TWI385244B - Chemical mechanical polishing composition for removing saw mark - Google Patents

Description

Chemical mechanical polishing composition for removing saw marks

This invention relates to a chemical mechanical polishing composition for thinning semiconductor wafers.

With the trend toward miniaturization and thinning of various electronic devices in recent years, the demand for thinning of semiconductor wafers is also increasing. In addition to the wafer miniaturization development of the semiconductor front-end process toward 45, 32 nm, the back-end packaging process is also actively developed in the field of 3D packaging. Wafer thinning is the most critical step in the 3D packaging process because it determines the minimum package size in Chip Scale Packaging (CSP) and System-in-packaging (SiP). The smaller the package size, the more different functions of the chip can be integrated in the same package, so that through a lighter, smaller package size, reduce power consumption, improve signal transmission speed, and provide more More chip functions.

The wafer thinning process includes thinning of semiconductor germanium wafers and thinning of through silicon vias (TSV) wafers.矽 Wafer thinning is the grinding and thinning of the material of semiconductor wafers.矽 Through-wafer wafer thinning is formed by etching or laser forming vias, and conductive materials such as copper, aluminum, tungsten, polysilicon, etc. are filled into the through-hole wafers forming conductive lines for thinning. Chemical. At present, the common process in the industry is to quickly thin the wafer by a mechanical grinding process, and then perform surface finishing polishing by a chemical mechanical polishing (CMP) process. It is necessary to eliminate the residual defect layer and the saw mark caused by mechanical polishing on the surface of the thinned wafer during the CMP process.

U.S. Patent No. 4,169,337 discloses the use of a blend of colloidal cerium oxide or silica gel with a water soluble amine as a grinding composition for polishing a semiconductor surface.

U.S. Patent No. 5,230,833 discloses an abrasive composition comprising colloidal ceria, an organic base and a bactericide.

U.S. Patent No. 5,391,258 discloses an abrasive composition for polishing a composite containing cerium, vermiculite or cerium, which comprises, in addition to abrasive particles, hydrogen peroxide and potassium hydrogen phthalate (potassium hydrogen). Phthalate).

Taiwan Patent No. 338,836 discloses a method of grinding a truncated portion of a semiconductor germanium substrate, which comprises a colloidal cerium oxide having an average particle diameter of 50-150 nm, a pH of 10-11, and a concentration of 30-. 50wt%.

Taiwan Patent No. 500,789 discloses a chemical mechanical polishing process for a tantalum material using an oxide slurry comprising deionized water, abrasive particles of fumed vermiculite, and a chemical reactant such as potassium hydroxide.

Although the use of the above mechanical grinding with an additional chemical mechanical polishing (CMP) process is a suitable wafer thinning process, there are still technical problems in the CMP process. Traditionally, a pH buffered alkaline cerium oxide CMP polishing slurry has been used to polish semiconductor wafers. However, it is inefficient to eliminate the saw marks caused by the mechanical polishing process, so the industry needs a novel chemical mechanical polishing liquid. Solve the above problem.

The inventors have found that a polishing composition containing an amine compound, a solvent, an abrasive and a polishing accelerator is suitable for polishing a semiconductor wafer, and can effectively remove the saw marks remaining on the surface of the semiconductor wafer after mechanical grinding. Mark).

Accordingly, it is an object of the present invention to provide an abrasive composition comprising an amine compound, a solvent, an abrasive, and a polishing accelerator.

Another object of the present invention is to provide a method of using the above abrasive composition in a semiconductor wafer process to remove saw marks on the surface of the wafer.

The abrasive suitable for use in the abrasive composition of the present invention may be selected from the group consisting of silica dioxide, cerium oxide, zirconium oxide, aluminum oxide, titanium oxide (Titanium oxide), A group of nickel oxide and mixtures thereof.

Amines suitable for use in the abrasive compositions of the present invention include, but are not limited to, monoamines, diamines or triamines having an alkyl or hydroxyl group; for example, methylamine, dimethylamine, Ethylamine, propylamine, isopropylamine, allylamine, butylamine, isobutylamine, cyclohexylamine, benzylamine, Monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, diisopropanolamine, N-methyl ethanolamine, N-methyl N-methyldiethanolamine, N,N-dimethylethanolamine, N,N-dimethylethylamine, N,N,N',N ',N"-pentamethyldiethylenetriamine (N,N,N',N',N"-pentamethyldiethylenetriamine), urea (urea), 1-amino-2-propanol (1-amino- 2-propanol), 2-amino-1-propanol, 3-amino-1-propanol, 2-[2-(two Methylamino)ethoxy] 2-(2-(dimethylamino)ethoxy]ethanol, 2-(2-aminoethoxy)ethanol, ethylenediamine, diethylene Diethylenetriamine, triethylenetetramine, hexamethylenediamine, o-phenylenediamine, 1,2-propyldiamine, 1 , 3-propyldiamine, 1,5-diamino-3-pentanol, 1,3-diamino-2-propanol (1,3-diamino-2-propanol), piperazine (piperazine containing piperazine hexahydrate and anhydrous piperazine), 1-(2-aminoethyl)piperazine (1-(2-amihoethyl) piperazine) , N-methylpiperazine, N-aminoethylpiperazine or 1,4-piperazine dipropanamine or a mixture thereof.

According to a preferred embodiment of the present invention, the amine compound is selected from the group consisting of ethanolamine, 1-amino-2-propanol, ethylenediamine, diethylenetriamine, dimethylamine, piperazine, and N-amino A group consisting of piperazine, diisopropanolamine, and o-phenylenediamine, and mixtures thereof.

The inventors have found that the polishing accelerators used in the abrasive compositions of the present invention affect the removal of the semiconductor wafer saw marks by the abrasive compositions of the present invention.

A grinding accelerator suitable for use in the abrasive composition of the present invention is selected from the group consisting of polyethylene ethylenimine, polypropylenimine, and mixtures thereof. The grinding accelerator preferably has a molecular weight of from 500 to 1,000,000, more preferably from 500 to 800,000.

The solvent to be used in the composition of the present invention is not particularly limited, and any solvent which dissolves the components of the composition of the present invention other than the abrasive is a suitable solvent. According to a particular embodiment of the invention, the solvent is water.

The grinding composition can be formulated into different concentrations of the polishing composition according to the addition amount of the polishing accelerator, and can also be used for different transportation, or to accelerate the grinding effect, and different amounts of addition can be added to prepare different times of the polishing composition concentrate for supplying. Required to use.

When the abrasive composition is used, the content of the component of the composition is preferably from 0.01% to 20%, more preferably from 0.05% to 15%, based on the concentration of each component of the composition; Preferably, the content of the abrasive is from 0.05% to 35%, more preferably from 0.1% to 30%, of the abrasive composition; and the amount of the polishing accelerator is preferably 0.0001% of the abrasive composition. -10%, more preferably 0.001%-5%. Further in accordance with a preferred embodiment of the present invention, the abrasive composition of the present invention has a pH of ≧9.

The abrasive composition of the present invention is suitable for use in a semiconductor wafer packaging process, and the composition of the present invention can be used directly when polishing a wafer with a polishing pad. Accordingly, the present invention further provides a method of polishing a semiconductor wafer comprising using the chemical mechanical polishing composition of the present invention to polish a semiconductor wafer to abrade the saw mark on the surface of the wafer.

Referring to FIG. 1, prior to the wafer thinning process using the chemical mechanical polishing composition of the present invention, one of the modes is to apply a soft protective film to the protected surface (101) of the semiconductor wafer before polishing. The first stage mechanical polishing of the semiconductor wafer is performed by using a grinding wheel in a grinding machine, and the surface material (100) of the wafer is largely removed, thereby achieving the purpose of thinning. The rough-ground surface of the wafer will leave a non-uniform surface called the saw mark (103), so a second-stage chemical mechanical polishing process is required to grind the wafer into a flat surface.

The second stage chemical mechanical polishing process is performed in a polishing machine to apply the semiconductor wafer to a polishing pad in contact with a polishing pad and to pass the chemical mechanical polishing composition of the present invention, the polishing composition having a flow rate And during the polishing process, the polishing pad and the semiconductor wafer respectively have a rotation speed to remove the surface of the semiconductor wafer by a thickness of about 1-100 μm and uniformly smooth the surface of the wafer.

According to a particular embodiment of the invention, the grinding pressure is preferably between 0.5 psi and 10 psi; more preferably between 1 psi and 8 psi.

The above semiconductor wafer rotation speed is preferably between 10 rpm and 600 rpm; more preferably between 30 rpm and 510 rpm.

The polishing pad rotation speed is preferably between 10 rpm and 600 rpm; more preferably between 30 rpm and 510 rpm.

The flow rate of the above-mentioned abrasive composition of the present invention is preferably between 50 ml/min and 500 ml/min; more preferably between 50 ml/min and 350 ml/min.

Hereinafter, embodiments and effects of the present invention will be described by way of examples and comparative examples. The following chemicals and equipment will be used in the examples and comparative examples, and unless otherwise specified, they are formulated and ground under normal temperature and normal pressure. It should be noted that the embodiments are for illustrative purposes only and are not to be construed as limiting.

Example Use of materials and equipment

Grinding machine: manufactured by Korea G&P TECHNOLOGY, model Poli 500.

Abrasive pad: manufactured by American company Rohm and Haas, model IC 1010.

Bare silicon wafer: A commercially available silicon wafer commercially available from Silicon Valley Microelectronics, Inc.

Atomic force microscope (AFM): manufactured by Vecco Instruments, Model No. Dimension 3100.

Polyethylenimine: It can be purchased from pharmaceutical suppliers such as ACROS and ALDRICH.

Abrasive: cerium oxide abrasive manufactured by Akzo Nobel, model number BINDZIL 2040, 9950, SP599L.

The preparation methods of the polishing composition of the present invention and the comparative examples, unless otherwise specified, all the components are first mixed to form a mixture, and the polishing treatment is directly performed.

The types of materials used in each mixture, the ingredients used in the polishing composition, and the weight percentages and pH values, as well as the relevant operating parameters for the grinding treatment, are shown in Table 1 below. The removal of the saw marks is measured by AFM measurement of surface roughness (Ra) and visual inspection of the saw marks.

The solvent in each of the polishing compositions is water, and unless otherwise specified, the abrasive in each of the polishing compositions is a cerium oxide abrasive. The same machine parameters (i.e., grinding pressure, wafer rotation speed, polishing pad rotation speed, and flow rate of the polishing composition) were used for each of the examples and comparative examples shown in Table 1.

The significance and influence of these components on the present invention will be discussed below based on changes in operating conditions.

Effect of different aminations and grinding accelerators on the removal of saw marks:

The above Examples 1 to 8 were subjected to grinding treatment with different aminations and cerium oxide abrasives before the addition of the polishing accelerator, and the saw marks on the surface of the semiconductor wafer could not be effectively removed. After the polishing liquid without the addition of the polishing accelerator, the surface roughness of the wafer is still more than 10 nm, and the sawing removal efficiency is very limited. It can be found by visual observation that there is still significant saw residue.

However, it can be seen from Examples 9 to 26 that after the addition of the polishing accelerator, the polishing efficiency of the polishing liquid is improved, and the surface roughness of the polished wafer can be effectively reduced to less than 10 nm, and the surface of the wafer is bright and smooth, and the saw marks are completely removed. Residual. The addition of polyethyleneimine to the slurry greatly enhances the effect of saw marks.

100. . . Surface of the semiconductor wafer

101. . . Protected surface of semiconductor wafer

102. . . Protective film

103. . . Saw mark

Figure 1 illustrates one embodiment of the grinding method of the present invention.

100. . . Surface of the semiconductor wafer

101. . . Protected surface of semiconductor wafer

102. . . Protective film

103. . . Saw mark

Claims (13)

A method of abrading a saw mark on a surface of a wafer in a semiconductor wafer process, comprising: grinding a composition with an abrasive composition, wherein the abrasive composition comprises an amine compound, an abrasive, a polishing accelerator, and a solvent, wherein the amine compound is selected Free diethanolamine, 1-amino-2-propanol, ethylenediamine, diethylenetriamine, dimethylamine, piperazine, N-aminoethylpiperazine, diisopropanolamine, o-phenylenediamine a group of mixtures thereof. The method of claim 1, wherein the abrasive is selected from the group consisting of cerium oxide, cerium oxide, zirconium oxide, aluminum oxide, titanium oxide, and nickel oxide, and mixtures thereof. The method of claim 1, wherein the grinding accelerator is polyethyleneimine, polypropyleneimine or a mixture thereof. The method of claim 3, wherein the grinding accelerator has a molecular weight of between 500 and 1,000,000. The method of claim 3, wherein the grinding accelerator has a molecular weight of between 500 and 800,000. The method of claim 1, wherein the solvent is water. The method of claim 1, wherein the amine compound is present in an amount of from 0.01% to 20% by weight based on the total weight of the abrasive composition. The method of claim 1, wherein the amine compound is present in an amount of from 0.05% to 15% by weight based on the total weight of the abrasive composition. The method of claim 1, wherein the abrasive is present in an amount of from 0.05% to 35% by weight based on the total weight of the abrasive composition. The method of claim 1, wherein the content of the abrasive is in the grinding combination 0.1%-30% of the total weight of the product. The method of claim 1, wherein the amount of the polishing accelerator is from 0.0001% to 10% by weight based on the total weight of the abrasive composition. The method of claim 1, wherein the grinding accelerator is present in an amount of from 0.001% to 5% by weight based on the total weight of the abrasive composition. The method of claim 1, wherein the grinding composition has a pH of ≧9.