JP2002270566A - Cleaning liquid and method of manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning liquid which can remove particles, organic impurities and metal impurities while preventing damage to a device. SOLUTION: The cleaning liquid contains 0.001% by weight or more of a compound forming a complex with metal containing at least copper or aluminium and 0.001% by weight or more of a surfactant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cleaning liquid and a method for manufacturing a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, in a process of manufacturing a semiconductor device, a liquid crystal display device, or an electronic component, a cleaning liquid containing an alkaline agent such as ammonia or a surfactant is used to remove particles and organic impurities. . Also,
To remove metal impurities, a cleaning solution containing hydrochloric acid and hydrofluoric acid is used.

[0003]

However, with the development of high-definition devices and the use of film materials which are more easily damaged, conventional cleaning solutions for strong acids and strong alkalis cannot be used.

An object of the present invention is to provide a cleaning solution capable of removing particles, organic impurities and metal impurities while suppressing damage to a device.

According to the present invention, there is provided a method of manufacturing a semiconductor device capable of satisfactorily cleaning contaminants on the surface of an insulating film after forming an embedded conductive member of copper on an insulating film of a semiconductor substrate by a chemical mechanical polishing method. It is intended to provide.

[0006]

The cleaning liquid according to the present invention comprises:
0.001% by weight or more of a compound which forms a complex with a metal containing at least copper or aluminum, and surfactant 0.1.
001% by weight or more.

In a method of manufacturing a semiconductor device according to the present invention, after forming an embedded conductive member made of a copper-based metal in an insulating film on a semiconductor substrate by a chemical mechanical polishing method in the presence of abrasive grains, at least copper is removed. It is characterized by being washed with a washing liquid containing 0.001% by weight or more of a compound forming a complex with the metal and 0.001% by weight or more of a surfactant.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a cleaning liquid according to the present invention will be described in detail.

This cleaning solution has a composition containing at least 0.001% by weight of a compound which forms a complex with at least a metal containing copper or aluminum, and at least 0.001% by weight of a surfactant.

Examples of the compound include aminocarboxylic acids such as aminoacetic acid (glycine), 2-quinolinecarboxylic acid (quinaldic acid), 2-pyridinecarboxylic acid, 2,6-pyridinecarboxylic acid, quinone, oxalic acid, and the like.
Tetramethylammonium hydroxide (TMA
H) and the like. In particular, the compound is a 2-quinoline carboxylic acid (quinaldic acid) that forms a chelate complex with a metal containing at least copper or aluminum;
Aminoacetic acid (glycine) is preferred.

When the content of the compound is less than 0.001% by weight, it becomes difficult to obtain a cleaning solution having sufficient cleaning performance. A more preferred content of the compound is
0.001 to 3% by weight, more preferably 0.05 to
1.0% by weight.

Examples of the surfactant include a nonionic surfactant such as polyoxyethylene nonyl phenyl ether, and an anionic surfactant such as ammonium alkyl sulfate such as ammonium dodecyl sulfate and ammonium alkylbenzene sulfate. In particular,
Anionic surfactants are preferred.

When the content of the surfactant is less than 0.001% by weight, it becomes difficult to obtain a cleaning solution having sufficient cleaning performance. More preferably, the content of the surfactant is 0.001 to 3% by weight, still more preferably 0.03% by weight.
5 to 1.0% by weight.

The washing liquid according to the present invention is allowed to further contain an organic alkali agent such as choline and a pH adjuster such as ammonia. By containing such a pH adjuster, it becomes possible to promote the dissociation of the compound and improve the ability to form a complex with at least a metal containing copper or aluminum.

Next, a method of manufacturing a semiconductor device according to the present invention will be described.

(First Step) First, at least one burying member selected from a groove and an opening is formed in an insulating film on a substrate, and a copper-based metal film is formed on the entire surface including the burying member.

Examples of the substrate include a semiconductor substrate and a glass substrate.

As the insulating film, for example, a silicon oxide film, a boron-doped glass film (BPSG film), a phosphorus-doped glass film (PSG film) or the like can be used. On this insulating film, silicon nitride, carbon, alumina, boron nitride,
The polishing stopper film made of diamond or the like is allowed to be covered.

As the copper-based metal, copper (Cu) or a copper alloy (Cu alloy) such as a Cu-Si alloy, a Cu-Al alloy, a Cu-Si-Al alloy, or a Cu-Ag alloy may be used. it can.

The copper-based metal film is formed, for example, by sputtering deposition,
It is formed by vacuum evaporation or plating.

It is possible to form a conductive barrier layer on the insulating film including at least one burying member selected from the groove and the opening on the semiconductor substrate before forming the copper-based metal film. By forming such a conductive barrier layer in the insulating film including the burying member, a wiring material film such as Cu is formed, and the trench and the opening surrounded by the conductive barrier layer by etch-back are formed. It is possible to form at least one buried conductive member selected from a wiring layer and a via fill in at least one buried member selected from the group consisting of: As a result, the conductive barrier layer prevents Cu as a wiring material from diffusing into the insulating film, thereby preventing contamination of the semiconductor substrate with Cu.

The conductive barrier layer is made of, for example, TiN, T
i, Nb, W, WN, TaN, TaSiN, Ta, C
It is made of one or more layers selected from o, Co, Zr, ZrN and CuTa alloy.

(Second Step) The copper-based metal film on the substrate is polished on a polishing pad in a state where at least polishing abrasive grains and water are present between the copper-based metal film and the copper-based metal film in the embedding member. To form a buried conductive member made of a copper-based metal, for example, a buried wiring layer. Subsequently, 0.001% by weight of a compound which forms a complex with at least a metal containing copper
The above-mentioned cleaning liquid containing 0.001% by weight or more of a surfactant is used for cleaning to mainly remove particles, organic impurities and metal impurities on the surface of the insulating film and the embedded conductive member.

Examples of the abrasive grains include alumina such as θ-alumina and colloidal alumina, silica such as colloidal silica, and cerium oxide.

Between the copper-based metal film and the polishing pad, a water-soluble organic material which reacts with the above-mentioned copper to form a copper complex which is substantially insoluble in water and which is more brittle than copper. The acid (first organic acid) and the oxidizing agent are allowed to be further present. Examples of the first organic acid include 2-quinolinecarboxylic acid (quinaldic acid), 2-pyridinecarboxylic acid, 2,6-pyridinecarboxylic acid, and quinone. As the oxidizing agent, for example, an oxidizing agent such as hydrogen peroxide (H ₂ O ₂ ) or sodium hypochlorite (NaClO) can be used. Further, between the copper-based metal film and the polishing pad, the above-mentioned organic acid (second organic acid) having one carboxyl group and one hydroxyl group is allowed to exist. Such second organic acids include, for example, lactic acid, tartaric acid, mandelic acid, malic acid and the like, and these can be used in the form of one kind or a mixture of two or more kinds. In particular, lactic acid is preferred.

The polishing is performed, for example, using a polishing apparatus shown in FIG. That is, a polishing pad 2 made of, for example, a foamed resin is placed on the turntable 1 of FIG.
Is coated. A supply pipe 3 for supplying a polishing composition containing polishing abrasive grains and water (or a polishing composition containing water) is disposed above the polishing pad 2. A substrate holder 5 having a support shaft 4 on the upper surface is arranged above the polishing pad 2 so as to be vertically movable and rotatable.

The polishing by the polishing apparatus shown in FIG. 1 is performed in the following three modes: (1) a mode in which a polishing composition containing abrasive grains and water is supplied onto a polishing pad; Disperse and fix abrasive grains on the polishing pad surface,
A form in which a polishing composition containing water without containing polishing abrasive grains is supplied on the polishing pad. (3) A polishing composition containing water is dispersed and temporarily fixed on the polishing pad, and the polishing composition contains water. , Or any of the following forms.

(1) Form of Supplying Polishing Composition Containing Polishing Abrasive Grains and Water onto Polishing Pad First, the copper metal film formed on the substrate 6 is held by the holder 5 so as to face the polishing pad 2. . Subsequently, a desired load is applied to the substrate 6 toward the polishing pad 2 by the support shaft 4 while the polishing composition 7 containing the polishing abrasive grains and water is supplied from the supply pipe 3, and the holder 5 and the turn The table 1 is rotated in the same direction. At this time, the copper-based metal film of the substrate is polished by polishing grains in the polishing composition supplied between the metal film and the polishing pad.

(2) Abrasive grains are dispersed on the surface of the polishing pad.
Fixing and supplying a polishing composition containing a thickener and water without containing abrasive grains on the polishing pad First, the copper metal film formed on the substrate 6 by the holder 5
Is held so as to face. Subsequently, a desired load is applied to the substrate 6 by the support shaft 4 toward the polishing pad 2 while the polishing composition 7 containing water without containing abrasive grains is supplied from the supply pipe 3, and 5 and the turntable 1 are rotated in the same direction. At this time, the copper-based metal film on the substrate is polished in the presence of a polishing composition containing fixed and exposed polishing abrasive grains and supplied water on the surface of the polishing pad.

(3) Abrasive grains are dispersed on the surface of the polishing pad.
A mode in which the polishing composition is temporarily fixed and a polishing composition containing water and not containing abrasive grains is supplied onto the polishing pad. First, the copper-based metal film formed on the substrate 6 by the holder 5 is opposed to the polishing pad 2. Hold. Subsequently, the support shaft 4 is supplied while the polishing composition 7 containing water, which does not contain the abrasive grains, is supplied from the supply pipe 3.
A desired load is applied to the substrate 6 toward the polishing pad 2 by the
Are rotated in the same direction. At this time, since the polishing abrasive grains temporarily fixed to the polishing pad are supplied between the copper-based metal film of the substrate and the polishing pad, the copper-based metal film of the substrate is separately supplied with the polishing abrasive grains. The polishing is performed in the presence of a polishing composition containing water.

In the above-mentioned cleaning step, it is allowed to use (a) a rotating brush or (b) a physical scrub by applying ultrasonic waves, which will be described below.

(A) While supplying the cleaning liquid to the insulating film including the embedded conductive member on the semiconductor substrate, a scribing for bringing a rotating cylindrical brush into contact with the surface of the insulating film including the embedded conductive member is used together. Perform washing.

(B) A cleaning liquid having the above-mentioned composition is contained in a container having an ultrasonic generating member attached to the bottom or the side wall, and the semiconductor substrate having the conductive member embedded therein is immersed in the cleaning liquid. Is driven to apply ultrasonic waves to the cleaning liquid to perform cleaning using scrub together.

As described above, the cleaning solution according to the present invention has a composition containing at least 0.001% by weight of a compound forming a complex with at least a metal containing copper or aluminum and at least 0.001% by weight of a surfactant. Have.

By using such a cleaning liquid in a semiconductor device, a liquid crystal display or an electronic component manufacturing process, unlike a conventional cleaning liquid of a strong acid or strong alkali, the cleaning liquid is not damaged and particles are not damaged. In addition, organic impurities and metal impurities can be effectively removed.

Further, according to the present invention, after an embedded conductive member made of a copper-based metal is formed in an insulating film on a semiconductor substrate by a chemical mechanical polishing method in the presence of abrasive grains, it is cleaned with a cleaning liquid having the above-mentioned composition. Thereby, particles, organic impurities and metal impurities on the surface of the insulating film including the buried conductive member can be removed and cleaned. As a result, a highly reliable semiconductor device in which defects due to particles, metal impurities, and the like are prevented can be manufactured.

In particular, by using (a) a rotating brush or (b) a physical scrub by applying ultrasonic waves in the cleaning step, particles, organic impurities and metal impurities on the surface of the insulating film including the buried conductive member are particularly used. Can be more effectively removed and cleaned.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments will be described below in detail.

(Examples 1 to 5) First, a washing solution having a composition in which quinaldic acid and ammonium dodecyl sulfate were each dissolved in water in an amount of 0.1% by weight (Example 1), and oxalic acid and ammonium dodecyl sulfate in water each having 0.1% by weight. Cleaning solution having a composition in which wt% is dissolved (Example 2), cleaning solution having a composition in which trimethylammonium hydroxide (TMAH) and ammonium dodecyl sulfate are each dissolved in water at 0.1% by weight (Example 3), aminoacetic acid (glycine) And ammonium dodecyl sulfate 0.1% by weight in water (Example 4). A washing solution (Example 4) was prepared by dissolving 0.1% by weight of aminoacetic acid (glycine) and ammonium dodecyl sulfate in water. (Example 5) was prepared.

Next, a Cu film is deposited on an 8-inch silicon wafer having a thermal oxide film formed on the surface, and the Cu film is chemically treated with a polishing composition containing θ-alumina as polishing grains using the above-mentioned polishing apparatus. A silicon wafer with a thermal oxide film that was forcibly contaminated by mechanical polishing was prepared. Subsequently, while supplying each of the cleaning liquids to the surface of the silicon wafer, scribe cleaning was performed by contacting a roll brush made of PVA.

The amount of residual metal and the number of residual particles of the wafer after such cleaning were measured. The results are shown in Table 1 below.

[0042]

[Table 1]

As is clear from Table 1, the cleaning liquids of Examples 1 to 5 containing a compound forming a complex with Cu and a surfactant exhibit high removal ability against metal impurities and particles.

In particular, it can be seen that the cleaning liquids of Examples 1, 4, and 5 containing quinaldic acid and glycine which form a chelate complex with Cu have high Cu removal performance. Further, it can be seen that the cleaning liquids of Examples 3, 4, and 5 containing TMAH and glycine have high removal performance for particles. Further, it can be seen that the cleaning solution of Example 5 containing glycine and added with an alkaline agent has higher removal performance for Cu and particles.

(Embodiment 6) First, as shown in FIG. 2A, on a silicon substrate 21 having a diffusion layer such as a source and a drain (not shown) formed on the surface thereof, for example, a thick film as an interlayer insulating film is formed by a CVD method. after depositing the SiO ₂ film 22 of 1000nm is, the depth 500nm having a shape corresponding to the wiring layer by photoetching technique on the SiO ₂ film 22
Are formed. Subsequently, as shown in FIG. 2B, a barrier layer 24 of TiN having a thickness of 15 nm and a Cu film 25 having a thickness of 600 nm are formed in this order on the SiO ₂ film 22 including the groove 23 by sputter deposition. Formed.

Next, the substrate 21 shown in FIG. 2B is held upside down on the substrate holder 5 of the polishing apparatus shown in FIG. 1, and the substrate is placed on the turntable 1 by the support shaft 4 of the holder 5. A load of 500 g / cm ² was applied to a polishing pad 2 made of IC1000;
Each of the turntable 1 and the holder 5 is 103
While rotating in the same direction at a speed of 100 rpm, the polishing composition was supplied to the polishing pad 2 from the supply pipe 3 at a speed of 50 ml / min.
The film 25 and the barrier layer 24 were polished until the surface of the SiO ₂ film 22 was exposed. Here, 2-quinoline carboxylic acid (quinaldic acid) is used as the copper-based metal polishing composition.
0.67% by weight, lactic acid 1.2% by weight, ammonium dodecyl sulfate 0.57% by weight, polyvinylpyrrolidone (PV
P) 0.4% by weight, 13.3% by weight of hydrogen peroxide, 2.0% by weight of [theta] -alumina and a composition having water were used. In the polishing step, the polishing composition did not undergo any etching at the time of contact with the Cu film, and polishing at the time of polishing with the polishing pad proceeded. For this reason, in the chemical mechanical polishing step, the convex Cu film 25 shown in FIG. 2B is preferentially polished from the surface in mechanical contact with the polishing pad, and the exposed barrier layer 24 is further polished. So-called etch back was done. As a result, as shown in FIG. 2C, the barrier layer 24 remains in the groove 23 and is buried flush with the surface of the SiO ₂ film 22 in the groove 23 covered with the barrier layer 24. Cu wiring layer 2
6 was formed.

Next, 0.1% by weight of aminoacetic acid (glycine) and 0.1% by weight of ammonium dodecyl sulfate are dissolved in water, and a cleaning solution having a composition of pH 9 to which ammonia is added is applied to the surface of the SiO ₂ film on which the embedded Cu wiring layer is formed. Scribe cleaning was performed by contacting a roll brush made of PVA while supplying the roll.

After the scribe cleaning, the surface of the SiO ₂ film including the embedded Cu wiring layer was observed. As a result, metal impurities and particles introduced into the surface by the chemical mechanical polishing step and the like were removed, and it was confirmed that the particles had extremely high cleanliness.

[0049]

As described above in detail, according to the present invention, particles,
It is possible to provide a cleaning liquid that can remove organic impurities and metal impurities and can be effectively applied to a semiconductor device, a liquid crystal display device, an electronic component manufacturing process, or the like.

Further, according to the present invention, after a copper embedded conductive member is formed on an insulating film of a semiconductor substrate by a chemical mechanical polishing method, contaminants on the surface of the insulating film can be satisfactorily cleaned, and high reliability can be obtained. And a method capable of manufacturing a semiconductor device having a uniformity.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a polishing apparatus used in a polishing step in manufacturing a semiconductor device of the present invention.

FIG. 2 is a sectional view showing a manufacturing process of a semiconductor device according to a sixth embodiment of the present invention.

[Explanation of symbols]

1 ... turntable 2 ... polishing pad, 3 ... supply pipe, 5 ... holder, 21 ... silicon substrate, 22 ... SiO ₂ film, 23 ... groove, 26 ... buried wiring layer.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C11D 17/08 C11D 17/08 H01L 21/3205 H01L 21/88 K (72) Inventor Yoshitaka Matsui Yokohama, Kanagawa 8 Shinsugita-machi, Isogo-ku, Toshiba F-term in the Toshiba Yokohama office (reference) 4H003 AB18 AB46 BA12 DA15 DC04 EA23 EB07 EB13 EB19 EB20 ED02 FA07 5F033 GG04 HH07 HH11 HH12 HH17 HH18 HH19 HH21 HH30 HH31PP QQ49 QQ93 QQ96 RR03 RR04 RR05 RR06 RR14 RR15

Claims (7)

[Claims] 1. A compound which forms a complex with a metal containing at least copper or aluminum, in an amount of 0.001% by weight or more,
A cleaning solution comprising 0.001% by weight or more of a surfactant. 2. The cleaning solution according to claim 1, wherein the compound forming a complex with the metal is a compound forming a chelate complex with the metal. 3. The cleaning solution according to claim 1, wherein the compound forming a chelate complex with the metal is an aminocarboxylic acid. 4. The cleaning solution according to claim 1, wherein the compound forming a chelate complex with the metal is aminoacetic acid or 2-quinolinecarboxylic acid. 5. The cleaning solution according to claim 3, further comprising an alkali adjuster. 6. A compound 0 that forms a complex with at least a metal containing copper after forming an embedded conductive member made of a copper-based metal in an insulating film on a semiconductor substrate by a chemical mechanical polishing method in the presence of abrasive grains. A method for manufacturing a semiconductor device, comprising: cleaning with a cleaning liquid containing 0.001% by weight or more and a surfactant of 0.001% by weight or more. 7. The method of manufacturing a semiconductor device according to claim 6, wherein said cleaning is performed by using a rotary brush or a physical scrub by applying ultrasonic waves.