Method for forming ultra-low dielectric constant film on semiconductor element and obtained semiconductor element
By forming and reaming the ultra-low dielectric constant films in step by step on semiconductor components and performing chemical mechanical planarization, the problem that the film cannot be completely filled and generated holes in semiconductor chips is solved, and high-quality and high-performance film preparation is achieved.
Patent Information
- Application Number
- CN202311543155.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-16
- Publication Date
- 2025-05-16
Smart Images
Figure CN120015618A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the field of semiconductor preparation, and in particular, to a method for forming an ultra-low dielectric constant film on a semiconductor element and the resulting semiconductor element. Background Art
[0002] In the modern era, microelectronics technology has become the foundation of the entire information industry and an important symbol of a country's comprehensive strength and economic development. With the development of integrated circuit technology, chips with high speed, high device density, low power consumption and low cost are becoming the main products of ultra-large-scale integrated circuit manufacturing.
[0003] The semiconductor industry is increasingly researching ultra-low dielectric constant films (ULK), which have a wide range of applications, especially in high-frequency devices, microprocessor fiber-optic communication devices, and organic light-emitting diodes.
[0004] In the process of semiconductor chip preparation, the back-end process requires the embedding of storage units, which may cause the ultra-low dielectric constant film to be unable to be completely filled, resulting in holes and failure. Summary of the invention
[0005] An object of the present disclosure is to provide a method for forming an ultra-low dielectric constant thin film on a semiconductor element and the resulting semiconductor element.
[0006] In order to achieve the above object, the present disclosure provides, in a first aspect, a method for forming an ultra-low dielectric constant film on a semiconductor element, the method comprising the following steps:
[0007] S1, forming a first portion of an ultra-low dielectric constant film on a surface of the semiconductor element provided with a plurality of memory cells;
[0008] The ratio of the maximum thickness of the first portion of the ultra-low dielectric constant film to the minimum distance between two adjacent storage units is less than 0.5;
[0009] The minimum thickness of the first portion of the ultra-low dielectric constant film is greater than the maximum height of the memory cell;
[0010] S2, performing a pore expansion treatment on the first portion of the ultra-low dielectric constant film by a plasma bombardment method to obtain the first portion of the ultra-low dielectric constant film after pore expansion with surface openings;
[0011] The depth of the surface opening is less than the minimum thickness of the first portion of the ultra-low dielectric constant film;
[0012] The aspect ratio of the surface opening is less than 1;
[0013] S3, forming a second portion of the ultra-low dielectric constant film on the first portion of the ultra-low dielectric constant film after the hole expansion;
[0014] S4. Performing chemical mechanical planarization on the second portion of the ultra-low dielectric constant film.
[0015] Optionally, the method further includes: before step S3, measuring the aspect ratio of the surface opening, and when the aspect ratio of the surface opening is greater than 1, alternately performing step S1 and step S2 until the aspect ratio of the surface opening is less than 1.
[0016] Optionally, in step S1, the method of forming the first portion of the ultra-low dielectric constant film includes chemical vapor deposition;
[0017] In step S3, the second portion of the ultra-low dielectric constant film is formed by chemical vapor deposition.
[0018] Optionally, in step S2, the plasma includes one or more of inert plasma and fluorine plasma.
[0019] Optionally, the first portion of the ultra-low dielectric constant film and the second portion of the ultra-low dielectric constant film include carbon-doped silicon dioxide.
[0020] Optionally, a ratio of the total thickness of the second portion of the ultra-low dielectric constant film to the total thickness of the first portion of the ultra-low dielectric constant film is (0.8-1):1.
[0021] Optionally, step S4 includes: performing the chemical mechanical planarization process on the second portion of the ultra-low dielectric constant film using a chemical grinder.
[0022] Optionally, the method further comprises: after step S4, curing the ultra-low dielectric constant film.
[0023] Optionally, the semiconductor element comprises a Cu layer and a dielectric barrier layer which are stacked;
[0024] The plurality of storage units are arranged at intervals on the dielectric barrier layer.
[0025] A second aspect of the present disclosure provides a semiconductor element with an ultra-low dielectric constant film prepared by the method described in the first aspect of the present disclosure.
[0026] Through the above technical scheme, the method disclosed in the present invention forms an ultra-low dielectric constant film on a semiconductor element provided with a plurality of storage units in steps, and at the same time controls the ratio of the thickness of the first part of the ultra-low dielectric constant film formed each time to the distance between two adjacent storage units, and after forming the first part of the ultra-low dielectric constant film each time, performs hole expansion treatment on it to avoid forming deep holes that are not conducive to deposition and filling holes, and holes with a smaller aspect ratio are conducive to completing the opening filling in subsequent steps, thereby reducing holes in the ultra-low dielectric constant film; then continue to form the second part of the ultra-low dielectric constant film, and finally perform chemical mechanical planarization treatment on the second part of the ultra-low dielectric constant film; the obtained ultra-low dielectric constant film does not have holes, has higher film quality and better performance.
[0027] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:
[0029] Figure 1 The flowchart is a specific embodiment of the method for forming an ultra-low dielectric constant film on a semiconductor element disclosed in the present invention.
[0030] Figure 2 It is a schematic diagram of the structure after the first part of the ultra-low dielectric constant film is formed in the present invention.
[0031] Figure 3 It is a schematic diagram of the structure obtained after the hole expansion process disclosed in the present invention.
[0032] Figure 4 It is a schematic diagram of the structure after the second part of the ultra-low dielectric constant film is formed in the present invention.
[0033] Figure 5 is a schematic diagram of the structure obtained after chemical mechanical planarization processing of the present invention. DETAILED DESCRIPTION
[0034] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.
[0035] like Figure 1 As shown, the first aspect of the present disclosure provides a method for forming an ultra-low dielectric constant film on a semiconductor element, the method comprising the following steps:
[0036] S1, forming a first portion of an ultra-low dielectric constant film on a surface of the semiconductor element provided with a plurality of memory cells;
[0037] The ratio of the maximum thickness of the first portion of the ultra-low dielectric constant film to the minimum distance between two adjacent storage units is less than 0.5;
[0038] The minimum thickness of the first portion of the ultra-low dielectric constant film is greater than the maximum height of the memory cell;
[0039] S2, performing a pore expansion treatment on the first portion of the ultra-low dielectric constant film by a plasma bombardment method to obtain the first portion of the ultra-low dielectric constant film after pore expansion with surface openings;
[0040] The depth of the surface opening is less than the minimum thickness of the first portion of the ultra-low dielectric constant film;
[0041] The aspect ratio of the surface opening is less than 1;
[0042] S3, forming a second portion of the ultra-low dielectric constant film on the first portion of the ultra-low dielectric constant film after the hole expansion;
[0043] S4. Performing chemical mechanical planarization on the second portion of the ultra-low dielectric constant film.
[0044] In the process of forming an ultra-low dielectric constant film on the surface of a semiconductor element provided with a plurality of storage units, holes appear in the ultra-low dielectric constant film due to the presence of the storage units. The inventors of the present disclosure have found in their research that by controlling the thickness of the ultra-low dielectric constant film formed in a single pass so that the ratio D / d of the single deposition thickness D to the minimum distance d between two storage units is less than 0.5, the formation of deep holes with a relatively large depth-to-width ratio can be reduced, and by expanding the holes of the ultra-low dielectric constant film formed in a single pass, the holes formed in the deposition can be converted into shallow openings with a relatively small depth-to-width ratio, thereby facilitating the completion of the hole filling through subsequent deposition steps, reducing the holes in the ultra-low dielectric constant film, and improving the film quality and performance.
[0045] In the present disclosure, "depth of surface openings" refers to the deepest depth of the surface openings.
[0046] In the present disclosure, the width of a surface opening refers to the maximum width of the opening.
[0047] In the present disclosure, the width of the uppermost end of all storage cells is not greater than the width of the lowermost end of the storage cells, that is, the ratio of the width of the uppermost end of all storage cells to the width of the lowermost end of the storage cells is less than 1; wherein, reference Figure 2The “uppermost end of the memory cell” refers to the end of the memory cell that is far away from the semiconductor element, and the “lowermost end of the memory cell” refers to the end of the memory cell that is close to the semiconductor element.
[0048] In the present disclosure, the thickness of the first ultra-low dielectric constant film can be uniform or non-uniform, and the minimum thickness of the first ultra-low dielectric constant film formed in a single step is above.
[0049] In the present disclosure, the minimum distance between any two adjacent storage units may be the same or different, and “the minimum distance between two adjacent storage units” refers to the minimum distance between any two adjacent storage units.
[0050] In the present disclosure, after the first step S1 is performed, a first portion of the formed ultra-low dielectric constant film covers the surface of the memory cell and fills the space between the memory cells.
[0051] According to one embodiment of the present disclosure, the method further includes: before step S3, measuring the aspect ratio of the surface opening, and when the aspect ratio of the surface opening is greater than 1, alternating steps S1 and S2 until the aspect ratio of the surface opening is less than 1.
[0052] According to one embodiment of the present disclosure, in step S1, the method of forming the first portion of the ultra-low dielectric constant film includes chemical vapor deposition, and its conditions are conventional in the art, for example, the pressure can be 7.5 torr, and the energy can be less than 400 W; the first portion of the ultra-low dielectric constant film has a plurality of holes, and the sizes of the holes are the same or different.
[0053] According to one embodiment of the present disclosure, in step S3, the method of forming the second part of the ultra-low dielectric constant film includes chemical vapor deposition, and its conditions are conventional in the art, for example, the pressure can be 7.5 torr, and the energy can be less than 400 W; wherein, the thickness of the second part of the ultra-low dielectric constant film can be uniform or non-uniform.
[0054] According to an embodiment of the present disclosure, in step S2, the type of plasma used in the plasma bombardment method is conventional in the art, for example, it may include one or more of inert plasma and fluorine plasma, specifically argon plasma.
[0055] In the present disclosure, in step S2, the conditions of the plasma bombardment method are conventional in the art.
[0056] According to an embodiment of the present disclosure, the first portion of the ultra-low dielectric constant film and the second portion of the ultra-low dielectric constant film have the same composition, for example, may include carbon-doped silicon dioxide.
[0057] According to one embodiment of the present disclosure, the ratio of the total thickness of the second part of the ultra-low dielectric constant film to the first part of the ultra-low dielectric constant film is set according to the subsequent process requirements, for example, it can be (0.8-1):1, wherein the "total thickness of the first part of the ultra-low dielectric constant film" refers to the total thickness of the first part of the ultra-low dielectric constant film formed in all steps S1. When the thickness of the first part of the ultra-low dielectric constant film and / or the second part of the ultra-low dielectric constant film is uneven, the minimum thickness is used for calculation.
[0058] According to one embodiment of the present disclosure, in step S4, the chemical mechanical planarization treatment method is conventional in the art, for example, step S4 includes: using a chemical grinder to perform chemical mechanical planarization treatment on the second portion of the ultra-low dielectric constant film, the second portion of the ultra-low dielectric constant film after treatment has no holes, and the total thickness of the first portion of the ultra-low dielectric constant film and the second portion of the ultra-low dielectric constant film is greater than the maximum height of the storage unit, wherein the total thickness is calculated based on the minimum thickness; the degree of chemical mechanical planarization treatment is performed according to subsequent process requirements.
[0059] According to one embodiment of the present disclosure, the method further includes: after step S4, curing the ultra-low dielectric constant film, wherein the ultra-low dielectric constant film includes a first portion of the ultra-low dielectric constant film and a second portion of the ultra-low dielectric constant film; the curing method is conventional in the art.
[0060] According to an embodiment of the present disclosure, the semiconductor element includes a Cu layer and a dielectric barrier layer which are stacked; and the plurality of storage units are arranged at intervals on the dielectric barrier layer.
[0061] In the present disclosure, a first portion of the ultra-low dielectric constant film covers the dielectric barrier layer and fills the spaces between the memory cells.
[0062] According to a specific embodiment of the present disclosure, the method for forming an ultra-low dielectric constant film on a semiconductor element of the present disclosure specifically includes the following steps:
[0063] S1. Provide a semiconductor element, the semiconductor element comprising a stacked Cu layer and a dielectric barrier layer, a plurality of storage units spaced apart are provided on the dielectric barrier layer, and the minimum distance between any two adjacent storage units is the same or different;
[0064] The first ultra-low dielectric constant film is formed on the surface of the semiconductor element by chemical vapor deposition, the pressure is 7.5 torr, the energy is less than 400W, and the first ultra-low dielectric constant film has a plurality of openings, the structure is as follows Figure 2 As shown;
[0065] The ratio of the maximum thickness of the ultra-low dielectric constant film in the first part to the minimum distance between two adjacent storage cells is less than 0.5;
[0066] The minimum thickness of the ultra-low dielectric constant film in the first part is above;
[0067] The minimum thickness of the ultra-low dielectric constant film in the first part is greater than the maximum height of the memory cell;
[0068] S2, using an argon plasma bombardment method to expand the first part of the ultra-low dielectric constant film to obtain the first part of the ultra-low dielectric constant film after expansion with surface openings, the structure of which is as follows Figure 3 As shown;
[0069] The depth of the surface opening is less than the minimum thickness of the first part of the ultra-low dielectric constant film;
[0070] Then, the aspect ratio of the surface opening is measured. If the aspect ratio is greater than 1, step S1 and step S2 are performed alternately until the aspect ratio of the surface opening is less than 1;
[0071] S3, forming a second ultra-low dielectric constant film on the first ultra-low dielectric constant film after hole expansion by chemical vapor deposition, with a pressure of 7.5 torr and an energy of less than 400 W, and a structure such as Figure 4 As shown;
[0072] S4, using a chemical grinder to perform chemical mechanical planarization on the second part of the ultra-low dielectric constant film, the structure is as follows Figure 5 As shown;
[0073] S5. Curing the ultra-low dielectric constant film to obtain a semiconductor element with the ultra-low dielectric constant film.
[0074] By adopting the above specific implementation manner, the holes in the ultra-low dielectric constant film can be further reduced, and an ultra-low dielectric constant film without holes can be obtained, which has higher film quality and better component performance.
[0075] A second aspect of the present disclosure provides a semiconductor element with an ultra-low dielectric constant film prepared by the method described in the first aspect of the present disclosure.
[0076] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.
[0077] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.
[0078] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.
Claims
1. A method for forming an ultra-low dielectric constant thin film on a semiconductor element, characterized in that: The method comprises the following steps: S1, forming a first portion of an ultra-low dielectric constant film on a surface of the semiconductor element provided with a plurality of memory cells; The ratio of the maximum thickness of the first portion of the ultra-low dielectric constant film to the minimum distance between two adjacent storage units is less than 0.5; The minimum thickness of the first portion of the ultra-low dielectric constant film is greater than the maximum height of the memory cell; S2, performing a pore expansion treatment on the first portion of the ultra-low dielectric constant film by a plasma bombardment method to obtain the first portion of the ultra-low dielectric constant film after pore expansion with surface openings; The depth of the surface opening is less than the minimum thickness of the first portion of the ultra-low dielectric constant film; The aspect ratio of the surface opening is less than 1; S3, forming a second portion of the ultra-low dielectric constant film on the first portion of the ultra-low dielectric constant film after the hole expansion; S4. Performing chemical mechanical planarization on the second portion of the ultra-low dielectric constant film.
2. The method according to claim 1, wherein: The method further includes: before step S3, measuring the aspect ratio of the surface opening, and when the aspect ratio of the surface opening is greater than 1, alternately performing steps S1 and S2 until the aspect ratio of the surface opening is less than 1.
3. The method according to claim 1, wherein: In step S1, the method of forming the first part of the ultra-low dielectric constant film includes chemical vapor deposition; In step S3 , the second portion of the ultra-low dielectric constant film is formed by chemical vapor deposition.
4. The method according to claim 1, wherein: In step S2, the plasma includes one or more of inert plasma and fluorine plasma.
5. The method according to claim 1, wherein: The first portion of the ultra-low dielectric constant film and the second portion of the ultra-low dielectric constant film include carbon-doped silicon dioxide.
6. The method according to claim 1, wherein: The ratio of the total thickness of the second portion of the ultra-low dielectric constant film to the total thickness of the first portion of the ultra-low dielectric constant film is (0.8-1):
1.
7. The method according to claim 1, wherein: Step S4 includes: performing the chemical mechanical planarization process on the second portion of the ultra-low dielectric constant film using a chemical grinder.
8. The method according to claim 1, wherein: The method further comprises: after step S4, curing the ultra-low dielectric constant film.
9. The method according to claim 1, wherein: The semiconductor element comprises a Cu layer and a dielectric barrier layer which are stacked; The plurality of storage units are arranged at intervals on the dielectric barrier layer.
10. A semiconductor element with an ultra-low dielectric constant film prepared by the method according to any one of claims 1 to 9.