JP2011029515A - Abrasive, polishing method, and method of manufacturing semiconductor integrated circuit device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an abrasive which is suitable for chemically and mechanically polishing a surface to be polished, containing single-crystal silicon and ensures improvement in controllability of a polishing speed in a method of manufacturing a semiconductor integrated circuit device, and to provide a polishing method. <P>SOLUTION: The abrasive is the one for chemically and mechanically polishing the surface to be polished, containing the single-crystal silicon, and contains cerium oxide particles and water-soluble polyamine and has a pH of 8 to 13. In the polishing method, the abrasive is supplied to a polishing pad and the surface to be polished, containing the single-crystal silicon, of the semiconductor integrated circuit device is brought into contact with the polishing pad to perform polishing by relative movement, and the surface to be polished is polished using the abrasive which contains the cerium oxide particles and water-soluble polyamine and has the pH of 8 to 13. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an abrasive, a polishing method, and a method for manufacturing a semiconductor integrated circuit device for chemically and mechanically polishing a surface to be polished containing single crystal silicon. More specifically, in the manufacture of a semiconductor integrated circuit device, a polishing agent for polishing a surface to be polished containing single crystal silicon such as a silicon substrate by a chemical mechanical polishing method and controlling the thickness of the substrate with high accuracy. The present invention relates to a polishing method and a method for manufacturing a semiconductor integrated circuit device using the polishing method.

  In recent years, it is necessary to realize higher-density packaging in order to promote higher integration and higher functionality of semiconductor integrated circuit devices. Therefore, development of a highly accurate thinning technique for a semiconductor integrated circuit substrate is required. In particular, the importance of a technique of polishing with high accuracy by a chemical mechanical polishing method (hereinafter referred to as CMP) after thinning with a grindstone or the like is increasing.

  For example, a standard 200 mm (8 inch) silicon substrate has a thickness of about 725 μm, and a 300 mm (12 inch) silicon substrate has a thickness of about 775 μm. In order to mount many chips in one package, After the semiconductor integrated circuit is formed on the surface of the silicon substrate, the silicon substrate may be thinned to a thickness of 20 μm or less. In such thinning, CMP is often used in order to polish the silicon substrate to a final thickness after grinding the silicon substrate to near the target thickness with a grinder.

  Conventionally, as a polishing agent for polishing a surface to be polished containing single crystal silicon such as a silicon substrate, a composition comprising abrasive grains composed of at least one of fumed silica and colloidal silica, and an amine which is a basic compound. The thing is proposed (for example, refer patent document 1). However, when this composition is used, it can be polished at a high speed by a chemical etching action, but if the polishing conditions such as the polishing pressure, the polishing surface plate, and the rotation speed of the polishing head are changed, the polishing is performed. Since the speed changes in a wide range from low speed to high speed, there is a problem that it is difficult to control the polishing speed.

  As described above, silicon oxide particles such as fumed silica and colloidal silica are often used as abrasive grains for high-precision abrasives of silicon crystals, while abrasives for polishing a silicon dioxide film at high speed. It is known to use cerium oxide particles as the grains. A technique for polishing polycrystalline silicon using cerium oxide particles has also been proposed (see Patent Document 2).

  However, it has been considered that such cerium oxide particles cannot be used as abrasive grains for polishing single crystal silicon having no crystal grain boundaries. That is, the polishing rate of the silicon crystal using cerium oxide particles is extremely slow, and the polishing hardly proceeds. Polycrystalline silicon is an aggregate of microcrystals separated by grain boundaries. Since the surface area of crystal grains is large and active, polishing is promoted in polycrystalline silicon, but there is no grain boundary in single crystal silicon. Since the surface was smooth, it was considered difficult to polish using cerium oxide particles.

JP 49-1111580 A International Publication No. 2006-098141 Pamphlet

  The present invention has been made to solve these problems, and is suitable for chemically and mechanically polishing a surface to be polished containing single crystal silicon in the manufacture of a semiconductor integrated circuit device. An object of the present invention is to provide an abrasive and a polishing method with improved properties.

  The inventors of the present invention have been able to effectively polish single crystal silicon by an abrasive that contains cerium oxide particles, a water-soluble polyamine, and water, and has a pH within a predetermined range, through repeated experiments and studies. I found that I can do it.

  A first aspect of the present invention is an abrasive for chemically and mechanically polishing a surface to be polished containing single crystal silicon, containing cerium oxide particles, a water-soluble polyamine, and water, each having a pH of 8 to It is characterized by being in the range of 13.

  According to a second aspect of the present invention, a polishing agent is supplied to a polishing pad, a surface to be polished containing single crystal silicon of a semiconductor integrated circuit device is brought into contact with the polishing pad, and polishing is performed by relative movement between the two. And the abrasive | polishing agent of a said 1st aspect is used as the said abrasive | polishing agent, It is characterized by the above-mentioned.

  A third aspect of the present invention is a method for manufacturing a semiconductor integrated circuit device, and the second aspect also includes a step of polishing a surface to be polished containing single crystal silicon by a polishing method.

  According to the present invention, in the manufacture of a semiconductor integrated circuit device, a surface to be polished containing single crystal silicon can be polished by precisely controlling the polishing rate, and the surface to be polished is highly planarized without polishing scratches. Can be obtained. Further, an abrasive having a sufficient polishing rate can be obtained even if the abrasive concentration is low.

It is a figure which shows an example of the grinding | polishing apparatus which can be used for the grinding | polishing method of this invention. It is a graph which shows the relationship between the grinding | polishing pressure and the grinding | polishing speed | velocity obtained by the Example and comparative example of this invention. It is a graph which shows the relationship between the rotation speed of a polishing surface plate, and polishing speed obtained by the Example and comparative example of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, tables, formulas, examples and the like. In addition, these figures, tables, formulas, examples, and descriptions illustrate the present invention, and do not limit the scope of the present invention. Other embodiments may belong to the category of the present invention as long as they meet the gist of the present invention. Moreover, in the figure, the same code | symbol represents the same element.

  The abrasive according to the present invention is an abrasive for chemically and mechanically polishing a surface to be polished including a surface made of single crystal silicon in the manufacture of, for example, a semiconductor integrated circuit device (hereinafter also referred to as a semiconductor device). The cerium oxide particles, water-soluble polyamine and water are contained, and the pH is in the range of 8-13. This abrasive may contain a dispersant.

  In the abrasive of the present invention, cerium oxide particles are used as abrasive grains. In the basic case, silanol groups are formed on the surface of the single crystal silicon due to the presence of the amine substance. Therefore, the polishing action by the chemical reaction is enhanced by using cerium oxide particles as abrasive grains instead of the conventional silica particles. Therefore, the polishing agent of the present invention exhibits a high (large) polishing rate relative to single crystal silicon.

  As the cerium oxide particles contained in the abrasive of the present invention, for example, cerium oxide particles disclosed in JP-A-11-12561 or JP-A-2001-35818 can be used. That is, a cerium oxide powder obtained by adding alkali to a cerium (IV) ammonium nitrate aqueous solution to form a cerium hydroxide gel, followed by filtration, washing and firing in this order can be used. Further, cerium oxide particles obtained by pulverizing and baking high-purity cerium carbonate, and further pulverizing and classifying the cerium carbonate can also be used, but are not particularly limited thereto.

  The average particle diameter (diameter) of the cerium oxide particles is 0.01 to 0.5 μm, particularly 0.02 to 0.3 μm, more preferably 0.05 to 0.2 μm, from the viewpoint of polishing characteristics and dispersion stability. It is preferable. If the average particle size is too large, scratches such as scratches are likely to occur on the surface to be polished containing single crystal silicon (for example, the surface of the semiconductor substrate). If the average particle size is too small, not only the polishing rate may be lowered, but also the ratio of the surface area per unit volume increases, so it is easily affected by the surface condition, and depending on conditions such as pH and additive concentration Aggregates easily. When aggregation occurs, polishing scratches such as scratches are likely to occur on the surface to be polished.

  The concentration (content ratio) of the cerium oxide particles in the abrasive of the present invention is preferably in the range of 0.0001 to 10.0% by mass in order to obtain a sufficient effect for controlling the polishing rate.

  As the water-soluble polyamine contained in the abrasive of the present invention, any water-soluble compound having two or more primary, secondary, or tertiary amino groups in one molecule can be used. be able to. The degree of water solubility of the polyamine compound may be any degree as long as it is completely dissolved in the abrasive liquid at the concentration used as the abrasive. Usually, it is a substance that dissolves in pure water by 1% by mass or more, preferably 5% by mass or more. Specifically, at least one selected from the group consisting of water-soluble polyether polyamine, water-soluble polyalkylene polyamine, polyethyleneimine, water-soluble polyvinylamine, water-soluble polyallylamine, water-soluble polylysine and water-soluble chitosan is preferable. . Particularly preferred water-soluble polyamines are water-soluble polyether polyamines and water-soluble polyalkylene polyamines. The water-soluble polyalkylene polyamines may include those having a cyclic structure in production, but in the present invention, amines having these cyclic structures can also be used as the water-soluble polyamine.

  The molecular weight of the water-soluble polyamine is not limited as long as the molecular weight is in the range showing water solubility, but the weight average molecular weight (Mw) is preferably in the range of 100 to 100,000, and in the range of 100 to 2000. More preferably. When Mw is less than 100, the blending effect is small. When Mw exceeds 100,000, even if it is water-soluble, it may adversely affect physical properties such as fluidity of the abrasive. Furthermore, when Mw exceeds 200, the solubility in pure water often decreases. Particularly preferred water-soluble polyamines are water-soluble polyether polyamines and water-soluble polyalkylene polyamines having an Mw of 100 to 2000.

  When water-soluble polyamine is added to the abrasive, polishing of single crystal silicon is promoted. This is considered to be due to the adsorption effect of water-soluble polyamine (for example, polyoxypropylenediamine) on the surface of the cerium oxide particles and the surface of the surface to be polished. Due to the chemical changes caused by such water-soluble polyamines, silanol groups are formed on the surface of single-crystal silicon, which makes it easy to be removed by the mechanical and chemical action of cerium oxide particles, which are abrasive grains. It is considered that polishing is promoted. Such a polishing mechanism is the same mechanism in which a hydrated layer on the surface of a silicate compound such as glass is polished at high speed by cerium oxide particles. As described above, in the polishing agent of the present invention, polishing is promoted not only by the chemical etching action by the water-soluble polyamine but also by the mechanical action of the cerium oxide particles, so that the polishing conditions such as the polishing pressure and the rotational speed are changed. Thus, precise control of the polishing rate can be easily performed.

  More preferable Mw of the water-soluble polyether polyamine and the water-soluble polyalkylene polyamine is 150 to 800 from the viewpoint that the dispersion stabilizing effect on the cerium oxide particles is high, and more preferable Mw is 150 to 400.

Here, the polyether polyamine means a compound having two or more primary, secondary or tertiary amino groups and two or more etheric oxygen atoms. A secondary amino group (—NH—: referred to as imino group) or a tertiary amino group may be used, but a primary amino group (—NH ₂ ) is more preferable. That is, the polyether polyamine in the present invention is preferably a compound having two or more primary amino groups and substantially not having a secondary amino group or a tertiary amino group. The use of two polyether diamines is preferred.

  The polyether polyamine is preferably a compound having a structure in which a hydrogen atom in a hydroxyl group of a polyhydric alcohol or polyether polyol is substituted with an aminoalkyl group. Here, as the polyhydric alcohol, a divalent to hexavalent alcohol, particularly, a divalent alcohol is preferable. As the polyether polyol, a divalent to hexavalent polyoxyalkylene polyol, particularly, a polyoxyalkylene diol is preferable. More specifically, the polyhydric alcohol is preferably a dihydric alcohol having 2 to 8 carbon atoms which may have an etheric oxygen atom, such as ethylene glycol, diethylene glycol, propylene glycol and dipropylene glycol. Polyether polyols include polyethylene glycols such as triethylene glycol and tetraethylene glycol (ie, polyoxyethylene diol), polypropylene glycols such as tripropylene glycol and tetrapropylene glycol (ie, polyoxypropylene diol), It is preferable to use a polyether diol in which the repeating unit is an oxyalkylene group having 2 to 6 carbon atoms, such as a polyoxyalkylene diol having two or more oxyalkylene groups such as poly (oxypropylene / oxyethylene) diol. Examples of aminoalkyl groups include 2-aminoethyl group, 2-aminopropyl group, 2-amino-1-methylethyl group, 3-aminopropyl group, 2-amino-1,1-dimethylethyl group, 4-aminobutyl. A C2-C6 aminoalkyl group such as a group is preferred.

  The polyalkylene polyamine means a compound in which three or more primary, secondary or tertiary amino groups are bonded via an alkylene group. A compound in which a primary amino group is bonded to the molecular end and a secondary amino group is bonded in the molecule (intermediate part) is preferable. A more preferred polyalkylene polyamine is a linear polyalkylene polyamine having a primary amino group at both ends of the molecule and one or more secondary amino groups in the molecule. There will be two or more binding moieties consisting of an alkylene group sandwiched between two amino groups, but these inter-amino group binding moieties may be the same or different from each other. All are the same, or the two amino group-bonding moieties bonded to the primary amino groups at both ends are preferably the same and different from the other amino group-bonding moieties. The number of carbon atoms contained in one amino group-bonding moiety is preferably 2-8, and in particular, the number of carbon atoms contained in two amino-amino group bonding moieties bonded to the primary amino groups at both ends is 2-8, and the others 2-6 are preferable as carbon number contained in the coupling | bond part between amino groups.

As the polyether diamine and polyalkylene polyamine, a compound represented by the following formula (1) (hereinafter also referred to as compound (1)) is preferable.
H ₂ N— (R—X—) _k —R—NH ₂ (1)

  In the formula, R represents an alkylene group having 2 to 8 carbon atoms, and X represents an oxygen atom or a secondary amino group (—NH—). When X is an oxygen atom, the compound represented by the formula (1) is a polyether diamine, and when X is a secondary amino group (—NH—), the compound represented by the formula (1) is a poly It is an alkylene polyamine. And when a compound (1) is polyetherdiamine, k represents the integer of 2-41, and when a compound (1) is a polyalkylene polyamine, k represents the integer of 1-41. A plurality of R in one molecule may be the same as or different from each other.

In particular, the polyether diamine is preferably a compound represented by the following formula (2) (hereinafter also referred to as the compound (2)), and the polyalkylene polyamine is a compound represented by the following formula (3) (hereinafter referred to as “polyether diamine”). And also shown as compound (3)).
H ₂ N—R ² —O— (R ¹ —O—) _m —R ² —NH ₂ (2)
H ₂ N—R ⁴ —NH— (R ³ —NH—) _n —R ⁴ —NH ₂ (3)

In the formula, R ¹ represents an ethylene group or a propylene group, R ² represents an alkylene group having 2 to 6 carbon atoms, and m represents an integer of 1 to 40. R ¹ and R ² may be the same or different. R ³ represents an alkylene group having 2 to 6 carbon atoms, R ⁴ represents an alkylene group having 2 to 8 carbon atoms, and n represents an integer of 1 to 40. R ³ and R ⁴ may be the same or different.

Specific examples of the polyether diamine represented by the formula (2) include polyoxypropylene diamine (R ¹ and R ² are propylene groups, m is a compound having 1 to 40), polyoxyethylene diamine (R ¹ and R ² are An ethylene group, m is a compound having 1 to 40), 4,7,10-trioxa-tridecane-1,13-diamine (a compound in which R ¹ is an ethylene group, R ² is a trimethylene group, and m is 2). Specific examples of the polyalkylene polyamine represented by the formula (3) include tetraethylenepentamine (R ³ and R ⁴ are ethylene groups, n is a compound of 2), pentaethylenehexamine (R ³ and R ⁴ are An ethylene group, a compound in which n is 3), heptaethyleneoctamine (a compound in which R ³ and R ⁴ are ethylene groups and n is 5), N, N′-bis (3-aminopropyl) -ethylenediamine (R ³ is ethylene) Group, R ⁴ is a trimethylene group, n is a compound of 1), N, N′-bis (2-aminoethyl) -1,4-butanediamine (R ³ is a tetramethylene group, R ⁴ is an ethylene group, and n is 1 compound).

  The concentration (content ratio) of the water-soluble polyamine in the abrasive of the present invention is preferably set appropriately in consideration of the polishing rate, the uniformity of the abrasive slurry, the Mw of the water-soluble polyamine, and the like. From the viewpoint of obtaining a sufficient effect of controlling the polishing rate, a range of 0.001 to 20% by mass is preferable. The range of 0.01-5 mass% is more preferable, and the range of 0.05-2 mass% is especially preferable.

  The abrasive of the present invention contains water as a dispersion medium for cerium oxide particles that are abrasive grains. The water is not particularly limited, but it is preferable to use pure water, ultrapure water, ion-exchanged water, or the like from the viewpoint of influence on other components, mixing of impurities, and less influence on pH and the like. .

  The abrasive of the present invention is used in a basic pH range. In consideration of the polishing characteristics and the dispersion stability of the abrasive grains, it is preferable to adjust the pH within the range of 8-13. When the pH of the abrasive is less than 8, the dispersibility may be lowered. On the other hand, when the pH exceeds 13, there is no problem in polishing characteristics, but there is a possibility that the surface to be polished is affected. That is, although the polishing rate is high, not only the surface to be polished is likely to be scratched but also the operability (handling property) may be deteriorated.

  In the abrasive | polishing agent of this invention, pH can be adjusted to the said range by mix | blending an acid. Examples of acids that can be incorporated into the abrasive include inorganic acids such as nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, boric acid, and carbonic acid, and organic acids such as oxalic acid, citric acid, formic acid, acetic acid, and benzenesulfonic acid. it can. The valence of these acids is preferably 10 or less, more preferably an acid having a valence of 8 or less, more preferably an acid having a valence of 5 or less. When an acid within this range is used, dissociation is good and the amount of acid added can be suppressed.

  The abrasive of the present invention may contain other components. A typical component that can be included is a dispersant. A dispersant is added to stably disperse cerium oxide particles in a dispersion medium such as pure water.

  As the dispersant, an anionic, cationic, nonionic or amphoteric surfactant or a water-soluble polymer having a surfactant activity can be used. Here, the surfactant means one having a weight average molecular weight (Mw) of 500 or less. In the present invention, the surfactant and the water-soluble polymer having a surfactant action do not contain compounds having primary, secondary and tertiary amino groups.

  Examples of surfactants having an Mw of 500 or less include alkylbenzene sulfonates, tetraalkylammonium salts, polyoxyethylene alkyl ethers, and the like. Examples of the water-soluble polymer having a surface active action include water-soluble polymers having a carboxylate group such as polyacrylate and other water-soluble polymers such as polyvinylpyrrolidone. In particular, a water-soluble polymer having an ammonium carboxylate base is preferable. Specifically, a polymer in which at least a part of the carboxylic acid group of polyacrylic acid is substituted with a carboxylic acid ammonium base (hereinafter, referred to as ammonium polyacrylate) is exemplified. The Mw of the water-soluble polymer having a surface active action is preferably more than 500, and particularly preferably in the range of 800 to 100,000.

  When such a dispersant (including a water-soluble polymer having a dispersing action) is used, the blending ratio is preferably 0.1 to 2.0% by mass with respect to the mass of the cerium oxide particles. It is more preferable to set it as 3-1.5 mass%. When the blending ratio of the dispersant is less than 0.1% by mass, the dispersibility of the cerium oxide particles that are abrasive grains tends to be insufficient. Further, when the blending ratio of the dispersant exceeds 2.0% by mass, the flatness of the surface to be polished and the polishing rate are easily affected.

  The abrasive according to the present invention does not necessarily have to be supplied to the polishing step as a mixture of all the constituent components. Only when it is supplied to the polishing step, all the constituent components may be mixed to form a composition of an abrasive. For example, it is divided into a liquid containing cerium oxide particles, water and, if necessary, an acid and a dispersing agent (for example, ammonium polyacrylate) and a liquid containing a water-soluble polyamine, and the mixing ratio is adjusted appropriately during polishing. May be used. Further, the two liquids divided by other division methods may be mixed and used by appropriately adjusting the ratio. For example, an abrasive may be prepared by adding an acid to a liquid in which cerium oxide particles, a water-soluble polyamine, water and, if necessary, a dispersant are mixed for pH adjustment.

  When the surface to be polished of the semiconductor device includes a surface made of single crystal silicon, the polishing rate can be easily controlled by using the abrasive of the present invention. Therefore, in manufacturing a semiconductor device, it is possible to control the polishing thickness with high accuracy when polishing a surface to be polished containing single crystal silicon. Moreover, since the abrasive | polishing agent of this invention does not have aggregation of the cerium oxide particle | grains which are abrasive grains, it is excellent also in the dispersion stability and the point which does not generate | occur | produce a polishing defect.

  The abrasive | polishing agent of this invention is especially useful when grind | polishing in order to make the back surface of the silicon substrate formed in the semiconductor device into thin pieces.

  When polishing the polished surface of a semiconductor device containing single crystal silicon using the polishing agent of the present invention, the polishing agent is supplied to the polishing pad, the polished surface of the semiconductor device and the polishing pad are brought into contact with each other, Polishing by relative movement between.

  In the polishing method of the present invention, a known polishing apparatus can be used as the polishing apparatus. FIG. 1 is a diagram showing an example of a polishing apparatus that can be used in an embodiment of the present invention. The polishing apparatus includes a polishing head 2 that holds a semiconductor device 1 having a surface to be polished containing single crystal silicon, a polishing surface plate 3, a polishing pad 4 that is attached to the surface of the polishing surface plate 3, and a polishing pad. 4 is provided with an abrasive supply pipe 6 for supplying the abrasive 5. Then, the semiconductor device 1 held by the polishing head 2 is brought into contact with the polishing pad 4, and the polishing head 2 and the polishing surface plate 3 are relatively rotated to perform polishing. Note that the polishing apparatus used in the embodiment of the present invention is not limited to such a structure.

  The polishing head 2 may perform a linear motion as well as a rotational motion. Further, the polishing surface plate 3 and the polishing pad 4 may be as large as or smaller than the semiconductor device 1. In that case, it is preferable that the entire surface of the semiconductor device 1 can be polished by relatively moving the polishing head 2 and the polishing surface plate 3. Furthermore, the polishing surface plate 3 and the polishing pad 4 do not have to perform rotational movement, and may move in one direction, for example, by a belt type.

  The polishing conditions of such a polishing apparatus are not particularly limited, but by applying a load to the polishing head 2 and pressing it against the polishing pad 4, the polishing pressure can be further increased and the polishing rate can be improved. The polishing pressure is preferably about 0.5 to 50 kPa, and more preferably about 3 to 40 kPa from the viewpoint of preventing polishing defects such as uniformity in the semiconductor device 1 at the polishing rate, flatness, and scratches. The number of rotations of the polishing surface plate 3 and the polishing head 2 is preferably about 50 to 500 rpm, but is not limited thereto.

  As the polishing pad 4, one made of a general nonwoven fabric, foamed polyurethane, porous resin, non-porous resin or the like can be used. Further, in order to promote the supply of the polishing agent 5 to the polishing pad 4 or to collect a certain amount of the polishing agent 5 on the polishing pad 4, the surface of the polishing pad 4 has a lattice shape, a concentric circle shape, a spiral shape, or the like. Groove processing may be performed.

  Examples of the present invention will be described below. In the examples, “%” means mass% unless otherwise specified. The characteristic values are measured and evaluated by the following methods.

[PH]
Measurement was performed at 25 ° C. using pH81-11 manufactured by Yokogawa Electric Corporation.

[Average grain size of abrasive grains]
It calculated | required using the laser scattering / diffraction apparatus (The Horiba make, brand name LA-920).

[Polishing properties]
(1) Polishing conditions Polishing was performed using a fully automatic CMP polishing apparatus (product name: Mirra, manufactured by Applied Materials). The polishing pad used was a 2-layer pad IC-1010 K-groove manufactured by Rodel, and MEC100-PH3.5L manufactured by Mitsubishi Materials was used for conditioning the polishing pad. The supply rate of the abrasive was 200 ml / min, and the polishing time was 5 minutes.

(2) Object to be polished Using an 8-inch silicon wafer substrate with a single-side mirror finish, the polishing characteristics of the abrasive were measured.

(3) Measurement / evaluation method of polishing characteristics For measurement of the polishing rate, a film thickness meter UV-1280SE manufactured by KLA-Tencor was used. For measurement of the surface roughness of the polished surface after polishing, an atomic force microscope Dimension 3100 manufactured by Veeco was used.

Examples 1-7
Abrasive grain cerium oxide particles, dispersant Mw5000 ammonium acrylate, water-soluble polyamine pentaethylenehexamine (trade name pentaethylenehexamine: product of pentaethylenehexamine and cyclic amine, manufactured by Wako Pure Chemical Industries, Ltd.) The content ratio of pentaethylenehexamine is 40-50%) and nitric acid are mixed with stirring in deionized water, and the concentration (content ratio) of cerium oxide particles with respect to the total mass of the liquid is 0.25%, Abrasive A having a concentration of ammonium polyacrylate of 530 ppm, a concentration of nitric acid of 240 ppm, and a concentration of pentaethylenehexamine (mixture with cyclic amine) of 0.10% was prepared. The pH of this abrasive A was 9.9, and the average particle diameter of the cerium oxide particles as the abrasive grains was 0.17 μm.

  Next, the polishing characteristics (polishing speed of the 8-inch silicon wafer substrate) of the abrasive A thus obtained were measured by changing the polishing pressure and the rotation speed of the polishing platen and the polishing head. The measurement results are shown in Table 1.

Example 8
The concentration (content ratio) of cerium oxide particles with respect to the total mass of the liquid is 500 ppm, the concentration of ammonium polyacrylate is 106 ppm, the concentration of nitric acid is 48 ppm, and the concentration of pentaethylenehexamine (a mixture with cyclic amine) is 0.10%. Abrasive B was prepared. The polishing characteristics were measured at a polishing pressure of 20.7 kPa, a polishing platen rotating speed of 127 rpm, and a polishing head rotating speed of 123 rpm. The measurement results are shown in Table 1.

Example 9
The concentration (content ratio) of cerium oxide particles with respect to the total mass of the liquid is 125 ppm, the concentration of ammonium polyacrylate is 27 ppm, the concentration of nitric acid is 12 ppm, and the concentration of pentaethylenehexamine (mixture with cyclic amine) is 0.10%. Abrasive C was prepared. The polishing characteristics were measured at a polishing pressure of 20.7 kPa, a polishing platen rotating speed of 127 rpm, and a polishing head rotating speed of 123 rpm. The measurement results are shown in Table 1.

Example 10
The concentration (content ratio) of cerium oxide particles with respect to the total mass of the liquid is 25 ppm, the concentration of ammonium polyacrylate is 5 ppm, the concentration of nitric acid is 2 ppm, and the concentration of pentaethylenehexamine (mixture with cyclic amine) is 0.10%. Abrasive D was prepared. The polishing characteristics were measured at a polishing pressure of 20.7 kPa, a polishing platen rotating speed of 127 rpm, and a polishing head rotating speed of 123 rpm. The measurement results are shown in Table 1.

Examples 11-15
The concentration (content ratio) of cerium oxide particles with respect to the total mass of the liquid is 6 ppm, the concentration of ammonium polyacrylate is 1 ppm, the concentration of nitric acid is 1 ppm, and the concentration of pentaethylenehexamine (mixture with cyclic amine) is 0.10%. Abrasive E was prepared. Next, the polishing characteristics (polishing speed of the 8-inch silicon wafer substrate) of the abrasive E thus obtained were measured by changing the polishing pressure and the rotation speed of the polishing platen and the polishing head. The measurement results are shown in Table 1.

Comparative Examples 1-7
Using polishing agent F (Planetite 6103 manufactured by Fujimi Incorporated) containing colloidal silica, water and a basic organic compound, the polishing pressure and the number of rotations of the polishing platen and the polishing head were set in the same manner as in Examples 1-7. At the same time, the polishing characteristics were measured. The measurement results are shown in Table 1.

  Next, in the measurement results shown in Table 1, the polishing speeds of Examples 3, 4 and 7 were determined using the polishing agent A, the rotation speed of the polishing platen was 127 rpm, and the rotation speed of the polishing head was 123 rpm. Plotted against. This graph is shown as abrasive A in FIG. For comparison, the polishing rate of Comparative Examples 3, 4 and 7 in which the polishing agent F was used and the rotation speeds of the polishing platen and the polishing head were the same as those in Examples 3, 4 and 7, was compared with the polishing pressure. The graph plotted in this manner is shown in FIG.

  Further, in the measurement results shown in Table 1, the polishing rates of Examples 5, 6 and 7 in which the polishing agent A was used and the polishing pressure was 27.6 kPa were plotted against the number of rotations of the polishing platen. This graph is shown as abrasive A in FIG. For comparison, the polishing rate of Comparative Examples 5, 6 and 7 using the polishing agent F and the polishing pressure of 27.6 kPa as in Examples 5, 6 and 7 is the rotation speed of the polishing platen. The plotted graph is shown in FIG.

  The following can be understood from the graphs of FIGS. 2 and 3. That is, according to Examples 1-7 which grind | polished using the abrasive | polishing agent A, compared with the comparative examples 1-7 which grind | polished using the conventional abrasive | polishing agent F, the linearity of polishing rate Is big. That is, when the polishing pressure or the rotation speed of the polishing surface plate is changed, the degree (proportionality) of changing the polishing rate in proportion to the change is large. Therefore, the controllability of the polishing rate according to the polishing conditions such as the polishing pressure, the polishing surface plate, and the rotation speed of the polishing head is increased.

Example 16
Polishing was performed for 5 minutes by using the polishing agent A at a polishing pressure of 27.6 kPa, a polishing platen rotating speed of 127 rpm, and a polishing head rotating speed of 123 rpm. And the surface roughness (Ra) of the to-be-polished surface before and behind grinding | polishing was each measured. The measurement results are shown in Table 2.

Comparative Example 8
Polishing was performed for 5 minutes using the polishing agent F under the same conditions as in Example 8 (polishing pressure 27.6 kPa, polishing plate rotation speed 127 rpm, polishing head rotation speed 123 rpm). And the surface roughness (Ra) of the to-be-polished surface before and behind grinding | polishing was each measured. The measurement results are shown in Table 2.

  From the measurement results of Table 2, in Example 16 using the polishing agent A, the polished surface after polishing has a surface roughness (Ra) equivalent to that of Comparative Example 8 using the conventional polishing agent F. You can see that Therefore, it can be seen that by using the polishing agent A, it is possible to obtain a polished surface having no polishing scratches and high flatness.

  According to the polishing agent and the polishing method of the present invention, in the manufacture of a semiconductor integrated circuit device, a surface to be polished containing single crystal silicon can be polished by precisely controlling the polishing rate, and there is no polishing flaw and high flatness. A polished surface can be obtained.

  DESCRIPTION OF SYMBOLS 1 ... Semiconductor device, 2 ... Polishing head, 3 ... Polishing surface plate, 4 ... Polishing pad, 5 ... Polishing agent, 6 ... Polishing agent supply piping.

Claims (7)

A polishing agent for chemically and mechanically polishing a surface to be polished containing single crystal silicon,
Containing cerium oxide particles, water-soluble polyamine and water,
An abrasive having a pH in the range of 8-13.   The abrasive according to claim 1, wherein the water-soluble polyamine is one or more compounds selected from the group consisting of a water-soluble polyether polyamine and a water-soluble polyalkylene polyamine.   The abrasive according to claim 1 or 2, wherein the water-soluble polyamine has a weight average molecular weight in the range of 100 to 100,000.   The abrasive according to claim 3, wherein the water-soluble polyamine is pentaethylenehexamine and / or polyoxypropylenediamine.   The abrasive | polishing agent of any one of Claims 1-4 in which the said water-soluble polyamine is contained in 0.01-20 mass%.   A method of supplying a polishing agent to a polishing pad, bringing a polishing surface containing single crystal silicon of a semiconductor integrated circuit device into contact with the polishing pad, and polishing by relative movement between the two, and claiming as the polishing agent Item 6. A polishing method using the abrasive according to any one of Items 1 to 5.   A method for manufacturing a semiconductor integrated circuit device, comprising a step of polishing a surface to be polished containing single crystal silicon by the polishing method according to claim 6.

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