CN103159955A

CN103159955A - Synthetic method of low dielectric constant material precursor

Info

Publication number: CN103159955A
Application number: CN2013100694304A
Authority: CN
Inventors: 丁士进; 丁子君; 张卫
Original assignee: Fudan University
Current assignee: Fudan University
Priority date: 2013-03-05
Filing date: 2013-03-05
Publication date: 2013-06-19
Anticipated expiration: 2033-03-05
Also published as: CN103159955B

Abstract

The invention belongs to the integrated circuit interconnection medium material technical field, and concretely relates to a synthetic method of a low dielectric constant material precursor, which relates to a method for synthesis and modification of a POSS polymer by a septuple-deleted cage type silsesquioxane (POSS) monomer. According to the invention, the septuple-deleted cage type silsesquioxane (POSS) monomer and an unsaturated compound 1,5-hexadiene are performed with an addition reaction to prepare the modified POSS. The modified polymer can be taken as the precursor of the low dielectric constant material, and can be used for an integrated circuit interconnection medium. The modified polymer contains inorganic and organic chemical bond components, thereby has the inorganic and organic material composite performances. In addition, the polymer contains a closed aperture with 2-3nm, thereby the dielectric constant of the material can be effectively reduced, and the low dielectric constant material precursor is an ideal precursor of a low dielectric constant medium film required by deep submicron integrated circuit interconnection.

Description

A kind of synthetic method of advanced low-k materials presoma

Technical field

The invention belongs to integrated circuit interconnection dielectric material technical field, be specifically related to a kind of synthetic method of advanced low-k materials presoma, be a kind of method of cage-type silsesquioxane (POSS) monomer synthesis modification POSS polymkeric substance of seven unfilled corners.

Background technology

Along with the unicircuit characteristic dimension enters deep-submicron, interconnection RC postpones to have become the important factor that affects circuit speed.Therefore, in order to reduce interconnect delay, various advanced low-k materials are continually developed out.In order to obtain low-k (k) dielectric material, we can pass through to reduce the polarizability of medium in theory, and the density of the polar molecule in the reduction unit volume realizes.Yet to obtain low k be limited by reducing its polarizability in uniform dielectric, and therefore introducing air gap (k ~ 1) to form the composite diphase material that is comprised of medium and air gap, is the effective way of the ultralow k material of acquisition in material.Cage-type silsesquioxane (POSS) as low k presoma, because containing the closed aperture of the 2-3nm that has an appointment in its molecule, introduced the intrinsic air gap so be counted as, this has reduced the density of material itself to a certain extent, thereby can become the desirable presoma of low-k materials.At present, low k presoma based on the POSS modification mainly contains epoxy resin, polyimide resin, urethane, organosilicon etc., wherein low k organosilicon polymer mainly comprises alkyl POSS, vinyl POSS, hydrogen base POSS etc., and its specific inductivity depends primarily on the storage effect of each organic group dielectric properties.The general formula of POSS is (R-SiO _3/2) _n, n is 6,8,10,12; R is H, alkyl, aryl or other organo-functional group.Carry out " re-assemble " and can form and have molecular structure level hybrid inorganic-organic matrix material thereby POSS is easy to the organic group located by the summit or reactive with active hydrogen, it has the advantage of organic polymer and inorganic materials, and the overall performance of material is better.In view of the importance of low-k materials at microelectronic, the exploitation with low-k materials presoma of POSS structure also becomes the study hotspot in low-k materials field.

Along with unicircuit advances fast, the low-k materials that is used for connected medium need to satisfy the requirements such as good thermostability, electric property and mechanical property.Yet common polymkeric substance low-k materials such as tetrafluoroethylene, silicone resin, polyimide etc. can't satisfy integrated circuit technology to the requirement of thermostability and mechanical property, so its practical application is subject to great restriction.Based on the presoma of POSS structure, not only have the intrinsic air gap, can also be connected with chemical bond with macromolecular chain, therefore can be with inorganic Si-O-Si well-formed's mechanical property and combining than the low-k characteristic of organic C-C and C-H structure.Yet the monomeric form that is used as the POSS building-up reactions in prior art is comparatively single, mostly is eight unfilled corner POSS monomers.The present invention proposes a kind of POSS monomer that adopts seven brand-new unfilled corners, come the method for synthetic low k presoma.

Summary of the invention

A kind of method that the purpose of this invention is to provide seven unfilled corner POSS monomer synthesis modification POSS polymkeric substance is for the presoma of integrated circuit interconnection medium low-K material.

The method of synthesis modification POSS polymkeric substance provided by the invention, to utilize the addition reaction of silicon with hydrogen principle, take a kind of seven unfilled corner POSS of novelty as reaction monomers, by with unsaturated compound 1, the 5-hexadiene carries out addition reaction of silicon with hydrogen, comes the POSS polymkeric substance (being reticulated structure POSS high polymer) of synthesis modification.Concrete steps are as follows:

The POSS monomer is entirely by name: interior-3,7,14-three (dimethylsilyl bis)-1,3,5,7,9,11,14-seven cyclopentyl three ring [7.3.3.15,11] seven siloxanes.With POSS monomer, unsaturated compound 1,5-hexadiene, catalyzer spongy platinum mix, add solvent toluene, mixed raw material and solvent are added reaction vessel schlank pipe (selecting the schlank pipe as reaction vessel to be because can take out like a cork inflatable body and the stopping property of maintenance system), POSS monomer, unsaturated compound 1, the molar ratio of 5-hexadiene, spongy platinum, toluene is: (9.77-10.95) * 10 ^-5: (1.5-1.91) * 10 ^-4: (4.4-5.2) * 10 ^-5: (0.12-0.15);

The schlank pipe is put into cooled with liquid nitrogen, until that the liquid state in system is transformed into gradually is solid-state, in this step, system is that in the process that prevents from vacuumizing, liquid raw material and solvent are pumped and affect the reaction accuracy with the reason of cooled with liquid nitrogen.In reaction process, use high pure nitrogen as protective atmosphere, namely be filled with high pure nitrogen (so circulation repeatedly) by the air of taking away in reaction vessel, realize that this reaction system carries out under the anhydrous and oxygen-free condition.Reaction times 20-28 hour (preferred 24 hours), temperature of reaction remain on 38-45 ℃ (preferred 42 ℃);

After reaction finishes, solution is filtered the remaining platinum catalyst of reaction with sand core funnel, guarantee that in reaction soln, heavy metal free is residual, the solution that all obtains after treatment step is clear solution.

In the present invention, react all liquid starting materials of using and all remove water treatment through distillation.

Advantage of the present invention:

(1) reacted system adopts sand core funnel to filter, and can effectively remove residual catalyst platinum after reaction, in gained modification POSS polymkeric substance without metal residual;

(2) the modification POSS polymkeric substance itself that is synthesized contains the closed aperture of a large amount of approximately 2-3nm, therefore can effectively reduce the specific inductivity of material itself, thereby satisfy deep submicron integrated circuit to the requirement of advanced low-k materials connected medium;

(3) contain inorganic and organic chemistry key composition in polymer-modified due to this, therefore have concurrently inorganic and composite performance organic materials.When being used for low k connected medium, can average out on low-k and physical strength two specific characters.

Description of drawings

Fig. 1 is reaction product ²⁹The Si-NMR nuclear magnetic resonance map.

Embodiment

With interior-3,7,14-three (dimethylsilyl bis)-1,3,5,7,9,11,14-seven cyclopentyl three ring [7.3.3.15,11] seven siloxanes (POSS monomer), 1,5-hexadiene, spongy platinum, toluene are according to 9.77 * 10 ^-5: 1.5 * 10 ^-4: 5.2 * 10 ^-5: 0.14 molar ratio mixes, and adds toluene as reaction solvent, and wherein all liquid raw materials all pass through anhydrous (distillation) processing.Then, mixed raw material is injected reaction vessel schlank pipe.Then, the schlank pipe is put into cooled with liquid nitrogen, until that the liquid state in system is transformed into gradually is solid-state.Use high pure nitrogen as protective atmosphere in reaction process, namely be filled with high pure nitrogen (so circulation repeatedly) by the air of taking away in reaction vessel, realize that this reaction system carries out under the anhydrous and oxygen-free condition.In approximately 24 hours reaction times, temperature of reaction remains on 40 ℃.Reacted solution filters out the spongy platinum catalyzer with sand core funnel, obtains the solution of clear after all processing steps is completed.

The nuclear magnetic resonance spectroscopy result as shown in Figure 1, ²⁹Si-NMR is the powerful that characterizes silicon compound.As seen from Figure 1, the peak (c and b) of two chemical shifts appears in the spectrogram of product, wherein on cage the Siliciumatom chemical shift owing to being subject to Me ₂The shielding of SiO and shift to High-Field appears at-67 ppm places.On cage before the chemical shift of Siliciumatom and reaction in the POSS monomer chemical shift of Siliciumatom identical, this explanation reaction post polymerization thing cage structure is not destroyed.The outer Me that hangs of cage ₂The chemistry of silicones displacement of SiO group is at-5 ppm places, this be due to after reaction between the POSS monomer due to the connection of hexadiene, cause the outer Me that hangs of cage ₂The chemistry of silicones displacement of SiO group is moved to High-Field.What deserves to be explained is in spectrogram at-110 ppm places a comparatively obvious roomy background peaks to have occurred, this generally exists because the nuclear-magnetism Glass tubing causes ²⁹All can occur in the Si-NMR test, its size weakens with the enhancing of fignal center.

Table 1 is reaction product to be carried out the result of x-ray photoelectron power spectrum (XPS) test analysis, can find out in product except due carbon (C), oxygen (O), silicon (Si) element, impurity platinum (Pt) element do not detected.As connected medium, the existence of metallic impurity can cause serious leakage current, so this example is specially measured the content of metallic impurity in product.Test result has exactly illustrated by the resulting presoma of this synthetic method, is being used for having good application prospect on low k interconnection material.

Table 1 is by the relative content of element in the resulting product of XPS test

Element	C	O	Pt	Si
					Atom relative percentage (%)	42.35%	28.02%	0.00%	29.55%

Claims

1. the synthetic method of an advanced low-k materials presoma, the advanced low-k materials presoma is reticulated structure POSS high polymer, it is characterized in that the concrete steps of synthesizing are:

With POSS monomer, unsaturated compound 1,5-hexadiene, catalyzer spongy platinum mix, add solvent toluene, mixed raw material and solvent are added reaction vessel schlank pipe, POSS monomer, unsaturated compound 1, the molar ratio of 5-hexadiene, spongy platinum, toluene is: (9.77-10.95) * 10 ^-5: (1.5-1.91) * 10 ^-4: (4.4-5.2) * 10 ^-5: (0.12-0.15);

The schlank pipe is put into cooled with liquid nitrogen, until that the liquid state in system is transformed into gradually is solid-state, in reaction process, use high pure nitrogen as protective atmosphere, reaction times 20-28 hour, temperature of reaction remained on 38-45 ℃;

After reaction finishes, solution is filtered the remaining platinum catalyst of reaction with sand core funnel, obtain clear solution.

2. synthetic method according to claim 1, is characterized in that all liquid raw materials all removed water treatment through distillation before mixing.