CN111378383B

CN111378383B - Application of polyether amine compound in polishing of PI dielectric material

Info

Publication number: CN111378383B
Application number: CN201811652979.5A
Authority: CN
Inventors: 李守田; 尹先升; 贾长征
Original assignee: Anji Microelectronics Shanghai Co Ltd
Current assignee: Anji Microelectronics Shanghai Co Ltd
Priority date: 2018-12-28
Filing date: 2018-12-28
Publication date: 2022-05-13
Anticipated expiration: 2038-12-28
Also published as: CN111378383A

Abstract

The invention provides an application of polyether amine compounds in polishing of PI dielectric materials, and the polyether amine compounds are added into chemical mechanical polishing liquid containing abrasive particles, so that the polishing rate of the PI dielectric materials can be properly inhibited, low points are protected in the process of flattening and polishing of PI films of dielectric materials of graphic wafers, over-polishing of low point areas is avoided, and the efficiency of flattening and polishing is improved.

Description

Application of polyether amine compound in polishing of PI dielectric material

Technical Field

The invention relates to the technical field of chemical mechanical polishing, in particular to application of a polyether amine compound in polishing of a PI dielectric material.

Background

At present, SiO₂Dielectric materials are materials commonly used in the semiconductor manufacturing industry, but such materials have a problem of a high dielectric constant (dielectric constant of about 4.0). The polymer material has a low dielectric constant, but most polymer materials have a glass transition temperature lower than 400 ℃, cannot withstand the process environment such as thermal cycling in semiconductor processing, and are not suitable for being used as dielectric materials for ULSI semiconductor devices.

However, Tai et al first reported the application of "CMP polishing to ULSI low dielectric constant PI materials" (see: 1999International Symposium on VLSI Technology, Systems, and applications, proceedings of Technical Papers (Cat. No.99TH8453), June 10,1999). Since Polyimide (PI) has excellent heat resistance and a simple synthesis process, it can simultaneously satisfy a plurality of performance requirements such as low dielectric constant, high mechanical strength, high glass transition temperature, etc., and is easy to form a film on the surface of a wafer, thus being widely applied to a Through Silicon Via (TSV) process as a dielectric material. Currently, the most commonly used PI dielectric material is PI-2610 (manufactured by Hitachi corporation) dielectric material manufactured by Hitachi corporation.

As PI is widely used in semiconductor production as a dielectric material, attention is also being paid to a polishing method for PI. In the current chemical mechanical polishing solution market, SS25 polishing solution containing 12.5% silicon oxide is an effective PI dielectric CMP polishing solution product. However, the polishing rate of the polishing solution to PI dielectric materials is low. Some CMP polishing solutions for PI dielectric materials using alumina or ceria as an abrasive exist in the market, and after the CMP polishing solutions are used for polishing the PI dielectric materials, the surface of a polished wafer presents a convex/concave surface structure. However, in the CMP polishing, if the polishing rate is too fast, over-polishing occurs at the depressed spots (low spots), resulting in deterioration of the polishing effect. Therefore, it is necessary to develop a polishing inhibitor to prevent the over-polishing phenomenon in the low spot region.

Disclosure of Invention

In order to solve the problems, the invention provides the application of the polyether amine compound in polishing the PI dielectric material, and the polyether amine compound is added into the chemical mechanical polishing solution containing the grinding particles, so that the polishing rate of the PI dielectric material can be properly inhibited, low points are protected in the process of flattening and polishing the PI film of the dielectric material of the graphic wafer, the over-polishing of the low point area is avoided, and the efficiency of flattening and polishing is improved.

Specifically, the invention provides an application of a polyetheramine compound in polishing of a chemical mechanical polishing solution, wherein the polyetheramine compound belongs to the Huntsman chemical reagent family. The main structure of the compound is as follows: the polyether backbone structure is composed of Propylene Oxide (PO), Ethylene Oxide (EO) or a mixed PO/EO structure, and the amino group is attached to the end of the polyether backbone.

Preferably, the polyetheramine compound is mixed with a chemical mechanical polishing solution for use, wherein the chemical mechanical polishing solution comprises an abrasive, and the polyetheramine compound has the following chemical structure:

wherein

Preferably, the concentration of the polyether amine compound is 10 mM-20 mM

Preferably, the abrasive is an alumina abrasive or a ceria abrasive.

Preferably, the content of the abrasive is 0.1-0.5%.

Preferably, the chemical mechanical polishing solution has a pH of 2.3 to 5.0, more preferably 2.3 to 3.6.

The chemical mechanical polishing solution of the present invention may further comprise components of a polishing solution conventionally used in the art for polishing dielectric materials.

In the present invention, the pH of the chemical mechanical polishing solution can be adjusted using a pH adjusting agent which is conventional in the art.

Compared with the prior art, the invention has the technical advantages that: the polyether amine compound is added into the chemical mechanical polishing solution containing the grinding particles, so that the polishing rate of the PI dielectric material can be properly inhibited, low points are protected in the planarization polishing process of the PI film of the dielectric material of the graphic wafer, the over-polishing of the low point area is avoided, and the planarization polishing efficiency is improved.

Detailed Description

The advantages of the present invention are further illustrated by the following specific examples, but the scope of the present invention is not limited to the following examples.

Table 1 shows examples 1-8 and comparative examples 1-7 of the chemical mechanical polishing liquid of the present invention. Wherein, in the comparative example, no polyetheramine is added, and in the example, the polyetheramine compound D230 with the structural formula is added.

TABLE 1 comparative examples 1 to 7 and polishing solutions 1 to 8 according to the invention

The chemical mechanical polishing solutions of examples 1 to 8 and comparative examples 1 to 7 were used to polish PI-2610 dielectric materials manufactured by Hitachi corporation, the polishing effects were compared, and the reduction rate of the polishing rate of each example polishing solution with respect to the polishing rate of the corresponding comparative example polishing solution was calculated, to obtain the comparison results shown in Table 2 below.

Wherein the polishing conditions are as follows: a Mirra polishing machine is selected for polishing, the polishing pad is an IC1010 polishing pad, the rotating speeds of a polishing disc and a polishing head are 93rpm and 87rpm respectively, the downward pressure is 4psi, the flow rate of polishing liquid is 150mL/min, and the polishing time is 60 seconds.

TABLE 2 polishing rates for comparative polishing solutions 1-7 and inventive polishing solutions 1-8 on PI-2610 dielectric materials

As can be seen from Table 2, the polishing solutions containing the polyetheramine-based compound according to the present invention significantly reduced the polishing rate of the polyimide dielectric material compared to those of comparative examples 1 to 7, when they contained the same abrasive and had the same pH. Further, as can be seen from Table 2, the polishing liquids containing different kinds of abrasives were different in the degree of decrease in the polishing rate of the example polishing liquids from the polishing liquids of the corresponding comparative examples, when the same amount of the polyether amine compound was added.

Moreover, as can be seen from the results in Table 2, the polishing rate of PI by the polishing solution of the present invention is less affected by the pH of the polishing solution and the content of the abrasive particles, and the polishing rate of the polishing solution is relatively stable, compared with the polishing solution containing no polyetheramine compound. As can be seen from the polishing rates of comparative examples 1-3, the polishing solutions containing no polyether amine compound exhibited higher and higher polishing rates of PI with increasing pH of the polishing solution, which was about 4 times higher than that at pH 2.3 at pH 5.0, whereas as can be seen from examples 1-3, the polishing rates of PI with increasing pH were significantly increased to a lesser extent, with increasing pH from 2.3 to 5.0, which was only 23.9%; meanwhile, as can be seen from comparison of comparative examples 2 and 4, the increase in the content of abrasive grains increases the polishing rate of the polishing solution by 8 times or more at the same pH, whereas in inventive examples 2 and 4, the polishing rate is increased by only 57.4% although the content of abrasive grains is also increased. Therefore, in the invention, the polishing solution is added with the polyether amine compound, so that the polishing rate of the polishing solution to PI is effectively reduced, and the stability of the polishing rate of the polishing solution is improved.

Meanwhile, as can also be seen from the comparison of examples 1 to 3 of the present invention with each other, polishing solutions containing 0.1% of alumina and 10mM of a polyetheramine-based compound exhibited a relatively lowest polishing rate of PI at a pH around 3.6.

In addition, it can be seen from the comparison between comparative examples 5 to 7 and examples 5 to 8 that the polishing solution shows the same phenomenon when cerium oxide is used as the abrasive particles, i.e., the polishing rate of the polishing solution of the present invention to PI is less affected by the pH of the polishing solution and the content of the abrasive particles, and the polishing rate of the polishing solution is relatively stable. In addition, as can be seen from the comparison of the polishing rates of examples 5 to 8 with those of examples 1 to 4, the polishing rate of the example using cerium oxide as the abrasive grains was reduced to a relatively small extent in the case of the same abrasive grains, the amount of the polyetheramine-based compound used and the pH, and also as can be seen from the polishing effect of example 8, it was necessary to add a larger amount of the polyetheramine-based compound to the polishing liquid using cerium oxide as the abrasive grains to achieve a similar polishing rate-suppressing effect. This is because cerium oxide is more beneficial to the polishing of PI than silicon oxide.

In summary, in combination with the above embodiments of the present invention and the comparison between the embodiments and the corresponding comparative examples, it can be seen that, when the polishing solution containing the polyetheramine compound is applied to the polishing of the PI dielectric material, the polishing rate of the PI dielectric material can be inhibited, the stability of the polishing rate can be improved, and the influence of the change of the pH of the polishing solution and the content of the abrasive particles on the polishing rate can be avoided to a certain extent. Meanwhile, the content of the polyether amine compound is adjusted, so that the polishing solution can be suitable for polishing solutions with different grinding particle types, polishing solution pH values and the like, and an ideal polishing rate of the PI dielectric material is obtained.

The "content" in the present application is a content of mass percent unless otherwise specified.

The embodiments of the present invention have been described in detail, but the embodiments are merely examples, and the present invention is not limited to the embodiments described above. Any equivalent modifications and substitutions to those skilled in the art are also within the scope of the present invention. Accordingly, equivalent changes and modifications made without departing from the spirit and scope of the present invention should be covered by the present invention.

Claims

1. Application of polyether amine compound in polishing of PI dielectric material, wherein the polyether amine compound

Mixing with chemical mechanical polishing liquid including abrasive and polyether amine

The compound has the following chemical structure:

；

the concentration of the polyether amine compound is 10 mM-20 mM; the abrasive is an alumina abrasive or a cerium oxide abrasive; the mass percentage content of the abrasive is 0.1% -0.5%; the pH value of the chemical mechanical polishing solution is 2.3-5.0.

2. Use according to claim 1,

the pH value of the chemical mechanical polishing solution is 2.3-3.6.