero, so that the hydrogen gas continues to process the low-K silicon oxide material.

2. The method according to claim 1, characterized in that The low-K silicon oxide material includes carbon-doped silicon oxide.

3. The method according to claim 1, characterized in that The low-K silicon oxide material includes a non-porous low-K silicon oxide material and a porous low-K silicon oxide material.

4. The method according to claim 1, characterized in that In step (1), the side of the wafer on which the low-K silicon oxide material is deposited faces the shower plate in the reaction chamber, and the distance between the shower plate and the wafer is adjusted to 10-20 mm.

5. The method according to claim 1, characterized in that In step (2), the wafer deposited with the low-K silicon oxide material is preheated to 220-260°C.

6. The method according to claim 1, characterized in that In step (3), the flow rate of argon gas is 2000-4000 sccm; and / or, in step (3), the ignition is performed for 1-20 seconds.

7. The method according to claim 1, characterized in that In step (4), the flow rate of hydrogen is gradually increased to 800-1600 sccm.

8. The method according to claim 1, characterized in that In step (3) and step (4), the pressure in the reaction chamber is ≤2 Torr.

9. The method according to claim 1, characterized in that Gradually reduce the flow rate of argon gas within 3-20 seconds until the flow rate of argon gas is zero; and / or gradually increase the flow rate of hydrogen gas to 800-1600 sccm within 3-20 seconds.

10. The method according to claim 1, characterized in that After the argon flow rate reaches zero, continue to pass hydrogen for 10-60s.

11. A wafer deposited with low-K silicon oxide material prepared by the method according to any one of claims 1 to 10.

12. An integrated circuit, characterized in that: The integrated circuit comprises the wafer of claim 11.

13. An application selected from the following group: (1) Use of the wafer according to claim 11 in reducing RC delay of an integrated circuit; (2) Use of the wafer according to claim 11 in reducing circuit leakage current of an integrated circuit; (3) Use of the wafer according to claim 11 in alleviating circuit heating of an integrated circuit; (4) Use of the wafer described in claim 11 to improve the operating speed of integrated circuits.

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