WO2006022334A1

WO2006022334A1 - Method for manufacturing semiconductor device

Info

Publication number: WO2006022334A1
Application number: PCT/JP2005/015444
Authority: WO
Inventors: Miho Jomen; Kenichi Hara
Original assignee: Tokyo Electron Limited
Priority date: 2004-08-26
Filing date: 2005-08-25
Publication date: 2006-03-02
Also published as: JP2006063386A

Abstract

A method for manufacturing a semiconductor device, characterized in that it comprises a step of etching an insulating film, to form a concave portion, a step of filling the concave portion with copper, to form a copper wiring, a step of subjecting the surface of the copper filling the above concave portion to a displacement plating with palladium, by the use of a displacement plating solution prepared by dissolving palladium in a solution of an organic acid having a carboxyl group, and a step of forming an adhered layer on the surface of the copper layer being displacement-plated with palladium by the use of an electroless plating solution.

Description

Specification

Manufacturing method of semiconductor device

Technical field

The present invention relates to a method of manufacturing a semiconductor device that includes a copper wiring embedded in an insulating film and on which a noria film is formed by electroless plating.

Background art

In recent years, a wiring technique using a copper wire instead of an aluminum wire has been implemented in response to a demand for improving the performance of a semiconductor device (semiconductor device). Copper has the characteristics that it has a lower resistance than aluminum and is excellent in electo-hole migration resistance (EM resistance), but also has a problem that it has a high possibility of diffusion into the semiconductor substrate and is easily oxidized. is doing. For this reason, various noria materials called noria metals and protective films are used between copper and an interlayer insulating film (hereinafter abbreviated as “insulating film”) wired in a multilayer structure in a semiconductor device. Yes.

[0003] In one of the methods for realizing the copper multilayer wiring as described above, in the damascene process, the surface of the insulating film in which the recess for embedding the wiring is formed is a barrier material such as tantalum nitride or titanium nitride ( Copper (Cu) for wiring is buried on it, and the surface is polished by a polishing process called CMP (Chemical Mechanical Polishing), so that copper and barrier in parts other than the recesses are covered. The material is removed. Then, an insulating film at the next stage is formed so as to close the upper part of the recess.

[0004] Here, if the next-stage insulating film is formed as it is on the copper wiring, copper diffuses into the insulating film. Therefore, it is necessary to form a noria film on the upper surface of the buried copper. Conventionally, silicon nitride, silicon carbide, silicon nitride carbide, or the like has been used as this noria film. For example, when a carbon-containing silicon oxide film (hereinafter referred to as “SiOC film”) is used as the insulating film, this noria film also serves as an etching stover at the time of etching.

[0005] However, a noria film formed of silicon nitride, silicon carbide, silicon nitride carbide, or the like has low adhesion to copper. For this reason, for example, when current flows through the copper wiring, As shown in the figure, the adhesiveness is poor, and the noria film 110 cannot physically hold the copper (copper atom) of the copper wire 101, and the copper atom moves to the interface with the noria film 110. In some cases, a space 111 called a void is formed. The copper atoms on the surface of the part where the space 111 is formed and no longer in contact with the noria film 110 are more easily moved.

110 will grow even bigger. As a result, the electrical characteristics deteriorate, and there is even a concern that the copper wiring 101 will eventually break. In FIG. 9, 112 is a barrier material, and 113 is a SiOC film which is one of insulating films.

On the other hand, recently, in order to improve the adhesion between copper and the barrier film 110, it has been proposed to form an adhesion layer (adhesion film) by electroless plating (for example, JP 2001—230220 (see paragraphs 0012-0015). In this method, first, as a pretreatment, a hydrochloric acid solution of palladium chloride is supplied to the surface of the semiconductor substrate on which the copper wiring is formed, and the upper surface force of the copper wiring is utilized by utilizing the difference in ionization tendency between copper and palladium. Substitution with S palladium forms a catalytically active layer. Subsequently, an electroless plating solution is supplied to the surface of the semiconductor substrate in place of the hydrochloric acid solution, and the CoWP (CoWP ( Adhesion layers such as cobalt tungsten containing phosphorus and NiWP (nickel tungsten containing phosphorus) are formed. Thereafter, a noria film 110 is formed on the upper surface of the adhesion layer. That is, the above publication describes that after the copper wiring is formed, the upper surface of the copper wiring is subjected to a sticking process to form an adhesion layer, and this adhesion layer is formed by adhesion between copper and the barrier film 110. It has the role of preventing the copper from diffusing into the insulating film.

[0007] However, when palladium substitution is performed using a hydrochloric acid solution of salt-palladium, the substitution reaction between copper and palladium proceeds because hydrochloric acid has a strong acid scent. On the other hand, for example, as shown in FIG. 10, so-called crevice corrosion is promoted at a portion in contact with the barrier material 112 on the surface of the copper wiring 101, particularly the side peripheral surface, that is, the copper is dissolved. There is a problem of end. Considering the ionization tendency, copper seems to be a substance that does not dissolve in hydrochloric acid. However, the barrier material 112 contains a metal such as tantalum (a metal different from copper). It is speculated that crevice corrosion like this will be promoted. The space 111 due to crevice corrosion remains unfilled even if an adhesion layer is formed. That is, a space 111 is formed between the noria material 112 and the copper wiring 101. As described above, the space 111 can cause deterioration of electrical characteristics and disconnection.

[0008] In recent years, semiconductor devices have been increasingly miniaturized and highly integrated. Along with this, there is a demand for the line width of the copper wiring 1 to be, for example, 65 nm or less, and further 45 nm or less. When the line width is large, a decrease in electrical characteristics caused by the formation of the space 111 is rarely a problem. However, when the line width is small as described above, the ratio to the line width increases even in a space of the same size, so the degree of reduction in electrical characteristics is large. For example, the wire breakage may occur after several tens of hours of use, and the fact is that the influence of the space 111 cannot be ignored.

[0009] In addition, as a technique for electroless plating, Japanese Patent Application Laid-Open No. 7-183327 (paragraph 0020) describes a palladium aqueous solution before electroless nickel plating is performed on the surface of aluminum which is an input / output terminal of a semiconductor chip. It is described that the pretreatment is performed. In addition, the publication discloses that an organic acid palladium such as palladium citrate is used as a noradium aqueous solution. However, there is no description relating to electroless plating on copper wiring.

[0010] The present invention has been devised to pay attention to the above problems and to effectively solve them. It is an object of the present invention to suppress etching of the surface of the copper wiring and replace the surface of the copper wiring embedded in the recess formed in the insulating film with good electrical characteristics over a long period of time. Another object of the present invention is to provide a semiconductor device manufacturing method capable of manufacturing a semiconductor device that can be maintained.

[0011] A method for manufacturing a semiconductor device of the present invention includes a step of etching a dielectric film to form a recess, a step of embedding copper in the recess to form a copper wiring, and a solution of an organic acid having a carboxyl group. Using a displacement plating solution formed by dissolving palladium, the step of depositing the surface of copper embedded in the recesses with palladium, and the electroless plating solution on the surface of the copper substituted with palladium. And a step of forming an adhesion layer using the method. A method for manufacturing a semiconductor device, comprising:

[0012] The copper surface embedded in the recess is, for example, the surface of a damascene copper wiring. [0013] The organic acid preferably contains at least one of malic acid and malonic acid.

In addition, the method for manufacturing a semiconductor device of the present invention may further include a step of interposing a noria material containing a metal different from copper between the copper wiring and the insulating film.

[0015] According to the present invention, the surface of the copper wiring is attached to the surface of the copper wiring by using a replacement adhesive solution obtained by dissolving palladium in a solution of an organic acid having a carboxyl group. Due to the small repulsive force, copper is less likely to be etched on the surface of the copper wiring, particularly at the interface with the noria material, when the copper is replaced with radium. For this reason, as a result of less space (gap) being formed between the barrier material and the copper wiring, a semiconductor device having a copper wiring that can maintain good electrical characteristics over a long period of time is manufactured. can do.

[0016] Further, according to the present invention, even when a natural oxide film is formed on the surface of the copper wiring before performing the palladium substitution plating, the organic acid having a carboxyl group is selected. It is possible to remove this acid film without dissolving it. For this reason, palladium can be uniformly deposited on the upper surface of the copper wiring, and as a result, an adhesive layer having high adhesion can be uniformly formed on the surface of the copper wiring by utilizing the catalytic action of the palladium. it can. For this reason, it is possible to suppress the diffusion of copper into the substrate, and more reliably maintain good electrical characteristics over a long period of time.

Brief Description of Drawings

FIG. 1A to FIG. 1D are explanatory views showing the state of a wafer processed by the semiconductor device manufacturing method of the present invention.

FIG. 2A to FIG. 2D are explanatory views showing the state of a wafer processed by the semiconductor device manufacturing method of the present invention.

FIG. 3 is an explanatory view showing a state of the surface of a wafer to be replaced.

FIG. 4 is a longitudinal sectional view showing an example of an apparatus used for carrying out the method for manufacturing a semiconductor device of the present invention.

[FIG. 5] FIG. 5 shows SEM imaging results of the surface of the wafer after the noradium substitution plating was carried out in an example carried out to confirm the effect of the present invention. [FIG. 6] FIG. 6 is a result of SEM imaging of the surface of the wafer after the adhesion layer was formed in the example performed to confirm the effect of the present invention.

[FIG. 7] FIG. 7 is a SEM imaging result of the surface of the wafer after the noradium substitution plating was performed in the comparative example performed to confirm the effect of the present invention.

FIG. 8 is a result of SEM imaging of the surface of the wafer after the adhesion layer was formed in a comparative example performed to confirm the effect of the present invention.

FIG. 9 is an explanatory view showing a state in which a space has been formed between the copper wiring and the barrier material.

[FIG. 10] FIG. 10 is an explanatory view showing a state of a copper wiring replaced with a hydrochloric acid solution of palladium.

BEST MODE FOR CARRYING OUT THE INVENTION

A method for manufacturing a semiconductor device according to an embodiment of the present invention will be described with reference to FIGS. 1A to 1D and FIGS. 2A to 2D. 1A to 1D and 2A to 2

D is a cross-sectional view of the surface portion of the semiconductor device.

First, a semiconductor wafer (hereinafter referred to as “wafer”) W, which is a substrate to be processed on which a semiconductor device is formed, will be described. As shown in FIG. 1A, an etch stopper layer is formed on the upper surface of, for example, a silicon oxide film (SiO 2) 20 as an underlying insulating film on the surface portion of the wafer W.

2

For example, a silicon nitride film (SiN) 22 having a thickness of 400 A is formed. Further, an SiOC film (carbon-containing silicon oxide film) 21 having a thickness of 700 A, for example, is laminated on the upper surface as an insulating film for the next stage.

[0020] Here, an example of a method for forming the SiO film 20, the SiOC film 21, and the SiN film 22 will be described.

2

Light up. Any of these films can be formed by a plasma film forming process. More specifically, each film is formed by placing the wafer w in an evacuated vacuum container and supplying a predetermined deposition gas for each film into the vacuum container to form a plasma. Can be membrane.

[0021] For example, CF gas or CF gas is etched on the wafer W as shown in FIG. 1A.

4 4 8

By using the etching gas, the SiOC film 21 is etched into a predetermined pattern. At this time, the underlying SiN film 22 acts as an etching stopper. As a result, Figure 1 As shown in B, in the SiOC film 21, a recess (contact hole) 200 having a line width of 64 nm or less, preferably 45 nm or less, for embedding copper for wiring is formed.

Subsequently, as shown in FIG. 1C, the surface force of the SiOC film 21 including the recess 200 is covered with a noria material (barrier metal) 24 such as tantalum nitride or titanium nitride. Subsequently, copper is embedded in the recess 200, for example, by sputtering. Thereafter, for example, by performing CMP polishing in which free particles are supplied to the surface and chemically polished, the copper and the barrier material 24 in portions other than the recesses 200 are removed as shown in FIG. 1D. As a result, the copper wiring 25 is formed in the recess 200.

[0023] Then, a substitution squeezed solution prepared by dissolving palladium in a solution of an organic acid having a carboxyl group, for example, a solution of an organic acid containing at least one of malic acid or malonic acid is prepared. . Then, palladium is selectively deposited on the upper surface of the copper wiring 25 by supplying the replacement plating solution onto the surface of the wafer W in FIG. 1D. Here, palladium does not precipitate on the SiOC film 21 and the barrier material 24 in the surface of the wafer W. That is, palladium is selectively deposited on the upper surface of the copper wiring 25. As a result, a noradium film 26 is formed (with palladium substitution).

[0024] Here, a supplementary explanation will be given for the substitution sachet used for the palladium substitution stake. For example, an aqueous organic acid solution can be produced by adding a predetermined amount of an organic acid to a solvent such as water. While adjusting the temperature of this organic acid aqueous solution to, for example, 60 ° C., for example, powdery palladium sulfate is added and dissolved so as to have, for example, 0.1 lgZ liter, whereby a suitable replacement squeezing solution can be obtained. . When the concentration of the organic acid is increased, the complex formation reaction in which the organic acid reacts with palladium to form a complex is promoted, and the precipitation of palladium is suppressed. Accordingly, the concentration of the organic acid is preferably set to a concentration that does not promote the complex formation reaction, specifically 15 to 25 gZ liters.

[0025] Such a substitution squeeze solution is adjusted to a predetermined temperature, for example, a temperature selected within a range from room temperature to 60 ° C, and is tempered to the same temperature as the replacement squeeze solution, for example. Supplied to the surface of the wet Ueno, W. Thus, for example, as schematically shown in FIG. 3, the redox potential is small at the interface between the copper wiring 25 and the substitution solution, and the copper is redox potential. The size of the electron! The received palladium is deposited on the surface of the copper wiring 25. At this time, if a natural oxide film (copper oxide) is formed on the surface of the copper wiring 25, the natural oxide film is dissolved by the presence of the carboxyl group. That is, by using the difference in ionization tendency between copper and palladium, the surface of the copper wiring 25 is selectively plated with palladium. Thereby, for example, a palladium film 26 having a thickness of 10 A is formed. Since the catalyst activity is high, the surface of the copper wiring 25 is activated. The palladium substitution suffices to deposit an amount of noradium that acts as a catalyst for forming the adhesion layer described later. In this specification, for the sake of convenience, the term “noradium film 26” is used. However, in practice, even if palladium is not formed on a film that covers the entire upper surface of the copper wiring 25, an amount of palladium that acts as a catalyst is present. It should be deposited.

Subsequently, a cleaning liquid such as pure water is supplied to the surface of the wafer W, and the surface of the wafer W is cleaned. Thereafter, a predetermined electroless plating solution for forming an adhesion layer (adhesion film) (hereinafter referred to as “treatment solution” for convenience of explanation) is supplied to the surface of the wafer W. At this time, palladium deposited on the surface in the process acts as a catalyst, and the surface of the copper wiring 25 is made of an alloy containing phosphorus (P) selectively, for example, an adhesion layer such as NiWP, NiP, CoP, CoWP 27 Is formed. The adhesion layer 27 has a film thickness of 100 to 200 A, for example. The treatment liquid is a metal salt containing the components that form the adhesion layer 27 (first metal salt and second metal salt in the case of an alloy), and metal ions precipitate as hydroxides under strong alkalinity. It contains a complexing agent for complexing metals, a reducing agent for catalytically reducing and precipitating metal ions, and a pH adjusting agent for adjusting the pH of the liquid. For example, depending on the type of adhesion layer 27 to be formed, at least one of the components listed below as the metal salt, complexing agent, reducing agent, and pH adjusting agent is selected, and a solvent such as A treatment liquid can be prepared by adding to pure water at a predetermined ratio.

[0027] That is, the first metal salt can be selected from, for example, cobalt sulfate, cobalt chloride, nickel sulfate, and nickel chloride.

[0028] As the second metal salt, for example, tungstic acid, sodium tungstate, and ammonium tungstate can be selected.

[0029] The complexing agent may be selected from, for example, citrate and sodium citrate. [0030] The reducing agent may be selected from, for example, hypophosphorous acid, sodium hypophosphite, and ammonium hypophosphite power.

[0031] The pH adjuster may be selected from sodium hydroxide and TMAH (tetramethylammonium hydroxide).

[0032] The components listed above are merely examples, and it is not always necessary to use these components. Further, in order to suppress a change in pH when the reduction reaction proceeds, a stabilizer such as boric acid, carbonic acid, or oxycarboxylic acid may be added. Furthermore, additives such as thiosulfuric acid and 2-MBT may be added to promote or suppress the deposition of the plating film, or to modify the plating film. Furthermore, a surfactant such as polyalkylene glycol or polyethylene glycol may be added in order to reduce the surface tension of the plating solution so that the plating solution is uniformly disposed on the surface of the wafer W. .

[0033] Such a processing liquid is temperature-controlled at a predetermined temperature, for example, a temperature selected within a range of 60 to 90 ° C. For example, the wafer W in a state where the temperature is adjusted to the same temperature as the processing liquid. Supplied on the surface. At this time, palladium acts as a catalyst on the surface of the copper wiring 25 with the radium substitution, and the metal ions in the treatment liquid are deposited, for example, an adhesion layer 27 having a film thickness of 100 to 200 A is formed. .

Thereafter, the wafer W is cleaned using a cleaning liquid such as pure water, and the wafer W is further dried. Thereafter, using the above-described method, for example, a silicon nitride film 28 is formed on the surface of Ueno and W (see FIG. 2C), and further, for example, a SiOC film 21 is formed on the upper surface as an insulating film of the next stage (see FIG. 2). (See 2D). The above-described processing is performed on the SiOC film 21 in substantially the same manner. As a result, the next-stage copper wiring is formed.

[0035] As described above, according to the present embodiment, a replacement sticking solution prepared by dissolving, for example, palladium sulfate in a solution of an organic acid having a carboxyl group is prepared, and the replacement sticking solution is used as a wafer. Supply to the surface of the copper wiring 25 of W to perform palladium substitution. Here, since the organic acid having a carboxyl group has a relatively small oxidizing power, even in a region where the copper wiring 25 is in contact with the barrier material 24 (the noria material can be a different metal from copper) It is unlikely that crevice corrosion will occur at the contact surface (interface) during copper displacement plating and copper will be dissolved. In other words, a space (corresponding to space 111) is formed between Noria 24 and copper wiring 25. It is rarely made. As a result, it is possible to manufacture a semiconductor device including the copper wiring 25 that can maintain good electrical characteristics over a long period of time.

[0036] Further, an organic acid having a carboxyl group (for example, malate or malonic acid) has an action of dissolving copper oxide. Therefore, for example, even if the wafer W before being replaced with palladium is exposed to an oxygen-containing atmosphere and a natural oxide film is formed on the upper surface of the copper wiring 25, the copper wiring 25 is not removed at the time of replacing with nitrogen. Only the natural acid film can be dissolved and removed without melting. As described above, palladium substitution is performed by utilizing the difference in ionization tendency between copper and palladium, so that the surface of the copper wiring 25 is covered with an acid film (acid copper). In some cases, the transfer of electrons between copper and palladium is suppressed, and the deposition of palladium may not proceed. However, according to the present embodiment, the palladium substitution reaction proceeds while removing the copper oxide from the carboxyl group contained in the substitution plating solution. Palladium can be deposited well on the surface. In other words, for example, means and management for preventing the natural oxide film from being formed on the wafer W so as not to be exposed to an atmosphere containing oxygen can be simplified or omitted.

[0037] As described above, when a wiring is formed by embedding a metal in the recess 200 formed in the SiOC film 21, the surface of the recess 200 is covered with the noble material 24 and the metal is also embedded in the force. . For this reason, the copper wiring 25 and the barrier material 24, which may be different types of metals, are present on the surface of the wafer W to be subjected to palladium substitution. On the other hand, it is necessary to select an acid that can dissolve palladium in order to prepare a nodule-containing solution. Such an acid tends to crevice the copper at the interface with the barrier material 24 (the present inventors have found that for oxalic acid, and when palladium has been dissolved for a long time, palladium precipitates in the solution. To make sure) In other words, when palladium displacement plating is applied to copper wiring, there is a trade-off between suppressing copper etching (corrosion) and stably dissolving noradium. The inventors of the present invention, paying attention to this point, have intensively studied the selection of an organic acid that does not dissolve copper while dissolving palladium, and has reached the present invention.

[0038] As described above, an organic acid solution having a low acidity is selected as a palladium solvent. As a result, the etching of the copper wiring can be suppressed, while the noradium substitution plating can be performed stably.

[0039] It should be noted that the present invention does not exclude the inclusion of hydrochloric acid or sulfuric acid in the replacement sachet at the time of filing the present application. If the base of the solution is an organic acid, a trace amount of hydrochloric acid or sulfuric acid may be contained as an additive. Even with such a substitution solution, the same effect as in the above embodiment can be obtained.

[0040] Next, in the above manufacturing method, an example of an apparatus used for the process of attaching palladium to the surface of the copper wiring 25 and the process of forming the adhesion layer 27 by electroless adhesion Will be described with reference to FIG. However, this does not limit the present invention.

As shown in FIG. 4, the back surface side force is also supported horizontally by the plurality of support tongues 30 of the wafer chuck 3 that constitutes the substrate support portion of the peripheral portion of the wafer W that is a semiconductor device. A central portion of the bottom plate of the wafer chuck 3 is connected to a rotation driving unit, for example, a hollow motor 32 via a cylindrical rotating shaft 31, for example. By the hollow motor 32, the substrate chuck 3 is configured to be rotatable about the vertical axis while supporting the wafer W.

[0042] The inner region surrounded by the plurality of support tongues 30 of the wafer chuck 3 can be opposed to the back surface of the wafer W through a gap and has, for example, a temperature control plate having substantially the same size as the wafer W. 33 is provided to be movable up and down. The temperature adjustment plate 33 includes a heating means (not shown) such as a heater inside. Further, the temperature control plate 33 is supported at the center on the back surface side thereof by, for example, a tubular support member 34 that is suspended. In addition, the lower side of the support member 34 is connected to an elevating unit (not shown) for elevating the temperature adjustment plate 33. Further, in the center of the surface of the temperature control plate 33, a small diameter for supplying (discharging) a temperature adjusting liquid, for example, temperature-controlled pure water, to the back surface of the wafer W in order to adjust the wafer W to a predetermined temperature. A discharge port 35 is formed. The discharge port 35 includes a liquid flow path 36 which is an internal space of the tubular support member 34, and a liquid supply path 37 connected to the liquid flow path 36, for example, a supply source of the temperature adjusting liquid via a pipe. Connected with 38. In the middle of the liquid supply path 37, a flow rate adjusting unit and a valve (not shown) can be provided.

[0043] Further, the side of the wafer W supported by the wafer chuck 3 is surrounded so as to receive liquid. A cup body 4 is provided to be movable up and down. A drain discharge port 41 is provided at the bottom of the cup body 4 for discharging the liquid spilled from the wafer W as a drain. Note that a power cup body 4 that is not shown is provided around the periphery of the force cup body 4 and is provided with a housing that forms an apparatus exterior body. The active gas will be filled!

[0044] The upper surface side of the wafer W supported by the wafer chuck 3 is opposed to the surface of the wafer W through a gap in the range of 0.1 to 2 mm, for example, and is the same as the Ueno and W. Alternatively, a liquid supply plate 5 having a size larger than that of the wafer W is provided to be movable up and down. The liquid supply plate 5 includes heating means (not shown) such as a heater. In addition, a plurality of discharge holes 51 for supplying either the processing liquid or the cleaning liquid to the surface of the wafer W are uniformly formed in the surface of the liquid supply plate 5. The liquid supply plate 5 is provided with a liquid storage section (not shown) for supplying the treatment liquid and the cleaning liquid to the discharge holes 51. A liquid supply path 52, for example, one end of a pipe is connected to the liquid reservoir. The other end of the liquid supply path 52 is connected to a processing liquid supply source 53 and a cleaning liquid supply source 54, respectively. In the middle of the liquid supply path 52, a flow rate adjusting unit and a valve (not shown) are provided. In the figure, reference numeral 55 denotes a switching unit for switching the flow path of the processing liquid and the cleaning liquid, for example, a three-way valve operated by a control unit (not shown).

For example, on the upper surface side of the wafer W, in order to supply the above-described replacement squeezing liquid to the surface of the wafer W, for example, the length (diameter) of the wafer W is more than half the width (diameter), that is, more than the radius A liquid supply nozzle 6 having a slit-like discharge port 60 formed in a length is provided so as to be movable up and down and back and forth. The liquid supply nozzle 6 is connected to a replacement liquid supply source 62 via a supply path 61 such as a pipe. In the middle of the supply path 61, a flow rate adjusting unit and a valve (not shown) are provided.

[0046] Furthermore, on the upper surface side of the wafer W, for example, the width of the wafer W for supplying a drying gas, for example, an inert gas such as nitrogen whose temperature and humidity are adjusted, to the surface of the wafer W is provided. A gas supply nozzle 7 having a slit-like discharge port 70 formed to have a length of more than half of (diameter), that is, a length of radius or more, is provided so as to be movable up and down and back and forth. this The gas supply nozzle 7 is connected to a drying gas supply source 72 via a supply path 71 such as a pipe. In the middle of the supply path 71, a flow rate adjusting unit and a valve (not shown) are provided.

[0047] A procedure for forming the palladium layer 26 and the adhesion layer 27 on the surface of the wafer W using the semiconductor device manufacturing apparatus described above will be described. First, the liquid supply plate 5 is set to its raised position and the cup body 4 is set to its lowered position so that it does not interfere with the wafers W and W that are carried in and out of the apparatus by a substrate transfer arm (not shown). . In this state, for example, a wafer W as shown in FIG. 1D is loaded. Wafer W is transferred to wafer chuck 3 and held in a horizontal position.

[0048] After that, while the substrate transfer means that has transferred Ueno and W moves backward, the cup body 4 moves to its raised position (the position shown in FIG. 4). Further, the temperature adjusting plate 33 heated to a predetermined temperature by the internal heater 33 force rises to a position of a separation distance of 0.1 to 2 mm, for example, with respect to the back surface of the wafer W, and is discharged from the discharge port 35 formed on the front surface. The temperature adjustment liquid adjusted to a predetermined temperature is discharged toward the back surface of the wafer W. The temperature adjusting liquid supplied to the back surface of the wafer W spreads over the entire back surface of the wafer W by spreading the gap between the wafer W and the temperature control plate 33 from the center to the outside. As a result, the wafer W is adjusted to a predetermined temperature, for example, a temperature selected within a range from room temperature to 60 ° C.

Subsequently, pure water is supplied to the surface of the wafer W, for example, as necessary. Thereafter, the arrangement of the liquid supply nozzle 6 is set so that the projected region of the slit-like discharge port 60 is set at a position straddling the outer edge of the central force of the wafer W, for example. Then, from the discharge port 60, the displacement squeezing liquid force adjusted to a predetermined temperature, for example, the same temperature as the wafer W, is discharged toward the surface of the wafer W at a predetermined flow rate. At this time, the wafer W is rotated by the hollow motor 32 at least once around the vertical axis. As a result, the replacement plating solution is supplied to the entire surface of the wafer W. Then, a liquid film (paddle) of the replacement plating liquid having a thickness of 2 mm, for example, is formed by the surface tension of the replacement plating liquid. Thereafter, the liquid supply nozzle 6 that stopped discharging moves backward. On the other hand, the state force with the replacement liquid on the surface is maintained for a predetermined time, for example, 30 seconds. Thereby, as described in detail above, the substitution reaction of copper and palladium proceeds, and the palladium layer 26 is formed on the upper surface of the copper wiring 25. Thereafter, for example, the liquid supply plate 5 heated to a predetermined temperature by an internal heater is lowered to the predetermined height position. Then, a cleaning liquid adjusted to a predetermined temperature, for example, 60 to 90 ° C., is supplied toward the wafer W through the discharge holes 51. Thereby, the displacement plating solution is removed from the surface of the wafer W. At the same time, the temperature of the temperature adjustment liquid supplied from the discharge port 35 of the temperature adjustment plate 33 is changed to adjust the wafer W to a predetermined temperature for electroless plating, for example, 60 to 90 ° C.

Subsequently, the liquid cleaning liquid discharged from the discharge holes 51 of the liquid supply plate 5 is switched to the processing liquid. As a result, the cleaning liquid on the surface of the wafer W is replaced with the processing liquid. The gap between the wafer W and the liquid supply plate 5 is filled with the processing liquid by the surface tension of the processing liquid. Then, the state in which the processing liquid is accumulated on the surface is held for a predetermined time, for example, 60 seconds. Thereby, as described in detail above, the electroless plating reaction proceeds by the catalytic action of palladium, and the adhesion layer 27 is formed on the upper surface of the copper wiring 25 (the upper surface of the palladium layer 26).

Thereafter, the liquid discharged from the discharge holes 51 is switched again to the cleaning liquid, and the processing liquid is removed from the surface of the wafer W. That is, the surface of the wafer W is cleaned. Subsequently, the arrangement of the gas supply nozzle 7 is set so that the projection area of the slit-like discharge port 70 is set at a position where, for example, the central force of the wafer W also straddles the outer edge. Then, the drying gas whose temperature and humidity are adjusted is discharged from the discharge port 70. At this time, the wafer W is rotated at high speed around the vertical axis by the hollow motor 32. As a result, spin drying is performed to shake off the liquid. That is, the wafer W is dried. The dried wafer W (corresponding to FIG. 2B) is also unloaded by a substrate transfer arm (not shown) and transferred to a device for processing the next process.

Each process performed in the semiconductor device manufacturing apparatus described above can be controlled by the computer device 80. The program executed in the computer device 80 for the control and the computer-readable recording medium including the program are also subject to protection in this case.

[0054] Examples carried out to confirm the effects of the present invention will be described below.

[Example 1] In this example, palladium substitution plating was performed using the above-mentioned substitution plating solution. Thereafter, the wafer was washed with water, and further a processing solution was supplied, and an adhesion layer 27 was formed by electroless plating. Details of the test conditions are as follows.

1. With palladium substitution

• Plating solution composition

Malic acid: 20gZ liter

Palladium sulfate: lgZ liter

• Processing temperature: 60 ° C

• Processing time: 30 seconds

2. Electroless plating

'Processing liquid composition: Cobalt sulfate, tungstic acid, citrate, hypophosphorous acid, TMAH • Processing temperature: 60 ° C

• Processing time: 60 seconds

Figure 5 shows the SEM imaging results of the surface of the wafer W after the palladium replacement plating. Figure 6 shows the SEM imaging results of the surface of the wafer W after the adhesion layer 27 is formed.

[0056] (Comparative Example 1)

In this comparative example, a sulfuric acid solution of palladium was used as the substitution tacking solution. Except for this, the processing was performed in the same manner as in Example 1. Details of the plating solution are as follows.

• Plating solution composition

Sulfuric acid: 4. 8% appropriate amount of sulfuric acid

Palladium sulfate: lgZ liter

Fig. 7 shows the SEM imaging results of the surface of wafer W after the palladium replacement plating. Figure 8 shows the SEM imaging results of the surface of the wafer W after the adhesion layer 27 is formed.

[0057] (Results and Discussion of Example 1 and Comparative Example 1)

As is apparent from the image result of FIG. 5, in Example 1, after the palladium substitution staking, The copper wiring 25 is not etched, and no space is formed at the interface with the noria material 24.

On the other hand, as is apparent from the image result of FIG. 7, in Comparative Example 1, the upper surface of the copper wiring 25 is etched, and a space is formed at the interface with the noria material 24.

Further, as is apparent from the results shown in FIGS. 6 and 8, if a space is formed at the time of palladium substitution, the space remains unfilled even if the adhesion layer 27 is formed. By using the replacement plating solution of Example 1 (substitution solution obtained by dissolving palladium in malic acid), the copper wiring 25 can be prevented from being etched at the time of palladium replacement and copper wiring. It was confirmed that the formation of a space between 25 and the barrier material 24 was significantly suppressed.

(Example 2)

In this example, in order to confirm the action of the carboxyl group, the substitution squeezing solution of Example 1 was supplied to the wafer W that was exposed to the air atmosphere and formed with a natural acid film on the surface. .

As a result, it was confirmed that the copper was not etched on the surface of the copper wiring 25 after the treatment and that the oxide film was removed. That is, if an organic acid having a carboxyl group is selected, it is confirmed that even if an acid film is formed on the surface of the copper wiring 25, the oxide film can be removed and palladium can be deposited. did it.

Claims

The scope of the claims

[1] etching the insulating film to form a recess;

Forming copper wiring by embedding copper in the recess;

A step of attaching the surface of the copper embedded in the concave portion with palladium using a substitution adhesive solution obtained by dissolving palladium in a solution of an organic acid having a carboxyl group; Forming an adhesion layer on the surface using an electroless plating solution;

A method for manufacturing a semiconductor device, comprising:

[2] The organic acid contains at least one of malic acid and malonic acid

The method for manufacturing a semiconductor device according to claim 1, wherein:

[3] A step of interposing a noria material including a metal different from copper between the copper wiring and the insulating film

The method for manufacturing a semiconductor device according to claim 1, further comprising:

[4] etching the insulating film to form a recess;

Forming copper wiring by embedding copper in the recess;

For manufacturing a semiconductor device comprising

A computer-readable recording medium including a program for controlling the computer.