JP2014038145A - Method for manufacturing multilayer electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a multilayer electronic component which can form a minute conductor pattern and via hole with high resolution by photolithography.SOLUTION: In a method for manufacturing a multilayer electronic component including at least one conductor layer and at least one insulating layer, an antireflection film is formed as a base layer and subsequently a photosensitive paste layer is formed on the antireflection film, at least one of the conductor layer and the insulating layer is formed from the photosensitive paste layer by photolithography, and the antireflection film is removed by heating, whereby a multilayer electronic component having a minute conductor pattern and via hole can be manufactured.

Description

  The present invention relates to a method for manufacturing a laminated electronic component by photolithography.

  In recent years, with the demand for miniaturization of electronic components, there has been a demand for technology for manufacturing electronic components that can be finely processed and have high precision. In particular, in laminated coil parts and the like, an insulating layer and a conductive layer are laminated, and the conductive layers are electrically connected to each other through via holes. Therefore, with the miniaturization of laminated coil parts, there are also through holes for forming via holes. High precision and fine processing is required. For this reason, in this type of electronic component, it is widely performed to form an insulating layer and a conductor layer by a photolithography technique suitable for fine processing.

  For example, Patent Document 1 manufactures a multilayer wiring chip component by a photolithography technique. Specifically, an outer layer is first formed, and then a photosensitive Ag paste is printed, exposed, and developed on the outer layer. A coil pattern is formed, a photosensitive glass paste is printed on the formed coil pattern, exposed to light, and developed to form a glass layer having via holes, and the coil pattern and the glass layer are formed a predetermined number of times, Finally, a multilayer wiring chip component is manufactured by forming and firing an outer layer.

International Publication No. 2008/093669

However, in the conventional manufacturing method described in Patent Document 1 using a negative photosensitive insulating paste, when an insulating layer having a via hole is formed on a conductor layer, for example, as shown in FIG. When the light beam 1 is applied to the conductor layer 4 and the photosensitive insulating paste 5 disposed on the substrate through the photomask 6 having a predetermined light shielding portion, the light beam 1 is reflected and scattered by the conductor layer 4. The scattered light 2 enters the light shielding portion, and the curing reaction proceeds to a part of the light shielding portion. After exposure, the developer is sprayed to remove the photosensitive insulating paste in the light-shielding part. Originally, it is difficult to remove as it goes deeper, and the curing reaction proceeds in part of the light-shielding part. further removal becomes difficult, as shown in FIG. 1 (b), pilot hole diameter t ₂ becomes smaller than that Ueana径t _1, the via holes tapered is formed. In this way, with the resolution of current photolithography technology, when an insulating layer having a fine via hole is formed on a conductor layer, the via hole does not penetrate due to the influence of reflection / scattering of the light beam by the conductor layer, resulting in an open defect. This causes problems.

  When an insulating layer having a via hole is formed on a conductor layer by photolithography using a positive photosensitive conductor paste, the light beam 1 is reflected / scattered by the conductor layer 4 as shown in FIG. Then, the scattered light 2 enters the light shielding portion. In the via hole 7 thus obtained, as shown in FIG. 2B, a via hole having a pilot hole diameter larger than the upper hole diameter is formed. When a via paste having such a shape is filled with a conductor paste, filling failure occurs at the bottom peripheral portion 8 of the via hole, and an air layer is formed. This expands at the time of firing and remains as large bubbles, resulting in problems such as failure to obtain desired performance.

  Further, when the conductor layer is formed by photolithography using a negative photosensitive conductor paste, the light beam 1 is reflected and scattered by the insulating layer 9 and the scattered light 2 is shielded as shown in FIG. The curing reaction proceeds to a part of the light shielding part of the photosensitive conductor paste layer 10. As a result, as shown in FIG. 3B, the obtained conductor layer 4 has a shape in which the bottom surface portion is expanded. In such a current photolithography technique, when a fine conductor pattern is formed, as shown in FIG. 3 (c), there are problems such as short-circuiting by connecting portions close to each other in the conductor pattern.

  Accordingly, an object of the present invention is to provide a method for manufacturing a laminated electronic component capable of forming a fine conductor pattern and / or a via hole with high resolution by photolithography.

  According to the present invention, there is provided a method for manufacturing a laminated electronic component including at least one conductor layer and at least one insulating layer, wherein an antireflection film is formed as a base layer, and then a photosensitive film is formed on the antireflection film. There is provided a method comprising forming a conductive paste layer, forming at least one of the conductor layer and the insulating layer from the photosensitive paste layer by photolithography, and removing the antireflection film by heating.

  According to the manufacturing method of the present invention, since reflection and scattering of light rays are suppressed by the antireflection film of the underlayer, when forming the via hole in the insulating layer using the negative photosensitive paste, the via hole is tapered. Therefore, it is possible to avoid open defects and defective filling of the conductor paste. Also, when using a positive photosensitive paste to form a via hole in the insulating layer, the diameter of the via hole's pilot hole is widened and the conductor paste around the bottom surface of the via hole is not sufficiently filled to avoid a void. can do. Further, when the conductive layer is formed using the negative photosensitive paste, it is possible to avoid the short-circuit portion of the conductor layer from spreading and contacting the conductor portions close to each other to cause a short circuit. Therefore, according to the manufacturing method of the present invention, it is possible to form a fine via hole and / or a fine conductor pattern regardless of the negative type or the positive type.

  According to the present invention, by installing an antireflection film as an underlayer, it is possible to prevent reflection and scattering of light when irradiated with light, and to form a conductor pattern and a via hole with higher resolution. A manufacturing method is provided.

FIG. 1A is a schematic cross-sectional view for explaining the formation of a via hole by a photolithography technique using a conventional negative photosensitive insulating paste. FIG. 1B is a schematic cross-sectional view after the formation of the via hole in FIG. FIG. 2A is a schematic cross-sectional view for explaining the formation of a via hole by a photolithography technique using a conventional positive photosensitive insulating paste. FIG. 2B is a schematic cross-sectional view after forming the via hole of FIG. FIG. 3A is a schematic cross-sectional view illustrating conductor pattern formation by a photolithography technique using a conventional negative photosensitive conductor paste. FIG. 3B is a schematic cross-sectional view after the conductor pattern is formed in FIG. FIG. 3C is a schematic cross-sectional view when conductor patterns close to each other are formed. It is a schematic perspective view of the laminated coil component manufactured by the manufacturing method of this invention. It is a schematic sectional drawing which shows each manufacturing process of the manufacturing method of the laminated coil component of FIG.

  Hereinafter, the production method of the present invention will be described in detail with reference to the drawings.

  In the present embodiment, a method for manufacturing a laminated coil component 11 as shown in FIG. 4 will be described as a laminated electronic component. The multilayer coil component 11 generally includes a multilayer body 14 having an insulator portion 12 and a coil-shaped conductor portion 13 embedded in the insulator portion 12, and the external electrode 15 is a multilayer body. 14 is provided so as to cover both end faces of the outer periphery.

  First, the outer layer is prepared. The outer layer 16 is formed, for example, by printing a photosensitive insulating paste on a holding layer (not shown) formed on a base material (not shown), drying, and exposing the entire surface to form an insulating layer. Is repeated a plurality of times to form the outer layer 16 having a predetermined thickness. As the photosensitive insulating paste, a photosensitive insulating paste as described later can be used.

  Next, as shown in FIG. 5A, a photosensitive conductive paste is printed on the outer layer 16, dried, exposed through a photomask having a predetermined pattern, and developed to form a conductive layer 17. Form.

  As the photosensitive conductive paste used in the present invention, a known positive type or negative type photosensitive conductive paste can be used, and is not limited, but is sensitive to Ag, Au, AuPd, AgPd, Cu or Ni. Examples thereof include a photosensitive metal paste containing components.

  Next, as shown in FIG. 5B, an antireflection film 18 is formed on the conductor layer 17. The antireflection film 18 may cover the entire surface including the conductor layer 17, but it is sufficient to cover at least the exposed portion and its periphery.

  The method for forming the antireflection film is not particularly limited as long as it can form the antireflection film, and examples thereof include an ink jet method and a spin coating method.

  The antireflection film contains a substance capable of absorbing light having a wavelength that cures the photosensitive component contained in the layer material formed thereon. The substance is not particularly limited, but it is preferable to use a dye because it is easily decomposed by heat and can be easily removed by heating. Specifically, when the photosensitive component is cured by absorbing light having a wavelength of 350 to 410 nm, examples of the substance include black azo dyes, yellow azo dyes, anthraquines, acenes, and anilines.

  The film thickness of the antireflection film is 0.05 to 0.5 μm, preferably 0.05 to 0.2 μm, and typically 0.1 μm. By making the antireflection film 0.5 μm or less, the antireflection film can be easily removed, and separation of the insulating layer and the conductor layer after the removal can be prevented. In addition, by setting the antireflection film to 0.05 μm or more, a sufficient antireflection effect can be obtained.

  The optical density of the antireflection film is not particularly limited, but is preferably 0.03 to 0.9, more preferably 0.03 to 0.75, and still more preferably 0.3 at the wavelength at which the photosensitive component is cured. ~ 0.75. By setting the optical density of the antireflection film to 0.9 or less, the antireflection film can be easily removed. By setting the optical density of the antireflection film to 0.03 or more, a desired antireflection effect can be obtained.

  Next, as shown in FIG. 5C, a photosensitive insulating paste layer 19 is formed on the antireflection film 18 by screen printing or the like, and light is transmitted through a photomask 20 in which a portion corresponding to the via hole is shielded. 21 is irradiated.

  As the photosensitive insulating paste used in the present invention, a known positive-type or negative-type photosensitive insulating paste can be used, and it is not limited, but photosensitive glass paste, photosensitive alumina paste, and photosensitive zirconia. Examples thereof include photosensitive inorganic pastes such as pastes.

  The light beam used in the present invention is not particularly limited as long as it contains light having a wavelength that cures the photosensitive component contained in the layer material to be exposed. The light source is not limited. For example, when the photosensitive component absorbs light having a wavelength of 350 to 410 nm and is cured, an ultrahigh pressure mercury lamp can be used.

  Next, as shown in FIG. 5D, the uncured photosensitive insulating paste is removed with a developer to form an insulating layer 23 having via holes 22.

  In the present invention, the thickness of the insulating layer is not particularly limited, but is 1 to 50 μm, preferably 5 to 30 μm. By setting the thickness of the insulating layer to 50 μm or less, a low-profile laminated coil component can be manufactured. Insulating properties can be ensured by setting the thickness of the insulating layer to 1 μm or more.

  Next, as shown in FIG. 5E, a photosensitive conductor paste is printed on the insulating layer 23 while filling the via holes 22, dried, and exposed through a photomask on which a predetermined pattern is drawn. Then, the conductive layer 24 is formed by development.

  The formation of the antireflection film, the formation of the insulating layer, and the formation of the conductor layer shown in FIGS. 5B to 5E are repeated a predetermined number of times. Finally, the outer layer of the insulating layer is formed, and an unfired laminate ( Corresponding to the laminate 14).

  Next, the anti-reflection film is removed by heating the obtained unfired laminate. By removing the antireflection film, as shown in FIG. 5F, the conductor layer 17 and the conductor layer 24 are connected to form a coil.

  Although the temperature at the time of removing an antireflection film will not be specifically limited if it is the temperature which the component of an antireflection film burns out, For example, it is 150-750 degreeC, Preferably it is 200-400 degreeC. Moreover, although heating time is not specifically limited, Preferably it is 0.5 to 5 hours, More preferably, it is 1-3 hours.

  Further, the removal of the antireflection film may be performed at any timing after the conductor layer is formed thereon by photolithography, but may be performed simultaneously with the following firing.

  Next, the unsintered laminate is fired to obtain the laminate 14, and external electrodes 15 electrically connected to the coils are formed at both ends of the laminate 14, and the laminate coil component as shown in FIG. Make it. As a calcination temperature, it is 700-1,000 degreeC, for example, Preferably it is 800-850 degreeC.

  Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment.

  For example, in the above-described embodiment, the antireflection film is formed as the base layer when the insulating layer is formed using the negative photosensitive insulating paste, but a positive photosensitive insulating paste can also be used. Note that when a positive photosensitive insulating paste is used, the light-shielding portion and the transmissive portion of the photomask are opposite to those when a negative photosensitive insulating paste is used.

  In the above embodiment, when the conductor layer is formed, the antireflection film is not formed as the underlayer. However, the method of the present invention forms the photosensitive conductor paste layer after forming the antireflection film as the underlayer. And a conductive layer is formed from the photosensitive conductive paste layer by photolithography. The photosensitive conductive paste used may be positive or negative. According to this method, a finer wiring pattern can be formed.

  In the method of the present invention, (i) an antireflection film is formed as a base layer, a photosensitive insulating paste layer is then formed on the antireflection film, and an insulating layer is formed from the photosensitive insulating paste layer by photolithography. And (ii) forming an antireflection film as an underlayer, then forming a photosensitive conductor paste layer on the antireflection film, and photolithography from the photosensitive conductor paste layer Although it may include both forming at least one of the conductor layers, in this case, the order of step (i) and step (ii) is not limited.

  In the following examples, the present invention will be described more specifically, but the present invention is not limited to these examples.

Example 1
-Preparation of photosensitive alumina paste Alumina powder (35 parts by weight), photosensitive varnish (63.5 parts by weight), polymaleic acid-based dispersant (1 part by weight), and pigment comprising a complex oxide of cobalt and aluminum (0 0.5 parts by weight) was mixed and kneaded with a three-roll mill to obtain a photosensitive alumina paste.

Preparation of photosensitive glass paste Glass powder (35 parts by weight), alumina powder (25 parts by weight), photosensitive varnish (38.5 parts by weight), polymaleic acid-based dispersant (1 part by weight), and yellow azo dye ( 0.5 parts by weight) was mixed and kneaded with a three-roll mill to obtain a photosensitive glass paste.

-Preparation of photosensitive silver paste Silver powder (80 parts by weight), photosensitive varnish (19.5 parts by weight), and polymaleic acid-based dispersant (parts by weight) are mixed and kneaded with a three-roll mill. A silver paste was obtained.

-Manufacture of laminated chip parts Step 1: A photosensitive alumina paste was screen-printed on an alumina substrate, exposed to the entire surface, and an alumina film was formed to form a holding layer. Next, a photosensitive glass paste was screen-printed on the holding layer, and the entire surface was exposed to form a glass layer. This was repeated until the glass layer became about 150 μm to form an outer layer.

  Step 2: A photosensitive silver paste was screen printed on the outer layer, exposed through a photomask having a desired pattern, and developed to form a conductor layer.

  Step 3: An ink of 20 wt% black azo dye was applied to the entire surface with a thickness of 0.1 μm by inkjet to form an antireflection film.

  Step 4: A photosensitive glass paste is screen-printed to a thickness of 20 μm on the antireflection film, exposed through a photomask having a light-shielding portion having a diameter of 60 μm corresponding to the via hole, and developed to insulate the via hole. A layer was formed.

  Step 5: The photosensitive silver paste was screen printed on the insulating layer while filling the via hole, exposed through a photomask having a desired pattern, and developed to form a conductor layer.

  Step 6: Steps 3 to 5 are repeated until the required number of layers is obtained. Finally, the photosensitive glass paste is screen-printed and exposed to the whole surface to form a glass layer. The glass layer has a thickness of about 150 μm. The outer layer was formed repeatedly until a laminated chip was obtained.

  Step 7: The obtained laminated chip was divided into one element using a dicer. This was heat treated at 300 ° C. for 3 hours for degreasing, and baked at 820 ° C. for 0.5 hour to obtain a baked laminated chip. In the laminated chip after firing, glass and silver are sintered, and at the same time, the antireflection film disappears, and the silver coil pattern is conducted through the via. Also, the alumina film disappears only with organic components and becomes alumina powder, and the substrate and the chip are separated.

  Step 8: After that, external electrodes were formed and plated to produce a multilayer chip component.

Example 2
A laminated chip component was produced in the same manner as in Example 1 except that the ink concentration was changed to 2 wt% in Step 3.

Example 3
In step 3, a laminated chip component was produced in the same manner as in Example 1 except that the ink concentration was 50 wt%.

Example 4
A laminated chip part was produced in the same manner as in Example 1 except that in step 3, the ink concentration was changed to 60 wt%.

Example 5
In step 3, a laminated chip part was produced in the same manner as in Example 1 except that the black azo dye was replaced with the yellow azo dye.

Comparative Example 1
A laminated chip part was produced in the same manner as in Example 1 except that the antireflection film in Step 3 was not formed.

Comparative Example 2
In step 3, a laminated chip part was produced in the same manner as in Example 1 except that the ink concentration was 1 wt%.

Evaluation / Via Diameter For each of Examples 1 to 5 and Comparative Examples 1 and 2, after forming a via hole in Step 4, the upper hole diameter and the lower hole diameter of the via hole were measured with a laser microscope. The results are shown in Table 1.

  Further, the shape of the via was evaluated by the ratio of the upper and lower via diameters (the lower hole diameter ÷ the upper hole diameter × 100). The results are also shown in Table 1.

-Continuity test About each of the said Examples 1-5 and Comparative Examples 1-2, 50 electrical continuity was investigated. As a result, the conductivity (number of conduction / number of tests × 100) is also shown in Table 1.

  Moreover, the thing which did not conduct by the said continuity test observed the cross section of the via hole, and investigated the cause of the conduction defect. The results are also shown in Table 1.

  As shown in Table 1, Examples 1 to 5 in which an antireflection film is formed using an ink having a concentration of 2 to 60 wt% (optical density = 0.03 to 0.9) are different in the upper and lower via diameter ratio (the lower hole Diameter ÷ upper hole diameter × 100) was 63 to 67%. In the continuity test, the continuity rates of Examples 1 to 3 and 5 were 100%. In Example 4, the conductivity was 90%, but this was not a defect in the open mode, but a defect in the delamination mode, and because the antireflection film was dark and not sufficiently degreased, the antireflection film It is thought that this can be eliminated by devising the degreasing conditions such as increasing the heating time for removing water.

  On the other hand, Comparative Example 1 in which the antireflection film was not formed had a small upper / lower via diameter ratio of 8% and a conductivity of 60%. Moreover, as a result of investigation, this is a failure in the open mode, and the cause of the conduction failure was that the diameter of the pilot hole in the via hole was too small to be filled with silver to the bottom.

  Further, in Comparative Example 2 in which the antireflection film was formed using ink having a concentration of 1 wt% (optical density = 0.01), the upper / lower via diameter ratio was as small as 17% and the conductivity was 80%. Further, as a result of the investigation, the poor hole diameter of the via hole was too small to be filled with silver to the lower part, which was the cause of the conduction failure. The cause of the decrease in the diameter of the pilot hole may be that the ink concentration is low and the antireflection effect is not sufficiently obtained.

  From the above results, it was confirmed that excellent effects were obtained in Examples 1 to 5, particularly Examples 1 to 3 and 5, using an antireflection film.

  Since the manufacturing method of the present invention has high resolution and can form fine conductor patterns and via holes, it can be used in a wide variety of applications as a manufacturing method of small laminated coil components.

DESCRIPTION OF SYMBOLS 1 Light 2 Scattered light 3 Base material 4 Conductor layer 5 Photosensitive insulating paste 6 Photomask 7 Via hole 8 Via hole bottom peripheral part 9 Insulating layer 10 Photosensitive conductor paste 11 Laminated coil component 12 Insulator part 13 Conductor part 14 Laminate 15 External electrode 16 Outer layer 17 Conductor layer 18 Antireflection film 19 Photosensitive insulating paste layer 20 Photomask 21 Light beam 22 Via hole 23 Insulating layer 24 Conductor layer t ₁ Upper diameter t ₂ Lower diameter

Claims (8)

  A method of manufacturing a laminated electronic component including at least one conductor layer and at least one insulating layer, wherein an antireflection film is formed as a base layer, and then a photosensitive paste layer is formed on the antireflection film. And forming at least one of the conductor layer and the insulating layer from the photosensitive paste layer by photolithography, and removing the antireflection film by heating.   The method according to claim 1, wherein the photosensitive paste layer is a photosensitive insulating paste layer, and the insulating layer is formed from the photosensitive insulating paste layer by photolithography.   The laminated electronic component includes at least two conductor layers and at least one insulating layer disposed between the two conductor layers and having a via hole for connecting them, and an antireflection film on the conductor layer And then forming a photosensitive insulating paste layer, forming an insulating layer having via holes from the photosensitive insulating paste layer by photolithography, and removing the antireflection film by heating. 2. The method according to 2.   The method according to claim 1, wherein the photosensitive paste layer is a photosensitive conductor paste layer, and the conductor layer is formed from the photosensitive conductor paste layer by photolithography. Forming an antireflection film as an underlayer, then forming a photosensitive insulating paste layer on the antireflection film, forming at least one of the insulating layers from the photosensitive insulating paste layer by photolithography, and Forming an antireflection film as a base layer, then forming a photosensitive conductor paste layer on the antireflection film, and forming at least one of the conductor layers by photolithography from the photosensitive conductor paste layer;
The method in any one of Claims 1-4 containing this.   The method according to claim 1, wherein the antireflection film contains a dye.   The method according to claim 1, wherein the optical density of the antireflection film is 0.03 to 0.9.   The method according to claim 1, wherein the antireflection film is removed simultaneously with the firing of the laminate.

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