CN101651131B

CN101651131B - Low dielectric constant insulating film and preparation method thereof

Info

Publication number: CN101651131B
Application number: CN2009101958197A
Authority: CN
Inventors: 丁士进; 钱可嘉; 张卫
Original assignee: Fudan University
Current assignee: Fudan University
Priority date: 2009-09-17
Filing date: 2009-09-17
Publication date: 2011-11-02
Anticipated expiration: 2029-09-17
Also published as: CN101651131A

Abstract

The invention belongs to the technical filed of integrated circuit materials, in particular to a low dielectric constant insulating film and a preparation method thereof. The low dielectric constant insulating film is a SiCONF film and comprises main components of silicon (Si), carbon (C), oxygen (O), nitrogen (N) and fluorine (F), and the thickness of the film is 20-500 nm. The low dielectric constant insulating medium SiCONF film can be prepared by a plasma enhanced chemical vapor deposition (PECVD) method; a plasma generation device added in PECVD equipment can be used as a device adopted by the method; and plasma is generated by the PECVD equipment and the radio-frequency range of the prior plasma radio-frequency excitation source can be used. The SiCONF film has low dielectric constant and leak current density, high thermal stability and favorable mechanical property and can be compatible with the prior integrated circuit process.

Description

A kind of low dielectric constant insulating film and preparation method thereof

Technical field

The invention belongs to the integrated circuit material technical field, be specifically related to a kind of low dielectric constant insulation medium SiCONF film and preparation method thereof, this film can be used in the integrated circuit manufacturing.

Background technology

Along with the continuous development of integrated circuit, the reducing of metal line interlamellar spacing and distance between centers of tracks, the interconnection parasitic capacitance of circuit reduces and increases rapidly with the raising of integrated circuit integrated level and characteristic size.Interconnect delay (RC delay) also because of the rapid increase of interconnection parasitic capacitance increases, has limited the arithmetic speed and the noise margin of integrated circuit, causes the increase of circuit dynamic power consumption simultaneously.In very lagre scale integrated circuit (VLSIC), replace traditional SiO with low-k (low k) film ₂(k=4.0) can reduce interconnection parasitic capacitance effectively as the dielectric film, thereby make circuit interconnection postpone to reduce.Therefore many researchers are exploring the film of some low-ks always.The more low dielectric constant films of research has fluorinated silicon oxide (SiOF) [1], contains organic substance silica (SiCOH) [2] and some organic polymers [3] etc. both at home and abroad at present, but these products or have production method complexity, the higher problem of cost, or exist electricity, calorifics, mechanical property can't satisfy the problems such as demand of integrated circuit technology.The objective of the invention is to adopt the technology compatible mutually, prepare a kind of dielectric film of low-k with integrated circuit technology.List of references:

[1]B.D.Hatton，K.Landskron，W.J.Hunks，M.R.Bennett，D.Shukaris，D.D.Perovic，G.A.Ozin，Materials?chemistry?for?low-k?materials.9(13)，22-31(2006).

[2]M.R.Baklanov，K.Meax，Porous?low?dielectric?constant?materials?for?microelectronics.Phil.Trans.R.Soc.A(2006)364，201-215(2005).

[3]K.Maex，M.R.Baklanov，D.Shamiryan，F.lacopi，S.H.Brongersma，Z.S.Yanovitskaya，Low?dielectric?constant?materials?for?microelectronics.Journal?of?AppliedPhysics.，93(11)，8793-8841(2003).

Summary of the invention

The objective of the invention is to propose a kind of electricity that is used for very lagre scale integrated circuit (VLSIC) and good mechanical properties, the simple low dielectric constant insulation dielectric film of preparation method.

Another object of the present invention provides the preparation method of the said goods.

The low dielectric constant insulation dielectric film that the present invention proposes is the SiCONF film, the main component of this film is silicon (Si), carbon (C), oxygen (O), nitrogen (N), fluorine (F), film thickness is 20～500nm, the Si atom content is 20～30% in the film, the C atom content is 2～20%, and the O atom content is 40～60%, and the N atom content is 2～10%, the F atom content is 5～10%, and total amount is 100%.With SiO ₂Dielectric is compared, F atom and C atom mix the dielectric constant that has reduced film effectively; Simultaneously, the existence of N atom makes the anti-electric creepage performance of film and mechanical performance be significantly improved in the film.Therefore, SiCONF film not only dielectric constant is low, and the electric breakdown strength height, and it is enough low to leak electricity, and mechanical strength is good.

The present invention can prepare above-mentioned low dielectric constant insulation medium SiCONF film with plasma chemical vapor deposition (PECVD) method.In chemical vapor deposition device, increase the device that plasma generator all can be used as the inventive method.Can produce plasma with plasma enhanced CVD equipment among the present invention, existing plasma radiofrequency driving source frequency range all can be used.Plasma radiofrequency driving source frequency of the present invention is 13.56MHz, and power is 1500～2000W, and deposition temperature is 150～400 ℃, and plasma reaction chamber air pressure is 60～80Pa, and the used raw material of deposit is silane (SiH ₄), nitrous oxide (N ₂O), hexafluoroization two carbon (C ₂F ₆), SiH wherein ₄Flow be 100～200sccm, N ₂The flow of O is 50～200sccm, C ₂F ₆Flow be 300～900sccm.

Along with the development of very lagre scale integrated circuit (VLSIC), the increase of interconnect delay, low dielectric constant films of the present invention is specially adapted to substitute traditional SiO in the very lagre scale integrated circuit (VLSIC) production ₂Film can very reduce interconnection parasitic capacitance effectively.

Low-k SiCONF film of the present invention has the following advantages:

1) dielectric constant is low, can drop to about 2.6;

2) the film leakage current density is low, and leakage current density is less than 1 * 10 under the field intensity of 1MV/cm ^-8A/cm ²

3) dielectric strength height surpasses 10MV/cm;

4) film chemical stable in properties, heat decomposition temperature can not absorb moisture more than 500 ℃ in air;

5) film satisfactory mechanical property, film hardness is more than 3GPa, and Young's modulus is more than 80GPa;

6) can be compatible well with prior integrated circuit process, can not influence the stability and the reliability of circuit because of using novel thin film.

The subordinate list explanation

Table 1 is the flow according to all gases source in several low dielectric constant insulation medium of the present invention SiCONF film preparation example;

Table 2 is various atom content percentages in the prepared low dielectric constant insulation medium SiCONF film of above-mentioned several example;

Table 3 is that dielectric constant, electrical properties and the mechanical property of the prepared low dielectric constant insulation medium SiCONF film of above-mentioned several example compares.

Embodiment

Below for adopting low dielectric constant insulation medium SiCONF film provided by the invention and preparation method thereof, the example of preparation low dielectric constant insulation medium SiCONF film.

With silane (SiH ₄), nitrous oxide (N ₂O), hexafluoroization two carbon (C ₂F ₆) mist is raw material, deposition film in plasma enhanced CVD (PECVD) equipment.Produce plasma between the circular plate electrode in deposition apparatus.Plasma radiofrequency driving source frequency is 13.56MHz, and radio-frequency power is 1800W, and deposition temperature is 200 ℃, and operating air pressure is 67Pa in the deposition chamber.Table 1 has been listed the flow of each gas in 3 kinds of different experiments; The element percentage that table 2 has been listed in the corresponding experiment gained film is formed; Table 3 has been listed dielectric constant, leakage current density and hardness, the Young's modulus of corresponding film.Work as SiH ₄And N ₂The flow of O is respectively 150sccm, C ₂F ₆Flow when being 750sccm, the dielectric constant of resulting film is 2.6, this film leakage current density under the electric field of 1MV/cm is 9.5 * 10 ^-9A/cm ², film hardness is 3.3GPa, Young's modulus is 93GPa.

Table 1

Table 2

Table 3

Claims

1. low dielectric constant insulating film, it is characterized in that thin film composition is Si, C, O, N, F, be designated as the SiCONF film, film thickness is 20～500nm, the Si atom content is 20～30% in the film, and the C atom content is 2～20%, and the O atom content is 40～60%, the N atom content is 2～10%, and the F atom content is 5～10%; And prepare by following step:

Produce plasma with the plasma-reinforced chemical vapor deposition device, deposition temperature is 150～400 ℃, and plasma reaction chamber air pressure is 60～80Pa, and the used raw material of deposit is SiH ₄, N ₂O and C ₂F ₆, SiH wherein ₄Flow be 100～200sccm, N ₂The flow of O is 50～200sccm, C ₂F ₆Flow be 300～900sccm.

2. the preparation method of a low dielectric constant insulating film as claimed in claim 1, it is characterized in that concrete steps are as follows: produce plasma with the plasma-reinforced chemical vapor deposition device, deposition temperature is 150～400 ℃, plasma reaction chamber air pressure is 60～80Pa, and the used raw material of deposit is SiH ₄, N ₂O and C ₂F ₆, SiH wherein ₄Flow be 100～200sccm, N ₂The flow of O is 50～200sccm, C ₂F ₆Flow be 300～900sccm.

3. low dielectric constant insulating film as claimed in claim 1 is as the application of dielectric film in the integrated circuit.