Preparation method of material applied to 5G communication with low dielectric constant

Abstract

The application relates to the technical field of semiconductors, in particular to a preparation method of a material with a low dielectric constant applied to 5G communication, which comprises a substrate, and a low dielectric constant dielectric layer arranged on the substrate; the low dielectric constant dielectric layer is a composite layer of a dielectric layer one and a dielectric layer two; the dielectric layer one is internally provided with a hole; a bonding surface of the dielectric layer one internally provided with the hole and the dielectric layer two is provided with a groove; a metal layer and a shielding layer are deposited in the groove; the grooves are connected to form a cross network; through the composite manufacturing of two low dielectric materials, the dielectric constant can be effectively reduced, the mechanical properties and the mechanical properties of the thin film are enhanced, the heat resistance of the thin film is improved, the influence of the etching process on the thin film can be reduced, the migration of the dielectric constant material can be effectively prevented, the situation that the metal wire is higher than the low dielectric constant material due to the material shrinkage caused by ultraviolet irradiation can be solved, and the damage of polishing to the thin film can be reduced.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically to a method for preparing a material with a low dielectric constant for use in 5G communication. Background Technology

[0002] Despite the continuous development of electronic technology, the microelectronics industry has largely maintained the validity of Moore's Law. To improve the performance and speed of integrated circuits, more and more transistors, smaller and smaller, are being integrated into chips. With the trend of miniaturization, the distance between different layers of wires in the chip is also decreasing. As the thickness of silicon dioxide, which is used as an insulating layer between wires, continues to shrink, its capacitance increases. The accumulated charge will inevitably interfere with signal transmission, reduce the reliability of the circuit, and limit the further increase of frequency.

[0003] The microelectronics industry will use low-dielectric-constant materials to replace traditional silicon dioxide insulating materials. Current research suggests that there are two main methods to reduce the dielectric constant of materials: First, reducing the material's inherent polarity, including reducing electronic, ionic, and molecular polarizability. This method primarily achieves this by doping silicon dioxide with impurities. Second, increasing the porosity of the material, i.e., introducing air bubbles into the dielectric layer, thereby reducing the material's molecular density. In studies on reducing molecular polarity, it has been found that molecular density per unit volume plays a crucial role in reducing the dielectric constant of materials; a decrease in molecular density contributes to a decrease in dielectric constant.

[0004] Currently, the common method used in this field is to add a so-called foaming agent during the thin film deposition process, and then treat the thin film with ultraviolet light on a heat-assisted basis after the deposition is completed, thereby leaving air bubbles in the film to reduce the k value. However, since low dielectric constant films still need to undergo harsh post-processing, the mechanical strength, toughness, heat resistance, acid resistance, etc. of low dielectric constant films obtained by conventional methods are insufficient to meet the needs of subsequent processing. Summary of the Invention

[0005] The problem to be solved by the present invention is to provide a method for preparing a material with low dielectric constant that has good mechanical properties and is simple to process for use in 5G communication.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a material with low dielectric constant for use in 5G communication, comprising a substrate, wherein a low dielectric constant dielectric layer is disposed on the substrate; The low dielectric constant dielectric layer is a composite layer of dielectric layer one and dielectric layer two. Dielectric layer one has holes inside, and the interface between dielectric layer one and dielectric layer two has trenches. Metal layer and shielding layer are deposited in the trenches, and the trenches are connected to form a cross network.

[0007] Furthermore, the second dielectric layer is a fluorinated silicate glass layer.

[0008] Furthermore, the dielectric layer is a modified silicon dioxide layer.

[0009] A method for preparing materials with low dielectric constants for use in 5G communications includes the following steps: Step 1: Prepare dielectric layer 1 on the substrate to obtain the substrate; Step 2: Coat the substrate from Step 1 with photoresist to form a pattern of grooves. Using the photoresist as a mask, etch the grooves on the semi-finished product and remove the photoresist by dry method to obtain the semi-finished product. Step 3: Deposit conductive metal into the trenches of the semi-finished product from Step 2 to form a metal cross network in the trenches. Coat the metal cross network with a shielding layer, dry, and polish to obtain dielectric layer 1. Step 4: Composite dielectric layer 2 with dielectric layer 1 from step 3 to obtain a low dielectric constant dielectric layer. Then, treat the low dielectric constant dielectric layer with ultraviolet light to obtain the finished product.

[0010] Furthermore, in step four, the second dielectric layer is formed by spin coating, with a spin coating thickness of 200-500 angstroms.

[0011] Furthermore, in step one, the conductive metal is deposited using chemical vapor deposition.

[0012] Furthermore, in step three, the material of the shielding layer is silicon carbide or silicon dioxide.

[0013] Furthermore, the fabrication steps of the first dielectric layer include: S1: Dissolve inorganic silicate in water and stir until homogeneous, add silane coupling agent, stir, and obtain modified silica gel solution; S2: Add dry ice powder to the modified silica gel solution, stir rapidly, and then freeze-dry to obtain dielectric layer one.

[0014] Furthermore, in S2, the freeze-drying temperature is -40°C, and the drying time is 12-48 hours.

[0015] Furthermore, in step four, the temperature of the ultraviolet light treatment is 300-450℃, and the air pressure is 2-10 mTorr.

[0016] Compared with the prior art, the advantages and positive effects of this invention are: The present invention provides a method for preparing a material with a low dielectric constant for 5G communication. By composite manufacturing of two low dielectric materials, the dielectric constant can be effectively reduced, and the mechanical and mechanical properties of the thin film can be enhanced. The heat resistance of the thin film can be improved, and the influence of the etching process on the thin film can be reduced. It can also effectively prevent the migration of dielectric materials and solve the problem that the metal interconnects are higher than the low dielectric material due to material shrinkage caused by ultraviolet irradiation, thereby reducing the damage to the thin film caused by polishing. Detailed Implementation

[0017] To better understand the present invention, the present invention will be further described below with reference to specific embodiments.

[0018] Example 1: Step 1: Prepare dielectric layer 1 on the substrate. Dissolve inorganic silicate in water and stir evenly. Add silane coupling agent and stir to obtain modified silica gel solution. Add dry ice powder to modified silica gel solution and stir rapidly. Then freeze dry at -40℃ for 12 hours to obtain a substrate with dielectric layer 1. Step 2: Coat the substrate from Step 1 with photoresist to form a pattern of grooves. Using the photoresist as a mask, etch the grooves on the semi-finished product and remove the photoresist by dry method to obtain the semi-finished product. Step 3: Deposit conductive metal into the trenches of the semi-finished product from Step 2 using chemical vapor deposition to form a metal cross network in the trenches. Coat the metal cross network with a shielding layer, silicon carbide or silicon dioxide, dry and polish to obtain dielectric layer 1. Step 4: Apply a layer of silicate to the outside of dielectric layer 1 from step 3 by spin coating. After curing, it becomes dielectric layer 2 with a thickness of 200 angstroms, resulting in a low dielectric constant dielectric layer. Then, treat the low dielectric constant dielectric layer with ultraviolet light at a temperature of 300°C and a pressure of 2 mTorr to obtain the finished product.

[0019] Example 2: Step 1: Prepare dielectric layer 1 on the substrate. Dissolve inorganic silicate in water and stir evenly. Add silane coupling agent and stir to obtain modified silica gel solution. Add dry ice powder to modified silica gel solution and stir rapidly. Then freeze dry at -40℃ for 48h to obtain a substrate with dielectric layer 1. Steps two and three are the same as in Example 1; Step 4: Apply a layer of silicate to the outside of dielectric layer 1 from step 3 by spin coating. After curing, it becomes dielectric layer 2 with a thickness of 500 angstroms, resulting in a low dielectric constant dielectric layer. Then, treat the low dielectric constant dielectric layer with ultraviolet light at a temperature of 450°C and a pressure of 10 mTorr to obtain the finished product.

[0020] Example 3: Step 1: Prepare dielectric layer 1 on the substrate. Dissolve inorganic silicate in water and stir evenly. Add silane coupling agent and stir to obtain modified silica gel solution. Add dry ice powder to modified silica gel solution and stir rapidly. Then freeze dry at -40℃ for 36 hours to obtain a substrate with dielectric layer 1. Steps two and three are the same as in Example 1; Step 4: Apply a layer of silicate to the outside of dielectric layer 1 from step 3 by spin coating. After curing, it becomes dielectric layer 2 with a thickness of 350 angstroms, resulting in a low dielectric constant dielectric layer. Then, treat the low dielectric constant dielectric layer with ultraviolet light at a temperature of 380°C and a pressure of 6 mTorr to obtain the finished product.

[0021] Comparative Example 1: Steps one and two are the same as in Example 3; Step 3: Deposit conductive metal into the trenches of the semi-finished product from Step 2 using chemical vapor deposition to form a metal cross network in the trenches. Coat the metal cross network with a shielding layer, such as silicon carbide or silicon dioxide, dry, and polish to obtain the finished product. Comparative Example 2: Steps one through three are the same as in Example 1; Step 4: Apply a layer of silicate to the outside of dielectric layer 1 from step 3 using a spin coating method. After curing, it becomes dielectric layer 2 with a thickness of 200 angstroms, resulting in a low dielectric constant dielectric layer and the finished product.

[0022] Experimental example: This experimental example examines the dielectric constant and physical properties of the material.

[0023] Control group A and control group B: The schemes provided by comparative example 1 and comparative example 2 were used respectively. The difference of control group A is that it does not have dielectric layer 2. The difference between control group B and control group B is that no ultraviolet light treatment was performed. Experimental groups A, B, and C: adopted the technical solutions of Examples 1-3 respectively; The dielectric constant and tensile strength of the experimental group AC and the control group AB were measured, and the tensile strength was measured again after heating to 200℃. The results are shown in Table 1.

[0024] Table 1. Determination of dielectric constant and tensile strength of materials

[0025] The determination of the properties of low dielectric constant materials shows that the dielectric constant of experimental group AC is lower than that of control group AB, and it has good tensile strength. It can also maintain relatively good mechanical properties at 200℃. Since control group A lacks dielectric layer 2, which is a silicate glass layer with good mechanical properties, and the composite can effectively reduce the dielectric constant of the material, the material in control group B lacks the ultraviolet light treatment step. Ultraviolet light can make the material more compact and can completely evaporate the dry ice powder in the material, thereby increasing the porosity, reducing the dielectric constant, and giving it better mechanical properties.

[0026] The present invention provides a method for preparing a material with a low dielectric constant for 5G communication. By composite manufacturing of two low dielectric materials, the dielectric constant can be effectively reduced, and the mechanical and mechanical properties of the thin film can be enhanced. The heat resistance of the thin film can be improved, and the influence of the etching process on the thin film can be reduced. It can also effectively prevent the migration of dielectric materials and solve the problem that the metal interconnects are higher than the low dielectric material due to material shrinkage caused by ultraviolet irradiation. This reduces the damage to the thin film during polishing and thus enables it to have a longer service life.

[0027] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of this patent.

Claims

1. A method for preparing a material with a low dielectric constant for use in 5G communication, characterized in that: The low dielectric constant material includes: a substrate, wherein a low dielectric constant dielectric layer is disposed on the substrate; The low dielectric constant dielectric layer is a composite layer of dielectric layer one and dielectric layer two. The dielectric layer one has holes inside, and the interface between dielectric layer one and dielectric layer two has trenches. A metal layer and a shielding layer are deposited in the trenches, and the trenches are connected to form a cross network. A method for preparing a low dielectric constant material includes: Step 1: Preparing a dielectric layer 1 on a substrate to obtain a substrate; Step 2: Coating photoresist onto the substrate in Step 1 to form a pattern of trenches, and using the photoresist as a mask to etch the trenches on the semi-finished product, then removing the photoresist by dry method to obtain the semi-finished product; Step 3: Depositing conductive metal into the trenches of the semi-finished product in Step 2 to form a metal cross-network within the trenches, coating a shielding layer within the metal cross-network, drying, and polishing to obtain a dielectric layer 1; Step 4: Composite a dielectric layer 2 onto the dielectric layer 1 in Step 3 to obtain a low dielectric constant dielectric layer, and subjecting the low dielectric constant dielectric layer to ultraviolet light treatment to obtain the finished product.

2. The method for preparing a material with low dielectric constant for 5G communication according to claim 1, characterized in that: The second dielectric layer is a fluorinated silicate glass layer.

3. The method for preparing a material with low dielectric constant for 5G communication according to claim 1, characterized in that: The dielectric layer is a modified silicon dioxide layer.

4. The method for preparing a material with low dielectric constant for 5G communication according to claim 1, characterized in that: In step four, the second dielectric layer is formed by spin coating, with a spin coating thickness of 200-500 angstroms.

5. The method for preparing a material with low dielectric constant for 5G communication according to claim 1, characterized in that: In step one, the conductive metal is deposited using chemical vapor deposition.

6. The method for preparing a material with low dielectric constant for 5G communication according to claim 1, characterized in that: In step three, the material of the shielding layer is silicon carbide or silicon dioxide.

7. A method for preparing a material with low dielectric constant for use in 5G communication according to claim 1, characterized in that: The fabrication steps of the first dielectric layer include: S1: Dissolve inorganic silicate in water and stir until homogeneous, add silane coupling agent, stir, and obtain modified silica gel solution; S2: Add dry ice powder to the modified silica gel solution, stir rapidly, and then freeze-dry to obtain dielectric layer one.

8. A method for preparing a material with low dielectric constant for use in 5G communication according to claim 7, characterized in that: In S2, the freeze-drying temperature is -40℃, and the drying time is 12-48 hours.

9. A method for preparing a material with low dielectric constant for use in 5G communication according to claim 1, characterized in that: In step four, the ultraviolet light treatment temperature is 300-450℃ and the air pressure is 2-10 mTorr.

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