KR101277342B1 - Polishing liquid for semiconductor substrate and method for polishing semiconductor substrate - Google Patents

Abstract

The present invention contains abrasive particles, 1,2,4-triazole and an alkaline compound, wherein the alkaline compound is a nitrogen-containing alkaline compound or an inorganic alkaline compound, the content of the alkaline compound is 0.1% by mass or more, and the pH is 9 or more 12. It relates to the polishing liquid for semiconductor substrates which is the following.

Description

Polishing liquid for semiconductor substrate and polishing method for semiconductor substrate {POLISHING LIQUID FOR SEMICONDUCTOR SUBSTRATE AND METHOD FOR POLISHING SEMICONDUCTOR SUBSTRATE}

The present invention relates to a polishing liquid for semiconductor substrates and a polishing method for semiconductor substrates, which are suitable for surface processing of semiconductor substrates.

The polishing process of the semiconductor substrate represented by silicon generally includes a lapping process for smoothing surface irregularities and uniformity in the thickness of the substrate and a polishing process (polishing process) for finishing with the desired surface precision. have. The polishing process is further divided into a primary polishing process called rough polishing and a final polishing process called precision polishing. The primary polishing process is further divided into two processes, sometimes called a primary polishing process and a secondary polishing process.

The polishing process is used not only for the manufacturing process of a normal semiconductor substrate but also for the regeneration process of a used semiconductor substrate. In recent years, the use of a polishing step has been studied in the manufacture of a semiconductor substrate having a structure called a silicon through via (TSV).

The structure called TSV is a structure in which the electrode which connects the device formed in the surface layer of a semiconductor substrate, and the back surface of a semiconductor substrate penetrates inside a semiconductor substrate. Conventionally, when a plurality of semiconductor elements are stacked to form one semiconductor device (semiconductor package), the connection between upper and lower semiconductor elements is performed by wire bonding. By adopting the above-described TSV structure instead of the wire bonding, the area required for the connection between the upper and lower semiconductor elements can be made smaller. Therefore, the technique of forming the TSV is expected as a new technique replacing wire bonding. have.

As a process of forming TSV, the process of forming a via in a semiconductor substrate, grinding (backgrinding) the back surface of the surface in which the via was formed, and penetrating the via is considered to be common. And using CMP (chemical mechanical polishing) in the process of grinding a back surface is examined (for example, refer the following nonpatent literature 1). As for the polishing liquid used in the polishing step on the back side, a high polishing rate is required from the viewpoint of production efficiency.

By the way, various polishing liquids have been proposed as polishing liquids for polishing silicon (Si) which is a typical material for forming a semiconductor substrate. For example, Patent Document 1 below shows that colloidal silica and silica gel are useful as abrasives on the surface of semiconductor crystals most frequently used in the manufacture of semiconductor devices. In addition, the following patent document 1 describes that the particle diameter of the colloidal silica of the sol used and the primary particle of the silica gel is 4-200 nm.

In the following Patent Document 2, a semiconductor substrate, in particular silicon, is prepared by using a colloidal silica or silica gel having a particle size of 4 to 200 nm, preferably 4 to 100 nm in combination with a water-soluble amine as an abrasive. It is disclosed that the surface of a semiconductor substrate can be polished effectively. The amount of the amine with respect to the silica present in the silica sol or gel is 0.5 to 5.0 mass%, preferably 1.0 to 5.0 mass%, most preferably 2.0 to 4.0 mass%.

In Patent Document 3 below, the polishing rate of a silicon substrate can be improved by using an aqueous silica composition to which 0.1 to 5.0 mass% (most preferably 2.0 to 4.0 mass%) of water-soluble quaternary ammonium salt or quaternary ammonium base is added. It is shown.

Patent Document 4 discloses a method of polishing a silicon or germanium semiconductor material in a high surface finish state. In the technique described in Patent Document 4 below, a polishing liquid having a modified colloidal silica gel, having a silica concentration of about 2 to about 50 mass% and a pH of 11 to 12.5, is used. In the modification treatment of the colloidal silica gel, the surface coating of about 1 to about 50 aluminum atoms per 100 silicon atoms on the surface of the uncoated particles with an aluminum atom chemically bonded to the surface of the silica particles having a specific surface area of about 25 to 600 m 2 / g. It was coated so as to. In general, in the region having a pH of 11 or more, while silica as the abrasive particles depolymerizes to become an alkali silicate to lower the pH, Patent Literature 4 does not cause depolymerization and can be polished quickly in a region having a pH of 11 or more. Is shown.

The following Patent Document 5 includes piperazine having a lower alkyl substituent attached to piperazine or nitrogen, and an aqueous colloidal silica sol or gel, wherein piperazine contains a polishing liquid containing 0.1 to 5% by mass relative to the SiO ₂ content of the sol. Is disclosed. In addition, Patent Document 5 below discloses a silicon wafer and a polishing method for the same material as this. According to this patent document 5, when piperazine is contained in the polishing liquid, a polishing rate equivalent to a small amount of colloidal silica is obtained as compared with the case of using aminoethylethanolamine. In addition, Patent Literature 5 below describes that the system of strongly basic piperazine can make a small amount of the addition of caustic alkali required for adjusting the pH.

Patent Document 6 below discloses an abrasive composition comprising an abrasive, at least one of azoles and derivatives thereof, and water. In addition, Patent Document 6 describes that azoles and derivatives thereof are added to the polishing composition, thereby improving the polishing ability of the polishing composition. As a reason, it is pointed out that the lone pair of electrons of the hetero 5-membered ring directly acts on a polishing object, and the Example which imidazole was specifically applied is disclosed.

Patent Literature 7 discloses a polishing liquid containing water, a water-soluble polymer such as colloidal silica, polyacrylamide, and a water-soluble salt such as calcium chloride as a polishing liquid for reducing irregularities on the surface of a semiconductor substrate. However, when the polishing liquid described in Patent Literature 7 is used, a problem arises in that the polishing rate decreases due to the addition of the water-soluble polymer, and the processing time becomes long.

Patent Document 8 discloses a polishing liquid for reducing LPD (light point defect), which is a kind of defect, wherein the concentration of either sodium ions or acetate ions in the polishing composition is 10 ppb or less, or sodium ions in the polishing composition and The concentration of acetate ions is each 10 ppb or less,

A polishing liquid is disclosed in which a polishing liquid preferably contains a water-soluble polymer such as hydroxyethyl cellulose, an alkali such as ammonia, and an abrasive grain such as colloidal silica. In the polishing liquid described in Patent Document 8, hydroxyethyl cellulose and polyvinyl alcohol are contained as the water-soluble polymer, and as the concentration of sodium ions and acetate ions decreases, LPD is improved. However, since the addition amount of the water-soluble polymer shown in the Example is 0.002 mass% or less, when the polishing liquid described in Patent Document 8 is used, effects such as reduction of defects other than LPD (for example, irregularities on the surface of the substrate) are insufficient. I think.

US Patent No. 3170273 U.S. Patent No. 4169337 U.S. Pat.No. Japanese Patent Publication (S) 57-58775 Japanese Patent Laid-Open No. 62-30333 Japanese Patent Laid-Open No. 2006-80302 Japanese Patent Publication No. 02-158684 Japanese Patent Publication No. 2008-53414

 OKI Technical Review October 2007 / No. 211 VOL.74 No.3

The polishing process of the semiconductor substrate is divided into a plurality of processes to achieve a reduction in processing time, efficiency, and high quality. The purpose of each polishing process is different, and the characteristics of the polishing liquid used in each polishing process are also different. have.

In the step of rough polishing, the removal of relatively large irregularities generated in the lapping process or the like and the removal of the damaged semiconductor substrate portion are required, so that a high polishing rate is required.

On the other hand, in the final polishing, a high level of smoothing of the surface which cannot be achieved by rough polishing and reduction of defects in the semiconductor substrate are large objects.

In order to satisfy the above characteristics, various polishing liquids and polishing methods as described in the prior art have been invented, but the above-described characteristics are not sufficiently satisfied, and further improvements in polishing liquids and polishing methods are required.

In the case of polishing a material forming a semiconductor substrate such as silicon, it is effective to increase the pH of the polishing liquid in order to speed up the polishing rate. However, such polishing liquids often have variations in their polishing characteristics. That is, while polishing liquids having the same composition, polishing characteristics such as polishing rate, scratches, flatness, in-plane uniformity, etc. may not be stable. Moreover, when the polishing liquid which increased the abrasive grain was used, the generation | occurrence | production of the flaw resulting from an abrasive grain and the increase of the cost in waste disposal were a problem.

A first object of the present invention is a semiconductor substrate polishing liquid and a semiconductor substrate polishing liquid which enable a processing of a semiconductor substrate having a reduced processing time, facilitating process management, and quality by a high speed and stable polishing. It is to provide a method for polishing a semiconductor substrate using a.

It is a second object of the present invention to provide a polishing liquid for a semiconductor substrate and a polishing method for a polishing liquid for a semiconductor substrate, which are capable of polishing the surface of the semiconductor substrate with less unevenness and smoothness and with less defects.

A third object of the present invention is to provide a polishing liquid for a semiconductor substrate and a polishing liquid for a semiconductor substrate, which can polish the surface of a semiconductor substrate to a smooth surface with little unevenness at a practical polishing rate and a small polishing amount. It's there.

The inventors have found that when silica (SiO ₂ ) is used for abrasive particles, the pH of the polishing liquid may decrease with time, and the polishing rate may decrease. In addition, the present inventors have found that by using certain additives in combination with silica, the pH and polishing rate can be controlled, and the roughness of the substrate surface after polishing can be reduced, and the present invention has been reached.

<Polishing liquid for first semiconductor substrate (first invention)>

The polishing liquid for a first semiconductor substrate according to the present invention contains abrasive particles, 1,2,4-triazole, and a basic compound, wherein the basic compound is a nitrogen-containing basic compound or an inorganic basic compound, and the content of the basic compound It is 0.1 mass% or more, and pH is 9 or more and 12 or less.

According to the first aspect of the invention, polishing of a semiconductor substrate made of a material such as silicon can be performed at high speed. Further, according to the first aspect of the invention, since the decrease in pH of the polishing liquid at the time of storage or use can be suppressed, the decrease and fluctuation of the polishing rate can be made very small.

In the first invention, the basic compound acts as a solubilizer for obtaining the polishing rate. And the more the addition amount of a basic compound in the polishing liquid for semiconductor substrates, there exists a tendency for a polishing rate to become high. From the viewpoint of obtaining a high polishing rate, the content of the basic compound is preferably 0.15% by mass or more, and more preferably 0.2% by mass or more. Moreover, it is preferable that content of a basic compound is 5 mass% or less, and, as for content of a basic compound from a viewpoint of suppressing deterioration of surface roughness by the increase of etching, and depolymerization of a silica, it is more preferable that it is 2 mass% or less.

In 1st invention, it is preferable that a nitrogen containing basic compound contains ammonium hydroxide or tetramethylammonium hydroxide. Moreover, in 1st invention, it is preferable that an inorganic basic compound contains potassium hydroxide or sodium hydroxide. These basic compounds are excellent in that they are low odor.

<Abrasive Liquid for Second Semiconductor Substrate (Second Invention)>

The polishing liquid for 2nd semiconductor substrates which concern on this invention contains the modified silica whose surface was modified by the aluminate, and an inorganic basic compound, content of modified silica is 0.01 mass% or more and 1.5 mass% or less, pH is 9 12 or more.

According to the second invention, polishing of a semiconductor substrate made of a material such as silicon can be performed at high speed. For this reason, in this invention, the processing time of a semiconductor substrate can be reduced.

In 2nd invention, it is preferable that the primary particle diameter of modified silica is 7-50 nm.

When the primary particle diameter of the modified silica is 7 nm or more, a practical polishing rate is easily obtained. Moreover, since the primary particle diameter of modified silica is 50 nm or less, it becomes easy to suppress generation | occurrence | production of grinding | polishing defects, such as a scratch.

In 2nd invention, it is preferable that an inorganic basic compound contains potassium hydroxide or sodium hydroxide.

As described above, also in the second invention, the inorganic basic compound acts as a dissolving agent for obtaining a polishing rate. The polishing rate tends to increase as the amount of the inorganic basic compound added in the polishing liquid for semiconductor substrates increases. In addition, in the second invention, the surface potential of the modified silica (polishing particles) is greatest by the combination of the modified silica and the inorganic basic compound, so that the polishing rate can be increased. Among the inorganic basic compounds, potassium hydroxide or sodium hydroxide is excellent in view of low odor.

It is preferable that 2nd invention further contains 1,2,4-triazole.

Thereby, since the fall of pH of polishing liquid at the time of storage and use can be suppressed, and the quality of polishing liquid is stabilized, the fall of a polishing rate and fluctuation can be made very small. As a result, it becomes possible to process a semiconductor substrate with stable polishing, facilitating process management, and quality.

In addition, as an invention according to a method of polishing a semiconductor substrate, the present invention is a method of polishing a semiconductor substrate for forming a silicon through via, comprising: forming an uneven portion on one surface of the silicon substrate; And a polishing step of backgrinding the other surface of the silicon substrate and a polishing step of polishing the other surface to expose the metal using the polishing liquid for the first or second semiconductor substrate.

As a result, the silicon damage layer after the backgrinding generated in the process of forming the silicon through via can be sufficiently flattened while maintaining a good polishing rate.

In addition, as an invention according to a method for polishing a semiconductor substrate, the present invention is a step of preparing a rough wafer by etching a silicon wafer after lapping or grinding a silicon wafer obtained by slicing a silicon single crystal ingot, and a first or second step. Provided is a polishing method for a semiconductor substrate having a rough polishing step of polishing a rough wafer using a polishing liquid for a semiconductor substrate. In addition, the final grinding | polishing process for finishing the silicon wafer used as a product in this application is "finish grinding | polishing", and the grinding | polishing process performed as a shearing layer of finish grinding | polishing is set to "coarse grinding | polishing".

With such a polishing method of the semiconductor substrate, the surface of the semiconductor substrate can be polished at high speed.

As an invention according to a method of polishing a semiconductor substrate, the present invention further provides a method of polishing a semiconductor substrate for reuse, comprising: wet etching a silicon wafer with adhered substances, and using a polishing liquid for a first or second semiconductor substrate. There is provided a polishing method of a semiconductor substrate having a rough polishing step of polishing a wet etched silicon wafer.

According to the polishing method of such a semiconductor substrate, it is possible to remove unnecessary deposits from the surface of the semiconductor substrate (test wafer or the like) recovered for reuse, and to perform polishing at high speed on a smooth surface with few irregularities.

<Abrasive liquid for third semiconductor substrate (third invention)>

The polishing liquid for third semiconductor substrates according to the present invention contains abrasive particles, 1,2,4-triazole, a water-soluble polymer, and a basic compound, and has a pH of 9 or more and 12 or less.

According to the third aspect of the invention, the surface of a semiconductor substrate made of a material such as silicon can be polished to a smooth surface with few irregularities.

Moreover, it is preferable that content of a water-soluble polymer is 0.001 mass% or more and 10 mass% or less with respect to the total mass of the polishing liquid for semiconductor substrates. Moreover, it is preferable that content of 1,2,4-triazole is 0.01 mass% or more and 10 mass% or less with respect to the total mass of the polishing liquid for semiconductor substrates.

By setting the content of the water-soluble polymer and the 1,2,4-triazole in the above range, it is possible to reliably polish the surface of the semiconductor substrate to a smooth surface with less unevenness.

<Four polishing liquid for fourth semiconductor substrate (fourth invention)>

The polishing liquid for a fourth semiconductor substrate according to the present invention contains abrasive particles, 1,2,4-triazole, a water-soluble polymer, and a basic compound, and the content of 1,2,4-triazole is a semiconductor substrate. 0.05 mass% or more and 0.5 mass% or less with respect to the total mass of the polishing liquid, content of water-soluble polymer is 0.001 mass% or more and 0.1 mass% or less with respect to the total mass of the polishing liquid for semiconductor substrates, and pH is 9 or more and 12 or less to be.

As a result, the surface of the semiconductor substrate made of a material such as silicon can be polished to a surface having less unevenness and smoothness and less defects.

In addition, as an invention according to a method of polishing a semiconductor substrate, the present invention is a process of preparing a wafer wafer by etching a silicon wafer after lapping or grinding a silicon wafer obtained by slicing a silicon single crystal ingot, and polishing a wafer wafer. Provided are a polishing method of a semiconductor substrate comprising a step and a finish polishing step of further polishing a silicon wafer after the rough polishing step by using the polishing liquid for the third or fourth semiconductor substrate.

Thereby, the minute unevenness which exists on a silicon wafer is fully eliminated, and it can grind | polish to the surface with few defects.

In addition, as an invention according to a method of polishing a semiconductor substrate, the present invention provides a method of polishing a semiconductor substrate for reuse, comprising the steps of wet etching a silicon wafer with deposits, a polishing step for polishing a wet etched silicon wafer, Provided is a polishing method of a semiconductor substrate comprising a finishing polishing step of further polishing a silicon wafer after a rough polishing step using a polishing liquid for a third or fourth semiconductor substrate.

Such a method of polishing a semiconductor substrate removes unnecessary deposits from the surface of a semiconductor substrate (test wafer, etc.) recovered for reuse, and removes minute irregularities present on the silicon wafer, thereby reusing a semiconductor substrate having fewer defects. It becomes possible to provide.

<5th semiconductor substrate polishing liquid (5th invention)>

The polishing liquid for a fifth semiconductor substrate according to the present invention contains abrasive particles, 1,2,4-triazole, a water-soluble polymer, and a basic compound, and the content of 1,2,4-triazole is a semiconductor. It is 0.2 mass% or more and 3.0 mass% with respect to the total mass of the polishing liquid for board | substrates, The content of a water-soluble polymer is 0.01 mass% or more and 0.2 mass% or less with respect to the total mass of the polishing liquid for semiconductor substrates, pH is 9 or more 12 It is as follows.

This makes it possible to preferentially polish the convex portions when there are irregularities on the surface of the substrate while maintaining a predetermined polishing rate for the semiconductor substrate.

In addition, as an invention according to a method of polishing a semiconductor substrate, the present invention provides a method of polishing a semiconductor substrate for reuse, comprising the steps of: wet etching a silicon wafer with deposits thereon and then grinding the silicon wafer to prepare a jaw wafer; Provided is a polishing method for a semiconductor substrate comprising a rough polishing step of polishing a rough wafer using a polishing liquid for a third or fifth semiconductor substrate.

According to the polishing method of such a semiconductor substrate, since rough polishing which has been conventionally performed in several steps can be performed in one step, it is possible to reduce the polishing loss of the semiconductor substrate generated in the rough polishing. As a result, the effect of increasing the number of times of reuse of the silicon wafer is also obtained.

In addition, according to the invention according to the method of polishing a semiconductor substrate, the present invention provides a method of polishing a semiconductor substrate for forming a silicon through via, comprising: forming a recess in one surface of the silicon substrate; And a polishing step of backgrinding the other surface of the silicon substrate and a polishing step of polishing the other surface to expose the metal using the polishing liquid for the third or fifth semiconductor substrate.

Thereby, the grinding trace after the backgrinding generated in the process of forming a silicon through via can be fully planarized with a small grinding | polishing amount.

In the above-described rough polishing step, the polishing amount of the rough wafer is L (nm), the initial step of the _rough wafer is R _t0 (nm), and the level of the rough _rough wafer after the rough polishing is R _t1 (nm). when defined as a, R _t0 ≤L≤R the crude wafer only L (nm) satisfying 1.3 × _t0 when the grinding (i.e., grinding only the polishing amount of no more than 1.3 times the initial step), L / (R _t0 -R It is preferable to satisfy both _t1 ) ≤ 1.3 and R _t1 ≤ 100 (nm). In addition, the final polishing amount is not more than the above-described relationship may be a range (R _t0 ≤L≤R _t0 × 1.3). FIG.

In addition, in the above-described method for polishing a semiconductor substrate, a finish polishing step of polishing the rough wafer after the rough polishing step by using the polishing liquid may be further provided, and the polishing liquid includes the abrasive particles and 1,2,4. It is preferable that -triazole, a water-soluble polymer, and a basic compound are contained and pH is 9 or more and 12 or less. Thereby, the surface of a semiconductor substrate can be polished with few unevenness | smoothness, and can be polished few defects.

In addition, in the above-described method for polishing a semiconductor substrate, a finish polishing step of polishing the rough wafer after the rough polishing step by using the polishing liquid may be further provided, and the polishing liquid includes the abrasive particles and 1,2,4. It contains -triazole, a water-soluble polymer, and a basic compound, and the content of 1,2,4-triazole is 0.05 mass% or more and 0.5 mass% or less with respect to the total mass of the polishing liquid for semiconductor substrates, It is preferable that content is 0.001 mass% or more and 0.1 mass% or less with respect to the total mass of the polishing liquid for semiconductor substrates, and pH is 9 or more and 12 or less. Thereby, the surface of a semiconductor substrate can be reliably less smooth and smooth, and it can become the finish polishing process to the surface with less defects.

In the polishing liquids for the third, fourth and fifth semiconductor substrates, the water-soluble polymer is preferably a nonionic polymer. By using a nonionic polymer, the effect of reducing the unevenness | corrugation of the surface of a semiconductor substrate becomes remarkable. It is preferable that a nonionic polymer is at least 1 sort (s) chosen from the copolymer of polyvinylpyrrolidone and polyvinylpyrrolidone. In addition, the water-soluble polymer may be a mixture containing at least one selected from copolymers of polyvinylpyrrolidone and polyvinylpyrrolidone.

In the polishing liquid for semiconductor substrates according to the present invention, it is preferable that the semiconductor substrate to be polished is silicon or a substrate containing silicon in the substrate configuration. That is, the present invention is particularly excellent in the polishing rate for silicon or a substrate including silicon in the substrate configuration.

In the method of polishing a semiconductor substrate according to the present invention, the surface of the semiconductor substrate is polished using the polishing liquid for semiconductor substrate according to the present invention. According to such a polishing method, the surface of a semiconductor substrate can be polished at a high speed on a smooth and few defect surface.

In the present invention, a polishing liquid for a semiconductor substrate and a semiconductor using the semiconductor substrate polishing liquid, which enable a high speed and stable polishing to reduce the processing time of the semiconductor substrate, facilitate the process management, and process the semiconductor substrate having a high quality. It is possible to provide a method for polishing a substrate.

In addition, the present invention provides a polishing liquid for a semiconductor substrate and a polishing method for a polishing liquid for a semiconductor substrate, wherein the surface of the semiconductor substrate can be polished to a surface with little unevenness and smoothness and less defects.

Further, the present invention provides a polishing liquid for a semiconductor substrate and a polishing liquid for a semiconductor substrate, which can polish the surface of a semiconductor substrate to a smooth surface with little unevenness at a small polishing amount at a practical polishing rate.

1 is a graph showing changes in pH of each polishing liquid after 24 hours from the time of producing each polishing liquid of Examples 1 to 4 and the conventional examples (Comparative Examples 1 to 11).
FIG. 2 shows the polishing rate immediately after the adjustment of each polishing liquid of Examples 1 to 4 and the conventional examples (Comparative Examples 1 to 11), and the polishing rate of each polishing liquid after 24 hours from the time of producing each polishing liquid. It is a graph.
FIG. 3 is a graph showing the relationship between the amount of abrasive grains (silica) added in each polishing liquid and the amount of change in pH of each polishing liquid after 24 hours from the time of producing each polishing liquid.
It is a measurement result by the level | step difference, surface roughness, and a fine shape measuring apparatus of Example 9.
It is a measurement result by the level | step difference, surface roughness, and a fine shape measuring apparatus of the comparative example 20.
6 is a graph showing pHs and polishing rates of polishing liquids of Examples 11 to 14 and the conventional examples (Comparative Examples 21 to 24).
The measurement result by the level difference, surface roughness, and a fine shape measuring apparatus of Example 19. FIG.
The measurement result by the level | step difference, surface roughness, and a fine shape measuring apparatus of the comparative example 33.
The measurement result by the level | step difference, surface roughness, and a fine shape measuring apparatus of the comparative example 34.
The measurement result by the level | step difference, surface roughness, and a fine shape measuring apparatus of the comparative example 35.
11 is a graph showing the relationship between the polishing amount L and the maximum height Rt of Example 45. FIG.
12 is a graph showing a relationship between the polishing amount L of the comparative example 43 and the maximum height Rt.
It is a schematic sectional drawing which shows the grinding | polishing method of the semiconductor substrate which concerns on one Embodiment of this invention.
Fig. 14 is a flowchart showing a general silicon wafer processing step.
Fig. 15 is a schematic diagram showing a polishing step of a general silicon wafer.
Fig. 16A is a flow chart showing a general regeneration process of a silicon wafer, and Fig. 16B is a regeneration of a silicon wafer in the case of using a polishing method of a semiconductor substrate according to an embodiment of the present invention. It is a flowchart which shows a process.
FIG. 17 is a graph showing the contents of 1,2,4-triazole and water-soluble polymers in the polishing liquids for third to fifth semiconductor substrates. FIG.

EMBODIMENT OF THE INVENTION Hereinafter, the polishing liquid for semiconductor substrates and the polishing method of the semiconductor substrate using this polishing liquid which concern on one Embodiment of this invention are demonstrated in detail, referring drawings.

<Polishing liquid for first semiconductor substrate>

As an embodiment of the first invention, the abrasive particles, 1,2,4-triazole and a basic compound are contained, wherein the basic compound is a nitrogen-containing basic compound or an inorganic basic compound, and the content of the basic compound is 0.1% by mass or more. And the polishing liquid for semiconductor substrates whose pH is 9 or more and 12 or less is demonstrated.

In the first embodiment, the pH of the polishing liquid can be suppressed even in a high alkali region of 9 or more and 12 or less, so that the decrease and fluctuation of the polishing rate due to the aging can be made very small, and a high speed semiconductor Polishing of the substrate becomes possible.

(pH)

In 1st Embodiment, in order to acquire the sufficient grinding | polishing rate with respect to a semiconductor substrate, the minimum of pH of the polishing liquid for semiconductor substrates shall be 9.0 or more. It is preferable that pH is 9.5 or more from the point which acquires the outstanding polishing rate. Moreover, in order to fully suppress that pH of polishing liquid falls at the time of storage or use, the upper limit of pH is 12.0, it is preferable that it is 11.5 or less, and it is more preferable that it is 11.0 or less.

pH can be adjusted with the addition amount of a 1,2, 4-triazole and / or a basic compound, for example. In addition, pH of the polishing liquid for semiconductor substrates can be measured with a pH meter (for example, Yokogawa Denki Co., Ltd. make, Model pH 81).

(1,2,4-triazole and basic compound)

An important feature of the polishing liquid for semiconductor substrates according to the first embodiment is that 1,2,4-triazole and a basic compound are used in combination. The reason why it is important to use 1,2,4-triazole and a basic compound together in order to obtain the effect of the present invention is not known in detail, but the polishing liquid for semiconductor substrates is 1,2,4-triazole and a basic compound. It is considered that one of the important factors for achieving the effect of the present invention is that the following matters 1 and 2 are achieved by containing all of them.

[Item 1] A large amount of addition of the basic compound.

[Item 2] The variation in pH of the polishing liquid for semiconductor substrates with the passage of time can be reduced.

The above item 1 will be described in detail. The basic compound acts as a solvent of the semiconductor substrate. Therefore, from the viewpoint of obtaining a high polishing rate, the more the amount of the basic compound added, the more preferable. However, for example, when the target value of the pH of the polishing liquid is set to 11 and potassium hydroxide is added as the basic compound, the pH of the polishing liquid for semiconductor substrates immediately rises. By the way, to leave the 1,2,4-triazole was added to the polishing liquid for a semiconductor substrate, pKa ₁ of 1,2,4-triazol-1 is due to the low to 2.2, for a semiconductor substrate accompanying the addition of a basic compound, the polishing solution The rise in pH can be suppressed. For this reason, it is possible to increase the basic compound by using together 1,2,4-triazole and a basic compound.

Even if 1,2,4-triazole is contained alone in the polishing liquid, there is little effect of improving the polishing rate. In order to improve the polishing rate, it is important to use 1,2,4-triazole in combination with a basic compound which acts as a solubilizer.

By adding an acid such as sulfuric acid or hydrochloric acid instead of 1,2,4-triazole, the basic compound can be increased, but in this case, the polishing rate for silicon is not sufficiently obtained, or the pH decreases after blending. It can be seen from the present inventors that the effect of suppressing the effect is small.

The above item 2 will be described. In the polishing liquid containing 1,2,4-triazole, the fall of pH can be made very small even if time passes from the compounding. In case of using 1,2,3-triazole (pKa ₁ = 2.1) or 1H-benzotriazole (pKa ₁ = 8.2) having a structure similar to this instead of 1,2,4-triazole, item ₁ above. As described above, it can be seen that the addition amount of the basic compound to the polishing liquid can be increased, but the effect of suppressing the decrease in pH after mixing is small and the effect of improving the polishing rate suitable for the addition amount of the basic compound is not obtained. Can be. In addition, when the imidazole compound is used instead of 1,2,4-triazole, since the pKa ₁ of the imidazole compound is high at 14.5, it is not possible to increase the amount of addition of the basic compound which acts as a solubilizer and lower the pH after blending. The effect of suppressing is also small.

The 1,2,4-triazole addition amount in the polishing liquid for semiconductor substrates which concerns on 1st Embodiment is 0.1 mass% or more in the point which can fully acquire the effect of suppressing pH fall of a polishing liquid, and improving a polishing rate. It is preferable, and it is more preferable that it is 0.25 mass% or more. The amount of 1,2,4-triazole added is preferably 10% by mass or less, more preferably 7% by mass or less, more preferably 5% by mass or less, from the viewpoint of easily preventing problems such as aggregation of abrasive particles. Most preferred. The agglomeration of the abrasive grains cannot be said to be attributable to only the addition amount of 1,2,4-triazole, but also to the particle size and the addition amount of the abrasive grains.

Examples of the basic compound contained in the polishing liquid for semiconductor substrates according to the first embodiment include one or more nitrogen-containing basic compounds selected from ammonium hydroxide and tetramethylammonium hydroxide, or potassium hydroxide and sodium hydroxide from the viewpoint of low odor. At least one inorganic basic compound selected is preferred. These can be used individually or in plurality.

(Polishing particles)

In 1st Embodiment, it is preferable to use a silica as abrasive grain contained in the polishing liquid for semiconductor substrates. This makes it easy to obtain a high polishing rate. As a silica which can be used, a well-known thing can be used widely, Specifically, a fumed silica, colloidal silica, a precipitation silica etc. are mentioned, for example. Among them, fumed silica or colloidal silica is preferred because it is easy to obtain high purity, and colloidal silica is more preferable in that polishing defects such as dispersion stability and scratches in water are less likely to occur. In addition, silica can also be used together with another abrasive particle as needed. As another abrasive particle which can be used together with a silica, alumina, ceria, titania, zirconia, an organic polymer etc. are mentioned specifically ,.

The primary particle size of the silica is preferably 5 nm or more, more preferably 7 nm or more, and particularly preferably 9 nm or more, in terms of obtaining a practical polishing rate. In addition, since the primary particle diameter of silica is easy to suppress generation | occurrence | production of grinding | polishing defects, such as a flaw, it is preferable that it is 200 nm or less, It is more preferable that it is 100 nm or less, It is especially preferable that it is 50 nm or less, It is 40 nm or less Very preferred. When the primary particle diameter of silica is in the above-mentioned range, it is thought that the polishing rate is most improved by the combination of the grinding | polishing promotion effect by the mechanical action which depends on a particle diameter, and the grinding | polishing promotion effect by the increase of the particle number by a small particle diameter. do.

In the first embodiment, the primary particle diameter of silica refers to the average diameter of the particles that can be calculated from the BET specific surface area V. From the measurement of the adsorption specific surface area (hereinafter referred to as BET specific surface area) by the gas adsorption method, It is calculated by Equation 1.

In Equation 1, D1 denotes a temporary particle size of a particle (unit: m), ρ denotes a particle density (unit: kg / m 3), and V denotes a BET specific surface area (unit: m 2 / g).

More specifically, first, the abrasive grains are dried in a vacuum freeze dryer, and the residue is finely ground in a mortar (magnetic, 100 ml) to obtain a sample for measurement, which is obtained by a BET specific surface area measuring apparatus manufactured by Yuasa Ionics Co., Ltd. ( The primary particle size D1 is calculated by measuring the BET specific surface area V using the product name Autosolve 6). In the case where the particles are colloidal silica, the density ρ of the particles is ρ = 2200 (kg / m 3).

Therefore, substituting the BET specific surface area V (m 2 / g),

As a result, the primary particle size can be obtained.

It is preferable that the addition amount of abrasive grain is 0.01 mass% or more and 5.0 mass% or less with respect to the whole polishing liquid, It is more preferable that they are 0.05 mass% or more and 3.0 mass% or less, It is further more preferable that they are 0.1 mass% or more and 1.0 mass% or less. By making the addition amount of abrasive grain into 0.01 mass% or more, sufficient polishing rate becomes easy to be obtained. Moreover, when the addition amount of abrasive grain is made into 5.0 mass% or less, it becomes easy to suppress generation | occurrence | production of defects, such as an abrasive phase.

(Other ingredients)

In the first embodiment, in addition to the above-described components, the components generally added to the polishing liquid, such as solvents other than water, an anticorrosive agent, an oxidizing agent, and a water-soluble polymer, are not restricted to the effects of the above-described polishing liquid. It can be added to the solvent polishing liquid.

(Preservation form)

The polishing liquid for semiconductor substrates of 1st Embodiment can be preserve | saved as a concentrated form which heightened the component density | concentration beforehand. In the use of the polishing liquid, the polishing liquid in the concentrated form can be diluted and used to the original component concentration with water or the like. Moreover, the component of the polishing liquid for semiconductor substrates can be preserve | saved as the liquid separation form divided into several, and these can also be mixed and used at the time of use.

In 1st Embodiment, the effect which suppresses the fall of pH after mix | blending of the polishing liquid for semiconductor substrates can be acquired irrespective of the addition amount of a silica. Moreover, in 1st Embodiment, since the addition amount of the basic compound which is a solubilizer can be increased, making pH of the polishing liquid for semiconductor substrates into a predetermined range, the chemical effect which contributes to polishing can be strengthened. As a result, it is thought that a high polishing rate can be obtained even if the amount of silica added as abrasive particles is reduced.

<Polishing Liquid for Second Semiconductor Substrate>

Next, as an embodiment of the second invention, the polishing liquid for the second semiconductor substrate will be described. In addition, the part which overlaps description with the 1st semiconductor substrate polishing liquid is abbreviate | omitted suitably.

In the polishing liquid for the first semiconductor substrate, a good polishing rate for silicon was obtained by using 1,2,4-triazole and a basic substance (irrespective of organic and inorganic), but the surface was By using modified silica modified by alumination and using this together with an inorganic basic substance, a favorable polishing rate for silicon can be obtained.

That is, in 2nd Embodiment, the semiconductor whose modified surface whose surface was modified by the aluminate, and an inorganic basic compound, content of the said modified silica is 0.01 mass% or more and 1.5 mass% or less, and pH is 9 or more and 12 or less A polishing liquid for a substrate is provided. Since the surface potential of the modified silica (abrasive particles) is the largest in the combination of the modified silica and the inorganic basic compound which is a solvent of the semiconductor substrate, the polishing rate can be increased.

(Modified silica)

Modification of the silica surface by alumination can be performed using aluminum compounds, such as potassium aluminate [(AlO (OH) ₂ K], etc. In the modification of a silica surface, it is alumina in the dispersion of silica, for example. By adding potassium carbonate and refluxing at 60 ° C or higher, the silanol group on the silica surface is made -Si-O-Al (OH) ₂ group which is easier to ionize.

As modified silica that can be used, for example, those modified by aluminization of surfaces such as fumed silica, colloidal silica, precipitated silica and the like can be used. Among them, modified fumed silica or modified colloidal silica is preferred because it is easy to obtain high purity, and modified colloidal silica is most preferred in that polishing defects such as dispersion stability and scratches in water are less likely to occur. Modified silica can also be used together with another abrasive particle as needed. As another abrasive particle which can be used together with a modified silica, alumina, ceria, titania, zirconia, an organic polymer, etc. are mentioned specifically ,.

Moreover, if organic amines, such as tetramethylammonium hydroxide, are used as a dissolving agent, the surface potential of abrasive grains may become small and the effect of a polishing rate improvement may not be acquired. In addition, when modified silica having a sulfonic acid group, an amino group or the like is used on the surface instead of the modified silica modified by aluminization, the surface potential of the modified silica (polishing particles) becomes small, and the effect of improving the polishing rate is not obtained. There is concern.

In 2nd Embodiment, the surface potential of modified silica refers to the zeta potential of modified silica measured with the zeta potential measuring apparatus. The value of the zeta potential reflects the surface state of the modified silica. In the high alkali region, the modified silica shows a negative zeta potential. When the value of a zeta potential is small, it can be considered that the compound which cancels a potential (for example, organic amines) and a modified silica interact. When the compound which cancels dislocation exists in the surface of modified silica, this inventor thinks that the grinding | polishing action | mechanism which is a mechanical mechanism of modified silica is buffered, and the original polishing force was not exhibited.

In the prior art described in Patent Document 4, the depolymerization of silica generated in the region where the pH of the polishing liquid is 10.5 or more is suppressed to obtain a polishing rate, but the effect of the present invention is different from the prior art described in Patent Document 4. In the present invention, since the polishing force inherent in the modified silica (abrasive particles) is exhibited by the combination of the modified silica modified by alumination and the inorganic basic compound, it is possible to obtain a polishing rate at least sufficient in the amount of the abrasive grain added. . It is preferable that the addition amount of the modified silica modified by the alumination is 0.01 mass% or more and 1.5 mass% or less with respect to the whole polishing liquid, It is more preferable that they are 0.05 mass% or more and 1.0 mass% or less, 0.1 mass% or more and 0.8 mass% It is more preferable that it is below. In this invention, sufficient polishing rate will be easy to be obtained by making the addition amount of modified silica into 0.01 mass% or more. In addition, in this invention, even if the addition amount of modified silica is small and 1.5 mass% or less, sufficient grinding | polishing rate can be obtained.

The primary particle size of the modified silica is preferably 5 nm or more, more preferably 7 nm or more, and particularly preferably 9 nm or more, from the viewpoint of obtaining a practical polishing rate. In addition, the primary particle size of the modified silica is preferably 200 nm or less, more preferably 100 nm or less, particularly preferably 50 nm or less, particularly preferably 40 nm or less, in that it is easy to suppress the occurrence of polishing defects such as scratches. Very preferred. When the primary particle size of the modified silica is in the above-described range, the polishing rate is most improved by a combination of the polishing promotion effect by the mechanical action depending on the particle diameter and the polishing promotion effect by the increase in the number of particles due to the grain size. I think.

In addition, the primary particle diameter of modified silica can be measured similarly to the primary particle diameter of silica in the polishing liquid for 1st semiconductor substrates.

(Inorganic basic compound)

The inorganic basic compound acts as a dissolving agent for obtaining the polishing rate, and maximizes the surface potential of the modified silica (polishing particles), so that the polishing rate can be increased. It is preferable that an inorganic basic compound is at least 1 sort (s) chosen from potassium hydroxide and sodium hydroxide from a low odor viewpoint. These can be used individually or in plurality. From the viewpoint of obtaining a high polishing rate, the more the amount of the inorganic basic compound added, the more preferable. Therefore, the amount is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.07% by mass or more. In addition, from the viewpoint of suppressing deterioration of surface roughness and depolymerization of silica due to an increase in etching, the content of the inorganic basic compound is preferably 5% by mass or less, more preferably 3% by mass or less, particularly preferably 1% by mass or less. Do.

In the second embodiment, the 1,2,4-triazole is not an essential configuration, but in order to obtain a higher polishing rate for silicon, it is preferable to further include 1,2,4-triazole.

In the case of using 1,2,4-triazole, not only the polishing rate is easily improved, but also the decrease and fluctuation of the polishing rate over time can be made smaller. As a result, high-speed and stable polishing makes it possible to reliably reduce the processing time of the semiconductor substrate, to facilitate the process management, and to process the semiconductor substrate having the high quality.

In this case, the amount of 1,2,4-triazole added to the polishing liquid for the second semiconductor substrate is preferably in the same range as that in the polishing liquid for the first semiconductor substrate.

<Abrasive liquid for third semiconductor substrate>

Next, as an embodiment of the third invention, the polishing liquid for the third semiconductor substrate will be described. In addition, the part which overlapped description with the polishing liquid for 1st and 2nd semiconductor substrate is abbreviate | omitted suitably.

The polishing liquid for semiconductor substrates of 3rd Embodiment contains abrasive grains, a 1, 2, 4-triazole, a water-soluble polymer, and a basic compound, and pH is 9 or more and 12 or less. By setting it as such a polishing liquid for semiconductor substrates, it becomes possible to grind the surface of a semiconductor substrate to the smooth and smooth surface.

More specifically, in the third embodiment, since the content of 1,2,4-triazole can be suppressed even in a high alkali region where the pH of the polishing liquid is 9 or more and 12 or less, the time is reduced over time. The fall and fluctuation | variation of the grinding | polishing rate by this is made very small, and the polishing of a stable semiconductor substrate becomes possible. And in 3rd Embodiment, the process of the semiconductor substrate provided with the quality by stable polishing is attained. Moreover, in 3rd Embodiment, by reducing the unevenness | corrugation of the surface of a board | substrate by a water-soluble polymer and 1, 2, 4-triazole, it becomes possible to grind the surface of a semiconductor substrate to the smooth surface with few unevenness | corrugation.

(1,2,4-triazole)

In addition, in order to acquire the above-mentioned effect by 1,2,4-triazole, it is preferable that content of 1,2,4-triazole is 0.001 mass% or more and 10 mass% or less with respect to the total mass of the polishing liquid for semiconductor substrates. desirable.

(Water soluble polymer)

Examples of the water-soluble polymer (water-soluble polymer) contained in the polishing liquid for semiconductor substrates include alginic acid, pectinic acid, carboxymethyl cellulose, agar, xanthan gum, chitosan, methyl glycol chitosan, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, and hydroxy. Polysaccharides such as propyl methyl cellulose, hydroxyethyl cellulose, curdlan and pullulan; Polyaspartic acid, polyglutamic acid, polylysine, polymalic acid, polymethacrylic acid, polymethacrylic acid ammonium salt, polymethacrylic acid sodium salt, polyamic acid, polymaleic acid, polyitaconic acid, polyfumaric acid, poly (p-styrene Carboxylic acid), polyvinyl sulfuric acid, polyacrylic acid, polyacrylamide, aminopolyacrylamide, ammonium polyacrylate, sodium polyacrylate, polyamic acid, ammonium polyamate, sodium polyamic acid and polyglyoxylic acid Polycarboxylic acids and salts thereof; Polyethyleneimine and its salts; Vinyl polymers such as polyvinyl alcohol, polyvinylpyrrolidone and polyacrolein, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, ethylene glycol-propylene glycol block copolymers, and the like. Among them, polysaccharides such as carboxymethyl cellulose, agar, xanthan gum, chitosan, methyl glycol chitosan, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, curdlan and pullulan, Nonionic polymers such as polyacrylamide, polyethyleneimine, polyvinyl alcohol, polyvinylpyrrolidone and polyacrolein, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, ethylene glycol-propylene glycol block copolymers are preferred, and poly More preferred are vinylpyrrolidone and copolymers thereof. In addition, said water-soluble polymer (water-soluble polymer) can be used individually or in mixture of multiple types. In addition, when mixing and using multiple types of said water-soluble polymer, it is preferable that the mixture contains at least 1 sort (s) chosen from polyvinylpyrrolidone and its copolymer.

The present inventors believe that the reduction of the unevenness of the surface of the semiconductor substrate in the present invention is caused by the adsorption of the water-soluble polymer onto the surface of the semiconductor substrate by the hydrophobic interaction between the semiconductor substrate and the hydrophobic portion of the water-soluble polymer. That is, the water-soluble polymer adsorbed on the surface of the semiconductor substrate is adsorbed by the unevenness of the surface of the semiconductor substrate, and the water-soluble polymer of the convex portion is easily removed by the polishing pad or the abrasive particles as compared with the concave portion. As a result, polishing of the convex portion is promoted and smooth. We think that surface is formed. For this reason, when the nonionic water-soluble polymer which does not have an ionic group is used as a water-soluble polymer, the effect which reduced unevenness | corrugation becomes remarkable.

It is preferable that it is 0.001 mass% or more and 10 mass% or less with respect to polishing liquid, and, as for the addition amount of a water-soluble polymer, it is more preferable that they are 0.01 mass% or more and 1 mass% or less. By making the addition amount of a water-soluble polymer into 0.001 mass% or more, the effect of reducing unevenness | corrugation tends to become large. Moreover, when the addition amount of a water-soluble polymer is 10 mass% or less, it becomes easy to prevent the fall of the fluidity | liquidity by the high viscosity and high viscosity of the polishing liquid accompanying addition of a water-soluble polymer, and it becomes easy to prevent aggregation of abrasive grains.

In general, if the dissolving action of the polishing liquid is enhanced, the unevenness of the surface of the semiconductor substrate tends to increase. However, although 1,2,4-triazole contained in the polishing liquid for semiconductor substrates which concerns on this invention is inferior to a water-soluble polymer, it has the effect of reducing the unevenness | corrugation of the surface of a board | substrate. For this reason, in this invention, by using together 1,2, 4-triazole and a water-soluble polymer, it becomes possible to grind the surface of a semiconductor substrate to the smooth surface with few unevenness | corrugation at a high grinding | polishing rate.

<Polishing Solution for Fourth Semiconductor Substrate>

Next, as an embodiment of the fourth invention, the polishing liquid for the fourth semiconductor substrate will be described. In addition, the part which overlaps description with the polishing liquid for 1st, 2nd and 3rd semiconductor substrates is abbreviate | omitted suitably.

The polishing liquid for semiconductor substrates of the fourth embodiment contains abrasive particles, 1,2,4-triazole, a water-soluble polymer, and a basic compound, and the amount of 1,2,4-triazole added is 0.05% by mass. It is 0.5 mass% or less, the addition amount of water-soluble polymer is 0.001 mass% or more and 0.1 mass% or less, and pH is 9 or more and 12 or less.

4th Embodiment is especially suitable for the finishing polishing use in the manufacturing process of a semiconductor wafer. That is, eliminating the unevenness existing on the silicon substrate rather than the polishing rate with respect to the silicon substrate, removing foreign matters remaining on the silicon substrate (such as abrasive particles and abrasion caused by abrasion of the polishing pad), and removing the semiconductor substrate. It is a polishing liquid focused on reducing crystal defects.

(pH)

In 4th Embodiment, pH is 9 or more and pH 9.5 or more is more preferable from a viewpoint of reducing the defect resulting from a foreign material adhering to the silicon substrate surface. Moreover, pH is 12 or less, 11 or less are preferable and 10.5 or less are more preferable from a viewpoint of suppressing generation | occurrence | production of the defect resulting from excessive etching.

(1,2,4-triazole)

In 4th Embodiment, the addition amount of the said 1,2,4-triazole is 0.05 mass% or more and 0.5 mass% or less. Improvement of the haze (HAZE: turbidity), which is an index of roughness of the wafer surface, in that the stability of pH of 1,2,4-triazole and the increase of the basic compound as a solubilizer are easily obtained. Since an effect is acquired, the addition amount is 0.05 mass% or more, and 0.1 mass% or more is preferable. On the other hand, the addition amount is 0.5 mass% or less, 0.4 mass% or less is more preferable, 0.3 mass% from the point which avoids the improvement effect of the haze suitable for the addition amount, and can suppress aggregation of abrasive grains further. The following is especially preferable.

(Water soluble polymer)

In 4th embodiment, the addition amount of a water-soluble polymer (water-soluble polymer) is 0.001 mass% or more and 0.1 mass% or less. Since the effect of reducing defects on the surface of the silicon substrate is sufficiently obtained, the addition amount is 0.001% by mass or more, preferably 0.003% by mass or more, more preferably 0.005% by mass or more, and particularly preferably 0.01% by mass or more. In addition, the addition amount is 0.1 mass% or less, 0.08 mass% or less is preferable, and 0.07 mass% or less is the point which can suppress that a problem, such as inhibition of grinding | polishing, an increase of a defect, and inhibition of a haze improvement, can be suppressed. It is preferable, 0.05 mass% or less is especially preferable, and 0.03 mass% or less is very preferable. In addition, the defect on a silicon substrate is used here as generic terms, such as a foreign material, such as abrasion powder which arises by the abrasion of abrasive grains or a polishing pad, and a crystal defect or a flaw which generate | occur | produced on a silicon substrate.

The reduction of defects due to the addition of the water-soluble polymer prevents the adhesion of the water-soluble polymer to the surface of the semiconductor substrate, thereby preventing foreign matters such as abrasion caused by abrasion of the abrasive particles and the polishing pad, from adhering to the surface of the semiconductor substrate. It is considered that it is obtained by suppressing the occurrence of etching in a specific direction due to dangling bonds (unbonded paper) or COP (Crystal Oriented Particles).

In addition, the haze and a defect value are the defect inspection currently marketed after wash | cleaning the silicon substrate surface after completion | finish of grinding | polishing (for example, washing | cleaning liquid containing 0.06% of ammonium hydroxide, 60 second using a general cleaning brush). It can be measured using the device.

Specifically, for example, values measured under the following conditions can be defined as haze and defects.

Defect inspection device: LS6700 (manufactured by Hitachi Denshi Engineer)

Process Condition File (Measuring Recipe): VeM10L

Defective measuring range: 0.1 μm-3.0 μm

Flooding condition: vertical

As described above, the fourth embodiment focuses on eliminating minute irregularities present on the silicon substrate and reducing defects, as compared to the polishing rate for the silicon substrate, as in the finish polishing application in the semiconductor wafer manufacturing process. . For this reason, as addition amount of abrasive grain, it is preferable to set it as 0.05 mass% or more and 0.5 mass% or less with respect to the whole polishing liquid. If it is 0.05 mass% or more, unevenness | corrugation can be eliminated, and if it is 0.5 mass% or less, it can suppress that a silicon substrate is excessively polished.

<5th Semiconductor Substrate Polishing Liquid>

Next, as 5th invention embodiment, the 5th semiconductor substrate polishing liquid is demonstrated. In addition, the part which overlaps description with the polishing liquid for 1st, 2nd and 3rd semiconductor substrates is abbreviate | omitted suitably.

The polishing liquid for semiconductor substrates of 5th Embodiment contains abrasive grain, 1,2,4-triazole, a water-soluble polymer, and a basic compound, The addition amount of the said 1,2,4-triazole is 0.2 mass% or more and 3.0 mass It is% or less, The addition amount of the said water-soluble polymer is 0.01 mass% or more and 0.2 mass% or less, and is a polishing liquid for semiconductor substrates whose pH is 9 or more and 12 or less.

(pH)

In the fifth embodiment, from the viewpoint of obtaining a predetermined polishing rate for the silicon, the pH is 9 or more, more preferably pH 9.5 or more, and even more preferably pH 10.0 or more. Moreover, from a viewpoint of suppressing the defect resulting from excessive etching, the said pH is 12 or less, and 11 or less are preferable.

In the fifth embodiment, the addition amount of 1,2,4-triazole is large and the amount of addition of the water-soluble polymer is large compared with the polishing liquid for fourth semiconductor substrates. By doing in this way, it can be set as the grinding | polishing liquid for semiconductor substrates which can grind | polish a convex part preferentially, if there is an unevenness | corrugation on the surface, while obtaining the predetermined | prescribed grinding | polishing rate with respect to a silicon substrate. In particular, in a silicon substrate having a high step, such as a silicon substrate which has been mechanically ground (grinded), it is possible to preferentially polish the convex portions of the step, and to remove the grinding traces generated during the grinding process.

According to the polishing method of such a semiconductor substrate, since the rough polishing which has been conventionally performed in several steps can be performed in one step, it is possible to reduce the polishing loss of the semiconductor substrate generated in the rough polishing. As a result, the effect of increasing the number of times of reuse of the silicon wafer is also obtained.

In the above-described rough polishing step, the polishing amount of the rough wafer is L (nm), the initial step of the _rough wafer is R _t0 (nm), and the level of the rough _rough wafer after the rough polishing is R _t1 (nm). when defined as a, R _t0 ≤L≤R the crude wafer only L (nm) satisfying 1.3 × _t0 when the grinding (i.e., grinding only the polishing amount of no more than 1.3 times the initial step), L / (R _t0 -R It is preferable to satisfy both _t1 ) ≤ 1.3 and R _t1 ≤ 100 (nm). In addition, the final polishing amount is not more than the above-described relationship may be a range (R _t0 ≤L≤R _t0 × 1.3). FIG.

Here, the polishing amount L means the thickness of the portion removed from the jaw wafer by polishing. In addition, initial stage _Rt0 is the maximum value of the difference of the height of the convex part and recessed part of the surface of the roughening wafer before _rough- polishing. The step R _t1 of the roughened roughened wafer is the maximum value of the difference between the heights of the convex portions and the concave portions of the roughened roughened wafer surface.

17 is a graph showing the contents of 1,2,4-triazole and a water-soluble polymer in the polishing liquids for the third to fifth semiconductor substrates. As described above, in the polishing liquid for the third semiconductor substrate, the content of 1,2,4-triazole is preferably 0.01% by mass or more and 10% by mass or less with respect to the total mass of the polishing liquid for semiconductor substrates, and is a water-soluble polymer. It is preferable that content of is 0.001 mass% or more and 10 mass% or less (the preferable range of the polishing liquid for 3rd semiconductor substrates of FIG. 17). In addition, in the polishing liquid for 4th semiconductor substrates, content of 1,2,4-triazole is 0.05 mass% or more and 0.5 mass% or less with respect to the total mass of the polishing liquid for semiconductor substrates, and content of water-soluble polymer is 0.001 It is mass% or more and 0.1 mass% or less. In the polishing liquid for a fifth semiconductor substrate, the content of 1,2,4-triazole is 0.2% by mass or more and 3.0% by mass or less with respect to the total mass of the polishing liquid for semiconductor substrates, and the content of the water-soluble polymer is 0.01. It is mass% or more and 0.2 mass% or less.

<Method of Polishing Semiconductor Substrate>

Next, the polishing method for polishing the surface of the semiconductor substrate using the polishing liquids for the first to fifth semiconductor substrates described so far will be described. As an example of a grinding | polishing method, for example, the polishing substrate and the substrate are pressed in a state where the polishing substrate (semiconductor substrate) is pressed against the polishing cloth while supplying the polishing liquid for the semiconductor substrate of the present embodiment on the polishing cloth of the polishing platen. The polishing substrate is moved relatively to polish the surface of the semiconductor substrate.

As a polishing apparatus that can be used in the polishing method of the present embodiment, for example, the polishing apparatus includes a holder holding a substrate to be polished, and a polishing plate to which a polishing cloth (pad) can be attached and a motor capable of changing the rotation speed is attached. A general polishing apparatus can be used. There is no restriction | limiting in particular as an abrasive cloth on a polishing plate, A general nonwoven fabric, a foamed polyurethane, a porous fluororesin etc. can be used. In order to relatively move the polishing cloth and the substrate to be polished while the semiconductor substrate is pressed against the polishing cloth, at least one of the substrate and the polishing plate may be moved. In addition to rotating the polishing platen, the polishing platen may also be polished by rotating or swinging the holder.

Moreover, as a grinding | polishing method, the grinding | polishing method of planetary rotation of a polishing table, the grinding | polishing method of moving a belt-like abrasive cloth linearly in one direction of a long direction, etc. are mentioned. In addition, the holder may be in any of the states of fixing, rotation, and swinging. These polishing methods are appropriately selected depending on the substrate to be polished and the polishing apparatus as long as the polishing cloth and the semiconductor substrate are relatively moved. While polishing, it is preferable to continuously supply a polishing liquid for a semiconductor substrate to a polishing cloth by a pump or the like.

<Polishing method using polishing liquid for first or second semiconductor substrate>

The polishing liquids for the first and second semiconductor substrates of the present embodiment have excellent polishing characteristics when the substrate containing silicon in silicon or the substrate configuration is polished using the polishing method as described above. Among them, the polishing rate for the substrate containing silicon in the silicon or the substrate configuration is excellent.

EMBODIMENT OF THE INVENTION Below, embodiment of the grinding | polishing method of a semiconductor substrate using the polishing liquid for 1st and 2nd semiconductor substrate is described.

(Silicone penetrating vias polishing method)

An example of the polishing process utilizing the polishing characteristics of the polishing liquids for the first and second semiconductor substrates will be described with reference to FIG. 13. In addition, of course, the grinding | polishing method of the semiconductor substrate of this invention is not limited to this example. It is a cross-sectional schematic diagram which shows an example of a silicon through-via formation process.

In Fig. 13 (a), the through via unevenness is formed in the semiconductor substrate 1 such as silicon, and the wiring metal 2 such as copper is formed so as to fill the unevenness. Next, the opposite surface (rear surface) of the surface in which the unevenness | corrugation of the semiconductor substrate 1 was formed is backgrinded by a well-known method. At this time, due to the strong mechanical action of the back grind, as shown in FIG. 13 (b), a silicon damage layer 3 subjected to mechanical damage is generated on the back surface of the semiconductor substrate 1. Finally, using the polishing liquid for semiconductor substrate of this embodiment, the said silicon damage layer 3 and the semiconductor substrate 1 are polished, and it grind | polishes until the wiring metal 2 is exposed to a back surface, FIG. A silicon through via as shown in c) is formed.

Fine irregularities may exist on the surface of the silicon damage layer 3, but according to the polishing method of the semiconductor substrate using the polishing liquid for semiconductor substrates of the present embodiment, a good polishing rate can be obtained even for a semiconductor substrate having irregularities on the surface. have. For this reason, the grinding | polishing method of the semiconductor substrate using the polishing liquid for semiconductor substrates of this embodiment can be used for various uses which grind a semiconductor substrate.

In other words, the present embodiment is a method for polishing a semiconductor substrate for forming a silicon through via, comprising: forming a recess in one side of the silicon substrate, embedding a metal in the recess, and backing the other side of the silicon substrate. A grinding | polishing method of the semiconductor substrate provided with the grinding | polishing process and the grinding | polishing process of grind | polishing the other surface so that a metal may be exposed using the grinding | polishing liquid for a 1st or 2nd semiconductor substrate.

In the backgrinding of the through-silicon vias, the polishing liquid for the third or fourth semiconductor substrate can be applied even when finishing polishing is applied in the final step.

(Polishing Method According to Silicon Wafer Manufacturing Process)

Another example of the polishing process utilizing the polishing characteristics of the polishing liquids for the first and second semiconductor substrates will be described with reference to FIGS. 14 and 15. 14 is a flow of a general silicon wafer processing technique. The silicon wafer is processed into a wafer shape through a process including a step of slicing a single crystal of silicon (slicing), a lapping process or a grinding process, an etching process, and the like. Since the lapping step or the grinding step is mechanically ground, damage to crystals, such as crystal defects, may be caused to the silicon crystal. Therefore, in the subsequent etching step, it is common to eliminate such damage and to eliminate some of the surface irregularities.

However, even in the silicon wafer after the etching process, sufficient flatness and damage to crystal defects, etc., are not achieved in order to manufacture a so-called semiconductor device. Therefore, as shown in FIG. 15, it is common to obtain a flat silicon wafer through a multi-step polishing process. In Fig. 15, two steps of rough polishing (rough polishing) processes of (a) to (b) and (b) to (c) and finish polishing (final polishing) processes of (d) to (c) are shown. This polishing process varies depending on the wafer manufacturer and the grade of the wafer, and may be further multistage.

The rough polishing performs polishing while sequentially changing the hardness of the polishing cloth to be used from hard to soft, and gradually eliminates unevenness and damage while reducing the film thickness. In the finish polishing step, the polishing rate for silicon is hardly required, and the purpose of the mirror polishing of the wafer is to remove the abrasive grains adhered to the rough polishing, eliminate fine irregularities, and eliminate the defects. One polishing process.

Here, the polishing liquids for the first and second semiconductor substrates are suitable for the rough polishing described above. That is, in this embodiment, after lapping or grinding a silicon wafer obtained by slicing a silicon single crystal ingot, the silicon wafer is etched to prepare a jaw wafer, and a polishing liquid for the first or second semiconductor substrate is used. And a rough polishing step for polishing a rough wafer.

(Polishing method by regeneration of silicon wafer)

In addition, the polishing liquids for the first and second semiconductor substrates can be suitably used in a method of polishing a recycled wafer by utilizing a high polishing rate for silicon. Hereinafter, a method of polishing a recycled wafer will be described.

In general, in each component process of manufacturing semiconductor devices from silicon wafers, a plurality of wafers are used as test wafers for process testing. As such a test wafer, what formed various films, such as an insulating film and a metal film, on the flat silicon substrate is mentioned. The purpose of manufacturing these test wafers is to periodically investigate the optimum conditions for coating and exposing a resist film on a silicon substrate when investigating optimum conditions for forming various films on a silicon substrate. In the case of monitoring with respect to the present invention, it has been used in various fields such as in evaluating polishing characteristics of polishing liquids for various films formed on a silicon substrate.

In order to use these test wafers again as a test wafer, a regeneration process is performed. In the regeneration treatment, generally, deposits such as the various films and the like are removed by wet etching, and a flat wafer is obtained again through a rough polishing and finish polishing process. Further, the test wafer may have large scratches until reaching the regeneration step, or may form irregularities during evaluation. In this case, it is common to remove a scratch and uneven | corrugated by a grinding process, and to obtain a flat wafer again by rough grinding and finish polishing.

Among the polishing liquids for semiconductor substrates of the present invention, the polishing liquids for the first and second semiconductor substrates can be suitably used for rough polishing such recycled wafers. That is, the present embodiment is a method of polishing a semiconductor substrate for reuse, wherein the wet etching of the silicon wafer to which the deposit adheres is carried out, and the wet-etched silicon wafer is polished using the polishing liquid for the first or second semiconductor substrate. It is a grinding | polishing method of the semiconductor substrate provided with the rough polishing process.

When the surface of the silicon substrate to be reused has irregularities or scratches, it is preferable to have a mechanical grinding step before the step of polishing using the polishing liquid for the first or second semiconductor substrate.

<Polishing method using polishing liquid for third or fourth semiconductor substrate>

Among the polishing liquids for semiconductor substrates of the present embodiment, the polishing liquid for the third semiconductor substrate contains abrasive particles, 1,2,4-triazole and a basic compound, and the polishing liquid for semiconductor substrates having a pH of 9 or more and 12 or less. By containing a water-soluble polymer, unevenness of the silicon surface can be eliminated.

In addition, in the polishing liquid for the third semiconductor substrate, in order to adjust the polishing rate or to change the target size of the unevenness to be eliminated, the addition amount of 1,2,4-triazole and a water-soluble polymer is optimized, if necessary. By controlling the pH and the like, it is possible to obtain the polishing liquid for the fourth semiconductor substrate.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of the grinding | polishing method of a semiconductor substrate using the grinding | polishing liquid for 3rd or 4th semiconductor substrates is described.

(Polishing Method According to Silicon Wafer Manufacturing Process)

As described above, in order to obtain a flat silicon wafer, as shown in FIG. 15, it is common to undergo a rough polishing (rough polishing) process and a finish polishing (final polishing) process. Here, the polishing liquids for the third and fourth semiconductor substrates are generated by solving the unevenness existing on the silicon substrate rather than the polishing rate with respect to silicon and by the foreign matter remaining on the silicon substrate (abrasive particles and abrasion of the polishing pad). It is a polishing liquid which focuses on removing the wear powder etc.), and is especially suitable for the finishing polishing use in the manufacturing process of a silicon wafer. That is, in this embodiment, after lapping or grinding a silicon wafer obtained by slicing a silicon single crystal ingot, the silicon wafer is etched to prepare a rough wafer, a rough polishing step of polishing the rough wafer, and a third or It is a grinding | polishing method of the semiconductor substrate provided with the finishing polishing process which further polishes a silicon wafer after a rough polishing process using the polishing liquid for 4th semiconductor substrates. Further, in the rough polishing step of polishing the rough wafer, a polishing liquid for the first or second semiconductor substrate may be used.

(Polishing method by regeneration of silicon wafer)

The polishing liquids for the third and fourth semiconductor substrates can also be applied to finish polishing in the step of obtaining the reclaimed wafer described above. In other words, the present embodiment is a method of polishing a semiconductor substrate for reuse, including a step of wet etching a silicon wafer with deposits, a rough polishing step of polishing a wet etched silicon wafer, and a third or fourth semiconductor substrate. It is a grinding | polishing method of the semiconductor substrate provided with the finishing grinding | polishing process which further grinds a silicon wafer after a rough polishing process using the polishing liquid for solvents. Further, in the rough polishing step of polishing the wet etched silicon wafer, a polishing liquid for the first or second semiconductor substrate may be used.

In addition, when the surface of the silicon substrate to be reused has irregularities or scratches, it is preferable to have a mechanical grinding step before the step of polishing using the polishing liquid for the third or fourth semiconductor substrate.

In addition, when the polishing liquid for the third or fourth semiconductor substrate is used in order to reduce defects on the silicon substrate rather than the polishing rate for silicon and to eliminate fine irregularities on the surface and to obtain a high mirror surface, the polishing pad may be used to some extent. It is preferable that it is soft, for example, it is preferable that the hardness (Asker C hardness) measured with Asker rubber hardness meter C type is smaller than 60 degree | times.

<Polishing Method Using Polishing Liquid for Third or Fifth Semiconductor Substrates>

In the polishing liquid for semiconductor substrates of the present embodiment, the polishing liquid for the fifth semiconductor substrate is obtained with a certain polishing rate for silicon while eliminating the surface irregularities as compared with the polishing liquid for the fourth semiconductor substrate. Thereby, it becomes possible to give priority to polishing the convex part of the semiconductor substrate which has comparatively large unevenness | corrugation. In addition, in the polishing method described later, a polishing liquid for a third semiconductor substrate may be used instead of the polishing liquid for a fifth semiconductor substrate.

EMBODIMENT OF THE INVENTION Below, embodiment of the grinding | polishing method of a semiconductor substrate using the polishing liquid for 5th semiconductor substrates is described.

Fig. 16A is a general regeneration process flow of a silicon wafer. The silicon wafer recovered for reuse becomes a rough wafer after undergoing a storage inspection, through a wet etching process for removing deposits and a grinding process for removing relatively large irregularities. After the crude wafer is cleaned by a predetermined method, it is roughly polished in multiple stages (primary polishing, secondary polishing…) in the rough polishing step, and further shipped through a final polishing step and a cleaning step as a recycled wafer. .

However, the reality is that the silicon wafer is cut more than necessary by multi-step polishing after grinding. Thus, improvements are still needed to reduce this "grinding allowance" and to reuse silicon wafers more efficiently.

On the other hand, by using the polishing liquid for the fifth semiconductor substrate, it is possible to provide a new polishing method that does not exist in the prior art which enables such improvement. That is, this embodiment is a method of polishing a semiconductor substrate for reuse, comprising: wet etching a silicon wafer with an adherend thereon, grinding the silicon wafer to prepare a rough wafer, and a polishing liquid for a fifth semiconductor substrate. It is a polishing method of a semiconductor substrate provided with the coarse polishing process which grinds a rough wafer using this process.

In the polishing method of such a semiconductor substrate, the rough polishing that has been conventionally performed in several steps can be performed in one step (see FIG. 16 (b)), so that the polishing margin of the semiconductor substrate generated in the rough polishing can be reduced. As a result, the effect of increasing the number of times of reuse of the silicon wafer is also obtained.

In the above-described rough polishing step, the polishing amount of the rough wafer is L (nm), the initial step of the _rough wafer is R _t0 (nm), and the level of the rough _rough wafer after the rough polishing is R _t1 (nm). when defined as a, R _t0 ≤L≤R the crude wafer only L (nm) satisfying 1.3 × _t0 when the grinding (i.e., grinding only the polishing amount of no more than 1.3 times the initial step), L / (R _t0 -R It is preferable to satisfy both _t1 ) ≤ 1.3 and R _t1 ≤ 100 (nm). In addition, the final polishing amount is not more than the above-described relationship may be a range (R _t0 ≤L≤R _t0 × 1.3). FIG.

Further, in the above-described method for polishing a semiconductor substrate, a finish polishing step of polishing the rough wafer after the rough polishing step by using the polishing liquid may be further provided, and the polishing liquid comprises abrasive particles, 1,2,4 It is preferable that -triazole, a water-soluble polymer, and a basic compound are contained and pH is 9 or more and 12 or less. As a result, it is possible to finish polish the surface of the semiconductor substrate at a high speed on a smooth surface with few unevennesses.

Further, in the above-described method for polishing a semiconductor substrate, a finish polishing step of polishing the rough wafer after the rough polishing step by using the polishing liquid may be further provided, and the polishing liquid comprises abrasive particles, 1,2,4 It contains -triazole, a water-soluble polymer, and a basic compound, and the content of 1,2,4-triazole is 0.05 mass% or more and 0.5 mass% or less with respect to the total mass of the polishing liquid for semiconductor substrates, It is preferable that content is 0.001 mass% or more and 0.1 mass% or less with respect to the total mass of the polishing liquid for semiconductor substrates, and pH is 9 or more and 12 or less. As a result, the surface of the semiconductor substrate can be reliably finished and polished at a high speed on a smooth and smooth surface having less unevenness.

In addition, the polishing liquid for the fifth semiconductor substrate can also be preferably applied to the TSV back surface polishing method. Generally, the back surface of TSV is not required to have the same flatness as the circuit surface (active surface). Therefore, after mechanical grinding is performed in one step, TSV back surface polishing is performed using the polishing liquid for the fifth semiconductor substrate, so that it is sufficiently practical. A TSV substrate that can withstand can be obtained. Conventionally, the backside polishing of TSV has undergone a plurality of mechanical grinding steps until polishing, but according to the method of the present invention, the TSV manufacturing process can be greatly simplified.

In addition, in the polishing liquid for the fifth semiconductor substrate, it is preferable that the polishing pad has a certain hardness in order to obtain a certain polishing rate for silicon while eliminating some large irregularities generated on the surface by grinding or the like. For example, the hardness (asker C hardness) measured by the Asker rubber hardness tester C type is preferably 60 degrees or more, more preferably 70 degrees or more, and even more preferably 80 degrees or more. By having these hardness, a favorable grinding | polishing rate is easy to be obtained and there exists a tendency which is also excellent in the resolution of unevenness | corrugation.

According to this polishing method, ideally, a plurality of stages of rough polishing are not necessary, so that a method of polishing a semiconductor wafer including one stage of rough polishing, or a semiconductor wafer comprising one stage of rough polishing and one stage of final polishing. A polishing method is provided.

[Example]

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

<Polishing liquid for first semiconductor substrate>

(Examples 1 to 8)

[Manufacture of Polishing Liquid for Semiconductor]

1,2,4-triazole, a basic compound and colloidal silica as abrasive particles were blended in the addition amounts shown in Table 1 according to the following procedure to prepare polishing liquids for semiconductors of Examples 1 to 8. .

In the production of each polishing liquid, 1,2,4-triazole is first dissolved in pure water corresponding to 50% by mass of the entire polishing liquid, and a basic compound is added thereto, followed by colloidal silica having a primary particle diameter of 35 nm. The mixture was dispersed and the balance was combined so as to have a total amount of 100% by mass of pure water.

(Examples 9 and 10)

[Manufacture of Polishing Liquid for Semiconductor]

1,2,4-triazole, a basic compound and colloidal silica as abrasive particles were blended in the addition amounts shown in Table 2 according to the following procedure to prepare polishing liquids for semiconductors of Examples 9 and 10. .

In the production of each polishing liquid, 1,2,4-triazole is first dissolved in pure water corresponding to 50% by mass of the entire polishing liquid, and a basic compound is added thereto, followed by colloidal silica having a primary particle diameter of 17 nm. It disperse | distributed and mix | blended so that the remainder may be 100 mass% in total with pure water.

[pH measurement]

The pH of each polishing liquid for semiconductors of Examples 1 to 10 was measured by the following method.

(Measurement of pH)

pH meter: Yokogawa Denki Co., Ltd. Model pH 81

Calibration: Two-point calibration with neutral phosphate pH buffer pH 6.86 (25 ° C) and borate pH standard solution (pH 9.18) (25 ° C)

Measuring temperature: 25 ℃

Magnetic Stirring Bar: AZWON HS-30D

Measurement procedure: The pH was measured while stirring the polishing liquid at 500 rpm using a stirrer coated with a fluorine resin having a diameter of about 4 cm and a diameter of about 0.5 cm.

When to measure: Immediately after compounding, after 1 day

The term "immediately after compounding" is less than 1 hour after completion of the above-described adjustment (mixing) of the semiconductor polishing liquid, and "after 1 day standing" means the adjustment (mixing) of the semiconductor polishing liquid described above. After standing still for 24 to 25 hours after that, it means, respectively.

The pH of each polishing liquid for semiconductors immediately after the mixing is shown in Tables 1 and 2. In addition, the pH of each polishing liquid for semiconductors after standing still for 1 day after mix | blending, and the amount of change in pH measured immediately after mix | blending are shown in Table 1.

[1 Polishing of Semiconductor Substrate]

While supplying the polishing liquid for the semiconductor substrate of Example 1 immediately after the mixing onto the polishing cloth of the polishing plate, the surface of the semiconductor substrate was rotated by relatively rotating the polishing plate with respect to the semiconductor substrate while the semiconductor substrate was pressed against the polishing cloth. Polished. In the same manner as in Example 1, the semiconductor substrate was polished using the respective polishing liquids of Examples 2 to 8 immediately after blending. The detail of grinding | polishing conditions is as follows.

(Polishing condition 1)

Polishing device: Nano factor manufacture FACT-200

Polishing cloth: Nitta Haas IC-1010

Polishing platen rotation speed: 80 rpm

Holder speed: no drive (free rotation)

Polishing pressure: 33.83 kPa (345 gf / cm 2)

Polishing liquid supply amount: 16 ml / min

Polishing time: 5 minutes

Semiconductor substrate (article to be polished): 2 cm square silicon wafer (P-type <100>)

[Polishing Semiconductor Substrates 2]

Similarly, while supplying the polishing liquid for semiconductor substrates of Examples 9 and 10 immediately after blending onto the polishing cloth of the polishing table, the semiconductor substrate is relatively rotated with respect to the semiconductor substrate while the semiconductor substrate is pressed against the polishing cloth. The surface of was polished. The detail of grinding | polishing conditions is as follows.

(Polishing condition 2)

Polishing device: MIRRA manufactured by Applied Materials

Polishing cloth: Nitta Haas IC-1010

Polishing platen rotation speed: 93 rpm

Holder rpm: 87 rpm

Polishing pressure: 20.7 kPa

Polishing liquid supply amount: 200 ml / min

Polishing time: 3 minutes

Semiconductor substrate (abrasive): 200 mm silicon wafer (P-type <100>)

[washing]

After polishing, the semiconductor substrate was washed with a polyvinyl alcohol brush and ultrasonic water. After washing, the semiconductor substrate was dried with a spin dryer.

[Measurement of Polishing Speed Immediately after Blending]

After polishing the silicon wafer by the above-described method using the polishing liquids for semiconductors of Examples 1 to 10 immediately after the blending, the amount of decrease in the mass of the silicon wafer caused by the polishing was measured. And the polishing rate (unit: nm / min) was measured from the mass reduction amount, wafer area, specific gravity of silicon, and polishing time. In addition, the electronic balance for analytical (Metro AB AB104) was used for the mass measurement of a silicon wafer. Measurement temperature was 25 degreeC, and measurement humidity was 40% RH or more. Silicon specific gravity was 2.33.

[Measurement of Polishing Rate after 1-Day]

In the same manner as in the case of using the respective polishing liquids for semiconductors of Examples 1 to 8 immediately after the blending, the polishing rate in the case of using the polishing liquids for semiconductors of Examples 1 to 8 after one day of standing was measured.

[Surface roughness evaluation]

After polishing the silicon wafer by the above-described method using the polishing liquids for semiconductors of Examples 9 and 10 immediately after the blending, the arithmetic mean of the polished surface of the silicon wafer was measured using a step, surface roughness, and fine shape measuring device. Roughness was measured on condition of the following.

Step, surface roughness, and fine shape measuring device: K16 Tenco manufactured P16-OF

Measurement Mode: Roughness

Measuring length: 200 μm

Measuring speed: 5 μm / sec

Measuring load: 1 mg

The evaluation results of Examples 1 to 8 are shown in Table 1, and the evaluation results of Examples 9 and 10 are shown in Table 2, respectively.

(Comparative Examples 1 to 14)

The colloidal silica which is a basic compound shown in following Table 3, Table 4, and abrasive grains was mix | blended in the addition amount shown in Table 3, Table 4 according to the following procedure, and the polishing liquid for each semiconductor substrate of Comparative Examples 1-14 was manufactured. It was. In the production of each polishing liquid, a basic compound is first added to pure water corresponding to 50% by mass of the entire polishing liquid, and then, colloidal silica having a primary particle diameter of 35 nm is dispersed, and the balance is 100% by mass in pure water. Blended. In addition, none of the polishing liquids of Comparative Examples 1 to 14 contained 1,2,4-triazole.

In the same manner as in Example 1, the pH of each of the polishing liquids for semiconductors of Comparative Examples 1 to 14 immediately after the blending, the pH of each polishing liquid for the semiconductors after 1 day standing, and the amount of change in pH after 1 day standing immediately after the blending were measured. It was. The measurement results are shown in Tables 3 and 4.

In the same manner as in Example 1, the polishing rate when the polishing liquids for semiconductors of Comparative Examples 1 to 14 immediately after the blending were used was measured. In addition, by the method similar to Example 1, the polishing rate at the time of using each semiconductor polishing liquid of Comparative Examples 1-14 after 1-day standing was measured. The measurement results are shown in Tables 3 and 4.

(Comparative Examples 15 to 18)

The compound having pKa shown in Table 5 (where pKa is pKa _{1, which} is the same below) and colloidal silica, which is abrasive particles, were formulated in the addition amounts shown in Table 5 according to the following procedure, and Comparative Examples 15 to The polishing liquid for each semiconductor substrate of 18 was produced. In manufacture of each polishing liquid, the compound which has pKa was dissolved in the pure water corresponded to 50 mass% of the whole polishing liquid, and the basic compound was added to this. Subsequently, colloidal silica having a primary particle diameter of 35 nm was dispersed, and the balance was combined so as to be 100% by mass in pure water. In addition, none of the polishing liquids of Comparative Examples 15 to 18 contained 1,2,4-triazole.

(Comparative Example 19)

The 1,2,4-triazole and the colloidal silica which are abrasive grains were mix | blended in the addition amount shown in Table 5 according to the following procedure, and the polishing liquid for semiconductor substrates of the comparative example 19 was manufactured. In the production of the polishing liquid, 1,2,4-triazole is dissolved in 1% by mass of pure water corresponding to 50% by mass of the entire polishing liquid, and the colloidal silica having a primary particle diameter of 35 nm is dispersed therein, and the remainder is It mix | blended so that it may become 100 mass% in total with pure water. In addition, the polishing liquid of Comparative Example 19 did not contain a basic compound.

In the same manner as in Example 1, the pH of each of the polishing liquids for semiconductors of Comparative Examples 15 to 19 immediately after the blending, the pH of each polishing liquid for the semiconductors after 1 day standing, and the amount of change in pH after 1 day standing immediately after the blending were measured. . The measurement results are shown in Table 5.

In the same manner as in Example 1, the polishing rate in the case of using the polishing liquids for semiconductors of Comparative Examples 15 to 19 immediately after the mixing was measured. In addition, by the method similar to Example 1, the polishing rate at the time of using each semiconductor polishing liquid of Comparative Examples 15-19 after 1-day standing was measured. The measurement results are shown in Table 5.

(Comparative Example 20)

The basic compound shown in following Table 6 and the colloidal silica which are abrasive grains were mix | blended in the addition amount shown in Table 6 according to the following procedure, and the polishing liquid for semiconductor substrates of the comparative example 20 was manufactured. In the production of the polishing liquid, first, a basic compound is added to pure water corresponding to 50% by mass of the entire polishing liquid, followed by dispersing colloidal silica having a primary particle diameter of 17 nm, and blending the balance to be 100% by mass in pure water. It was. In addition, the polishing liquid of Comparative Example 20 did not contain 1,2,4-triazole.

In the same manner as in Example 1, the pH of the polishing liquid for semiconductors of Comparative Example 20 immediately after the blending and the polishing rate when the polishing liquid for semiconductors of Comparative Example 20 immediately after the blending were used were measured. In addition, in the same manner as in Examples 9 and 10, the arithmetic mean roughness of the polished surface of the silicon wafer after polishing using the polishing liquid for semiconductors of Comparative Example 20 was measured. The measurement results and arithmetic mean roughness are shown in Table 6.

In FIG. 1, the pH immediately after mix | blending each polishing liquid of Examples 1-4 and Comparative Examples 1-11, and the amount of pH change of each polishing liquid after 1-day standing are shown. 2 shows the pH and polishing rate immediately after the mixing of each polishing liquid of Examples 1 to 4 and Comparative Examples 1 to 11, and the pH and polishing rate after daily standing of each polishing liquid. 3, the relationship between the addition amount of the abrasive grains (silica) in each polishing liquid of Examples and Comparative Examples and the pH change amount of each polishing liquid after 1 day of standing immediately after the mixing is shown. 1 to 3, "TA" is an example containing 1,2,4-triazole, and other than that is a comparative example which does not contain 1,2,4-triazole. In addition, "TMAH" means containing tetramethylammonium hydroxide, and "KOH" means containing potassium hydroxide.

As described above, the polishing liquid for semiconductor substrates of Examples 1 to 8 contains silica and 1,2,4-triazole, and is a basic compound (tetramethylammonium hydroxide or an inorganic basic compound as a nitrogen-containing basic compound). As potassium hydroxide). And in the polishing liquid for semiconductor substrates of Examples 1-8, content of a basic compound is 0.1 mass% or more, and pH is 9 or more and 12 or less. In Examples 1 to 8, the pH immediately after the blending was not significantly different between the polishing rate immediately after the blending of the polishing liquid and the polishing rate after 1 day standing, compared to the comparative examples similar to the respective examples. It was also found that the pH change amount was very small. Therefore, it was found that the polishing liquid for semiconductor substrates of the present invention can polish silicon at high speed, and its polishing rate is stable.

On the other hand, Comparative Examples 1 to 5 contain tetramethylammonium hydroxide as a dissolving agent similarly to Examples 1 to 6. However, the pH of Comparative Examples 1-5 is almost the same as the Example by addition of very small amount of tetramethylammonium hydroxide. In Comparative Examples 1 to 5, it was found that the polishing rate was slower than the example, the pH change amount was too high immediately after the mixing of the polishing liquid and after 1 day standing, and the polishing rate after 1 day standing was also lowered.

In addition, Comparative Examples 6-14 contain potassium hydroxide as a solubilizer. Similarly to the comparative example described above, the pHs of the comparative examples 6 to 14 are almost the same as the examples by the addition of a very small amount of potassium hydroxide. In Comparative Examples 6 to 14, it was found that the polishing rate was slower than the example, the pH change amount was too high immediately after the mixing of the polishing liquid and after 1 day standing, and the polishing rate after 1 day standing was also lowered. Moreover, in Comparative Examples 6-14, compared with the polishing liquid which uses tetramethylammonium hydroxide as a dissolving agent, there exists a tendency for the amount of pH change after 1-day standing to become large.

In Comparative Example 15, the same azole imidazole was added instead of 1,2,4-triazole. In Comparative Example 15, since pKa was high at 14.5, the pH was the same as that of Example 3 by the addition of a very small amount of tetramethylammonium hydroxide. In Comparative Example 15, the polishing rate was slower than that of Example 3, and the same azole type as 1,2,4-triazole was used, but the pH change amount was too high immediately after the mixing of the polishing liquid and after 1 day of standing, It was found that the polishing rate also decreased after standing.

In Comparative Example 16, the same azole type 1,2,3-benzotriazole was added instead of 1,2,4-triazole. In the comparative example 16, pKa was 8.2 and the quantity which can add tetramethylammonium hydroxide was larger than the case where 1,2, 3- benzotriazole was not added. However, in Comparative Example 16, it was found that the polishing rate was slower than that in Example 3, the pH change amount immediately after the mixing of the polishing liquid and after 1 day standing was also large, and the polishing rate after 1 day standing was also lowered.

In Comparative Examples 17 and 18, an acid was added instead of 1,2,4-triazole. In Comparative Example 17 in which malic acid was added, more amount of tetramethylammonium hydroxide was added than in the case of no addition of malic acid, and more amount could be added than in Example 3. In the comparative example 17, although the polishing rate was the same as Example 3, it turned out that the pH change amount is also large immediately after mix | blending polishing liquid and after 1 day stand still, and also the polishing rate after 1 day stand still falls. In Comparative Example 18 in which sulfuric acid was added, more amount of potassium hydroxide was added than in the case of not adding sulfuric acid, and more amount could be added than in Example 7. However, in Comparative Example 18, it was found that the polishing rate was slower than that of Example 7, the change in pH immediately after the mixing of the polishing liquid and after 1 day standing was also large, and the rate of polishing after 1 day standing was also lowered.

Comparative Example 19 is a polishing liquid containing 1,2,4-triazole alone. In Comparative Example 19, changes in pH and polishing rate immediately after the mixing of the polishing liquid and after 1 day of standing were not recognized, but the polishing rate was low at less than 200 nm / min, and the polishing rate alone was 1,2,4-triazole alone. It can be seen that there is little effect to improve.

Moreover, when Example 9 and 10 and Comparative Example 20 were compared, it turned out that the surface roughness after completion | finish of polishing can be suppressed because a polishing liquid contains 1,2,4-triazole.

<Polishing Liquid for Second Semiconductor Substrate>

[Production of Abrasive Liquid for Zeta Potential Measurement]

The basic compound (potassium hydroxide) was added to the pure water corresponded to 50 mass% of the whole polishing liquid for semiconductors until pH became nine. Subsequently, 0.5 mass% of modified colloidal silica whose surface was modified by an aluminate was added as an abrasive grain (abrasive particle), and it mix | blended so that it might become a total of 95 mass% with pure water. A basic compound (potassium hydroxide) was added to pH 11, and the remainder was mix | blended so that it may become 100 mass% in total with pure water. Thus, the polishing liquid C for zeta potential measurement was manufactured.

The modified colloidal silica added to the polishing liquid C for zeta potential measurement adds potassium aluminate [(AlO (OH) ₂ K]) to a dispersion of silica, and refluxs at 60 ° C or higher to obtain silanol groups on the silica surface, It was obtained with -Si-O-Al (OH) ₂ group which is more easily ionized.

Polishing liquids A, B, D, E, F, G, and H for zeta potential measurement were prepared in the same manner as the polishing liquid C for zeta potential measurement, except that the abrasive grains and the basic compound shown in Table 7 were used. . In addition, all the abrasive grains shown in Table 7 were purchased from the abrasive manufacturer.

[Measurement of Zeta Potential]

The zeta potential of the abrasive grains in each of the zeta potential measurement polishing liquids was measured under the following measurement conditions.

Measuring principle: laser doppler

Zeta Potentiometer: ZETASIZER3000HS (MALVERN)

Measuring temperature: 25 ℃

Refractive Index of the Dispersant: 1.331

Viscosity of Dispersion Medium: 0.893 cP

(Examples 11 to 16)

[Manufacture of Polishing Liquid for Semiconductor]

The modified silica by aluminate and the inorganic basic compound shown in following Table 8 were mix | blended in the addition amount shown in Table 8 according to the following procedure, and each polishing liquid for semiconductors of Examples 11-16 was produced. In addition, "modified silica by an aluminate" shown in Table 8 is a modified colloidal silica modified by an aluminate, and is the same as that added to the said zeta potential measurement polishing liquid C.

In manufacture of each polishing liquid, potassium hydroxide which is an inorganic basic compound was first added to the pure water corresponded to 50 mass% of the whole polishing liquid until pH turns to nine. Subsequently, the modified colloidal silica modified by aluminate was dispersed as an abrasive grain, and it mix | blended so that it might become 95 mass% in total with pure water. Furthermore, potassium hydroxide was added to desired pH, and the remainder was mix | blended so that it may become 100 mass% in total with pure water.

(Example 17)

As shown in Table 8, 1 mass% of 1,2,4-triazole was dissolved in 50 mass% of the whole polishing liquid by considerable pure water, and potassium hydroxide was added to this until the pH became 9. Subsequently, the modified colloidal silica modified by aluminate was dispersed as an abrasive grain, and it mix | blended so that it might become 95 mass% in total with pure water. Potassium hydroxide was added to pH 11, and the remainder was mix | blended so that it may become 100 mass% in total with pure water. Thus, the polishing liquid for semiconductor substrates of Example 17 was manufactured.

[pH measurement]

PH of each polishing liquid for semiconductors of Examples 11-17 was measured with the following method. Table 8 shows the pH of each polishing liquid for semiconductors.

(Measurement of pH)

pH meter: Yokogawa Denki Co., Ltd. Model pH 81

Calibration: Two-point calibration with neutral phosphate pH buffer pH 6.86 (25 ° C) and borate pH standard solution (pH 9.18) (25 ° C)

Measuring temperature: 25 ℃

Magnetic Stirring Bar: AZWON HS-30D

Measurement procedure: The pH was measured while stirring the polishing liquid at 500 rpm using a stirrer coated with a fluorine resin having a diameter of about 4 cm and a diameter of about 0.5 cm.

Measurement time: Immediately after blending the polishing liquid

Polishing of Semiconductor Substrates

On the polishing cloth of the polishing platen, while supplying the polishing liquid for the semiconductor substrate of Example 11 immediately after the mixing, the surface of the semiconductor substrate was rotated by relatively rotating the polishing platen relative to the semiconductor substrate while the semiconductor substrate was pressed against the polishing cloth. Polished. In the same manner as in Example 11, the semiconductor substrate was polished using the polishing liquids of Examples 12 to 17 immediately after the formulation. The detail of grinding | polishing conditions is as follows.

(Polishing condition)

Polishing device: Nano factor manufacture FACT-200

Polishing cloth: Nitta Haas IC-1010

Polishing platen rotation speed: 80 rpm

Holder speed: no drive (free rotation)

Polishing pressure: 33.83 kPa (345 gf / cm 2)

Polishing liquid supply amount: 16 ml / min

Polishing time: 5 minutes

Semiconductor substrate (abrasive): 2 cm square silicon wafer (P-type <100>)

[washing]

After polishing, the semiconductor substrate was washed with a polyvinyl alcohol brush and ultrasonic water. After washing, the semiconductor substrate was dried with a spin dryer.

[Measuring of polishing speed]

After polishing the silicon wafer by the above-described method using the polishing liquids for semiconductors of Examples 11 to 17 immediately after the blending, the amount of decrease in the mass of the silicon wafer accompanying the polishing was measured. Then, the polishing rate (unit: nm / min) was measured from the decrease in mass, wafer area, specific gravity of silicon, and polishing time. The measurement results are shown in Table 2. In addition, the electronic balance for analytical (Metro AB AB104) was used for the mass measurement of a silicon wafer. Measurement temperature was 25 degreeC, and measurement humidity was 40% RH or more. Silicon specific gravity was 2.33.

(Comparative Examples 21 to 27)

The unmodified colloidal silica and basic compound shown in following Tables 9 and 10 were mix | blended in the addition amount shown to Tables 9 and 10 according to the following procedure, and each polishing liquid for semiconductors of Comparative Examples 21-27 was produced. In addition, all the silica shown in Tables 9 and 10 was purchased from an abrasive manufacturer.

In the production of each polishing liquid, first, a basic compound was added to pure water corresponding to 50% by mass of the entire polishing liquid until the pH became 9. Then, as the abrasive, unmodified colloidal silica was dispersed and blended so as to be 95% by mass in pure water. Furthermore, a basic compound was added to desired pH, and the remainder was mix | blended so that it may become 100 mass% in total with pure water.

(Comparative Example 28)

As shown in Table 10, 1 mass% of 1,2,4-triazole was melt | dissolved in the pure water corresponded to 50 mass% of the whole polishing liquid, and potassium hydroxide was added to this until it became pH 9. . Then, as the abrasive, unmodified colloidal silica was dispersed and blended so as to be 95% by mass in pure water. Potassium hydroxide was added to pH 11, and the remainder was mix | blended so that it may become 100 mass% in total with pure water. Thus, the polishing liquid for semiconductor substrates of the comparative example 28 was manufactured.

(Comparative Examples 29 to 32)

The modified silica and basic compound shown in Table 10 were mix | blended in the addition amount shown in Table 10 according to the following procedure, and each polishing liquid for semiconductors of Comparative Examples 29-32 was produced.

In the production of each polishing liquid, first, a basic compound was added to pure water corresponding to 50% by mass of the entire polishing liquid until the pH became 9. Then, the modified modified colloidal silica was dispersed as abrasive grains and blended so as to be 95% by mass in pure water. Furthermore, a basic compound was added until pH was 11, and the remainder was mix | blended so that it may become 100 mass% in total with pure water.

By the method similar to Example 11, pH of each polishing liquid for semiconductors of Comparative Examples 21-32 just after mixing | blending was measured. The measurement results are shown in Tables 9 and 10.

By the method similar to Example 11, the polishing rate at the time of using each semiconductor polishing liquid of Comparative Examples 21-32 immediately after mixing | blending was measured. The measurement results are shown in Tables 9 and 10.

6 shows the pH and polishing rate of each polishing liquid of Examples 11 to 14 and Comparative Examples 21 to 24. FIG.

In Examples 11 to 14, 16 and Comparative Examples 21 to 24, 26, 27, 29 and 32, when the added amount and pH of the abrasive grains were compared with the same Example and Comparative Example, the polishing rate of the Example was always higher than that of the Comparative Example. It was confirmed.

In Example 17, although the addition amount and pH of an abrasive grain were smaller than the comparative example 25, it was confirmed that the polishing rate of Example 17 is higher than the comparative example 25. In addition, although Example 17 and Comparative Example 28 both contain 1,2,4-triazole and although the primary particle diameter, addition amount, and pH of both abrasive grains are the same, the polishing rate of Example 17 is the comparative example 28 Higher was confirmed.

<Abrasive liquid for third semiconductor substrate>

(Examples 18 to 24)

[Manufacture of Polishing Liquid for Semiconductor]

Abrasive particles, water-soluble polymers (water-soluble polymers), 1,2,4-triazole and basic compounds were blended in the addition amounts shown in Table 11 according to the following procedures, and each of the polishing liquids for semiconductors of Examples 18 to 24 was used. Was prepared. As the water-soluble polymer, any one of three kinds of polyvinylpyrrolidones (PVP_K15, PVP_K30, PVP_K90) having different K values was used for the production of each polishing liquid. Here, K value represented by K15 etc. is a viscosity characteristic value related to molecular weight, and is a relative viscosity value in 25 degreeC measured with a capillary viscometer.

In the production of each polishing liquid, first, 1,2,4-triazole and polyvinylpyrrolidone (PVP) are dissolved in pure water corresponding to 50% by mass of the entire polishing liquid, and the basic compound has a pH of 9 Until it is added. Subsequently, 0.5 mass% of colloidal silica whose primary particle diameter was 17 nm was disperse | distributed, and it mix | blended so that it might become 95 mass% in total with pure water. Then, the basic compound was added until the desired pH was reached, and the balance was combined so as to be 100% by mass in total.

[pH measurement]

The pH of each polishing liquid for semiconductors of Examples 18 to 24 was measured by the following method. The pH of each semiconductor polishing liquid is shown in Table 11.

(Measurement of pH)

pH meter: Yokogawa Denki Co., Ltd. Model pH 81

Calibration: Two-point calibration with neutral phosphate pH buffer pH 6.86 (25 ° C) and borate pH standard solution (pH 9.18) (25 ° C)

Measuring temperature: 25 ℃

Magnetic Stirring Bar: AZWON HS-30D

Measurement procedure: The pH was measured while stirring the polishing liquid at 500 rpm using a stirrer coated with a fluorine resin having a diameter of about 4 cm and a diameter of about 0.5 cm.

Measurement time: Immediately after compounding the polishing liquid (In addition, immediately after mixing means less than 1 hour after completion of the adjustment (mixing) of the polishing liquid for semiconductors, which is the same below).

Polishing of Semiconductor Substrates

The surface of the semiconductor substrate is polished by relatively rotating the polishing platen relative to the semiconductor substrate while the semiconductor substrate is pressed against the polishing cloth while supplying the polishing liquid for the semiconductor substrate of Example 18 immediately after the mixing onto the polishing cloth of the polishing platen. It was. In the same manner as in Example 18, the semiconductor substrate was polished using the polishing liquids of Examples 19 to 24 immediately after the formulation. The detail of grinding | polishing conditions is as follows.

(Polishing condition)

Polishing device: Nano factor manufacture FACT-200

Polishing cloth: Nitta Haas IC-1010

Polishing platen rotation speed: 80 rpm

Holder speed: no drive (free rotation)

Polishing pressure: 33.83 kPa (345 gf / cm 2)

Polishing liquid supply amount: 16 ml / min

Polishing time: 5 minutes

Semiconductor substrate (abrasive): 2 cm square silicon wafer (P-type <100>)

[washing]

After polishing, the semiconductor substrate was washed with a polyvinyl alcohol brush and ultrasonic water. After washing, the semiconductor substrate was dried with a spin dryer.

[Measuring of polishing speed]

After polishing the silicon wafer by the above-described method using the polishing liquids for semiconductors of Examples 18 to 24 immediately after the blending, the amount of decrease in the mass of the silicon wafer accompanying the polishing was measured. The polishing rate (unit: nm / min) was calculated from the mass reduction amount, the wafer area, the specific gravity of silicon, and the polishing time. The calculation results are shown in Table 11. In addition, the electronic balance for analytical (Metro AB AB104) was used for the mass measurement of a silicon wafer. Measurement temperature was 25 degreeC, and measurement humidity was 40% RH or more. Silicon specific gravity was 2.33.

[Surface roughness evaluation]

After polishing the silicon wafer by the above-described method using the polishing liquids of Examples 18 to 24, the arithmetic mean roughness of the polished surface of the silicon wafer was measured under the following conditions by using a step, surface roughness and fine shape measuring device. It was. The measurement results are shown in Table 11.

(Measuring conditions)

Step, surface roughness, and fine shape measuring device: K16 Tenco manufactured P16-OF

Measurement Mode: Roughness

Measuring length: 200 μm

Measuring speed: 5 μm / sec

Measuring load: 1 mg

(Comparative Example 33)

The abrasive grain shown in following Table 12, the water-soluble polymer (water-soluble polymer), and an inorganic basic compound were mix | blended in the addition amount shown in Table 12 according to the following procedure, and the polishing liquid for semiconductors of the comparative example 33 was produced. In addition, 1,2,4-triazole was not added to the polishing liquid of Comparative Example 33.

In the production of the polishing liquid of Comparative Example 33, 0.05% by mass of polyvinylpyrrolidone (PVP_K30) is dissolved in pure water corresponding to 50% by mass of the whole polishing liquid, and potassium hydroxide is added thereto until the pH reaches 9. Added. Subsequently, 0.5 mass% of colloidal silica whose primary particle diameter was 17 nm was disperse | distributed, and it mix | blended so that it might become 95 mass% in total with pure water. And potassium hydroxide was added to desired pH, and the remainder was mix | blended so that it may become 100 mass% in total with pure water.

(Comparative Example 34)

The polishing particles, 1,2,4-triazole and the inorganic basic compound shown in Table 12 below were blended in the amounts shown in Table 12 according to the following procedure to prepare a polishing liquid for semiconductors of Comparative Example 2.

In addition, polyvinylpyrrolidone was not added to the polishing liquid of Comparative Example 34.

In the production of the polishing liquid of Comparative Example 34, 0.5 mass% of 1,2,4-triazole is dissolved in pure water corresponding to 50 mass% of the entire polishing liquid, and potassium hydroxide is added thereto until pH is 9. Added. Subsequently, 0.5 mass% of colloidal silica whose primary particle diameter was 17 nm was disperse | distributed, and it mix | blended so that it might become 95 mass% in total with pure water. And potassium hydroxide was added to desired pH, and the remainder was mix | blended so that it may become 100 mass% in total with pure water.

(Comparative Example 35)

The abrasive grain shown in Table 12 and an inorganic basic compound were mix | blended in the addition amount shown in Table 12 according to the following procedure, and the polishing liquid for semiconductors of the comparative example 35 was manufactured. In addition, 1,2,4-triazole and polyvinylpyrrolidone were not added to the polishing liquid of Comparative Example 35.

In manufacture of the polishing liquid of the comparative example 35, potassium hydroxide was added to the pure water corresponded to 50 mass% of the whole polishing liquid until the pH became 9. Subsequently, 0.5 mass% of colloidal silica whose primary particle diameter was 17 nm was disperse | distributed, and it mix | blended so that it might become 95 mass% in total with pure water. And potassium hydroxide was added to desired pH, and the remainder was mix | blended so that it may become 100 mass% in total with pure water.

In the same manner as in Example 18, the arithmetic mean roughness and maximum height of the surface of the semiconductor substrate after polishing using the pH and polishing rate of each of the polishing liquids for semiconductors of Comparative Examples 33 to 35, and each polishing liquid of Comparative Examples 33 to 35 Was measured. The measurement results are shown in Table 12.

In Example 19, compared with the comparative example 33 similar to Example 19 except having not containing 1,2,4-triazole, it was confirmed that a grinding | polishing rate is high, and arithmetic mean roughness and the maximum height are small. In Comparative Examples 34 and 35, it was confirmed that the arithmetic mean roughness and the maximum height were larger than those in Examples 18 to 24. In view of the above, it was confirmed in the present invention that the surface of the semiconductor substrate can be polished to a smooth and smooth surface at a high polishing rate.

<Polishing Solution for Fourth Semiconductor Substrate>

(Examples 25 to 36)

[Manufacture of Polishing Liquid for Semiconductor]

Abrasive particles, water-soluble polymers (water-soluble polymers), 1,2,4-triazole, and basic compounds were blended in the amounts shown in Table 13 below according to the following procedures, and each of the polishing liquids for semiconductors of Examples 25 to 36 Was prepared. Polyvinylpyrrolidone (PVP_K30) was used as a water-soluble polymer for manufacture of each polishing liquid. K value is a viscosity characteristic value related to molecular weight, and is a relative viscosity value at 25 ° C. measured by a capillary viscometer.

In the production of each polishing liquid, first, 1,2,4-triazole and polyvinylpyrrolidone (PVP) are dissolved in pure water corresponding to 50% by mass of the entire polishing liquid, and the basic compound has a pH of 9 Until it is added. Subsequently, after dispersing 0.3 mass% of colloidal silica having a primary particle diameter of 17 nm, the mixture was blended so as to have a total of 95 mass% with pure water. Then, the basic compound was added until the desired pH was reached, and the balance was combined so as to be 100% by mass in total.

[pH measurement]

The pH of each semiconductor polishing liquid of Examples 25-36 was measured similarly to Example 18. The pH of each polishing liquid for semiconductors is shown in Table 13.

[Adjustment of Polishing Semiconductor Substrate]

A silicon wafer 300 mm in diameter was polished under the following conditions, and the silicon wafer whose surface was polished was adjusted.

Polishing Wafer: 300mm Silicon Wafer

Polishing Machine: Reflexion (Applied Materials)

Polishing platen rotation speed: 123 rpm

Holder rpm: 117 rpm

Polishing pressure: 13.7 kPa

Polishing liquid supply amount: 250 ml / min

Polishing pad: SUBA600 (made by Nitta Haas)

Polishing liquid: 0.5% silica abrasive grain (primary particle diameter 17 nm), tetramethylammonium hydroxide (hereinafter referred to as "TMAH"), pH 10.5

Polishing time: 90 seconds

Polishing of Semiconductor Substrates

On the polishing cloth of the polishing platen, while supplying the polishing liquid for the semiconductor substrate of Example 25 immediately after the mixing, the surface of the semiconductor substrate was rotated relatively by rotating the polishing platen relative to the semiconductor substrate while the semiconductor substrate was pressed against the polishing cloth. Polished. In the same manner as in Example 25, the semiconductor substrate was polished using the polishing liquids of Examples 26 to 36 immediately after the formulation. The detail of grinding | polishing conditions is as follows.

(Polishing condition)

Abrasive wafer: 300 mm silicon wafer after rough polishing prepared above

Polishing Machine: Reflexion (Applied Materials)

Polishing platen rotation speed: 123 rpm

Holder rpm: 117 rpm

Polishing pressure: 9.7 kPa

Polishing liquid supply amount: 250 ml / min

Polishing pads: Supreme RN-H Pad 30.5 "D PJ; CX01 by Nitta Haas

Polishing time: 10 minutes

[washing]

After the polishing, the wafer was washed under the following conditions.

Washer: MESA (Applied Materials, Inc.)

Cleaning solution: 0.06% by volume ammonium hydroxide

Brush clean time: 60 seconds

[Measurement of defect function and haze value]

After polishing and cleaning a silicon wafer by the above-mentioned method using the polishing liquids of Examples 25 to 36, the values expressed as the number of defects and the haze (haze) value were measured using the following apparatus. The measurement results are shown in Table 13.

Defect inspection device: LS6700 (manufactured by Hitachi Denshi Engineer)

Process Condition File (Measuring Recipe): VeM10L

Defective measuring range: 0.1 μm-3.0 μm

Flooding condition: vertical

(Comparative Examples 36 to 39)

[Manufacture of Polishing Liquid for Semiconductor]

Abrasive particles, a water-soluble polymer (water-soluble polymer), 1,2,4-triazole, and a basic compound were blended in the addition amounts shown in Table 14 according to the following procedure, and each polishing liquid for semiconductors of Comparative Examples 36 to 39 was prepared. Prepared. Polyvinylpyrrolidone (PVP_K30) was used as a water-soluble polymer for manufacture of each polishing liquid. K value is a viscosity characteristic value related to molecular weight, and is a relative viscosity value at 25 ° C. measured by a capillary viscometer.

In the production of each polishing liquid, first, 1,2,4-triazole and polyvinylpyrrolidone (PVP) are dissolved in pure water corresponding to 50% by mass of the entire polishing liquid, and the basic compound has a pH of 9 Until it is added. Subsequently, after dispersing 0.3 mass% of colloidal silica having a primary particle diameter of 17 nm, the mixture was blended so as to have a total of 95 mass% with pure water. Then, the basic compound was added until the desired pH was reached, and the balance was combined so as to be 100% by mass in total.

In the same manner as in Example 25, the pH of each semiconductor polishing liquid of Comparative Examples 36 to 39 and the defect number and haze value of the surface of the silicon wafer after polishing using each polishing liquid of Comparative Examples 36 to 39 were measured. The measurement results are shown in Table 14.

In Examples 25-36, it was confirmed that not only the number of defects but also the value of the haze used as an index of surface roughness were small compared with Comparative Examples 36-39, and the unevenness | corrugation can be eliminated.

<5th Semiconductor Substrate Polishing Liquid>

(Examples 37 to 44)

[Manufacture of Polishing Liquid for Semiconductor]

Abrasive particles, water-soluble polymers (water-soluble polymers), 1,2,4-triazole and basic compounds were blended in the amounts shown in Table 15 below in accordance with the following procedures, and each of the polishing liquids for semiconductors of Examples 37 to 44. Was prepared. As the water-soluble polymer, any one of three kinds of polyvinylpyrrolidone (PVP_K15, PVP_K30, PVP_K90) having different K values was used for the production of each polishing liquid. K value is a viscosity characteristic value related with molecular weight, and is a relative viscosity value at 25 degreeC measured by a capillary viscometer.

In the production of each polishing liquid, first, 1,2,4-triazole and polyvinylpyrrolidone (PVP) are dissolved in pure water corresponding to 50% by mass of the entire polishing liquid, and the basic compound has a pH of 9 Until it is added. Subsequently, 0.5 mass% of colloidal silica whose primary particle diameter was 17 nm was disperse | distributed, and it mix | blended so that it might become 95 mass% in total with pure water. Then, the basic compound was added until the desired pH was reached, and the balance was combined so as to be 100% by mass in total.

[pH measurement]

The pH of each polishing liquid for semiconductors of Examples 37 to 44 was measured in the same manner as in Example 18. The pH of each polishing liquid for semiconductors is shown in Table 15.

Polishing of Semiconductor Substrates

On the polishing cloth of the polishing platen, while supplying the polishing liquid for the semiconductor substrate of Example 37 immediately after the mixing, the surface of the semiconductor substrate was rotated by relatively rotating the polishing platen relative to the semiconductor substrate while pressing the semiconductor substrate to the polishing cloth. Polished. In the same manner as in Example 37, the semiconductor substrate was polished using the polishing liquids of Examples 38 to 44 immediately after the formulation. The detail of grinding | polishing conditions is as follows.

(Polishing condition)

Abrasive wafer: 300 mm silicon wafer after grinding

Polishing Machine: Reflexion (Applied Materials)

Polishing platen rotation speed: 123 rpm

Holder rpm: 117 rpm

Polishing pressure: 13.7 kPa

Polishing liquid supply amount: 250 ml / min

Polishing pad: MH-S15C (made by Nitta Haas)

[washing]

After the polishing, the wafer was washed under the following conditions.

Washer: MESA (Applied Materials, Inc.)

Cleaning solution: 0.06% by volume ammonium hydroxide

Brush clean time: 60 seconds

[Measuring of polishing speed]

After polishing the silicon wafer by the above-described method, the amount of decrease in the mass of the silicon wafer accompanying the polishing was measured. The polishing rate (unit: nm / min) was calculated from the amount of mass reduction, wafer area (706.5 cm 2), specific gravity of silicon, and polishing time. In addition, the electronic balance for analytical (Metro AB AB104) was used for the mass measurement of a silicon wafer. Measurement temperature was 25 degreeC, and measurement humidity was 40% RH or more. Silicon specific gravity was 2.33. The measurement results are shown in Table 15.

[Surface roughness evaluation]

After polishing a silicon wafer by the above-mentioned method, defect evaluation of the polished surface of a silicon wafer was performed on condition of the following using the level | step difference, surface roughness, and a fine shape measuring apparatus. Also, the target polishing amount of the jaw wafer is L (nm), the initial step (maximum height) R _t0 (nm) of the jaw wafer is set, and the step (maximum height) R _t1 (nm) of the roughened jaw wafer is used. It was. The measurement results are shown in Table 15.

(Measuring conditions)

Step, surface roughness, and fine shape measuring device: K16 Tenco manufactured P16-OF

Measurement Mode: Roughness

Measuring length: 5 mm

Measuring load: 1 mg

(Comparative Examples 40 to 42)

[Manufacture of Polishing Liquid for Semiconductor]

Polishing particles, 1,2,4-triazole and basic compounds were blended in the amounts shown in Table 16 below in accordance with the following procedures to prepare polishing liquids for semiconductors of Comparative Examples 40 to 42.

In the production of each polishing liquid, 1,2,4-triazole was first dissolved in pure water corresponding to 50% by mass of the entire polishing liquid, and a basic compound was added thereto until the pH became 9. Next, in Comparative Example 40, 0.5 mass% of colloidal silica having a primary particle diameter of 36 nm was dispersed, and then blended so as to be 95 mass% in pure water. Then, the basic compound was added until the desired pH was reached, and the balance was combined so as to be 100% by mass in total. In Comparative Example 41, 0.5 mass% of colloidal silica having a primary particle diameter of 7 nm was dispersed, and then blended so as to be 95 mass% in pure water. Then, the basic compound was added until the desired pH was reached, and the balance was combined so as to be 100% by mass in total. In Comparative Example 42, 0.5 mass% of colloidal silica having a primary particle diameter of 17 nm was dispersed, and then blended so as to be 95 mass% in pure water. Then, the basic compound was added until the desired pH was reached, and the balance was combined so as to be 100% by mass in total. In addition, 1,2,4-triazole was not added to the comparative example 42.

In the same manner as in Example 37, the polishing rate measurement and the surface roughness evaluation when the silicon wafer was polished using the pH of each semiconductor polishing liquid of Comparative Examples 40 to 42 and each polishing liquid of Comparative Examples 40 to 42 Was performed. The measurement results are shown in Table 16.

Embodiment, 37 to 44 and the Comparative Examples 40 to 42 and is eliminated efficiency of the grinding traces of the polishing amount superior to L, the polishing after the grinding traces depth R _t1 was small. In other words, it was confirmed that the unevenness can be eliminated with a small amount of polishing.

The polishing liquids of Example 37 and Comparative Example 40 were polished again to investigate the polishing amount L and the grinding trace machinability in more detail (Example 45 and Comparative Example 43, respectively). The silicon wafer with grinding traces of about 1000 nm depth in advance is polished by dividing into seven times, and the portion (center) of 0 mm from the center of the wafer at each polishing amount L, and the portion of 60 mm from the center of the wafer (middle Middle; Middle, the maximum height Rt of the portion 120 mm from the center of the wafer (end 1; Edge 1) and the portion 140 mm from the center of the wafer (end 2; Edge 2) were measured and evaluated. Evaluation results are shown in Table 17 and Table 18, and FIGS. 11 and 12.

In Example 45, compared with the comparative example 43, the maximum height Rt with respect to the grinding | polishing amount L becomes low at a quick stage, and it turns out that the removal trace of a grinding trace is excellent.

Semiconductor substrate, wiring metal, silicon damage layer

Claims (25)

Containing abrasive particles, 1,2,4-triazole and a basic compound,
The basic compound is a nitrogen-containing basic compound or an inorganic basic compound,
Content of the said basic compound is 0.1 mass% or more,
pH is 9 or more and 12 or less
Polishing liquid for silicone materials. The nitrogen-containing basic compound according to claim 1, wherein the nitrogen-containing basic compound contains ammonium hydroxide or tetramethylammonium hydroxide.
Polishing liquid for silicone materials. The inorganic basic compound according to claim 1 or 2, wherein the inorganic basic compound contains potassium hydroxide or sodium hydroxide.
Polishing liquid for silicone materials. A modified silica whose surface is modified by aluminate, and an inorganic basic compound,
Content of the said modified silica is 0.01 mass% or more and 1.5 mass% or less,
pH is 9 or more and 12 or less
Polishing liquid for silicone materials. The method of claim 4, wherein the primary particle diameter of the modified silica is 7 to 50 nm.
Polishing liquid for silicone materials. The inorganic basic compound according to claim 4 or 5, wherein the inorganic basic compound contains potassium hydroxide or sodium hydroxide.
Polishing liquid for silicone materials. The method of claim 4 or 5, further comprising 1,2,4-triazole.
Polishing liquid for silicone materials. A method of polishing a semiconductor substrate for forming a silicon through via,
Forming a recess in one side of the silicon substrate;
Embedding a metal in the recess;
Backgrinding the other side of the silicon substrate;
Polishing of the semiconductor substrate provided with the grinding | polishing process of grind | polishing the said other surface so that the said metal may be exposed using the polishing liquid for silicon materials as described in any one of Claims 1, 2, 4, and 5. Way. After lapping or grinding the silicon wafer obtained by slicing a silicon single crystal ingot, etching the silicon wafer to prepare a rough wafer;
A polishing method of a semiconductor substrate, comprising a rough polishing step of polishing the jaw wafer by using the polishing liquid for silicon material according to any one of claims 1, 2, 4, and 5. As a method of polishing a semiconductor substrate for reuse,
Wet etching the silicon wafer to which the deposit is attached;
A polishing method of a semiconductor substrate comprising a rough polishing step of polishing the wet-etched silicon wafer using the polishing liquid for silicon material according to any one of claims 1, 2, 4, and 5. . Containing abrasive particles, 1,2,4-triazole, a water-soluble polymer, and a basic compound,
pH is 9 or more and 12 or less
Polishing liquid for silicone materials. The content of the water-soluble polymer is 0.001% by mass or more and 10% by mass or less with respect to the total mass of the polishing liquid for a silicon material.
Polishing liquid for silicone materials. The content of the 1,2,4-triazole is 0.01% by mass or more and 10% by mass or less based on the total mass of the polishing liquid for a silicon material.
Polishing liquid for silicone materials. Containing abrasive particles, 1,2,4-triazole, a water-soluble polymer, and a basic compound,
Content of the said 1,2,4-triazole is 0.05 mass% or more and 0.5 mass% or less with respect to the total mass of the polishing liquid for silicone materials,
Content of the said water-soluble polymer is 0.001 mass% or more and 0.1 mass% or less with respect to the total mass of the polishing liquid for silicone materials,
pH is 9 or more and 12 or less
Polishing liquid for silicone materials. After lapping or grinding the silicon wafer obtained by slicing a silicon single crystal ingot, etching the silicon wafer to prepare a rough wafer;
A rough polishing step of polishing the jaw wafer;
A polishing method of a semiconductor substrate, comprising a finishing polishing step of further polishing a silicon wafer after the rough polishing step using the polishing liquid for silicon material according to any one of claims 11, 12, and 14. As a method of polishing a semiconductor substrate for reuse,
Wet etching the silicon wafer to which the deposit is attached;
An abrasive polishing process for polishing the wet etched silicon wafer;
A polishing method of a semiconductor substrate, comprising a finishing polishing step of further polishing a silicon wafer after the rough polishing step using the polishing liquid for silicon material according to any one of claims 11, 12, and 14. Containing abrasive particles, 1,2,4-triazole, a water-soluble polymer, and a basic compound,
Content of the said 1,2,4-triazole is 0.2 mass% or more and 3.0 mass% or less with respect to the total mass of the polishing liquid for silicone materials,
Content of the said water-soluble polymer is 0.01 mass% or more and 0.2 mass% or less with respect to the total mass of the polishing liquid for silicone materials,
pH is 9 or more and 12 or less
Polishing liquid for silicone materials. As a method of polishing a semiconductor substrate for reuse,
Preparing a jaw wafer by grinding the silicon wafer after wet etching the silicon wafer to which the deposit is attached;
The polishing method of the semiconductor substrate provided with the rough grinding process which grinds the said rough wafer using the polishing liquid for silicon materials as described in any one of Claims 11, 12, and 17. 19. The method of claim 18, wherein in the rough polishing step, the polishing amount of the jaw wafer is L (nm), the initial step of the jaw wafer is set to R _t0 (nm), and the step of the roughened jaw wafer is in the case of _{R t1 (nm), R t0} ≤L≤R when polishing a wafer by action _t0 × 1.3 L (nm) to _{meet, L / (R t0 -R t1} ) ≤1.3 and R _t1 ≤100 A method of polishing a semiconductor substrate, which satisfies (nm) together. 19. The method of claim 18, further comprising a finish polishing step of polishing the rough wafer after the rough polishing step by using a polishing liquid,
The polishing liquid contains abrasive particles, 1,2,4-triazole, a water-soluble polymer, and a basic compound,
pH is 9 or more and 12 or less
Polishing method of a semiconductor substrate. 19. The method of claim 18, further comprising a finish polishing step of polishing the rough wafer after the rough polishing step by using a polishing liquid,
The polishing liquid contains abrasive particles, 1,2,4-triazole, a water-soluble polymer, and a basic compound,
Content of the said 1,2,4-triazole is 0.05 mass% or more and 0.5 mass% or less with respect to the total mass of a polishing liquid,
Content of the said water-soluble polymer is 0.001 mass% or more and 0.1 mass% or less with respect to the total mass of a polishing liquid,
pH is 9 or more and 12 or less
Polishing method of a semiconductor substrate. The method according to any one of claims 11, 12, 14 and 17, wherein the water-soluble polymer is a nonionic polymer.
Polishing liquid for silicone materials. The nonionic polymer according to claim 22, wherein the nonionic polymer is at least one selected from a copolymer of polyvinylpyrrolidone and polyvinylpyrrolidone.
Polishing liquid for silicone materials. The mixture according to any one of claims 11, 12, 14 and 17, wherein the water-soluble polymer comprises at least one selected from copolymers of polyvinylpyrrolidone and polyvinylpyrrolidone. sign
Polishing liquid for silicone materials. delete

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