KR20030071955A - Composition for acidic copper coating additive for filling up via hole, and method for filling up via hole using the same - Google Patents

Abstract

PURPOSE: A composition is provided to be capable of preventing excessive deposition at a via hole opening part when performing a work with a high current density. CONSTITUTION: An acidic copper coating additive composition comprises polyethylene glycol of 0.005g to 0.4g, polyvinylpyrrolidone of 0.001g to 0.1g, and octylphenol ethoxy-lates of 0.03g-0.5g. The coated matter is coated by infiltrating the matter in a copper plating electrolysis including the composition and plating the matter under the conditions of a high current density of 1.0-4.0A/dm2 and a temperature of 20-30 degrees. The electrolysis includes H2SO4, CuSO45H2O and Cl.

Description

Composition for acidic copper coating additive for filling up via hole, and method for filling up via hole using the same}

The present invention relates to an acid copper plating additive composition for via hole filling and a via hole filling method using the same, and more specifically, by adding a specific amount of an acidic additive composition to an existing electrolytic copper plating solution, a via is obtained under a high current density working environment. The present invention relates to an acid copper plating additive composition for filling a via hole and a method of filling a via hole using the same, which prevents excessive precipitation in a hole opening and prevents generation of voids, thereby completely filling the via holes within a short working time without generation of voids.

In recent years, build-up methods have been introduced as a new multilayer printed circuit board manufacturing method in order to cope with the advancement of electronic devices with increasing density or multilayering of printed circuit boards. As said buildup method, the via-hole inner wall through plating is performed as an interlayer connection method of another conductor. Usually, after filling an insulating resin or a conductive paste on the inner wall of the via hole and forming an insulating layer, planarization is performed, but in this case, there is a limit to planarization.

Accordingly, in order to solve the above problems, a multilayered resin multilayer substrate having an inner via via structure electrically connecting arbitrary layers and a printed circuit board using interlayer connection through minute bumps have been devised. On the other hand, as the conductor pattern gradually becomes finer, the via filling method of filling the via hole with copper plating has been attracting attention as an excellent method in terms of process and connection reliability.

Currently applied via filling techniques include a method of electrically conducting a via hole and then filling the inside of the via hole using an insulating resin or a conductive paste. However, when using this method, voids are generated inside the via hole, the surface is dented, and the thermal expansion coefficient difference between the metal and the insulating resin adversely affects the connection reliability and lowers the electrical conductivity. There is a problem. Therefore, the via hole filling method for filling the inside of the via hole with metal copper in the process of becoming finer wiring can be via-on-via (or stack-via) to further increase the circuit wiring density and to provide connection reliability. It is also stable in terms of application, and its application is further expanded.

As the filling method of the via hole, a method of filling the via hole through electric copper plating is widely applied. However, when the via hole is filled by using a composition of an electrocopper additive and a bath through a conventional electroplating technique, even if the filling is not performed in the via hole or the filling is performed, voids are formed in the via hole. There is a problem that occurs. On the other hand, in order to remove such voids must be carried out at a low current density of less than 0.05A / dm ² , in this case it takes more than 3 hours plating time is not applicable to the production site.

Therefore, in order to suppress the generation of voids due to over-precipitation in the via hole opening, the precipitation and dissolution in the opening may be repeatedly repeated and filled from the bottom of the via hole by the pulse reverse method, but in this case, plating When copper is used as the positive electrode because of repeated precipitation and dissolution at the same time, there is a problem such as contamination of the electrolytic bath due to dissolution of the black film or activation of the positive electrode, and a long time is required to completely charge it.

Therefore, there is an urgent need for an acid copper plating additive and a filling method for via hole filling, which not only completely fills the via hole without generating voids, but also shortens the via hole filling time when working at a high current density.

In the present invention, in order to solve the above-mentioned problems, a suppressor, a leveler and a brightener, which are basic components of a conventional additive based on the conventional acidic copper plating additive and the electrolytic solution, are provided in the via hole and the via hole. As a result of extensive research focused on the fact that each plays a different role in filling, the composition of a specific component of an additive that prevents the formation of voids by preventing excessive precipitation in the via hole opening even when working at a high current density And specific usage thereof has been found, and the present invention has been completed based thereon.

Accordingly, it is an object of the present invention to provide an acid copper plating additive composition for filling a via hole that can prevent excessive precipitation in the via hole opening even when performing operation at a high current density.

Another object of the present invention is to provide a via hole filling method capable of completely filling a via hole within a short working time without generating voids.

Copper plating additive composition of the present invention for achieving the above object is an additive composition contained in 1 liter of via plating solution for filling a via hole of a printed circuit board, polyethylene glycol 0.005g ~ 0.4g, polyvinylyl pyrrolidone 0.001g ~ 0.1 g, 3-mercoptopropane sulfonic acid 0.001 g to 0.02 g and octylphenol ethoxylate 0.03 g to 0.5 g.

The method of the present invention for achieving the above another object is a high current density working environment of 1.0 ~ 4.0A / dm ² and temperature conditions of 20 ~ 30 ℃ by immersing the plated object in the copper plating electrolyte containing the acidic copper plating additive composition Electrolytic plating under.

Hereinafter, the present invention will be described in more detail.

BACKGROUND OF THE INVENTION In a fine wiring of a build-up printed circuit board or a wafer, an electroplating method for filling a via hole or a groove by applying copper plating is widely used. Such an electroplating method is performed for the purpose of forming lands for improving the mounting density of printed circuit boards or securing connection reliability of fine wafers.

In general, electrolytic copper plating is carried out as follows. In the case where electrolytic copper is to be plated on the insulated portion of the printed circuit board or the wafer, by forming a thin copper layer on the insulated portion by electroless copper plating or sputtering method, it is possible to secure the conductivity even in the portion which is not originally conductive. The electroplated copper is then deposited as a cathode in the electrolytic copper plating bath to finish the copper plating.

As the electrolytic copper plating solution, a conventional copper plating solution including copper sulfate and pyrophosphoric acid may be used. In general, various additives such as a suppressor, a brighter, and a leveler are further blended with the plating liquid to obtain a copper plating layer having excellent physical properties and appearance. That is, by mixing an additive suitable for the basic copper plating solution to not only control the precipitation crystal grains, but also to control the uniform precipitation rate to obtain the desired characteristics.

However, in the case of using an electrolytic copper plating solution containing a conventional additive, the electrolytic work proceeds, and the brightener component as an additive also tends to decompose on the anode electrode side. This phenomenon is particularly noticeable when using an insoluble anode. Therefore, not only the life as a plating liquid is shortened, but also the composition state of the plating liquid is changed from time to time, which affects the precipitation state of the plating layer, so that it is difficult to achieve uniform precipitation. As a result, an undesired precipitation state is caused, which causes a decrease in the work yield.

In the case of the failure due to the typical precipitation state, the current is not evenly distributed to the bottom portion of the via hole or the groove portion, and the current concentration occurs not only by the shape effect, but also because the precipitation occurs in the copper portion of the surface layer only, so that the uniform precipitation state is achieved. It occurs under conditions that cannot be formed. In such a case, voids are generated inside the via hole or the groove, and a portion where precipitation is insufficient is generated, resulting in a significant reduction in connection reliability as a circuit.

In addition, in the case where the composition state of the copper plating liquid is changed, in order to perform the plating more reliably, it is necessary to continuously observe the composition state of the copper plating liquid and to perform a proper operation according to the changed state. That is, frequent solution etching must be performed. When the solution etching is performed manually, it is complicated, but when it is mechanized, the price of equipment is increased, thereby reducing the competitiveness in terms of the price of the product.

Therefore, in the present invention, in the copper plating solution for filling the via hole with copper plating in order to form stacked vias according to the demand for densification and miniaturization of the conductor pattern of the printed circuit board, the specific acid additive composition is added to the existing electrolytic copper plating solution. Acid copper plating additive composition and via using the same, which can completely fill the via hole in a fast working time without the formation of voids by preventing the formation of voids by preventing the formation of excess holes in the via hole opening even in a high current density working environment A hole filling method is provided.

The acid copper plating additive composition for filling blind via holes of the present invention is an additive composition contained in 1 L of via plating solution for filling via holes in a printed circuit board, and includes polyethylene glycol 0.005 g to 0.4 g and polyvinylyl pyrrolidone 0.001 g to 0.1 g, 3-mercoptopropane sulfonic acid 0.001 g to 0.02 g and octylphenol ethoxylate 0.03 g to 0.5 g.

The polyethylene glycol is an inhibitor component to be incorporated into the electrolytic copper plating solution, and the polyethylene glycol is preferably used in an amount of 0.005 g to 0.4 g in 1 L of the electrolytic copper plating solution. When the amount is less than 0.005 g, the inlet of the via hole is blocked first. If this occurs, the particle of plating becomes dense when the content exceeds 0.4g, but no via hole is filled.

In addition, the polyvinylyl pyrrolidone is a leveler component blended with the electrolytic copper plating solution, and the amount of the polyvinylyl pyrrolidone used is preferably 0.001 g to 0.1 g in 1 L of the electrolytic copper plating solution, and the amount of the polyvinylyl pyrrolidone is 0.001 g. If less than 10 g, the via hole is not filled. If the amount exceeds 0.1 g, not only the via hole is filled, but the precipitated shape of the surface is cascaded, so that an even surface cannot be obtained.

The 3-mercoptopropane sulfonic acid is a brightener component blended into the electrolytic copper plating solution, and the amount of the 3-mercoptopropane sulfonic acid is preferably 0.001 g to 0.02 g in 1 L of the electrolytic copper plating solution. If less than 0.001g, the via hole is not filled and the growth particles are large and coarse. If the amount exceeds 0.02g, the opening of the via hole is clogged first so that voids are generated and filling is not performed.

On the other hand, the octylphenol ethoxylate is a surfactant component blended into the electrolytic copper plating solution, the amount of octyl phenol ethoxylate is preferably 0.03g to 0.5g in 1L of the electrolytic copper plating solution, the usage amount is less than 0.03g When the inlet of the via hole is first blocked, voids are generated and coarse plated particles are formed. If the content exceeds 0.5 g, the plated particles become dense but no filling is performed.

The copper plating solution for via hole filling of the printed circuit board according to the present invention is not only the additive composition described above, but also 45 to 75 g of H ₂ SO _4, 180 to 240 g of CuSO ₄ · 5H ₂ , and Cl 40 to 90 (50) in 1 L of the total solution. ) Mg.

In addition, the acidic copper plating solution composition according to the present invention is added to the copper plating electrolyte under a high current density of 1.0 to 4.0 A / dm ² and a mild temperature condition of 20 to 30 ° C., so that it is applied within a short working time without generating voids. Since the via hole filling method capable of completely filling the via holes can be provided, precise fine plating can be achieved in a densified printed circuit board.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited thereto.

Here, the numerical values in parentheses represent the content according to the optimal data.

Example 1

In a printed circuit board, a via hole having a diameter of 75 μm and a depth of 65 μm is processed, and the inside thereof is room temperature (25 ° C.) under a current density of 2.0 A / dm ² in a bath containing an electrolytic plating solution having the following composition. After the plating was performed, the plated shape and the degree of filling of the filled via hole cross sections were confirmed.

Composition:

H ₂ SO ₄ 45 to 75 (60) g / l

CuSO ₄ · 5H ₂ O180 ~ 240 (220) g / ℓ

Cl 40-90 (50) mg / l

Polyethylene glycol (PEG) 0.007 g / ℓ

Octylphenol ethoxylate0.05 g / l

Polyvinyl Pyrrolidone0.002 g / L

3-mercoptopropane sulfonic acid 0.002 g / l

Under the above-described compositions and conditions, the inside of the via hole filled through copper plating was free of voids, completely filled, and the deposited state of the plating layer was also very dense.

Comparative Example 1

After the same procedure as in Example 1 except that the composition of the copper plating solution inorganic material was as follows, the plated shape and the degree of filling of the filled via hole cross sections were confirmed.

Composition:

H ₂ SO ₄ 45 to 75 (60) g / l

CuSO ₄ · 5H ₂ O180 ~ 240 (220) g / ℓ

Cl 40-90 (50) mg / l

As such, the inside of the plated via hole in the bath including the basic copper plating solution composition without the additive was not completely filled, and voids were generated in the via hole.

Comparative Example 2

After the same procedure as in Example 1 except that the composition of the copper plating solution was as follows, the plated shape and the degree of filling of the filled via hole cross sections were confirmed.

Composition:

H ₂ SO ₄ 45 to 75 (60) g / l

CuSO ₄ · 5H ₂ O180 ~ 240 (220) g / ℓ

Cl 40-90 (50) mg / l

PEG0.007 g / ℓ

As such, the openings of the plated via holes in the bath containing the composition to which PEG was added as an additive to the basic copper plating solution were not completely blocked, but the growth of the plating film was formed to be blocked later, and the plating layer was formed coarse and coarse. It became.

Comparative Example 3

After the same procedure as in Example 1 except that the composition of the copper plating solution was as follows, the plated shape and the degree of filling of the filled via hole cross sections were confirmed.

Composition:

H ₂ SO ₄ 45 to 75 (60) g / l

CuSO ₄ · 5H ₂ O180 ~ 240 (220) g / ℓ

Cl 40-90 (50) mg / l

PEG0.007 g / ℓ

Polyvinyl Pyrrolidone0.002 g / L

As such, the via holes plated in the bath containing the composition to which PEG and polyvinyl pyrrolidone were added as additives to the basic copper plating solution did not improve the clogging of the openings and did not fill in the via holes. However, the density against insects was relatively good.

Comparative Example 4

After the same procedure as in Example 1 except that the composition of the copper plating solution was as follows, the plated shape and the degree of filling of the filled via hole cross sections were confirmed.

Composition:

H ₂ SO ₄ 45 to 75 (60) g / l

CuSO ₄ · 5H ₂ O180 ~ 240 (220) g / ℓ

Cl 40-90 (50) mg / l

PEG0.007 g / ℓ

Polyvinyl Pyrrolidone0.002 g / L

3-mercoptopropane sulfonic acid 0.001 g / l

As such, the interior of the plated via hole was filled in a bath comprising a composition comprising PEG, polyvinyl pyrrolidone, and 3-mercoptopropane sulfonic acid as an additive to the basic copper plating solution, and the texture of the plating layer was significantly increased. Although compact, voids occurred.

Comparative Example 5

Except that the amount of each of the additives in the copper plating solution is the same as in Comparative Example 4, and then the plated shape and the filling degree of the filled via hole cross-section was confirmed.

Composition:

H ₂ SO ₄ 45 to 75 (60) g / l

CuSO ₄ · 5H ₂ O180 ~ 240 (220) g / ℓ

Cl 40-90 (50) mg / l

PEG0.6g / ℓ

Polyvinyl Pyrrolidone0.0005 g / ℓ

3-mercoptopropane sulfonic acid0.025 mg / l

As such, when the amount of the PEG, polyvinyl pyrrolidone, and 3-mercoptopropane sulfonic acid, which are additives in the basic copper plating solution, is adjusted to the concentration range of the polishing agent formulated in the general acid copper plating solution, voids are generated and filling of the via holes. Was not done.

Comparative Example 6

Except not using PEG in the additive composition of the copper plating solution was carried out in the same manner as in Example 1, and then the plated shape and filling degree of the filled via hole cross-section was confirmed.

Composition:

H ₂ SO ₄ 45 to 75 (60) g / l

CuSO ₄ · 5H ₂ O 180-240 (220) g / l

Cl 40-90 (50) mg / l

Octylphenol ethoxylate0.05 g / l

Polyvinyl Pyrrolidone0.002 g / L

3-mercoptopropane sulfonic acid 0.002 g / l

As such, the interior of the via-holes plated in a bath comprising a composition comprising the addition of octylphenol ethoxylate, polyvinyl pyrrolidone, and 3-mercoptopropane sulfonic acid to the basic copper plating solution except PEG in the additives of the present invention. Was filled and the structure of the plating layer was also very dense, but the openings were first clogged to create voids.

Thus, the additive according to the present invention is not intended as a composition comprising any component such as PEG or octylphenol ethoxylate, but in the via hole opening only when applied to the copper plating solution as a combination of each component containing a specific content. It was found that the over-precipitation prevented the opening from clogging first, thereby completely filling the via hole within a short working time without generating voids.

As described above, according to the present invention, in the copper plating solution for filling the inside of the via hole with copper plating to form stacked vias according to the demand for densification and miniaturization of the conductor pattern of the printed circuit board, By adding a certain amount of a specific acid additive composition to prevent excessive precipitation in the via hole opening even in a high current density working environment to prevent the formation of voids, an acidic copper plating additive composition capable of completely filling the via hole in a fast working time and a via using the same It is possible to provide a hole filling method.

Claims (4)

In the additive composition contained in 1 L of via-filling copper plating solution of a printed circuit board, polyethylene glycol 0.005g to 0.4g, polyvinylyl pyrrolidone 0.001g to 0.1g, 3-mercoptopropane sulfonic acid 0.001g An acidic copper plating additive composition for filling a via hole, consisting of -0.02 g and octylphenol ethoxylate 0.03 g-0.5 g. A plated material is immersed in a copper plating electrolyte comprising the acidic copper plating additive composition according to claim ¹ , and the electroplating is carried out under a high current density of 1.0 to 4.0 A / dm ² and an electrolytic plating under a temperature condition of 20 to 30 ° C. Via hole filling method. The method of claim 2, wherein the electrolyte comprises H ₂ SO _4, CuSO ₄ · 5H ₂ O, and Cl. In the copper plating solution for via hole filling of a printed circuit board, A copper plating solution composition comprising the additive composition according to claim 1, 45 to 75 g of H ₂ SO _4, 180 to 240 g of CuSO ₄ · 5H ₂ O, and 40 to 90 (50) mg of Cl.