JP2010016046A - Polysilazane-dissolving treatment liquid, and manufacturing method of semiconductor device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a semiconductor device which allows stable process treatment. <P>SOLUTION: This manufacturing method of a semiconductor device includes processes of: supplying an application liquid prepared by dissolving polysilazane in a solvent onto a semiconductor substrate; forming a coating film containing the polysilazane by rotating the semiconductor substrate; supplying a rinse liquid to the back face of the semiconductor substrate, to apply back rinse thereto to clean the back face; drying the semiconductor substrate after the back rinse, to remove the rinse liquid; and providing an insulation film containing silicon oxide by heat-treating the semiconductor substrate, to remove the solvent from the coating film. Each of the solvent and the rinse liquid contains terpenes, at least in a part and is such that the acid value is smaller than 0.036 mgKOH/g. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a treatment liquid for dissolving polysilazane and a method for manufacturing a semiconductor device using the same.

  Siloxanes and silazanes are known as silicon-containing compounds used as coating films for semiconductor devices. In any case, the value as a low dielectric constant insulating film (Low-k) material, an interlayer insulating film (ILD) material, or a buried material is high. It has also been proposed to use polysilazane (PSZ) for PMD (Pre-Metal Dielectric) and IMD (Inter-Metal Dielectric) (see, for example, Patent Document 1).

  Propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA) or the like is often used as a solvent for dissolving siloxanes to prepare a coating solution. The same is used for thinner (rinsing liquid) for wafer edge cutting and back surface cleaning (back rinsing).

  The rinse liquid is selected according to the type of the silicon-containing compound. For example, low molecular weight siloxane is used for silsesquioxane. As the polysilazanes, xylene, di-n-butyl ether, or naphthalene-based substances are used (for example, see Patent Documents 2, 3, and 4).

Further, a method of using a terpene such as α-pinene as a solvent or a rinsing liquid has been proposed in order to form an insulating film with high throughput by a coating method while reducing carbon dioxide emission. (See Patent Documents 5 and 6.)
Polysilazane reacts with substances such as moisture and alcohol to form a gel, and finally precipitates as a solidified product of silica. The gelation of polysilazane is caused by moisture or impurities contained in the rinse liquid, moisture in the air, or the like, or by self-decomposition of polysilazane itself. Along with gelation, a toxic and flammable dangerous gas containing ammonia, silane and hydrogen is generated.

  In the coating apparatus, the coating liquid after coating is mixed with the rinsing liquid and stored in a waste liquid storage unit installed under the coater cup via a waste liquid line. When the coating liquid is polysilazane, in such a waste liquid line or waste liquid storage, there is a possibility that the water or impurities contained in the rinse liquid react with the polysilazane to gel. Since the waste liquid is in contact with air, the water in the air is absorbed and gelation of polysilazane occurs.

  If the waste liquid storage is provided with a lid, contact with air is avoided, so the possibility of gelation is reduced. However, if the lid is too close, the internal pressure in the storage rises due to gas generation and bursts. There is danger. On the other hand, in the case of a lid with good air permeability or a lid with a check valve, the generated dangerous gas may diffuse into the atmosphere and harm the health of the operator.

  Gelation and solidification in the waste liquid line may cause clogging in the piping and may cause a disaster such as leakage. The solidified matter causes dust and causes a decrease in the manufacturing yield of the semiconductor device. Since gelation and solidification are progressive, regular equipment maintenance is essential.

  In order to prevent polysilazane from gelling or solidifying, cleaning is performed by periodically flowing a rinse liquid into a waste liquid line or a waste liquid storage. An excessive rinsing solution is supplied to reduce the concentration of polysilazane to delay gelation. Such treatment requires the use of excess rinse solution.

It is required to suppress the gelation of polysilazane for reasons such as health effects, disaster prevention, and maintenance of application equipment.
JP 2004-179614 A JP 2003-197611 A JP 2005-236050 A Japanese Patent No. 3479648 JP 2007-242958 A JP 2006-216704 A

  An object of the present invention is to provide a polysilazane-dissolving treatment liquid that hardly causes gelation and has little influence on the human body, and a method for manufacturing a semiconductor device capable of stable process treatment.

  The treatment liquid for dissolving polysilazane according to one embodiment of the present invention is characterized in that it contains at least a part of terpenes and has an acid value of less than 0.036 mgKOH / g.

A method of manufacturing a semiconductor device according to one embodiment of the present invention includes a step of supplying a coating liquid obtained by dissolving polysilazane in a solvent on a semiconductor substrate to form a coating film containing the polysilazane.
Supplying a rinsing liquid to the back surface of the semiconductor substrate to perform a back rinse, and cleaning the back surface;
Drying the semiconductor substrate after the back rinse to remove the rinse liquid; and heat treating the semiconductor substrate to remove the solvent from the coating film to obtain an insulating film including a silicon oxide film. And
The solvent and the rinsing liquid are characterized in that at least a part thereof is composed of the above-described polysilazane dissolution treatment liquid.

A method of manufacturing a semiconductor device according to another aspect of the present invention includes a step of supplying a coating liquid obtained by dissolving polysilazane in a solvent on a semiconductor substrate to form a coating film containing the polysilazane.
Supplying a rinsing liquid to the edge portion of the semiconductor substrate to perform edge cutting;
Drying the semiconductor substrate after the edge cutting to remove the rinse liquid; and heat treating the semiconductor substrate to remove the solvent from the coating film to obtain an insulating film including a silicon oxide film. And
At least a part of the solvent and the rinsing liquid is the aforementioned polysilazane dissolving treatment liquid.

  According to one embodiment of the present invention, a processing solution for dissolving polysilazane that hardly causes gelation and has little influence on the human body, and a method for manufacturing a semiconductor device capable of stable process processing are provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The treatment liquid according to the embodiment of the present invention is used as a solvent for dissolving a silicon-containing compound in order to form an insulating film by a coating method. Moreover, after application | coating, it is used as the rinse liquid for edge cutting of a wafer, or a back rinse.

  The flow of the coating process will be described with reference to FIGS.

  In FIG. 1, the structure of the coater apparatus to be used is shown. As shown in the figure, a spin chuck 2 for supporting a semiconductor wafer (not shown) is disposed in the coater cup 1, and an edge cut nozzle 3a and a backside rinse nozzle 3b are provided. A rinse solution is supplied from these nozzles to a predetermined region of the semiconductor wafer. Outside the coater cup 1, a solvent bath 4 containing a solvent and a dummy dispensing port 6 for discarding the coating liquid are arranged. The chemical nozzle 5 is used for supplying a coating liquid (chemical liquid) onto the semiconductor wafer. In FIG. 1, the chemical nozzle 5 is held in the solvent vapor in the solvent bath 4 in order to prevent the tip from being dried.

  In application, first, as shown in FIG. 2, the semiconductor wafer 7 is supported by the spin chuck 2 and fixed by vacuum suction. The wafer is placed on a cooling plate (not shown) and adjusted to have a constant temperature. The condition at this time can be set at, for example, 23 ° C. for 60 seconds.

  The concentration of the coating liquid at the tip of the chemical liquid nozzle 5 changes by reacting with moisture in the air. Even when the solvent evaporates, the concentration of the coating solution changes. In order to avoid this, it is necessary to supply a clean coating solution before discharging the coating solution onto the semiconductor wafer 7. Therefore, as shown in FIG. 3, the chemical nozzle 5 is moved to the dummy dispense port 6 to discard the coating liquid contained in the nozzle (dummy dispense).

  In some cases, the tip of the nozzle is washed with a solvent before performing the dummy dispensing. This step may be omitted when processing wafers continuously.

  Subsequently, as shown in FIG. 4, the chemical solution nozzle 5 is moved onto the semiconductor wafer 7, and a coating solution is discharged to form a coating film 8. There are two types of discharge methods, a static method and a dynamic method. The static method refers to a method of supplying a coating solution to the center of a stationary wafer. On the other hand, the dynamic method is a method of supplying a coating solution while rotating a wafer. Dynamic dispensing is widely used because a film with good film thickness uniformity can be formed with a small discharge amount.

The coating liquid used for forming the coating film 8 contains polysilazane as a silicon-containing compound. Either inorganic or organic polysilazane may be used, and examples of the inorganic polysilazane include linear compounds having a repeating unit represented by the following general formula (I).

Such inorganic polysilazane preferably has a weight average molecular weight of 690 to 2,000. In particular, it has 3 to 10 SiH ₃ groups in one molecule, and the elemental ratio by chemical analysis is Si: 59 to 61, N: 31 to 34, and H: 6.5 to 7.5, respectively. Specific perhydropolysilazanes and perhydropolysilazanes having a polystyrene-reduced average molecular weight in the range of 3,000 to 20,000 are mentioned.

Perhydropolysilazane can be produced by any method. Basically, it contains a chain portion and a cyclic portion in the molecule, and is represented by the following chemical formula, for example.

An example of the perhydropolysilazane structure is shown below.

Further, a compound represented by the following general formula (II) or a modified product thereof can be used. The number average molecular weight is preferably within the range of about 100 to 50,000.

In the general formula (II), R ¹ , R ² and R ³ are each independently a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, or a silicon other than these groups, such as a fluoroalkyl group. A group in which the direct bond is carbon is an alkylsilyl group, an alkylamino group, or an alkoxy group. However, at least one of R ¹ , R ² and R ³ is a hydrogen atom.

Specifically, in the above general formula (II), polyorgano (hydro) silazane in which a hydrogen atom is introduced as R ¹ and R ² and an organic group is introduced as R ³ can be mentioned. Further, those having a cyclic structure having a degree of polymerization of 3 to 5 with-(R ² SiHNH)-as a repeating unit, (R ³ SiHNH) _x [(R ² SiH) _1.5 N] _1-x (0.4 A compound represented by <X <1) and having a chain structure and a cyclic structure in the molecule can also be used.

In the general formula (II), a hydrogen atom is introduced as R ¹ , an organic group is introduced as R ² and R ³ , an organic group is introduced as R ¹ and R ² , and a hydrogen atom is introduced as R ³ Some of them have a cyclic structure mainly having a degree of polymerization of 3 to 5, using-(R ¹ R ² SiNR ³ )-as a repeating unit.

Furthermore, for example, polyorgano (hydro) silazane having a crosslinked structure represented by the general formula in the molecule can be mentioned.

R ¹ SiX ₃ (X: halogen) is decomposed by ammonia to obtain polysilazane R ¹ Si (NH) _x having a crosslinked structure. Also, polysilazane can be obtained by co-ammonia decomposition of R ¹ SiX ₃ and (R ² ) ₂ SiX ₂ . Such compounds can also be used. Specifically, it is polysilazane having the structure shown below.

In addition, a polysiloxazan having a repeating unit represented by [(SiH ₂ ) _n (NH) _m ] or [(SiH ₂ ) _r O] (n, m and r are 1, 2 or 3, respectively) Examples thereof include modified polysilazane obtained by adding alcohol such as methanol or hexamethyldisilazane to the terminal N atom to perhydropolysilazane, and metal-containing polysilazane containing a metal such as aluminum.

  Furthermore, polyborosilazane, inorganic silazane high polymer, modified polysilazane, copolymerized silazane, low temperature ceramicized polysilazane, silicon alkoxide-added polysilazane, glycidol-added polysilazane, acetylacetate added or added with catalytic compounds Examples thereof include polysilazanes such as nato complex-added polysilazane and metal carboxylate-added polysilazane.

  A polysilazane composition prepared by adding amines and / or acids to the above-described polysilazane or modified product can also be used.

In addition to polysilazane, a silane compound may be contained. A silane compound is represented by the following general formula, for example.

In the general formula (1), R ¹¹ and R ¹² may be the same or different and each represents a hydrogen atom or a substituent. Examples of the substituent include an alkyl group, an alkoxy group, an alkenyl group, a hydroxyl group, and an amino group. When a hydrogen atom is introduced into both R ¹¹ and R ¹² , it is a silane compound.

  Furthermore, polysiloxane, silsesquioxane, polysilazane, etc. may be contained. A mixture or copolymer of the above compound group may also be used.

  A coating liquid is prepared by dissolving the polysilazane as described above and, if necessary, other silicon-containing compounds in a solvent. The solvent is also used as a rinse liquid supplied from the edge cut nozzle 3a or the backside rinse nozzle 3b. In general, xylene or di-n-butyl ether is used as a solvent. However, in one embodiment of the present invention, at least a part of the solvent is constituted by a specific processing liquid. Specifically, it is a treatment liquid containing at least a part of terpenes and having an acid value of less than 0.036 mgKOH / g, which will be described later.

  When the discharge of the coating liquid is completed, the thickness of the coating film 8 is adjusted by rotating the wafer 7 at a predetermined number of revolutions as shown in FIG. The film thickness is determined by the viscosity (concentration) of the coating solution and the rotational speed. At this time, the chemical nozzle 5 returns to the solvent bath 4 and waits there.

  After the film thickness of the coating film 8 is stabilized, edge bead remove (EBR) / back rinse is performed. Specifically, as shown in FIG. 6, the edge cutting is performed by supplying the rinsing liquid 9 from the edge cutting nozzle 3a and removing the coating film on the wafer edge portion. At this time, attention should be paid so that the end portion of the coating film in contact with the rinsing liquid 9 does not swell or droop. At the same time as the EBR, the back rinse is performed by supplying the rinse liquid 9 from the back rinse nozzle 3b to the back surface of the wafer and washing away the coating solution that has entered the back surface of the wafer.

  At least a part of the rinsing liquid is composed of a specific processing liquid similar to the case of the solvent. That is, it is a treatment liquid containing at least a part of terpenes and having an acid value of less than 0.036 mgKOH / g.

  After the EBR / back rinse, the supply of the rinse liquid is stopped as shown in FIG. 7, the wafer 7 is rotated, and the edge portion and the back surface are dried.

  After drying, the wafer 7 is removed from the coater as shown in FIG. 8 and transferred to a hot plate (not shown). On the hot plate, the coating film is dried by baking at an appropriate temperature. For example, baking is performed at 150 ° C. for 180 seconds, the solvent is removed from the coating film, and a coating insulating film is formed.

  Thereafter, the wafer is cooled, for example, by a cooling plate, and a series of coating processes is completed. The cooling condition can be 60 seconds at 23 ° C., for example.

  The rinsing liquid is mixed with the coating liquid and flows through the waste liquid line, and is finally stored in a waste liquid storage (not shown) installed below the coater cup. In the waste liquid line or storage, a phenomenon such as gelation or solidification of polysilazane occurs. In order to prevent this, conventionally, a rinsing solution is periodically flowed for cleaning, or an excessive rinsing solution is supplied to reduce the concentration of polysilazane.

  As a result of intensive studies, the present inventors have found that a composition capable of suppressing the gelation of polysilazane exists in the solvent and the rinsing liquid of the coating liquid, and have made the present invention. At least a part of the solvent and the rinsing liquid of the coating liquid is constituted by the polysilazane dissolution treatment liquid according to an embodiment of the present invention.

  The treatment liquid for dissolving polysilazane according to an embodiment of the present invention contains terpenes at least partially. In general, terpenes are substances that exist widely in nature, and are abundant in natural plant essential oils and are excellent in safety. Industrially, many compounds extracted from plant trunks, leaves, and fruits, and obtained from pine crabs and orange peels, are often used.

The terpene is a generic name for a series of compounds based on the isoprene rule represented by the molecular formula of (C ₅ H ₈ ) _n , and includes monoterpenes (n = 2), sesquiterpenes (n = 3), and the like. In general, the terpene compounds include terpene hydrocarbon compounds such as α-pinene, β-pinene, dipentene, limonene, myrcene, allocymene, camphene α-ferrandrene, α-terpinene, γ-terpinene, terpinolene, paramentane, and paracymene. Terpene-based oxygen-containing compounds such as cineol, terpineol, carvone, menthol, peryl alcohol, and perylaldehyde.

  In particular, α-pinene, β-pinene, dipentene, d-limonene, and 1,8-cineole are preferable as terpenes, and these can be used alone or in combination of two or more.

  The present inventors paid attention to the acid value of such terpenes and found that terpenes having a reduced acid value are effective in suppressing gelation of polysilazane. The acid value is a numerical value representing the amount of potassium hydroxide required to neutralize 1 g of fatty acid in milligram units. The acid value of terpenes is determined depending on the content of acidic components such as terpene carboxylic acid, and it is presumed that the higher the content, the higher the value. The acid value of commercially available normal terpenes is 0.08 mgKOH / g or more.

  In the embodiment of the present invention, the acid value of the treatment liquid is defined to be less than 0.036 mgKOH / g. That is, not only when using it as a solvent for preparing a coating solution, but also when using it as a rinsing solution, the acid value of the treatment solution is defined to be less than 0.036 mgKOH / g. When the acid value of the treatment liquid such as the solvent and the rinse liquid is 0.036 mgKOH / g or more, the gelation of polysilazane cannot be suppressed. Such knowledge is obtained by the present inventors. The acid value of the treatment liquid according to the embodiment of the present invention is preferably 0.03 mgKOH / g or less, and more preferably 0.02 mgKOH / g or less.

  By performing a treatment such as a removal treatment or an adsorption treatment, the acid value of the treatment liquid can be reduced to less than 0.036 mgKOH / g. Specific examples include precision distillation treatment, molecular distillation treatment, thin film distillation treatment, alkali treatment, water washing treatment, ion exchange resin treatment, and activated carbon treatment. Such processing may be performed alone or in combination.

  For example, the alkali treatment can be performed using an aqueous solution such as sodium hydroxide or ammonia. A large excess of aqueous alkaline solution is added to the untreated terpenes and stirred for a predetermined time. After standing, oil-water separation is performed to obtain terpenes having a reduced acid value.

  The treatment liquid according to the embodiment of the present invention preferably has a moisture content of 250 ppm or less. If it exceeds 250 ppm, gelation of polysilazane tends to occur. The water content is more preferably 200 ppm or less. Even when the water content is as low as 100 ppm or less, when the acid value is 0.036 mgKOH / g or more, the progress of gelation of polysilazane is accelerated. That is, the present inventors have found that the acid value of the polysilazane on the gelation is greater than the water content.

  However, if the polarity of the terpenes is increased, moisture is likely to be contained, so that polysilazane is easily gelled. On the other hand, if the polarity of the terpenes is too low, the solubility of polysilazane is deteriorated and the EBR characteristics may be deteriorated.

  In the treatment liquid, fine particles having a diameter of 0.5 μm or more may be inevitably mixed. When such fine particles are present in the solvent, the fine particles adhere to the surface of the wafer, resulting in problems such as forming defects in the pattern. In addition, if it is present in the rinse liquid, fine particles adhere to the back surface of the wafer, which causes adverse effects such as causing contamination of the manufacturing apparatus. Therefore, in the treatment liquid according to the embodiment of the present invention, it is preferable that the number of fine particles having a diameter of 0.5 μm or more contained in 1 ml is 50 or less. The number of fine particles in the treatment liquid can be measured by, for example, a particle counter. The content of such fine particles is more preferably 10 or less.

  If the treatment liquid composed of the terpenes as described above is contained in an amount of at least 80% by weight of the solvent or the rinse liquid, the effect can be obtained. If the content is 90% by weight or more, the progress of gelation of polysilazane can be significantly suppressed.

  The balance of the solvent can be a general hydrocarbon solvent or the like. The remainder of the rinsing liquid can also be a general hydrocarbon solvent or the like.

(Embodiment 1)
Several types of treatment liquids as shown in Table 1 below were prepared. The acid value of terpenes (α-pinene, d-limonene, and β-pinene) was reduced by adding a large excess of sodium hydroxide to the untreated product and subjecting it to an alkali treatment. The acid value of the untreated product is 0.08 mgKOH / g or more.

  In the treatment of the untreated product, first, an equal amount of 20% aqueous sodium hydroxide solution was added to each terpene having an acid value of 0.08 mgKOH / g or more, followed by stirring for 20 minutes. After standing, oil-water separation was performed to obtain the desired terpenes. The acid value of terpenes was measured using Mitsubishi Chemical's automatic titrator GT-06.

  Further, the water content of each terpene was determined by the Karl Fischer method using AQ-2000 manufactured by Hiranuma Seisakusho. Since the water content of the terpenes after oil-water separation was 100 ppm or less, terpenes whose water content was adjusted to 150 ppm by adding water were also prepared.

  For comparison, a naphthalene-based treatment liquid conventionally used as a rinse liquid was also prepared.

The acid value and water content of each treatment solution are summarized in Table 1 below together with the purity.

No. Using the treatment liquids 1 to 10 as rinsing liquids, the liquids are each mixed with a coating liquid containing polysilazane and examined for solubility and gelation.
A polysilazane coating solution (Spinfil 65001 (dibutyl ether solvent)) manufactured by AZ Electronic Materials was prepared as a coating solution raw material.

  The polysilazane coating solution and each treatment solution were mixed at a volume ratio of 9: 1, and the solubility was examined. The solubility was evaluated based on the presence or absence of turbidity by visually checking the state of the mixed solution immediately after mixing. “O” if no turbidity occurs, “X” if turbidity is observed.

Furthermore, each liquid mixture containing each processing liquid and coating liquid was allowed to stand at room temperature, and the number of days until gelation started was measured. The results obtained for each treatment solution are summarized in Table 2 below together with the solubility evaluation.

  As shown in Table 2 above, the untreated terpenes (treatment liquids Nos. 3, 6, and 9) having an acid value of 0.08 mg KOH / g or more are all “x” in solubility, and are 4 days old. Gelation has started within. The naphthalene rinse solution (No. 10) had good solubility, but gelation occurred in 4 days.

  On the other hand, in the treatment liquids (No. 1, 2, 4, 5, 7, 8) that have been treated to reduce the acid value, in addition to good solubility, the number of days until the start of gelation Is 8 days long. Even if it is a processing liquid (No. 2, 5, 8) whose water content is 150 ppm, if the acid value is reduced, the effect of gelation suppression is not impaired at all.

  Next, a plurality of α-pinenes having different acid values were prepared, mixed with the same polysilazane coating solution as described above, and the gelation start days were examined. The acid value was made into nine types of 0.014-0.08 mgKOH / g.

  The relationship between the acid value and the number of days for gelation is shown in the graph of FIG. When the acid value is 0.08 mgKOH / g, gelation starts in 4 days. Even if the acid value is reduced, the gelation start days are constant until 0.036 mgKOH / g. It has been shown that when the acid value is reduced to less than 0.036 mg KOH / g, the gelation start days are lengthened.

  Thus, it was confirmed that gelation is suppressed if the acid value of terpenes is less than 0.036 mgKOH / g. Based on these results, in the polysilazane dissolution treatment liquid according to the embodiment of the present invention, the acid value of the terpenes was defined to be less than 0.036 mgKOH / g.

(Embodiment 2)
In this embodiment, no. A polysilazane coating film was formed using the treatment liquid 2 as a rinsing liquid. As the coating solution, the same polysilazane coating solution as in Embodiment 1 was used.

Table 3 below shows the application process recipe and the time required for each process. First, as shown in FIG. 2, the wafer 7 is placed on the spin chuck 2 in the coater cup 1. As shown in FIG. 3, the chemical solution nozzle 5 is taken out from the solvent bath 4, and dummy dispensing (discharging) is performed for a short time to make the coating solution at the tip of the nozzle a new solution. The coating liquid is discharged by pressurizing the inside of the chemical liquid tube with a high-pressure gas or feeding it with a liquid feed pump. (In Table 3, these details are omitted.)
Next, as shown in FIG. 4, while rotating the wafer 7 at 1200 rpm, the coating liquid is discharged onto the wafer 7 at a flow rate of 1 ml / s for 2 seconds. Further, the coating film 8 is formed on the entire surface of the wafer 7 as shown in FIG. The discharge amount of the coating liquid is 2 ml. The wafer 7 is rotated at an arbitrary number of rotations for 13 seconds so that the coating film 8 can be obtained with a desired film thickness. The coating film 8 is dried while the solvent is evaporated, and finally settles to a certain film thickness. Therefore, a certain amount of rotation time is required, and the film thickness can be adjusted by changing the number of rotations. In the case of a 300 mm wafer, the rotation speed is between 500 and 2500 rpm.

  In order to remove the coating solution that has wrapped around the edge portion and the back surface of the wafer 7, as shown in FIG. 6, EBR and back rinse are performed. This is performed by supplying the rinsing liquid 9 from the edge cut nozzle 3a and the backside rinse nozzle 3b to the end and back surface of the wafer 7 while rotating the wafer 7 at medium rotation. The flow rate of the rinsing liquid 9 is about 10 to 100 ml / min. Finally, as shown in FIG. 7, the rinse liquid 9 supplied to the end and back surface of the wafer 7 is dried by rotating the wafer 7. The number of rotations can be set to 3000 rpm, for example. A rotation time of 5 seconds is sufficient.

The total processing time in the coating process is 45 seconds per wafer, which is less than 1 minute.

  In addition, in the process using a naphthalene-type solvent as a rinse liquid, it was confirmed that the time of 25 seconds or more is required for a drying process. The total processing time in the coating process is 65 seconds per wafer, which exceeds 1 minute. In addition to this, gelation of polysilazane occurs as described above.

  On the other hand, by using α-pinene having a reduced acid value as the rinsing liquid 9, it is possible to shorten the processing time of 20 seconds per wafer as compared with the current process. The overall processing time can be set to within 1 minute per wafer, and the gelation of polysilazane is suppressed.

(Embodiment 3)
Hereinafter, an embodiment of an STI (Shallow Trench Isolation) embedding method will be described. First, referring to FIGS. 10 to 13, a procedure for manufacturing a memory cell having a CMOS structure will be described.

  First, a silicon dioxide film (thickness of about 10 nm) 11 is formed on the surface of the silicon substrate 10 by thermal oxidation, and a silicon nitride film (thickness of about 200 nm) 12 as a CMP stopper film 12 is formed thereon by low pressure CVD. Form. The film thickness of the film formed on the substrate can be changed as appropriate. For example, the film thickness of the CMP stopper film 12 may be about 100 to 300 nm.

  As shown in FIG. 10, an element isolation trench (STI trench) 13 is formed by photolithography and dry etching so as to penetrate the CMP stopper film 12 and the silicon dioxide film 11 and reach the silicon substrate 10. The width and depth of the STI groove 13 vary depending on the device structure and generation. Typically, the width is about 30 nm to 10 μm and the depth is about 200 to 500 nm, but the present invention is not limited to this.

  Next, using the same coating liquid as that of the first embodiment as an insulating film material, a coating film is formed by coating the entire surface of the Si substrate 10 by spin coating. At this time, no. Back rinse and edge cutting of the back surface of the silicon substrate 10 are performed using the processing liquids 1 and 2. As described above, no. By performing the back rinse using the treatment liquids 1 and 2, the gelation of the polysilazane is suppressed. In addition, the drying time is shortened and the processing speed is shortened.

  Note that another film such as a silicon dioxide film may be formed on the silicon nitride film 12 prior to the formation of the coating film. After coating, baking is performed on a hot plate at 150 ° C. for 3 minutes to volatilize and remove the solvent from the coating film to form a PHPS film 15 as shown in FIG.

  Next, an oxidation treatment is performed in an atmosphere containing water vapor to change the PHPS film 15 into the silicon dioxide film 16 as shown in FIG. The oxidation treatment can be performed at a temperature of 230 ° C. or higher and 900 ° C. or lower, for example. When the temperature is lower than 230 ° C., the silicon dioxide film obtained by oxidizing the PHPS film is very porous. For this reason, it is easily removed by etching with a solution containing hydrofluoric acid, and it becomes difficult to form an element isolation insulating film having an arbitrary height. On the other hand, if the oxidation is performed at a temperature exceeding 900 ° C. in an atmosphere containing water vapor, the side surface of the STI groove 13 is oxidized thickly. In the worst case, dislocation may occur in the Si substrate 10 and is not suitable as an STI formation method for a device having a 100 nm class design rule.

  In order to stabilize the atmosphere and temperature in the furnace, the oxidation time is preferably 5 minutes or longer. However, if the oxidation is performed excessively for a long time, the side surface of the STI groove 13 may be oxidized thickly. Therefore, it is desirable that the upper limit of the oxidation time be limited to about 60 minutes.

  Subsequently, the silicon dioxide film 16 is selectively removed by a technique such as CMP to expose the surface of the CMP stopper film 12 as shown in FIG. 13 and leave the silicon dioxide film 16 in the STI trench 13. Through the above steps, an element isolation insulating film is embedded in the STI trench 13.

  The silicon dioxide film 16 can be densified by heat treatment at 700 ° C. or higher and 1,100 ° C. or lower in an inert gas atmosphere. If it is less than 700 degreeC, it will become difficult to fully densify the silicon dioxide film 16. FIG. On the other hand, if it exceeds 1,100 ° C., the diffusion depth of the channel layer previously formed by ion implantation may be increased depending on the device. What is necessary is just to select the time of heat processing suitably in the range for 1 second-120 minutes. By performing the heat treatment under such conditions, moisture is removed from the silicon dioxide film 16 to achieve densification, and as a result, the electrical characteristics of the device can be improved.

  This densification may be performed before CMP.

  In the present embodiment, when the element isolation insulating film is embedded in the STI trench, gelation of polysilazane contained in the insulating film raw material is suppressed, so that stable process processing is possible.

(Embodiment 4)
A procedure for manufacturing a NAND-structured memory cell will be described with reference to FIGS.

  First, a gate insulating film (thickness 8 nm or less) 18 is formed on the surface of the silicon substrate 10 by thermal oxidation, and a polycrystalline silicon having a thickness of 100 nm is formed thereon as a first gate (floating gate) electrode film 19. A film is formed. The first gate electrode film 19 can also be formed using WSi, CoSi or the like other than the polycrystalline silicon film, and the film thickness can be appropriately selected within the range of 100 to 200 nm. On the first gate electrode film 19, a silicon nitride film (thickness of about 200 nm) is formed as a CMP stopper film 12 by a low pressure CVD method. As the CMP stopper film 12, a polycrystalline silicon film having a thickness of about 100 to 200 nm may be formed instead of the silicon nitride film.

  As shown in FIG. 14, the STI trench 13 is formed by photolithography and dry etching so as to penetrate the CMP stopper film 12, the first gate electrode film 19 and the gate insulating film 18 and reach the Si substrate 10. . The width and depth of the STI groove 13 vary depending on the device structure and generation. Typically, the width is about 30 nm to 10 μm and the depth is about 200 to 500 nm, but the present invention is not limited to this.

  Next, using the same coating liquid as that of the first embodiment as an insulating film material, a coating film is formed by coating the entire surface of the Si substrate 10 by spin coating. At this time, no. Back rinse and edge cutting of the back surface of the silicon substrate 10 are performed using the processing liquids 1 and 2. As already explained, no. By performing the back rinse using the treatment liquids 1 and 2, the gelation of the polysilazane is suppressed. In addition, the drying time is shortened and the processing speed is shortened. In this way, a PHPS film 15 as shown in FIG. 15 is formed, and oxidation treatment is performed in an atmosphere containing water vapor as in the third embodiment to form a silicon dioxide film 16 as shown in FIG.

  Further, the silicon dioxide film 16 on the CMP stopper film 12 is selectively removed by a technique such as CMP to expose the surface of the CMP stopper film 12 as shown in FIG. 16 is left. Through the above steps, the silicon dioxide film 16 is embedded in the STI trench 13 as an element isolation insulating film.

  The silicon dioxide film 16 can be densified by heat treatment at 700 ° C. or higher and 1,100 ° C. or lower in an inert gas atmosphere in a process before or after CMP. If it is less than 700 degreeC, it will become difficult to fully densify the silicon dioxide film 16. FIG. On the other hand, if it exceeds 1,100 ° C., the diffusion depth of the channel layer previously formed by ion implantation may be increased depending on the device. What is necessary is just to select the time of heat processing suitably in the range for 1 second-120 minutes. By performing the heat treatment under such conditions, moisture is removed from the silicon dioxide film 16 to achieve densification, and as a result, the electrical characteristics of the device can be improved.

  Subsequently, the CMP stopper film 12 is removed by etching using a phosphoric acid solution, and the upper portion of the silicon dioxide oxide film 16 is removed by wet etching using a dilute hydrofluoric acid solution. As a result, a part of the upper part of the side surface of the first gate electrode film 19 is exposed to about 100 nm. Further, an interelectrode insulating film 20 is deposited by a conventional method, and a second gate (control gate) electrode film 21 is formed thereon to obtain a NAND structure memory cell as shown in FIG. As the interelectrode insulating film 20, a silicon oxide film / silicon nitride film / silicon oxide film (total film thickness of about 20 nm) by CVD is used, and the second gate electrode film 21 is formed by polycrystalline silicon by CVD. A film / tungsten film (total film thickness of about 50 nm) is used.

  In this embodiment, when a silicon dioxide film is embedded and formed as an element isolation insulating film in a NAND-structured memory cell, gelation of polysilazane contained in the insulating film material is suppressed, so that stable process processing is possible. Become.

(Embodiment 5)
Before supplying the coating liquid onto the semiconductor substrate, forming a semiconductor element including an impurity region and a gate electrode on the semiconductor substrate, providing a through hole in the insulating film to expose the impurity region, and conducting the through hole A PMD (Pre-Metal Dielectric) can be formed by embedding a material.

  Such a method will be described with reference to FIGS.

  As shown in FIG. 19, an interlayer insulating film 27 is formed on the entire surface of the silicon substrate 24 on which transistors including the impurity regions 25a and 25b and the gate electrode 26 are formed. Although not shown, the gate electrode 26 is provided on the silicon substrate 24 via a gate insulating film.

  A coating film is formed by applying the same coating liquid as that of Embodiment 1 as an insulating film raw material to the entire surface of the substrate by spin coating. At this time, no. Back rinse and edge cutting of the back surface of the silicon substrate 24 are performed using the processing liquids 1 and 2. As already explained, no. By performing the back rinse using the treatment liquids 1 and 2, the gelation of the polysilazane is suppressed. In addition, the drying time is shortened and the processing speed is shortened. After coating, baking is performed on a hot plate to volatilize and remove the solvent from the coating film. Thus, the PSZ film 28 is formed as shown in FIG.

  If a coating solution capable of obtaining flatness as much as possible is prepared, the flattening process CMP can be omitted. Next, an oxidation process is performed in an atmosphere containing water vapor to change the PSZ film 28 into the silicon dioxide film 40. The oxidation treatment is performed at a temperature that does not oxidize the gate electrode, and is preferably 600 ° C. or lower. Thereafter, annealing may be performed in an inert gas atmosphere to further oxidize. In order to planarize, the silicon dioxide film 40 may be subjected to CMP.

  On the silicon dioxide film 40, an SiN film 29 is formed as shown in FIG. This SiN film 29 acts as an etching stopper and can be deposited with a film thickness of about 200 nm by CVD, for example.

  Subsequently, lithography and RIE etching are performed by a conventional method to provide contact holes 30 in the SiN film 29, the silicon dioxide film 40, and the interlayer insulating film 27 as shown in FIG.

  A conductive material is embedded in the obtained contact hole 30 by a conventional method to form a metal wiring 31 as shown in FIG. Further, an interlayer insulating film 32 is formed on the entire surface.

  In the present embodiment, when forming PMD using polysilazane, gelation of polysilazane contained in the insulating film raw material is suppressed, so that stable process processing is possible.

(Embodiment 6)
Before supplying the coating liquid onto the semiconductor substrate, a step of providing a first wiring on the semiconductor substrate, a step of providing a through hole in the insulating film to expose the first wiring, and a conductive material embedded in the through hole An IMD (Inter-Metal Dielectric) can be formed by further providing a step of forming the second wiring.

  Such a method will be described with reference to FIGS.

  As shown in FIG. 24, a SiN film 36 and a PSZ film 37 are sequentially formed on a silicon substrate 34 provided with a metal wiring (for example, W) 35. The PSZ film 37 can be formed by the following method. That is, a coating film is formed by coating the entire surface of the substrate by spin coating using the same coating liquid as that of the first embodiment described above as an insulating film material. At this time, no. Back rinse and edge cutting of the back surface of the silicon substrate 24 are performed using the processing liquids 1 and 2. As already explained, no. By performing the back rinse using the treatment liquids 1 and 2, the gelation of lysilazane is suppressed. In addition, the drying time is shortened and the processing speed is shortened.

  After coating, baking is performed on a hot plate to volatilize and remove the solvent from the coating film. Next, an oxidation process is performed in an atmosphere containing water vapor to change the PSZ film 37 into the silicon dioxide film 41. This oxidation treatment is desirably performed at a low temperature so as not to affect the wiring.

  The silicon dioxide film 41 is subjected to lithography and RIE etching by a conventional method to form a contact hole 38 as shown in FIG. Further, the underlying SiN film 36 is removed by etching to expose the metal wiring 35.

  Next, a metal (for example, Al) is buried in the contact hole 38 by a conventional method, and a metal wiring 39 is formed as shown in FIG.

  In this embodiment, when forming an IMD using polysilazane, gelation of polysilazane contained in the insulating film raw material is suppressed, so that stable process processing is possible.

Process sectional drawing showing the manufacturing method of the semiconductor device in one Embodiment of this invention. Sectional drawing showing the process of following FIG. Sectional drawing showing the process of following FIG. Sectional drawing showing the process of following FIG. Sectional drawing showing the process of following FIG. Sectional drawing showing the process of following FIG. Sectional drawing showing the process of following FIG. Sectional drawing showing the process of following FIG. The graph showing the relationship between the acid value of a process liquid and the gelation start days of polysilazane. Process sectional drawing showing the manufacturing method of the semiconductor device in one Embodiment of this invention. FIG. 11 is a cross-sectional view illustrating a process following FIG. 10. FIG. 12 is a cross-sectional view illustrating a process following FIG. 11. Sectional drawing showing the process of following FIG. Process sectional drawing showing the manufacturing method of the semiconductor device in other embodiment of this invention. FIG. 15 is a cross-sectional view illustrating a process following FIG. 14. FIG. 16 is a cross-sectional view illustrating a process following FIG. 15. FIG. 17 is a cross-sectional view illustrating a process following FIG. 16. FIG. 18 is a cross-sectional view illustrating a process following FIG. 17. Process sectional drawing showing the manufacturing method of the semiconductor device in other embodiment of this invention. FIG. 20 is a cross-sectional view illustrating a process following FIG. 19. FIG. 21 is a cross-sectional view illustrating a process following the process in FIG. 20. FIG. 22 is a cross-sectional view illustrating a process following FIG. 21. FIG. 23 is a cross-sectional view illustrating a process following FIG. 22. Process sectional drawing showing the manufacturing method of the semiconductor device in other embodiment of this invention. FIG. 25 is a cross-sectional view illustrating a process following FIG. 24. FIG. 26 is a cross-sectional view illustrating a process following FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Coater cup; 2 ... Spin chuck; 3a ... Edge cut nozzle 3b ... Back side rinse nozzle; 4 ... Solvent bath; 5 ... Chemical solution nozzle 6 ... Dummy dispensing port; 7 ... Semiconductor wafer; 8 ... Coating film; liquid S ... coating solution; 10 ... silicon substrate; 11 ... SiO ₂ film 12 ... CMP stopper film; 13 ... STI trench 15 ... perhydropolysilazane (PHPS) film; 16 ... SiO ₂ film 18 ... gate insulating film; 19 ... first DESCRIPTION OF SYMBOLS 1 Gate (floating gate) electrode film 20 ... Interelectrode insulating film; 21 ... Second gate (control gate) electrode film 24 ... Silicon substrate; 25a, 25b ... Impurity region; 26 ... Gate electrode 27 ... Interlayer insulating film; 28 ... Polysilazane (PSZ) film; 29 ... SiN film 30 ... Contact hole; 31 ... Wiring; 32 ... Interlayer insulating film; 34 ... silicon substrate 35 ... metal wiring; 36 ... SiN film; 37 ... PSZ films; 38 ... contact hole 39 ... metal wiring; 40 ... SiO ₂ film; 41 ... SiO ₂ film.

Claims (5)

  A treatment liquid for dissolving polysilazane, characterized in that it contains terpenes at least in part and has an acid value of less than 0.036 mg KOH / g.   The treatment liquid for dissolving polysilazane according to claim 1, wherein the terpenes are selected from the group consisting of α-pinene, β-pinene and d-limonene. Supplying a coating liquid obtained by dissolving polysilazane in a solvent on a semiconductor substrate, and forming a coating film containing the polysilazane;
Supplying a rinsing liquid to the back surface of the semiconductor substrate to perform a back rinse, and cleaning the back surface;
Drying the semiconductor substrate after the back rinse to remove the rinse liquid; and heat treating the semiconductor substrate to remove the solvent from the coating film to obtain an insulating film including a silicon oxide film. And
The method for manufacturing a semiconductor device, wherein at least a part of the solvent and the rinsing liquid are made of the polysilazane dissolving treatment liquid according to claim 1. Supplying a coating liquid obtained by dissolving polysilazane in a solvent on a semiconductor substrate, and forming a coating film containing the polysilazane;
Supplying a rinsing liquid to the edge portion of the semiconductor substrate to perform edge cutting;
Drying the semiconductor substrate after the edge cutting to remove the rinse liquid; and heat treating the semiconductor substrate to remove the solvent from the coating film to obtain an insulating film including a silicon oxide film. And
3. The method for manufacturing a semiconductor device according to claim 1, wherein at least a part of the solvent and the rinsing liquid is the polysilazane dissolution treatment liquid according to claim 1.   5. The method according to claim 3, further comprising a step of providing a groove in the semiconductor substrate before supplying the coating liquid onto the semiconductor substrate, wherein the insulating film is embedded in the groove. Semiconductor device manufacturing method.

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