JP2008223082A - Additive for copper plating, copper plating liquid using the additive for copper plating and copper electroplating method using the copper plating liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an additive for copper plating by which a stable effect can be obtained even if an insoluble anode is used. <P>SOLUTION: In the additive for copper plating containing a polyalkene oxide compound, the polyalkene oxide compound has constitutional formula, shown below, to which a functional group or halogen element is introduced in either one or both of its terminals and has a number average molecular weight of 100 to 2,000,000. When m in the constitutional formula is specified to 1 to 8 and R<SB>1</SB>or R<SB>1</SB>is defined as a functional group, the functional group is defined as any functional group selected from a functional group including a sulfonic group, N or S and a functional group selected from a functional group having an unsaturated bond. Further, when the additive for copper plating including the polyalkene oxide compound of 10,000 to 2,000,000 in molecular weight is employed, there is no need for making combination use of the additives, such as bis(3-sulfopropyl) disulfide and janus green, and the more preferable copper plating can be performed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an additive for copper plating, a copper plating solution using the copper plating additive, and an electrolytic copper plating method using the copper plating solution.

  In recent years, electronic devices typified by mobile phones and personal computers have been remarkably reduced in size, increased in density, and improved in performance, and printed wiring boards used for these have been required to be lighter, thinner, and smaller. On the other hand, higher speed and higher capacity of semiconductor devices are progressing simultaneously. Further, a package wiring board on which a semiconductor device is mounted is required to be lighter, thinner and smaller than a general multilayer printed wiring board.

  As a technique for manufacturing a multilayer printed wiring board having the above-mentioned fine wiring, a build-up method has attracted attention. In this build-up method, via filling is performed in which the formed small-diameter via hole is filled with copper plating as a method of electrically connecting the inner layer wiring and the outer layer wiring or the interlayer between the inner layer wirings.

  Therefore, Patent Document 1 discloses an acidic copper plating bath that can perform copper plating with high reliability on a substrate having a microhole such as a through hole or a via hole, or a resin film having a surface coated with a metal such as copper. And (a) polymer of alkylamine and glycols 0.01-2 g / L (b) polymer component 0.01-10 g / L (C) Carrier component An additive for an acidic copper plating bath containing 0.02 to 200 mg / L, an acidic copper plating bath containing the additive, and a plating method using the plating bath are disclosed.

  Patent Document 2 discloses a method of performing copper sulfate plating using a copper sulfate plating bath containing a polyethylene glycol (Poly-Ethylene Glycol: hereinafter referred to as “PEG”) derivative and not containing chloride ions. It is disclosed.

  Non-Patent Document 1 and Non-Patent Document 2 disclose that copper sulfate plating is performed using a copper sulfate plating bath containing a PEG derivative having a molecular weight of 4000 and not containing chloride ions.

Patent Document 3 discloses a defect-free embedded copper plating for a plating surface having a sub-μm level gap such as a minute via or a trench or a relatively wide gap of several tens to several hundreds of μm. As a copper sulfate plating solution for embedding that can be performed and has a very smooth copper plating process, a polymeric surfactant that suppresses the electrodeposition reaction, a sulfur-based saturated organic compound that accelerates the electrodeposition rate, and smoothness control In the embedding copper sulfate plating solution containing the leveling agent, the leveling agent is a general formula (C ₃ H ₉ N) _x · (C ₃ H ₅ ClO) _y (wherein x and y are arbitrary) A positive integer), more specifically, any one or two of polyepichlorohydrin, polyepichlorohydrindiol, or polyepichlorohydrintriol, or 2 The thing using the organic type compound chosen from the seed | species or more is disclosed.

  In the above document, an additive for suppressing the electrodeposition reaction, an additive for accelerating the electrodeposition rate, and smoothness are used in order to reduce defects when performing the filling plating of fine vias using the copper plating method. It is disclosed that a copper plating solution containing at least three kinds of additives for controlling the above is used. An example is disclosed in which PEG is used as an additive for suppressing the electrodeposition reaction, the molecular weight of which is 1000 to 6000, and about 10,000 at the maximum. Moreover, it is disclosed that in these copper plating solutions, the chlorine concentration is adjusted to about 0.04 g / L to obtain the effect of an additive that suppresses the electrodeposition reaction.

  As described above, in order for the PEG contained in the copper plating solution to suppress the electrodeposition reaction, a combination with chlorine is required, and a certain amount of chlorine is required in the copper plating solution. is there. The deposited copper layer also takes in chlorine adsorbed on the copper surface and exhibits certain characteristics. That is, the chlorine concentration in the copper plating solution decreases. And even if the chlorine concentration in the copper plating solution varies only slightly, the appearance, properties, etc. of the plated copper tend to be greatly affected. Therefore, in the copper plating solution containing chlorine, it is important to manage the chlorine concentration, which increases the management cost.

  Moreover, when performing electrolytic copper plating, in order to keep the fluctuation | variation of the copper concentration in a copper plating solution small, soluble anodes, such as phosphorous copper, are often used for an anode. Then, the anode is dissolved by electrolysis, and anode slime is generated. When this anode slime adheres to the material to be plated, it may be caught in the plating layer, and this portion becomes a defect in copper plating on a fine portion. Therefore, in order to avoid generation of anode slime, an insoluble anode such as a dimension stable anode (hereinafter referred to as “DSA”) in which a titanium plate is coated with iridium oxide or the like is often selected. .

JP 2003-328179 A JP-A-2005-256120 JP 2005-307259 A Sugimoto Masaharu, Yamaguchi Kazunori, Yoshimizu Hiroki, Kasai Hiroaki, Honma Hideo; Polymer Processing, Vol. Masahara Sugimoto, Kazuki Yamaguchi, Hiroaki Kousai, Hideo Honma; Journal of Applied Polymer Science, Vol. 96, 837-840 (2005)

  However, when electrolysis is performed using DSA or the like as an anode for a copper plating solution containing chlorine at a certain level, chlorine is gasified due to the influence of the oxidation reaction at the anode, and a larger amount than in the case of using a soluble anode is present in the copper plating solution. Will be lost from. Then, it becomes difficult for the additive which suppresses an electrodeposition reaction to exhibit the original suppression function stably. That is, the copper plating solution that requires the presence of chlorine has a disadvantage that the characteristics of the obtained plated copper vary greatly when DSA or the like is used for the anode. Therefore, in order to stably carry out copper plating with a good appearance on wiring boards and the like that are made finer, it is necessary to use a copper plating solution that can provide stable plated copper even when DSA or the like is used. .

  As described above, the amount of chlorine that can coexist in the copper plating solution can be reduced as much as possible, and if possible, the coexistence of chlorine is unnecessary. The resulting copper plating additive was sought.

  Therefore, the present inventors have conducted intensive research to solve the above-mentioned problems, an additive for copper plating containing a polyalkene oxide compound, a copper plating solution using the additive for copper plating, and its copper He came up with an electrolytic copper plating method using a plating solution.

Additive for copper plating according to the present invention: The additive for copper plating according to the present invention is an additive for copper plating containing a polyalkene oxide compound, and the polyalkene oxide compound is either one of its terminals or It has a structural formula shown in the following chemical formula 2 having both functional groups or halogen elements, and has a number average molecular weight of 100 to 2,000,000.

In the additive for copper plating according to the present invention, the functional groups R ₁ and R ₂ in the structural formula shown in Chemical Formula ₂ are selected from a sulfone group, a functional group containing N and S, and a functional group having an unsaturated bond. It is also preferred that any functional group is.

  In the additive for copper plating according to the present invention, m in the structural formula shown in Chemical Formula 2 is preferably 1-8.

Copper plating solution according to the present invention: The copper plating solution according to the present invention includes the additive for copper plating.

  In the copper plating solution according to the present invention, the concentration of the polyalkene oxide compound is also preferably 0.0001 g / L to 10 g / L.

  In the copper plating solution which concerns on this invention, it is also preferable to use 1 or more types selected from a sulfate ion or a halogen ion as an anion component.

  In the copper plating solution according to the present invention, it is also preferable to use cyan ion or pyrophosphate ion as the anion component.

The electrolytic copper plating method according to the present invention: copper plating method according to the present invention, using the copper plating solution is characterized by performing the electrolysis at cathode current density ^{0.1A / dm 2 ~50A / dm 2} .

  And in the electrolytic copper plating method which concerns on this invention, it is also preferable to perform the said electrolysis using an insoluble anode.

  When electrolytic copper plating is performed using a copper plating solution containing an additive for copper plating according to the present invention, good plated copper can be stably obtained even if the amount of chlorine in the copper plating solution is small. That is, even when this copper plating solution is used and electrolytic copper plating is performed using DSA or the like as an anode, the variation of the chlorine concentration in the copper plating solution is small. Therefore, if a copper plating solution is prepared using the additive for copper plating, copper plating such as bright copper plating and via filling is suitably performed using DSA or the like in the manufacturing process of miniaturized wiring boards and the like. can do.

  Form of additive for copper plating according to the present invention: The additive for copper plating according to the present invention is an additive for copper plating containing a polyalkene oxide compound. This polyalkene oxide compound is adsorbed on the copper surface deposited in the copper plating step and functions as an additive for controlling the electrodeposition reaction on the copper surface. The polyalkene oxide compound has a structural formula represented by the following chemical formula 3 having a functional group or a halogen element at one or both of its ends, and is referred to as a number average molecular weight (hereinafter simply referred to as “molecular weight”). ) Is 100 to 2,000,000.

  The polyalkene oxide compound contained in the additive for copper plating can be directly adsorbed on the deposited copper surface by providing a functional group or a halogen element at one or both of its ends. In other words, direct adsorption on the copper surface enables the amount of chlorine coexisting in the copper plating solution to be small, or control the copper precipitation state and make the precipitation uniform without intentional addition. become. Therefore, the copper plating solution using the additive for copper plating containing the polyalkene oxide compound is a copper plating containing an additive in which PEG and chlorine are combined even if the addition of chlorine to the copper plating solution is extremely small. It is possible to obtain plated copper that is as good as or better than when the liquid is used.

  Of the polyalkene oxide compounds having the structural formula shown in Chemical Formula 3, a polyalkene oxide compound containing a halogen element, particularly chlorine, at both ends can be particularly preferably used. In polyalkene oxide compounds containing chlorine, the chlorine provided at both ends of the structural formula exhibits the same effect as the chlorine contained in the copper plating solution containing PEG and chlorine. The effect to make is great.

  By the way, the PEG conventionally used as a polymer surfactant is a compound having a polarity different from that of the polyalkene oxide compound according to the present invention. The structural formula of PEG is shown in Chemical Formula 4 below. When this is compared with Chemical Formula 3, the structure at both ends is completely different, and it can be seen that it cannot be adsorbed on copper unless chlorine is interposed because of this structural formula.

  From the comparison of the above structural formulas, it is also possible to use a copper plating solution using an additive for copper plating containing a halogen element, particularly a polyalkene oxide compound containing chlorine at both ends, without adding chlorine to the copper plating solution. It is apparent that this is a copper plating solution that can obtain a plating state equivalent to or better than the plating state obtained by using a copper plating solution to which PEG and chlorine are added. Moreover, since it is estimated that the uptake | capture of the chlorine to plating copper has decreased, it is thought that the characteristic of the copper formed is also changing.

In the additive for copper plating according to the present invention, the functional groups R ₁ and R ₂ of the polyalkene oxide compound are any selected from a sulfone group, a functional group containing N or S, and a functional group having an unsaturated bond. It is also preferable to use such a functional group. When R ₁ or R ₂ is a sulfone group, it can be a sodium salt. Any functional group containing N or S can be an amino group or a thiol group. A functional group having an unsaturated bond can be a phenylene group, a phenyl oxide group, a phenylazophenoxy group, or the like. The inclusion of these functional groups also has a polarity different from that of the PEG, and in the copper plating solution containing the additive containing the polyalkene oxide compound, the necessity of chlorine intervention in the plating solution is reduced. It is. The functional groups and the like used in the polyalkene oxide compounds exemplified above are preferable because they can be carried out under atmospheric pressure during the synthesis reaction and are easy to produce. Other functional groups are used. This does not indicate that similar effects cannot be obtained.

  In the additive for copper plating according to the present invention, the polyalkene oxide compound preferably has a molecular weight of 100 to 2,000,000. When the molecular weight is less than 100, the function of suppressing the electrodeposition reaction as a polymer surfactant is poor. Therefore, when the molecular weight of the polyalkene oxide compound is in the low molecular weight region, the combined use of bis (3-sulfoporopyl) disulfide (hereinafter referred to as “SPS”), Janus Green (hereinafter referred to as “JGB”), or the like. There is a tendency to become necessary. On the other hand, if the molecular weight exceeds 2000000, even if it has a structure in which a functional group or chlorine is introduced at both ends, the solubility in water is small, so that it is easy to precipitate in an aqueous solution system, resulting in difficulty in use. A trend comes out.

  Therefore, it is more preferable to use a polyalkene oxide compound having a molecular weight of 1,000 to 2,000,000. It is more preferable to use PEG-Cl having a molecular weight of 1,000 to 2,000,000. This is because when the additive for copper plating containing PEG-Cl is used, the chlorine concentration in the copper plating solution can be set lower.

  These polyalkene oxide compounds having a target molecular weight can be obtained by using a synthesis method described later using PEG having a molecular weight matched with the molecular weight as a synthesis raw material. The molecular weight of the polyalkene oxide compound thus obtained can be measured by GPC (Gel Permeation Chromatography) or the like.

  In the additive for copper plating according to the present invention, m in the structural formula shown in Chemical Formula 3 is preferably 1-8. When m exceeds 8, even if it has a structure having chlorine or a functional group at both ends, the C—O bond is reduced and the function as a polymer surfactant is inferior. Moreover, what set m to 2 or 3 is more preferable since the same effect as the case where PEG and polypropylene glycol are used appropriately can be obtained stably. If m and the molecular weight are set, the number n in the structural formula shown in Chemical Formula 3 is automatically determined.

  Below, the specific example of the polyalkene oxide compound contained in the additive for copper plating which concerns on this invention is shown. As a representative example of the compound in which m is 2, the structural formula of α, ω-dichloropolyethylene glycol (hereinafter referred to as “PEG-Cl”) is represented by the following formula: embedded image Polyethylene glycol-α, ω-disulfonic acid sodium salt The structural formula of (hereinafter referred to as “PEG-S”) is represented by Chemical Formula 6, and the structural formula of α, ω-diphenoxypolyethylene glycol (hereinafter referred to as “PEG-Ph”) is represented by Chemical Formula 7, The structural formula of ω-diphenylazophenoxypolyethylene glycol (hereinafter referred to as “PEG-Az”) is shown in Chemical Formula 8.

  Since the above compound has an ethylene chain having m of 2 as a basic structure, it can be synthesized using PEG having a matched molecular weight as a raw material. The synthesis method of each compound will be described in detail in Examples. When a polyalkene oxide compound having m of 3 is synthesized, polypropylene glycol can be used as a raw material. Further, when a polyalkene oxide compound having m of 4 is synthesized, polybutene glycol can be used as a raw material. Thus, a polyalkene oxide compound having a target molecular weight and structure can be obtained by using, as a synthesis raw material, polyalkene glycol or the like having the same number of m and molecular weight. The structure of the polyalkene oxide compound obtained as a result of synthesis can be confirmed using an FT-IR spectroscopic analyzer, an NMR apparatus, or the like.

  Form of copper plating solution according to the present invention: The copper plating solution according to the present invention is characterized by including the additive for copper plating. When the additive for copper plating contained in the copper plating solution contains a polyalkene oxide compound having a molecular weight of 100 to 2,000,000, when the plating solution is used, the polyalkene oxide compound contained in the copper plating solution becomes Adsorbs well on the deposited copper surface. Therefore, when electroplating is performed, copper plating having excellent gloss can be obtained. Further, when via filling is performed, a blind via hole (filled via) in which copper is buried in a good state is obtained. At this time, the functional group or chlorine and the molecular weight contained in the polyalkene oxide compound contained in the copper plating additive are selected in consideration of the function as a polymer surfactant, the solubility in an aqueous solution system, and the like. As described above, an additive for copper plating containing a polyalkene oxide compound having a molecular weight of 10,000 to 2,000,000 as long as the copper plating solution can obtain a stable plating state without using other additives in combination. It is more preferred to prepare a copper plating solution using

  In the copper plating solution according to the present invention, the polyalkene oxide compound concentration is preferably 0.0001 g / L to 10 g / L. When the polyalkene oxide compound concentration is less than 0.0001 g / L, the amount of the polyalkene oxide compound adsorbed on the copper surface becomes insufficient, and the function as a polymer surfactant that suppresses the electrodeposition reaction is sufficient. I can't show it. Further, even when the concentration of the polyalkene oxide compound is 10 g / L or more, no further improvement is seen in the gloss and via filling properties of the deposited copper film, and a tendency to increase the electrolysis voltage is observed. It is not preferable. From the above viewpoint, the polyalkene oxide compound concentration is more preferably 0.01 g / L to 1.0 g / L. Within this concentration range, fluctuations in the polyalkene oxide compound concentration do not remarkably appear as fluctuations in the gloss and via filling properties of the deposited copper film. The concentration of the polyalkene oxide compound in these copper plating solutions can be analyzed using HPLC (High Performance Liquid Chromatography) or the like.

  Moreover, if a copper plating solution containing an additive for copper plating containing PEG-Cl having a molecular weight of 4000 to 500,000 as a polyalkene oxide compound is used, copper having good glossiness and via filling properties can be obtained without adding chlorine. Plating is obtained. Specifically, when a copper plating solution adjusted to the following composition is used, if the blind via hole has a depth of 50 μm and an opening diameter of φ90 μm, a via filling rate described later can be 90% or more.

CuSO ₄ 65g / L
H ₂ SO ₄ 200 g / L
PEG-Cl 0.01 g / L
SPS 0.01g / L
JGB 0.01g / L

  Furthermore, using a copper plating solution containing a PEG-Cl having a molecular weight of 10,000 to 500,000 and adjusting the PEG-Cl concentration to 0.01 g / L to 1.0 g / L, SPS and JGB Even if no copper is added, a copper plating almost equivalent to the case of using a copper plating solution adjusted to the above composition can be obtained. As described above, the chlorine provided at the end of the structural formula is stably adsorbed on the copper surface, and the effect of the polymer surfactant that suppresses the precipitation reaction is stably exhibited.

In the copper plating solution according to the present invention, any copper plating solution such as a copper sulfate-based copper plating solution or a copper pyrophosphate-based copper plating solution can be used. However, it is preferable to use one or more selected from sulfate ion or halogen ion as an anionic component because of its many track records of use as an acidic copper plating solution in combination with an additive. For example, when using a sulfuric acid copper plating bath, the additive concentration can be adjusted based on the composition shown below, and electrolysis can be performed at a liquid temperature of 25 ° C. and a current density of 3 A / dm ² .

_{CuSO 4 · 7H 2 O 50~250g /} L
H ₂ SO ₄ 50~250g / L

Similarly, the use of cyanide ion or pyrophosphate ion is preferable because it has been used as an alkaline copper plating solution combined with an additive. For example, when using a copper pyrophosphate plating bath, the additive concentration can be adjusted based on the composition shown below, and electrolysis can be performed at a liquid temperature of 50 ° C. and a current density of 0.5 A / dm ² .

Cu ²⁺ 20-35 g / L
_{^{P 2 O 7 4- 150~250g / L}} (P 2 O 7 / Cu ratio: 6.5 to 8.0)
PO ₄ ^3- less than 60 g / L pH 8-9

  That is, the additive for copper plating according to the present invention is not limited to the copper plating solution containing the anionic component, and the effect can be exhibited as long as it is a copper plating solution that relies on the additive to suppress the electrodeposition reaction. And the examination of optimization in each copper plating solution composition can use a hull cell test etc. Further, although not confirmed in view of the above-described adsorption mechanism on the copper surface, it is expected that the additive for copper plating according to the present invention can exhibit the same precipitation suppressing effect even when used in an electroless copper plating solution. is doing.

Form of electrolytic copper plating method according to the present invention: The electrolytic copper plating method according to the present invention is characterized in that electrolysis is performed using the copper plating solution. At this time, the cathode current density do electrolysis at ^{0.1A / dm 2 ~50A / dm 2} . When electrolysis is performed at a current density lower than 0.1 A / dm ² , the time required to obtain the desired copper film thickness or to perform via filling becomes long, and industrial productivity cannot be satisfied. On the other hand, when electrolysis is performed at a current density exceeding 50 A / dm ² , it is not preferable because good plated copper cannot be obtained, such as the glossiness and via filling property of the obtained copper film cannot be satisfied. Therefore, electrolysis at a cathode current density of 0.5 A / dm ^{2 to} 10 A / dm ² can stably obtain good plated copper, and is more preferable from an economical viewpoint. The cathode current density referred to here is a value calculated based on the total area of the surfaces to be plated exposed in the substrate to be plated in general DC electrolysis. When a PR (Pulse Reverse) electrolysis method or the like is selected, an appropriate range needs to be adjusted separately.

  In the electrolytic copper plating method according to the present invention, the electrolysis is preferably performed using an insoluble anode. This is because there is no generation of anode slime or the like, and it is difficult to affect the quality of the electrodeposited copper. When the copper plating solution using the additive for copper plating according to the present invention is used, the chlorine concentration of the copper plating solution can be made lower than that of the prior art or not intentionally added. If the chlorine concentration of the copper plating solution is low, even if electrolysis is performed using an insoluble anode, chlorine is difficult to gasify, and fluctuation (decrease) in the chlorine concentration is small. Therefore, even if an insoluble anode is used, good plated copper can be obtained stably and continuously. In the case of an acidic bath such as a sulfuric acid bath, a method for adjusting the copper concentration used in the production process of the electrolytic copper foil can be applied to the adjustment of the copper concentration when electrolysis is performed using an insoluble anode. For example, the copper plating solution is circulated through a melting tower filled with a copper wire or the like.

  In this example, PEG-Cl having a molecular weight of 4000 was synthesized, and a copper plating solution containing this polyalkene oxide compound was prepared to evaluate the gloss.

<Synthesis of PEG-Cl with a molecular weight of 4000>
2.0 g of PEG having a molecular weight of 4000 (PEG 4000 manufactured by Wako Pure Chemical Industries, Ltd.) was placed in a beaker and dissolved in 5 mL of thionyl chloride dropwise on an ice water bath. After confirming that all of the PEG was dissolved, the solution was gradually heated to 60 ° C. with stirring and stirred overnight (12 hours or longer) to obtain a reaction solution. Thereafter, this reaction solution was put into 50 mL of cooled diethyl ether to precipitate a crude PEG-Cl product. The diethyl ether solution containing this crude PEG-Cl product was filtered, and the solid content obtained by separation was dried under reduced pressure to obtain a crude PEG-Cl product.

  Subsequently, in order to purify the crude PEG-Cl product, a crude purification step and a recrystallization step were performed. The crude purification step was composed of the following three steps. Heating and dissolving the PEG-Cl crude product in 10 mL of 2-propanol. The step of slowly cooling the solution to −5 ° C. to precipitate a crude PEG-Cl product. A step of filtering the solution from which the crude PEG-Cl purified product is deposited, and separating and recovering the crude PEG-Cl purified product. Then, the following recrystallization process was repeated 3 times for this crude PEG-Cl product to obtain a purified PEG-Cl product. One step of the recrystallization step was composed of the following steps. Heating and dissolving the PEG-Cl crude product in a small amount of methylene chloride. The step of cooling the solution to room temperature and filtering and separating the precipitate deposited in the solution. A step of performing reprecipitation treatment by adding the filtrate obtained in the above step into 10 times amount of cooled diethyl ether. A step of filtering the diethyl ether solution to recover the re-precipitated PEG-Cl purified product.

<Identification of structural formula of synthetic additive>
For identification of the structural formula of the synthetic additive obtained above, an FT-IR spectroscopic analyzer (Spectrum One: manufactured by Perkin Elmer Co., Ltd.) and NMR (Varian Mercury 400: manufactured by Varian Technologies Japan Limited) were used. Examples of evaluating PEG-Cl having a molecular weight of 4000 and PEG-S having a molecular weight of 4000 described later by C-NMR are shown in FIGS. In FIG. 1 showing the result of C-NMR evaluation of PEG-Cl having a molecular weight of 4000, methylene group bonded to chlorine was detected at a position of 43.0 ppm, and methylene group bonded to oxygen at a position of 70.6 ppm. Of carbon has been detected. Moreover, in FIG. 2 which shows the result of having evaluated the PEG-S of molecular weight 4000 by C-NMR, carbon of the methylene group couple | bonded with the sulfonic acid was detected in the position of 50.8 ppm, and the range of 69.4 ppm-70.7 ppm The carbon of the methylene group bonded to oxygen was detected. Thus, it can confirm that the polyalkene oxide compound synthesize | combined by the said method has a target structure.

<Glossiness evaluation>
The effect of the copper plating additive containing the polyalkene oxide compound synthesized above was evaluated by the gloss of the copper film obtained by copper plating. The gloss was evaluated in the current density range in which a glossy copper film was obtained by the Hull cell test. The copper plating solution for gloss evaluation was an acidic copper sulfate bath. This copper plating solution is added to pure water so that copper sulfate CuSO ₄ · 7H ₂ O is 200 g / L and sulfuric acid H ₂ SO ₄ is 50 g / L, hydrochloric acid is 0.015 g / L, and SPS is added. It was prepared by adding 0.031 g / L. This acidic copper sulfate bath to which no polyalkene oxide compound was added as an additive was used as the basic bath 1.

The copper plating solution used for the gloss evaluation in this example was prepared by adding PEG-Cl having a molecular weight of 4000 to the basic bath 1 so that the PEG-Cl concentration was 0.01 g / L. This copper plating solution was poured into the reference line of Hull Cell (10A15 type: manufactured by Yamamoto Gold Tester Co., Ltd.), using a brass plate for the cathode and DSA for the anode, a liquid temperature of 25 ° C., and an average current density of 2 A / dm. ² for 10 minutes. The results of the test, the current density range in which the copper film having a luster was obtained ^{was 0.8A / dm 2 ~12.0A / dm 2} . Table 1 shows the composition and gloss evaluation results of the copper plating solution together with the copper plating solution composition and gloss evaluation results in Example 2 and Comparative Example 1.

  In this example, PEG-S having a molecular weight of 4000 was synthesized, and a copper plating solution containing this polyalkene oxide compound was prepared to evaluate the gloss.

<Synthesis of PEG-S with a molecular weight of 4000>
A mixed solvent of 6 mL of pure water and 2 mL of ethanol (99.5%) was prepared in the flask, and 2.0 g of PEG-Cl having a molecular weight of 4000 synthesized in the same manner as in Example 1 and 0. 4 g was added. This solution was refluxed for 48 hours, and the solution after the refluxing was gradually cooled to room temperature. After adding activated carbon 0.04g to this cooled solution and stirring for 2 hours, this solution was filtered and activated carbon was removed, and the primary reaction solution was obtained. The solvent was evaporated from the primary reaction solution, and the remaining solid was dissolved in 10 mL of methylene chloride. Then, anhydrous sodium sulfate was added to this solution for dehydration, and sodium sulfate was filtered off to obtain a secondary reaction solution. This secondary reaction solution was put into 80 mL of cooled diethyl ether to precipitate a PEG-S crude product. The diethyl ether solution containing this crude PEG-S product was filtered, and the solid content obtained by separation was dried under reduced pressure to obtain a crude PEG-S product. This crude PEG-S product was purified by carrying out the same crude purification step and recrystallization step as PEG-Cl in Example 1.

<Glossiness evaluation>
The effect of the copper plating additive containing the polyalkene oxide compound synthesized above was evaluated by the gloss of the copper film obtained by copper plating. The glossiness evaluation was performed by adding PEG-S having a molecular weight of 4000 to the basic bath 1 instead of the PEG-Cl having a molecular weight of 4000 used in Example 1 for the copper plating solution used in the Hull cell test, and the PEG-S concentration was 0. The procedure was the same as in Example 1 except that the amount was adjusted to 0.01 g / L. As a result, the current density range in which a glossy copper film was obtained was 0.2 A / dm ^{2 to} 12.0 A / dm ² as shown in Table 1.

<Evaluation of via filling properties>
In this example, the effect of the additive for copper plating containing PEG-Cl synthesized in Example 1 was evaluated by via filling properties. The copper plating solution for evaluating via filling properties used here was also an acidic copper sulfate bath. This copper plating solution was prepared by adding copper sulfate CuSO ₄ · 7H ₂ O to pure water at 65 g / L and sulfuric acid H ₂ SO ₄ at 200 g / L. This acidic copper sulfate bath without any additives was designated as basic bath 2. Furthermore, an acidic copper sulfate bath to which no polyalkene oxide compound was added was prepared by adding SPS to this basic bath 2 to 0.01 g / L and JGB to 0.01 g / L. This acidic copper sulfate bath was designated as basic bath 3 and was used as the basic bath used in this example.

  For the evaluation of the via filling property, a substrate on which blind via holes were arranged was used. FIG. 3 schematically shows a cross section. The substrate on which the blind via hole 1 was formed was prepared as follows. As the core material, an FR-4 copper clad laminate having a size of 50 mm × 150 mm and a thickness of 0.6 mm, in which 18 μm electrolytic copper foil 2 was bonded to both surfaces of insulating resin 3 was used. And build-up resin 4 (ABF-SH-9K: Ajinomoto Co., Inc. product) whose thickness 5 is 50 micrometers was bonded together on both surfaces of this core material. Thereafter, in the arrangement schematically shown in FIG. 4, a plurality of three types of blind via holes X (10 in the figure), Y (11 in the figure), and Z (12 in the figure) are provided in the buildup resin 4 on the surface of the core material. Individually formed. In the process of forming the blind via hole, after drilling the build-up resin 4 using a carbon dioxide laser, desmear treatment was performed to expose the electrolytic copper foil 2 at the bottom.

  The size of the blind via hole formed as described above was such that the opening diameter 6 was X = 60 μm, Y was φ90 μm, Z was φ150 μm, the bottom diameter 7 was X = φ60 μm, Y was φ80 μm, and Z was φ90 μm. . In the arrangement on the via filling property evaluation surface in FIG. 4, the portion 13 where the blind via hole X, the blind via hole Y and the blind via hole Z are arranged at a pitch of 1.2 mm is (a), and the portion 14 where the blind via hole Z is arranged at a pitch of 0.25 mm. (B) The portion 15 arranged at a pitch of 0.5 mm was defined as (c). The test substrate is composed of two 25A × 30mm size blind via hole processing surfaces 16 in which (a), (b), and (c) are sequentially arranged, and the 50 mm × 150 mm size substrate. Arranged on both sides.

  Next, the outline of the plating apparatus used for the via filling test is shown in FIG. 20 is a view of the plating tank 27 as viewed from the side, and 21 is a view of the plating tank 27 as viewed from above. At both ends of the plating tank 27, DSA 23 that is an insoluble anode is arranged with the surface coated with iridium oxide or the like facing the inside of the plating tank 27. The test substrate 22 is inserted along the guide to a position not reaching the tank bottom of the plating tank 27 so that it can be placed between the two DSAs 23. At the tank bottom, the copper plating solution 24 is continuously stirred using a magnetic stirrer 26. One of the two rectifiers 25 has the negative output side connected to the test board 22 and the positive output side connected to the DSA 23 facing one surface of the test board. Similarly, the other rectifier 25 has the negative output side connected to the test board 22 and the positive output side connected to another DSA 23 facing the other surface of the test board.

  In the via filling test, after the above arrangement is configured, the two rectifiers 25 are simultaneously switched on to perform copper plating for a predetermined time. FIG. 6 schematically shows a cross-sectional shape after performing via filling in the blind via hole 1 formed on the test substrate. In the evaluation of the via filling property for these blind via holes 1, as representative of the formation status of the copper plating portion 8 of the filled via, the plated copper thickness 9 (referred to as T1) and the total copper thickness 10 on the bottom portion are represented. (T2) was measured from cross-sectional observation. A value obtained as T1 ÷ T2 × 100 (%) was used as an index as a via filling rate.

The copper plating solution 24 used for the via filling test was prepared by adding PEG-Cl having a molecular weight of 4000 to the basic bath 3 so that the PEG-Cl concentration was 0.01 g / L. This copper plating solution 24 was put in an electrolytic bath 27 and stirred using a magnetic stirrer 26 at a solution temperature of 25 ° C. (room temperature). In this state, the test substrate 22 was inserted as a cathode into a fixed position of the electrolytic cell 27. After 30 seconds had passed since the test substrate 22 was immersed in the copper plating solution 24, the switches of the two rectifiers 25 were simultaneously turned on and electrolysis was performed at a cathode current density of 1 A / dm ² for 114 minutes. The test substrate 22 after the electrolysis was taken out from the electrolytic cell 27, immediately washed with running water, and dried with a dryer.

  The obtained test substrate was subjected to cross-sectional observation at 10 points each of the blind via hole X, blind via hole Y, and blind via hole Z in the processed surface (A), and the via filling rate at each point was obtained. The average value of the measurement results was taken as the via filling rate for each blind via hole. As a result, the via filling rate was 94% for the blind via hole X, 92% for the blind via hole Y, and 82% for the blind via hole Z. The composition of the copper plating solution used here and the evaluation results regarding via filling are shown in Table 2 together with the compositions and evaluation results of the copper plating solutions used in Examples 4 to 7 and Comparative Example 2.

<Evaluation of via filling properties>
In this example, the effect of the additive for copper plating containing PEG-S having a molecular weight of 4000 synthesized in Example 2 was evaluated by via filling properties. Specifically, instead of the PEG-Cl having a molecular weight of 4000 used in Example 3, a copper plating solution prepared so that the concentration of PEG-S having a molecular weight of 4000 was 0.01 g / L, and the others were used in Examples. A via filling test was performed under the same conditions as in No. 3. As a result, as shown in Table 2, the via filling rate was 91% for the blind via hole X, 90% for the blind via hole Y, and 80% for the blind via hole Z.

  In this example, PEG-Ph having a molecular weight of 4000 was synthesized, and a copper plating solution containing this polyalkene oxide compound was prepared to evaluate via filling properties.

<Synthesis of PEG-Ph with a molecular weight of 4000>
To 10 mL of DMF (dimethylformamide) in the flask, 2.0 g of PEG-Cl having a molecular weight of 4000 synthesized in the same manner as in Example 1, 0.41 g of phenol, and 0.21 g of anhydrous potassium carbonate were added and refluxed for 48 hours. did. Immediately after completion of the reflux, the mixture was filtered, and the filtrate was gradually cooled to room temperature to obtain a reaction solution. This reaction solution was put into 100 mL of cooled diethyl ether to precipitate a crude PEG-Ph product. The solution containing this crude PEG-Ph product was filtered and the solid content obtained by separation was dried under reduced pressure to obtain a crude PEG-Ph product. This crude PEG-Ph product was purified by carrying out the same crude purification step and recrystallization step as PEG-Cl in Example 1.

<Evaluation of via filling properties>
Instead of PEG-Cl having a molecular weight of 4000 used in Example 3, a copper plating solution prepared so that the concentration of PEG-Ph having a molecular weight of 4000 was 0.01 g / L, and other conditions were the same as those in Example 3. A via filling test was conducted. As a result, as shown in Table 2, the via filling rate was 90% for the blind via hole X, 89% for the blind via hole Y, and 80% for the blind via hole Z.

  In this example, PEG-Az having a molecular weight of 4000 was synthesized, and a copper plating solution containing this polyalkene oxide compound was prepared to evaluate via filling properties.

<Synthesis of PEG-Az with a molecular weight of 4000>
To 10 mL of DMF in the flask, 2.0 g of PEG-Cl having a molecular weight of 4000 synthesized in the same manner as in Example 1, 0.3 g of 4,4′-phenylazophenol and 0.21 g of anhydrous potassium carbonate were added for 48 hours. Refluxed. Immediately after the refluxing, the mixture was filtered, and the filtrate was gradually cooled to room temperature to obtain a reaction solution. This reaction solution was put into 100 mL of cooled diethyl ether to precipitate a crude PEG-Az product. The solution containing this crude PEG-Az product was filtered, and the solid content obtained by separation was dried under reduced pressure to obtain a crude PEG-Az product. This crude PEG-Az product was purified by carrying out the same crude purification step and recrystallization step as PEG-Cl in Example 1.

<Evaluation of via filling properties>
Instead of the PEG-Cl having a molecular weight of 4000 used in Example 3, a copper plating solution prepared so that the PEG-Az concentration having a molecular weight of 4000 was 0.01 g / L, and other conditions were the same as those in Example 3. A via filling test was conducted. As a result, as shown in Table 2, the via filling rate was 90% for the blind via hole X, 89% for the blind via hole Y, and 80% for the blind via hole Z.

  In this example, PEG-Cl having a molecular weight of 10,000 was synthesized, and a copper plating solution containing this polyalkene oxide compound was prepared to evaluate via filling properties.

<Synthesis of PEG-Cl with a molecular weight of 10,000>
The same operation as in the synthesis of PEG-Cl having a molecular weight of 4000 in Example 1 was carried out except that 30 g of PEG having a molecular weight of 10,000 (PEG 10,000 manufactured by Merck) was used as a synthesis raw material.

<Evaluation of via filling properties>
First, PEG-Cl having a molecular weight of 10,000 was added to the basic bath 2 as a polyalkene oxide compound to prepare a copper plating solution so that the PEG-Cl concentration was 0.1 g / L. Using this copper plating solution, a via filling test was carried out under the same conditions as in Example 3. As a result, as shown in Table 2, the via filling rate was 90% for the blind via hole X, 90% for the blind via hole Y, and 88% for the blind via hole Z.

  In this example, PEG-Cl having a molecular weight of 20000 was synthesized, and a copper plating solution containing this polyalkene oxide compound was prepared to evaluate via filling properties.

<Synthesis of PEG-Cl with a molecular weight of 20000>
The same operation as in the synthesis of PEG-Cl having a molecular weight of 4000 in Example 1 was carried out except that 60 g of PEG having a molecular weight of 20000 (PEG 20000 manufactured by Wako Pure Chemical Industries, Ltd.) was used as a synthetic raw material.

<Evaluation of via filling properties>
First, as the polyalkene oxide compound, PEG-Cl having a molecular weight of 20000 was added to the basic bath 2 to prepare a copper plating solution so that the PEG-Cl concentration was 0.1 g / L. Using this copper plating solution, a via filling test was carried out under the same conditions as in Example 3. As a result, as shown in Table 2, the via filling rate was 89% for the blind via hole X, 86% for the blind via hole Y, and 91% for the blind via hole Z.

  In this example, PEG-Cl having a molecular weight of 500,000 was synthesized, and a copper plating solution containing this polyalkene oxide compound was prepared to evaluate via filling properties.

<Synthesis of PEG-Cl with a molecular weight of 500,000>
The same operation as in the synthesis of PEG-Cl having a molecular weight of 4000 in Example 1 was carried out except that 125 g of PEG having a molecular weight of 500,000 (PEG 500,000 manufactured by Wako Pure Chemical Industries, Ltd.) was used as a synthetic raw material.

<Evaluation of via filling properties>
First, as a polyalkene oxide compound, PEG-Cl having a molecular weight of 500,000 was added to the basic bath 2 to prepare a PEG-Cl concentration of 0.01 g / L. Using this copper plating solution, a via filling test was carried out under the same conditions as in Example 3. As a result, as shown in Table 2, the via filling rate was 90% for the blind via hole X, 88% for the blind via hole Y, and 89% for the blind via hole Z.

Comparative example

(Comparative Example 1)
<Glossiness evaluation>
In this comparative example, gloss was evaluated using PEG having a molecular weight of 4000. The evaluation of glossiness was performed by replacing the copper plating solution used in the Hull cell test with PEG-Cl having a molecular weight of 4000 instead of PEG-Cl having a molecular weight of 4000 used in Example 1, and adjusting the basic bath 1 to 0.01 g / L. The procedure was the same as in Example 1, except that it was prepared by adding to the above. As a result, the current density range in which a glossy copper film was obtained was 0.2 A / dm ^{2 to} 12.0 A / dm ² as shown in Table 1.

[Comparative Example 2]
<Evaluation of via filling properties>
In this comparative example, via filling properties were evaluated using PEG having a molecular weight of 4000. The evaluation of via filling was performed by adding PEG having a molecular weight of 4000 instead of PEG-Cl having a molecular weight of 4000 used in Example 1 to the basic bath 3 so that the PEG concentration was 0.01 g / L, and further adding hydrochloric acid. A copper plating solution with a chlorine concentration of 0.05 g / L was prepared by addition. The other conditions were the same as in Example 3 except that this copper plating solution was used. As a result, as shown in Table 2, the via filling rate was 100% for the blind via hole X, 99% for the blind via hole Y, and 77% for the blind via hole Z.

<Glossy contrast>
According to Table 1, the current density range in which a glossy copper film can be obtained by electrolyzing a copper plating solution using the copper plating additive according to the present invention is PEG, SPS, and chlorine, which have been used conventionally. It is equivalent to the current density range in which a glossy copper film is obtained using a copper plating solution to which is added.

<Contrast of via filling properties>
According to Table 2, the via filling property of the copper plating solution using the copper plating additive according to the present invention is that PEG, SPS, JGB and chlorine that have been used conventionally are added without adding chlorine. It is equal to or better than the via filling property of the added copper plating solution. And the via filling property of the copper plating solution using the additive for copper plating according to the present invention having a molecular weight of 10,000 or more is the same as that of PEG, SPS, JGB which has been used conventionally without adding SPS or JGB. It is equivalent to the via filling property of a copper plating solution added with chlorine.

  Electroplating is performed using a copper plating solution using an additive for copper plating containing a polyalkene oxide compound having a structural formula having functional groups at both ends and having a number average molecular weight of 100 to 2,000,000 according to the present invention. And even if there is little chlorine amount in a copper plating solution, the copper membrane | film | coat with favorable glossiness is stably obtained. Further, when via filling is performed, a blind via hole (filled via) in which copper is buried in a good state is obtained. That is, since it is not necessary to add chlorine at the level of the prior art, it is a copper plating solution that can be suitably used even when DSA is used for the anode. Furthermore, when a polyalkene oxide compound having a large molecular weight is selected, the use of other additives such as SPS and JGB is not necessary, and the management of the copper plating solution is facilitated. As a result, a glossy copper film and a well-filled filled via can be obtained more stably than before. Therefore, the copper plating additive according to the present invention can be applied not only to printed wiring board applications but also to copper plating when manufacturing integrated circuits, decorative fields where bright copper plating is required, and the like.

It is the analysis result by C-NMR of PEG-Cl. It is the analysis result by C-NMR of PEG-S. It is a schematic cross section of a via filling property evaluation board. It is a figure which shows arrangement | positioning of a blind via hole on a via filling property evaluation board | substrate. It is a schematic diagram which shows the apparatus structure used for the via filling test. It is a schematic cross section showing a blind via hole after performing via filling.

Explanation of symbols

1 Blind Via Hole 2 Electrolytic Copper Foil 3 Insulating Resin 4 Build-up Resin 5 Build-up Resin Thickness 6 Aperture Diameter 7 Bottom Diameter 8 Plating Copper 10 Blind Via Hole X with an Opening Diameter of φ60 μm
11 Blind via hole Y with an opening diameter of φ90μm
12 Blind via hole Z with an opening diameter of φ150μm
13 Parts where blind via holes are arranged at a pitch of 1.2 mm (a)
14 Parts where blind via holes are arranged at a pitch of 0.25 mm (b)
15 Portion where blind via holes are arranged at a pitch of 0.5 mm (c)
16 Surface (A) in which blind via hole arrangements (a), (b), and (c) are repeatedly arranged sequentially
17 Bottom plated copper thickness (T1)
18 Total copper thickness (T2)
20 Via filling test equipment (side)
21 Via Filling Test Equipment (bird's eye view)
22 Test board 23 DSA
24 Rectifier 25 Copper plating solution 26 Magnetic stirrer 27 Plating tank

Claims (9)

An additive for copper plating containing a polyalkene oxide compound,
The polyalkene oxide compound has a structural formula shown in the following chemical formula 1 having a functional group or a halogen element at one or both of its ends, and has a number average molecular weight of 100 to 2,000,000. Additive for plating.

The functional groups R ₁ and R ₂ in the structural formula shown in Chemical Formula ₁ are any functional group selected from a sulfone group, a functional group containing N or S, and a functional group having an unsaturated bond. The additive for copper plating as described. The additive for copper plating according to claim 1 or 2, wherein m in the structural formula shown in Chemical Formula 1 is 1 to 8. The copper plating liquid containing the additive for copper plating in any one of Claims 1-3. The copper plating solution according to claim 4, wherein the concentration of the polyalkene oxide compound is 0.0001 g / L to 10 g / L. The copper plating solution according to claim 4 or 5, wherein the copper plating solution uses at least one selected from sulfate ions or halogen ions as an anion component. The said copper plating solution is a copper plating solution of Claim 4 or Claim 5 which uses a cyanide ion or a pyrophosphate ion as an anion component. Using a copper plating solution according to any one of claims 4 to claim 7, electrolytic copper plating method of performing electrolysis at cathode current density ^{0.1A / dm 2 ~50A / dm 2} . The electrolytic copper plating method according to claim 8, wherein the electrolysis is performed using an insoluble anode.

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