WO2020196640A1 - Electroconductive paste composition and crystalline silicon solar cell - Google Patents

Electroconductive paste composition and crystalline silicon solar cell Download PDF

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WO2020196640A1
WO2020196640A1 PCT/JP2020/013378 JP2020013378W WO2020196640A1 WO 2020196640 A1 WO2020196640 A1 WO 2020196640A1 JP 2020013378 W JP2020013378 W JP 2020013378W WO 2020196640 A1 WO2020196640 A1 WO 2020196640A1
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paste composition
conductive paste
copper
mass
silver powder
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PCT/JP2020/013378
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French (fr)
Japanese (ja)
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正博 中原
マルワン ダムリン
一雄 荒川
石川　和憲
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東洋アルミニウム株式会社
横浜ゴム株式会社
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Priority to CN202080023253.4A priority Critical patent/CN113646903A/en
Publication of WO2020196640A1 publication Critical patent/WO2020196640A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/20—Conductive material dispersed in non-conductive organic material
    • H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0224—Electrodes

Definitions

  • the present invention relates to a conductive paste composition for forming electrodes of a crystalline silicon solar cell and a crystalline silicon solar cell obtained by using the conductive paste composition.
  • electrodes are generally formed on the surface of a silicon substrate using a conductive paste composition for forming electrodes for electrical connection with the outside. is there.
  • the conductive paste composition is printed on the surface of the silicon substrate by screen printing or the like, and then fired in the atmosphere at about 800 ° C. to form the electrodes. Then, when electrically connecting the electrode and the outside, it is common to join the electrode and the interconnector material by soldering.
  • Patent Document 1 relates to a method for manufacturing a film thickness electrode of a solar cell, and claims 1 include a conductive powder, a glass frit, an organic polymer of 3.5 to 12.5% by weight (wt%), and a solvent. It is disclosed that a conductive paste containing the above, wherein wt% is based on the total weight of the conductive powder, the glass frit and the organic polymer. Also claimed in claim 2 are 19-68 wt% conductive powder, 0.1-8 wt% glass frit, 2-10 wt% organic polymer and 28-72 wt% based on the total weight of the conductive paste. A conductive paste containing a solvent is disclosed.
  • the conductive paste described in Patent Document 1 has a large volume ratio of the organic polymer (binder) to the silver powder and a large heat shrinkage in the debinder process when the silver is lowered, so that after soldering. There is a problem that the adhesion strength of the solder is insufficient.
  • the present invention has been completed in view of the above problems of the prior art, and even when the content of silver powder in the conductive paste is 60% by mass or less (low silver), after electrode formation It is an object of the present invention to provide a conductive paste composition capable of obtaining excellent adhesion strength in soldering, and a crystalline silicon solar cell using the same.
  • the present inventors have set the volume ratio of the organic polymer (binder) to the silver powder in a specific range, which contains silver powder, glass powder and organic vehicle.
  • the conductive paste composition excellent adhesion strength can be obtained in soldering after electrode formation even when the content of silver powder in the conductive paste is 60% by mass or less (low silver). It was found that this was possible, and the present invention was completed.
  • the present invention relates to the following conductive paste composition and a crystalline silicon solar cell using the same.
  • a conductive paste composition containing silver powder, glass powder and an organic vehicle.
  • the organic vehicle contains an organic polymer and a solvent, and the volume ratio of the organic polymer to the silver powder is 0.25 or more and 0.40 or less.
  • a conductive paste composition characterized in that. 2.
  • the copper compounds include copper (II) acetylacetonate, copper (II) neodecanoate, copper (I) oxide, copper (II) oxide, bis (8-quinolinolato) copper (II), and bis (triphenylphosphine) copper.
  • the conductive paste composition according to Item 2 above which is at least one selected from the group consisting of tetrahydrobolate and copper (II) trifluoromethanesulfonate. 4.
  • Item 2 or 3 wherein the copper compound is contained in an amount of 0.1 part by mass or more and 1.0 part by mass or less in terms of copper with respect to 100 parts by mass of the silver powder. 5.
  • the conductive paste composition of the present invention even when the content of silver powder in the conductive paste composition is 60% by mass or less (low silver), an electrode is formed on the surface of the silicon substrate by using this. After that, it has excellent adhesion strength after soldering in the electrical connection between the electrode and the outside. Therefore, for example, when the electrode and the interconnector material are soldered, excellent adhesion strength can be ensured.
  • the conductive paste composition of the present invention contains silver powder, glass powder and an organic vehicle.
  • the organic vehicle contains an organic polymer and a solvent, and the volume ratio of the organic polymer to the silver powder is 0.25 or more and 0.40 or less. It is characterized by that.
  • the conductive paste composition of the present invention having the above characteristics, even when the content of silver powder in the conductive paste composition is 60% by mass or less (low silver), the surface of the silicon substrate is used. After forming the electrode, it has excellent adhesion strength after soldering in the electrical connection between the electrode and the outside. Therefore, for example, when the electrode and the interconnector material are soldered, excellent adhesion strength can be ensured.
  • the conductive paste composition of the present invention uses silver powder as the conductive powder. That is, the electrode formed by using the conductive paste composition of the present invention is a so-called silver electrode.
  • the shape of the silver powder is not particularly limited, and examples thereof include spherical and flake (scale) shapes. Among these, the spherical shape is preferable from the viewpoint that the effect of the present invention can be easily obtained and the strength of the obtained electrode is advantageous.
  • the spherical shape means the shape of a particle having a major axis / minor axis ratio of 2 or less.
  • the flake shape means a shape in which the ratio of the major axis / the minor axis exceeds 2.
  • the major axis and minor axis of the silver powder can be determined based on an image obtained from a scanning electron microscope (SEM).
  • SEM scanning electron microscope
  • the "major axis” refers to the longest distance of the line segments passing through the substantially center of gravity of the silver powder in the particle image obtained by SEM.
  • the “minor diameter” refers to the shortest distance of the line segments passing through the substantially center of gravity of the silver powder in the particle image obtained by SEM.
  • 100 silver powders are arbitrarily selected in the above image, the major axis of the 100 silver powders is measured, and the average value calculated from the major axis of the 100 silver powders is the average of the major axis of the silver powder. (Average value). The same applies to the average minor axis of silver powder.
  • the average particle size (D50) of the silver powder is not limited, but is preferably 2.0 ⁇ m or less from the viewpoint that the effect of the present invention can be easily obtained and the strength of the obtained electrode is advantageous. It is more preferably 1.0 ⁇ m or less.
  • silver powder having an average particle diameter (D50) of several tens of nm (for example, 10 to 90 nm) called nanosilver can be used.
  • the shape of the nanosilver is not particularly limited, and examples thereof include spherical ones. Therefore, the average particle size (D50) of the silver powder is preferably set in the range of several tens of nm to 2.0 ⁇ m or less.
  • the average particle size (D50) of the silver powder is determined by measuring the particle size distribution on a volume basis using a laser diffraction type particle size distribution measuring device.
  • a laser diffraction type particle size distribution measuring device for example, micro Examples thereof include a laser diffraction / scattering type particle size distribution measuring device “Microtrac MT3000II series” manufactured by Truck Bell.
  • the major axis (width) of the flake-shaped silver powder is preferably 2.0 ⁇ m or less on average, preferably 1.0 ⁇ m or less, from the viewpoint that the effects of the present invention can be easily obtained and the strength of the obtained electrode is advantageous. Is more preferable.
  • the minor axis (thickness) of the flake-shaped silver powder is preferably less than 1.0 ⁇ m on average from the viewpoint that the effects of the present invention can be easily obtained and the strength of the obtained electrode is advantageous. It is more preferably 1 ⁇ m or less.
  • the flake-shaped silver powder for example, silver having a minor axis (thickness) average (average value) of several tens of nm (for example, 10 to 90 nm) and a major axis (width) average of 0.3 to 6 ⁇ m. Powders are preferred.
  • Examples of commercially available flaky silver powder include trade name N300, which is commercially available from Toxen Industries, Ltd.
  • the content of the silver powder in the conductive paste composition of the present invention is not limited, but due to the recent demand for lower silver content, adhesion after soldering even when the content of the silver powder is set to 60% by mass or less. The effect of being excellent in strength can be ensured. From the viewpoint of efficiently obtaining the effects of the present invention, the content of the silver powder in the conductive paste composition is more preferably 49% by mass or less, and the lower limit of the content of the silver powder is about 40% by mass.
  • Glass powder The glass powder is said to have an action of assisting the reaction between the conductive material (silver powder in the present invention) and silicon, and the sintering of the conductive material itself.
  • the glass powder is not particularly limited, and can be, for example, a known glass component contained in the paste composition used for forming the electrode layer of the solar cell.
  • Specific examples of the glass powder include a group consisting of lead (Pb), bismuth (Bi), vanadium (V), boron (B), silicon (Si), tin (Sn), phosphorus (P) and zinc (Zn). At least one selected from.
  • lead-containing glass powder or lead-free glass powder such as bismuth-based, vanadium-based, tin-phosphorus-based, zinc borosilicate-based, and alkaline borosilicate-based can be used.
  • the glass powder is B 2 O 3 , Bi 2 O 3 , ZnO, SiO 2 , Al 2 O 3 , BaO, PbO, CaO, SrO, V 2 O 5 , Sb 2 O 3 , WO 3 , P 2 It can contain at least one component selected from the group consisting of O 5 and Te O 2 .
  • ZnO and / or PbO is preferable, and PbO is more preferable, from the viewpoint that the effects of the present invention can be easily obtained and easily obtained.
  • the glass powder contains ZnO and / or PbO, it is preferable to further contain B 2 O 3 and / or SiO 2, and when the glass powder contains PbO, it is preferable to further contain SiO 2. ..
  • the softening point of the glass powder can be, for example, 750 ° C. or lower.
  • the average particle size of the particles contained in the glass powder can be, for example, 1 to 3 ⁇ m.
  • the content of the glass powder in the conductive paste composition of the present invention is not limited, but is preferably 0.5 to 10% by mass, more preferably 1 to 5% by mass. In this case, the adhesion between the silicon substrate and the passivation film (and / or the antireflection film) is good, and the electrical resistance is unlikely to increase. Further, the content of the glass powder is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5.0% by mass with respect to 100 parts by mass of the silver powder.
  • Organic vehicle contains an organic polymer (binder) and a solvent, and can further contain various additives as needed.
  • solvents can be used, and specific examples thereof include diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, and dipropylene glycol monomethyl ether.
  • the amount of the solvent used can be appropriately set within the range of the standard amount used in the field in consideration of the coatability of the conductive paste composition and the like.
  • antioxidants for example, antioxidants, corrosion inhibitors, antifoaming agents, thickeners, tack fires, coupling agents, antistatic agents, polymerization inhibitors, thixotropy agents, anti-sediment agents and the like are used. be able to.
  • polyethylene glycol ester compound polyethylene glycol ether compound, polyoxyethylene sorbitan ester compound, sorbitan alkyl ester compound, aliphatic polyvalent carboxylic acid compound, phosphoric acid ester compound, amidoamine salt of polyester acid, polyethylene oxide.
  • System compounds, fatty acid amide wax and the like can be used.
  • organic polymers such as ethyl cellulose, cellulose ester, nitrocellulose, polyvinyl butyral, phenol resin, melamine resin, urea resin, xylene resin, alkyd resin, and unsaturated polyester resin.
  • the content of the organic polymer contained in the organic vehicle may be such that the volume ratio of the organic polymer to the silver powder (that is, the organic polymer / silver powder) is 0.25 or more and 0.40 or less.
  • the volume ratio is more preferably 0.30 or more and 0.40 or less.
  • the conductive paste composition of the present invention preferably contains a copper compound, if necessary, in addition to the silver powder, the glass powder and the organic vehicle.
  • the surface of the silicon substrate is used through a passivation film (and / or an antireflection film) using a conductive paste composition.
  • the glass powder reacts with the copper compound before acting on the passivation film (and / or the antireflection film) during firing, and the glass powder forms the passivation film (and / or the antireflection film).
  • the copper compound is not limited as long as it can obtain the above action, but for example, copper (II) acetylacetonate, copper (II) neodecanoate, copper (I) oxide, copper (II) oxide, bis (8).
  • -At least one selected from the group consisting of quinolinolato) copper (II), bis (triphenylphosphine) copper tetrahydroborate and copper (II) trifluoromethanesulfonate can be preferably used.
  • at least one of copper (I) oxide, copper (II) oxide, copper (II) acetylacetonate and the like is preferable from the viewpoint of dispersibility of the copper compound in the conductive paste.
  • the content of the copper compound is preferably 0.1 part by mass or more and 1.0 part by mass or less with respect to 100 parts by mass of the silver powder.
  • the conductive paste composition of the present invention is useful as a conductive paste composition for forming electrodes of crystalline silicon solar cells. That is, in the conductive paste composition of the present invention, for example, after optionally laminating the passivation film 2 (and / or the antireflection film 2) on the silicon substrate 1 (silicon semiconductor substrate 1) as illustrated in FIG.
  • the electrode 4 can be formed by printing the conductive paste composition 3 of the present invention on an electrode shape by a method such as screen printing and then firing in the air at about 800 ° C.
  • the present invention also includes the invention of a crystalline silicon solar cell including an electrode formed by using the conductive paste composition of the present invention.
  • the test body for evaluation was manufactured as follows.
  • a silicon substrate made of p-type single crystal silicon shown in FIG. 1 (A) was prepared (substrate: 6 inches, thickness 160 ⁇ m, resistivity 2 ⁇ ⁇ cm).
  • the antireflection film 2 containing silicon nitride as a main component was formed by the plasma CVD method.
  • the conductive paste composition 3 was printed on the surface of the silicon substrate 1 via the antireflection film 2 using a screen printing machine to have a printing width of 1.5 mm. I printed it so that it would be.
  • the deployability of the conductive paste composition on the screen plate was evaluated by observing the appearance.
  • ⁇ that is less likely to be blurred and spreads evenly Those with faintness ⁇ I evaluated it.
  • a copper ribbon (width 1.0 mm) for interconnect is soldered on the electrode 4 to which flux is applied in advance at a temperature of 270 ° C. for 3 seconds. To prepare a test sample.
  • the tensile strength is greater than 2.0 N / mm, it can be said that the tensile strength is sufficiently good to withstand actual use.
  • Example 2 The same procedure as in Example 1 was carried out except that an organic vehicle in which 3.8 parts by mass of ethyl cellulose (specific gravity 1.12) was dissolved in 95.2 parts by mass of tarpineol was used.
  • Example 3 The same procedure as in Example 1 was carried out except that an organic vehicle in which 3.2 parts by mass of ethyl cellulose (specific gravity 1.12) was dissolved in 95.8 parts by mass of tarpineol was used.
  • Example 4 The same procedure as in Example 1 was carried out except that an organic vehicle in which 2.7 parts by mass of ethyl cellulose (specific gravity 1.12) was dissolved in 96.3 parts by mass of tarpineol was used.
  • Example 5 The same procedure as in Example 1 was carried out except that an organic vehicle in which 4.0 parts by mass of polyvinyl butyral (specific gravity 1.10) was dissolved in 95.0 parts by mass of tarpineol was used.
  • Example 6 Example 1 and Example 1 except that an organic vehicle in which 3.8 parts by mass of ethyl cellulose (specific gravity 1.12) was dissolved in 94.7 parts by mass of tarpineol was used and 0.5 parts by mass of copper (II) oxide was added as a copper compound. The same was true.
  • Comparative Example 1 The same procedure as in Example 1 was carried out except that an organic vehicle in which 2.5 parts by mass of ethyl cellulose (specific gravity 1.12) was dissolved in 96.5 parts by mass of tarpineol was used.
  • Comparative Example 2 The same procedure as in Example 1 was carried out except that an organic vehicle in which 4.5 parts by mass of ethyl cellulose (specific gravity 1.12) was dissolved in 94.5 parts by mass of tarpineol was used.
  • Comparative Example 3 The same procedure as in Example 1 was carried out except that an organic vehicle in which 5.0 parts by mass of polyvinyl butyral (specific gravity 1.10) was dissolved in 94.0 parts by mass of tarpineol was used.
  • Table 1 below shows the conditions and test results of each example and comparative example.

Abstract

The present invention provides: an electroconductive paste composition with which it is possible to obtain an excellent adhesion strength during soldering after electrode formation, even when the amount of silver power contained in an electroconductive paste is 60 mass% or below (low silver); and a crystalline silicon solar cell in which the electroconductive paste composition is used.　The present invention is, specifically, an electroconductive paste composition containing silver powder, glass powder, and an organic vehicle, wherein the electroconductive paste composition is characterized in that the organic vehicle contains an organic polymer and a solvent, and the volume ratio of the organic polymer relative to the silver powder is 0.25 to 0.40 inclusive.

Description

導電性ペースト組成物及びそれを用いた結晶系シリコン太陽電池セルConductive paste composition and crystalline silicon solar cell using it
　本発明は、結晶系シリコン太陽電池セルの電極形成用の導電性ペースト組成物及びその導電性ペースト組成物を用いて得られた結晶系シリコン太陽電池セルに関する。 The present invention relates to a conductive paste composition for forming electrodes of a crystalline silicon solar cell and a crystalline silicon solar cell obtained by using the conductive paste composition.
　結晶系シリコン太陽電池セルなどの半導体デバイスにおいては、外部との電気的接続のために、電極形成用の導電性ペースト組成物を用いてシリコン基板の表面に電極が形成されることが一般的である。 In semiconductor devices such as crystalline silicon solar cells, electrodes are generally formed on the surface of a silicon substrate using a conductive paste composition for forming electrodes for electrical connection with the outside. is there.
　電極を形成する際はシリコン基板の表面に導電性ペースト組成物をスクリーン印刷などで印刷後、８００℃程度の大気中で焼成することにより電極が形成される。そして、電極と外部とを電気的接続する際は、電極とインターコネクタ材とをはんだ付けにより接合することが一般的である。 When forming the electrodes, the conductive paste composition is printed on the surface of the silicon substrate by screen printing or the like, and then fired in the atmosphere at about 800 ° C. to form the electrodes. Then, when electrically connecting the electrode and the outside, it is common to join the electrode and the interconnector material by soldering.
　特許文献１は太陽電池セルの膜厚電極の製造方法に関し、請求項１には、導電性粉末と、ガラスフリットと、有機ポリマー３．５～１２．５重量パーセント（ｗｔ％）と、溶剤とを含む導電性ペーストであって、前記ｗｔ％が前記導電性粉末、前記ガラスフリット及び前記有機ポリマーの全重量に基づく導電性ペーストを用いることが開示されている。また、請求項２には、導電性ペーストの全重量に基づいて、１９～６８ｗｔ％の導電性粉末、０．１～８ｗｔ％のガラスフリット、２～１０ｗｔ％の有機ポリマー及び２８～７２ｗｔ％の溶剤を含む導電性ペーストが開示されている。 Patent Document 1 relates to a method for manufacturing a film thickness electrode of a solar cell, and claims 1 include a conductive powder, a glass frit, an organic polymer of 3.5 to 12.5% by weight (wt%), and a solvent. It is disclosed that a conductive paste containing the above, wherein wt% is based on the total weight of the conductive powder, the glass frit and the organic polymer. Also claimed in claim 2 are 19-68 wt% conductive powder, 0.1-8 wt% glass frit, 2-10 wt% organic polymer and 28-72 wt% based on the total weight of the conductive paste. A conductive paste containing a solvent is disclosed.
　近年、太陽電池セルは高性能化が進んでいる一方、コストメリットの観点から導電性ペースト中の低銀化（銀含有比率の低減；例えば６０質量％以下）が求められている。また、長期安定性の観点から、電極と外部との電気的接続における、はんだ付け後の密着強度に優れることも求められている。 In recent years, while the performance of solar cells has been improved, low silver content (reduction of silver content ratio; for example, 60% by mass or less) in the conductive paste is required from the viewpoint of cost merit. Further, from the viewpoint of long-term stability, it is also required to have excellent adhesion strength after soldering in the electrical connection between the electrode and the outside.
特開２０１４－５３２８７号公報Japanese Unexamined Patent Publication No. 2014-53287
　しかしながら、特に特許文献１に記載の導電性ペーストは、低銀化した場合には銀粉末に対する有機ポリマー（バインダー）の体積比が大きくなり、脱バインダー過程における熱収縮も大きくなるため、はんだ付け後の密着強度が不足するという問題がある。 However, in particular, the conductive paste described in Patent Document 1 has a large volume ratio of the organic polymer (binder) to the silver powder and a large heat shrinkage in the debinder process when the silver is lowered, so that after soldering. There is a problem that the adhesion strength of the solder is insufficient.
　本発明は、上記従来技術の問題に鑑みて完成されたものであり、導電性ペースト中の銀粉末の含有量が６０質量％以下（低銀化）の場合であっても、電極形成後のはんだ付けにおいて優れた密着強度が得られる導電性ペースト組成物、及びそれを用いた結晶系シリコン太陽電池セルを提供することを目的とする。 The present invention has been completed in view of the above problems of the prior art, and even when the content of silver powder in the conductive paste is 60% by mass or less (low silver), after electrode formation It is an object of the present invention to provide a conductive paste composition capable of obtaining excellent adhesion strength in soldering, and a crystalline silicon solar cell using the same.
　本発明者らは上記課題を解決するために鋭意研究を重ねた結果、銀粉末、ガラス粉末及び有機ビヒクルを含有し、前記銀粉末に対する前記有機ポリマー（バインダー）の体積比が特定範囲に設定された導電性ペースト組成物によれば、導電性ペースト中の銀粉末の含有量が６０質量％以下（低銀化）の場合であっても、電極形成後のはんだ付けにおいて優れた密着強度が得られることを見出し、本発明を完成するに至った。 As a result of diligent research to solve the above problems, the present inventors have set the volume ratio of the organic polymer (binder) to the silver powder in a specific range, which contains silver powder, glass powder and organic vehicle. According to the conductive paste composition, excellent adhesion strength can be obtained in soldering after electrode formation even when the content of silver powder in the conductive paste is 60% by mass or less (low silver). It was found that this was possible, and the present invention was completed.
　すなわち、本発明は下記の導電性ペースト組成物、及びそれを用いた結晶系シリコン太陽電池セルに関する。
１．銀粉末、ガラス粉末及び有機ビヒクルを含有する導電性ペースト組成物であって、
　前記有機ビヒクルは有機ポリマーと溶剤とを含有し、前記銀粉末に対する前記有機ポリマーの体積比が０．２５以上０．４０以下である、
ことを特徴とする、導電性ペースト組成物。
２．銅化合物を更に含有する、上記項１に記載の導電性ペースト組成物。
３．前記銅化合物は、銅（ＩＩ）アセチルアセトナート、ネオデカン酸銅（ＩＩ）、酸化銅（Ｉ）、酸化銅（ＩＩ）、ビス（８－キノリノラト）銅（ＩＩ）、ビス（トリフェニルホスフィン）銅テトラヒドロボレート及びトリフロロメタンスルホン酸銅（ＩＩ）からなる群から選択される少なくとも一種である、上記項２に記載の導電性ペースト組成物。
４．前記銀粉末１００質量部に対して前記銅化合物を銅換算で０．１質量部以上１．０質量部以下含有する、上記項２又は３に記載の導電性ペースト組成物。
５．前記導電性ペースト組成物中の前記銀粉末の含有量が６０質量％以下である、上記項１～４のいずれかに記載の導電性ペースト組成物。
６．上記項１～５のいずれかに記載の導電性ペースト組成物を用いて形成した電極を備えた結晶系シリコン太陽電池セル。 That is, the present invention relates to the following conductive paste composition and a crystalline silicon solar cell using the same.
1. 1. A conductive paste composition containing silver powder, glass powder and an organic vehicle.
The organic vehicle contains an organic polymer and a solvent, and the volume ratio of the organic polymer to the silver powder is 0.25 or more and 0.40 or less.
A conductive paste composition, characterized in that.
2. 2. Item 2. The conductive paste composition according to Item 1, further containing a copper compound.
3. 3. The copper compounds include copper (II) acetylacetonate, copper (II) neodecanoate, copper (I) oxide, copper (II) oxide, bis (8-quinolinolato) copper (II), and bis (triphenylphosphine) copper. The conductive paste composition according to Item 2 above, which is at least one selected from the group consisting of tetrahydrobolate and copper (II) trifluoromethanesulfonate.
4. Item 2. The conductive paste composition according to Item 2 or 3, wherein the copper compound is contained in an amount of 0.1 part by mass or more and 1.0 part by mass or less in terms of copper with respect to 100 parts by mass of the silver powder.
5. Item 2. The conductive paste composition according to any one of Items 1 to 4, wherein the content of the silver powder in the conductive paste composition is 60% by mass or less.
6. A crystalline silicon solar cell having an electrode formed by using the conductive paste composition according to any one of Items 1 to 5 above.
　本発明の導電性ペースト組成物によれば、導電性ペースト組成物中の銀粉末の含有量が６０質量％以下（低銀化）の場合でも、これを用いてシリコン基板の表面に電極を形成後、電極と外部との電気的接続における、はんだ付け後の密着強度に優れる。よって、例えば電極とインターコネクタ材とをはんだ付けした場合に優れた密着強度が確保できる。 According to the conductive paste composition of the present invention, even when the content of silver powder in the conductive paste composition is 60% by mass or less (low silver), an electrode is formed on the surface of the silicon substrate by using this. After that, it has excellent adhesion strength after soldering in the electrical connection between the electrode and the outside. Therefore, for example, when the electrode and the interconnector material are soldered, excellent adhesion strength can be ensured.
シリコン基板の表面にパッシベーション膜（及び／又は反射防止膜）を介して本発明の導電性ペースト組成物を用いて電極を形成する工程の一態様を示すフロー図である。It is a flow chart which shows one aspect of the process of forming an electrode by using the conductive paste composition of this invention through a passivation film (and / or an antireflection film) on the surface of a silicon substrate.
　以下、本発明について詳細に説明する。なお、本明細書において、「～」で示される範囲は特に説明する場合を除き、「以上、以下」を意味する。 Hereinafter, the present invention will be described in detail. In addition, in this specification, the range indicated by "-" means "greater than or equal to or less than" unless otherwise specified.
　本発明の導電性ペースト組成物は、銀粉末、ガラス粉末及び有機ビヒクルを含有し、
　前記有機ビヒクルは有機ポリマーと溶剤とを含有し、前記銀粉末に対する前記有機ポリマーの体積比が０．２５以上０．４０以下である、
ことを特徴とする。 The conductive paste composition of the present invention contains silver powder, glass powder and an organic vehicle.
The organic vehicle contains an organic polymer and a solvent, and the volume ratio of the organic polymer to the silver powder is 0.25 or more and 0.40 or less.
It is characterized by that.
　上記特徴を有する本発明の導電性ペースト組成物によれば、導電性ペースト組成物中の銀粉末の含有量が６０質量％以下（低銀化）の場合でも、これを用いてシリコン基板の表面に電極を形成後、電極と外部との電気的接続における、はんだ付け後の密着強度に優れる。よって、例えば電極とインターコネクタ材とをはんだ付けした場合に優れた密着強度が確保できる。 According to the conductive paste composition of the present invention having the above characteristics, even when the content of silver powder in the conductive paste composition is 60% by mass or less (low silver), the surface of the silicon substrate is used. After forming the electrode, it has excellent adhesion strength after soldering in the electrical connection between the electrode and the outside. Therefore, for example, when the electrode and the interconnector material are soldered, excellent adhesion strength can be ensured.
　以下、導電性ペースト組成物を構成する各成分について説明する。 Hereinafter, each component constituting the conductive paste composition will be described.
（銀粉末）
　本発明の導電性ペースト組成物は導電性粉末として銀粉末を用いる。つまり、本発明の導電性ペースト組成物を用いて形成される電極はいわゆる銀電極である。 (Silver powder)
The conductive paste composition of the present invention uses silver powder as the conductive powder. That is, the electrode formed by using the conductive paste composition of the present invention is a so-called silver electrode.
　銀粉末の形状は特に制限されず、例えば、球状、フレーク（鱗片）状が挙げられる。この中でも、本発明の効果が得られ易く、且つ得られる電極の強度の点で有利である観点から球状であることが好ましい。 The shape of the silver powder is not particularly limited, and examples thereof include spherical and flake (scale) shapes. Among these, the spherical shape is preferable from the viewpoint that the effect of the present invention can be easily obtained and the strength of the obtained electrode is advantageous.
　ここで、球状とは、長径／短径の比率が２以下の粒子の形状をいう。また、フレーク状とは、長径／短径の比率が２超過の形状をいう。 Here, the spherical shape means the shape of a particle having a major axis / minor axis ratio of 2 or less. Further, the flake shape means a shape in which the ratio of the major axis / the minor axis exceeds 2.
　銀粉末の長径及び短径は、走査型電子顕微鏡（ＳＥＭ）から得られる画像に基づいて求めることができる。「長径」とは、ＳＥＭにより得られた粒子画像において、銀粉末の略重心を通過する線分のうち最も距離の長いものを指す。「短径」とは、ＳＥＭにより得られた粒子画像において、銀粉末の略重心を通過する線分のうち最も距離の短いものを指す。 The major axis and minor axis of the silver powder can be determined based on an image obtained from a scanning electron microscope (SEM). The "major axis" refers to the longest distance of the line segments passing through the substantially center of gravity of the silver powder in the particle image obtained by SEM. The "minor diameter" refers to the shortest distance of the line segments passing through the substantially center of gravity of the silver powder in the particle image obtained by SEM.
　また、上記画像において任意に１００個の銀粉末を選択し、上記１００個の銀粉末の長径を測定し、上記１００個の銀粉末の長径から算出された平均値を、銀粉末の長径の平均（平均値）とする。銀粉末の短径の平均についても同様である。 Further, 100 silver powders are arbitrarily selected in the above image, the major axis of the 100 silver powders is measured, and the average value calculated from the major axis of the 100 silver powders is the average of the major axis of the silver powder. (Average value). The same applies to the average minor axis of silver powder.
　銀粉末の平均粒子径（Ｄ５０）は限定的ではないが、本発明の効果が得られ易く、且つ得られる電極の強度の点で有利である観点から、２．０μｍ以下であることが好ましく、１．０μｍ以下であることがより好ましい。また、ナノ銀と呼ばれる平均粒子径（Ｄ５０）が数十ｎｍ（例えば、１０～９０ｎｍ）の銀粉末を使用することができる。ナノ銀の形状は特に制限されないが例えば球状のものが挙げられる。よって、銀粉末の平均粒子径（Ｄ５０）としては、数十ｎｍ～２．０μｍ以下の範囲で設定することが好ましい。 The average particle size (D50) of the silver powder is not limited, but is preferably 2.0 μm or less from the viewpoint that the effect of the present invention can be easily obtained and the strength of the obtained electrode is advantageous. It is more preferably 1.0 μm or less. Further, silver powder having an average particle diameter (D50) of several tens of nm (for example, 10 to 90 nm) called nanosilver can be used. The shape of the nanosilver is not particularly limited, and examples thereof include spherical ones. Therefore, the average particle size (D50) of the silver powder is preferably set in the range of several tens of nm to 2.0 μm or less.
　銀粉末の平均粒子径（Ｄ５０）は、レーザー回折式粒度分布測定装置を用いて体積基準の粒度分布を測定することにより求められる、このようなレーザー回折式粒度分布測定装置としては、例えば、マイクロトラック・ベル社製のレーザー回折散乱式粒子径分布測定装置「マイクロトラックＭＴ３０００ＩＩシリーズ」が挙げられる。 The average particle size (D50) of the silver powder is determined by measuring the particle size distribution on a volume basis using a laser diffraction type particle size distribution measuring device. As such a laser diffraction type particle size distribution measuring device, for example, micro Examples thereof include a laser diffraction / scattering type particle size distribution measuring device “Microtrac MT3000II series” manufactured by Truck Bell.
　フレーク状銀粉末の長径（横幅）は、本発明の効果が得られ易く、且つ得られる電極の強度の点で有利である観点から、平均２．０μｍ以下であることが好ましく、１．０μｍ以下であることがより好ましい。 The major axis (width) of the flake-shaped silver powder is preferably 2.0 μm or less on average, preferably 1.0 μm or less, from the viewpoint that the effects of the present invention can be easily obtained and the strength of the obtained electrode is advantageous. Is more preferable.
　フレーク状銀粉末の短径（厚さ）は、本発明の効果が得られ易く、且つ得られる電極の強度の点で有利である観点から、平均１．０μｍ未満であることが好ましく、０．１μｍ以下であることがより好ましい。 The minor axis (thickness) of the flake-shaped silver powder is preferably less than 1.0 μm on average from the viewpoint that the effects of the present invention can be easily obtained and the strength of the obtained electrode is advantageous. It is more preferably 1 μm or less.
　フレーク状銀粉末としては、例えば、短径（厚さ）の平均（平均値）が数十ｎｍ（例えば、１０～９０ｎｍ）であり、長径（横幅）の平均が０．３～６μｍである銀粉末が好適ものとして挙げられる。 As the flake-shaped silver powder, for example, silver having a minor axis (thickness) average (average value) of several tens of nm (for example, 10 to 90 nm) and a major axis (width) average of 0.3 to 6 μm. Powders are preferred.
　フレーク状銀粉末の市販品としては、例えば、トクセン工業株式会社より市販されている商品名Ｎ３００等が挙げられる。 Examples of commercially available flaky silver powder include trade name N300, which is commercially available from Toxen Industries, Ltd.
　本発明の導電性ペースト組成物中の銀粉末の含有量は限定的ではないが、近年の低銀化の要請から銀粉末の含有量を６０質量％以下に設定した場合でもはんだ付け後の密着強度に優れるという効果を確保することができる。本発明の効果を効率的に得るという観点では導電性ペースト組成物中の銀粉末の含有量は４９質量％以下がより好ましく、銀粉末の含有量の下限値としては４０質量％程度である。 The content of the silver powder in the conductive paste composition of the present invention is not limited, but due to the recent demand for lower silver content, adhesion after soldering even when the content of the silver powder is set to 60% by mass or less. The effect of being excellent in strength can be ensured. From the viewpoint of efficiently obtaining the effects of the present invention, the content of the silver powder in the conductive paste composition is more preferably 49% by mass or less, and the lower limit of the content of the silver powder is about 40% by mass.
（ガラス粉末）
　ガラス粉末は、導電性材料（本発明では銀粉末）とシリコンとの反応、及び、導電性材料自身の焼結を助ける作用があるとされている。 (Glass powder)
The glass powder is said to have an action of assisting the reaction between the conductive material (silver powder in the present invention) and silicon, and the sintering of the conductive material itself.
　ガラス粉末としては特に限定されず、例えば、太陽電池セルの電極層を形成するために使用されているペースト組成物に含まれる公知のガラス成分とすることができる。ガラス粉末の具体例としては、鉛（Ｐｂ）、ビスマス（Ｂｉ）、バナジウム（Ｖ）、ホウ素（Ｂ）、シリコン（Ｓｉ）、スズ（Ｓｎ）、リン（Ｐ）及び亜鉛（Ｚｎ）からなる群から選択される少なくとも一種が挙げられる。また、鉛を含むガラス粉末、又は、ビスマス系、バナジウム系、スズ－リン系、ホウケイ酸亜鉛系、アルカリホウケイ酸系等の無鉛のガラス粉末を用いることができる。 The glass powder is not particularly limited, and can be, for example, a known glass component contained in the paste composition used for forming the electrode layer of the solar cell. Specific examples of the glass powder include a group consisting of lead (Pb), bismuth (Bi), vanadium (V), boron (B), silicon (Si), tin (Sn), phosphorus (P) and zinc (Zn). At least one selected from. Further, lead-containing glass powder or lead-free glass powder such as bismuth-based, vanadium-based, tin-phosphorus-based, zinc borosilicate-based, and alkaline borosilicate-based can be used.
　具体的にガラス粉末は、Ｂ２Ｏ３、Ｂｉ２Ｏ３、ＺｎＯ、ＳｉＯ２、Ａｌ２Ｏ３、ＢａＯ、ＰｂＯ、ＣａＯ、ＳｒＯ、Ｖ２Ｏ５、Ｓｂ２Ｏ３、ＷＯ３、Ｐ２Ｏ５及びＴｅＯ２からなる群より選ばれる少なくとも１種の成分を含むことができる。これらの中でも、本発明の効果が得られ易く、且つ入手し易いという観点からＺｎＯ及び／又はＰｂＯが好ましく、ＰｂＯがより好ましい。なお、ガラス粉末がＺｎＯ及び／又はＰｂＯを含む場合には、更にＢ２Ｏ３及び／又はＳｉＯ２を含むことが好ましく、ガラス粉末がＰｂＯを含む場合には、更にＳｉＯ２を含むことが好ましい。 Specifically, the glass powder is B 2 O 3 , Bi 2 O 3 , ZnO, SiO 2 , Al 2 O 3 , BaO, PbO, CaO, SrO, V 2 O 5 , Sb 2 O 3 , WO 3 , P 2 It can contain at least one component selected from the group consisting of O 5 and Te O 2 . Among these, ZnO and / or PbO is preferable, and PbO is more preferable, from the viewpoint that the effects of the present invention can be easily obtained and easily obtained. When the glass powder contains ZnO and / or PbO, it is preferable to further contain B 2 O 3 and / or SiO 2, and when the glass powder contains PbO, it is preferable to further contain SiO 2. ..
　ガラス粉末の軟化点は、例えば、７５０℃以下とすることができる。ガラス粉末に含まれる粒子の平均粒子径は、例えば、１～３μｍとすることができる。 The softening point of the glass powder can be, for example, 750 ° C. or lower. The average particle size of the particles contained in the glass powder can be, for example, 1 to 3 μm.
　本発明の導電性ペースト組成物中のガラス粉末の含有量は限定的ではないが、０．５～１０質量％が好ましく、１～５質量％がより好ましい。この場合、シリコン基板及びパッシベーション膜（及び／又は反射防止膜）との密着性が良好となり、また、電気抵抗も増大しにくい。更にガラス粉末の含有量は、銀粉末１００質量部に対して０．１～１０質量部であることが好ましく、０．５～５．０質量％であることがより好ましい。 The content of the glass powder in the conductive paste composition of the present invention is not limited, but is preferably 0.5 to 10% by mass, more preferably 1 to 5% by mass. In this case, the adhesion between the silicon substrate and the passivation film (and / or the antireflection film) is good, and the electrical resistance is unlikely to increase. Further, the content of the glass powder is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5.0% by mass with respect to 100 parts by mass of the silver powder.
（有機ビヒクル）
　有機ビヒクルは、有機ポリマー（バインダー）及び溶剤を含有し、必要に応じて更に各種添加剤を含有することができる。 (Organic vehicle)
The organic vehicle contains an organic polymer (binder) and a solvent, and can further contain various additives as needed.
　溶剤は、公知の種類が使用可能であり、具体的には、ジエチレングリコールモノブチルエーテル、ジエチレングリコールモノブチルエーテルアセテート、ジプロピレングリコールモノメチルエーテル等が挙げられる。溶剤の使用量は、導電性ペースト組成物の塗布性などを考慮して当該分野で標準的な使用量の範囲で適宜設定できる。 Known types of solvents can be used, and specific examples thereof include diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, and dipropylene glycol monomethyl ether. The amount of the solvent used can be appropriately set within the range of the standard amount used in the field in consideration of the coatability of the conductive paste composition and the like.
　各種添加剤としては、例えば、酸化防止剤、腐食抑制剤、消泡剤、増粘剤、タックファイヤー、カップリング剤、静電付与剤、重合禁止剤、チキソトロピー剤、沈降防止剤等を使用することができる。具体的には、例えば、ポリエチレングリコールエステル化合物、ポリエチレングリコールエーテル化合物、ポリオキシエチレンソルビタンエステル化合物、ソルビタンアルキルエステル化合物、脂肪族多価カルボン酸化合物、燐酸エステル化合物、ポリエステル酸のアマイドアミン塩、酸化ポリエチレン系化合物、脂肪酸アマイドワックス等を使用することができる。 As various additives, for example, antioxidants, corrosion inhibitors, antifoaming agents, thickeners, tack fires, coupling agents, antistatic agents, polymerization inhibitors, thixotropy agents, anti-sediment agents and the like are used. be able to. Specifically, for example, polyethylene glycol ester compound, polyethylene glycol ether compound, polyoxyethylene sorbitan ester compound, sorbitan alkyl ester compound, aliphatic polyvalent carboxylic acid compound, phosphoric acid ester compound, amidoamine salt of polyester acid, polyethylene oxide. System compounds, fatty acid amide wax and the like can be used.
　有機ポリマー（樹脂又は重合体）としては公知の種類が使用可能であり、エチルセルロース、セルロースエステル、ニトロセルロース、ポリビニールブチラール、フェノール樹脂、メラミン樹脂、ユリア樹脂、キシレン樹脂、アルキッド樹脂、不飽和ポリエステル樹脂、アクリル樹脂、ポリイミド樹脂、フラン樹脂、ウレタン樹脂、イソシアネート化合物、シアネート化合物等の熱硬化樹脂、ポリエチレン、ポリプロピレン、ポリスチレン、ＡＢＳ樹脂、ポリメタクリル酸メチル、ポリ塩化ビニル、ポリ塩化ビニリデン、ポリ酢酸ビニル、ポリビニルアルコール、ポリアセタール、ポリカーボネート、ポリエチレンテレフタレート、ポリブチレンテレフタレート、ポリフェニレンオキサイド、ポリスルフォン、ポリイミド、ポリエーテルスルフォン、ポリアリレート、ポリエーテルエーテルケトン、ポリ４フッ化エチレン、シリコン樹脂、ロジン系樹脂等が挙げられる。これらの有機ポリマーは単独又は二種以上を組み合わせて用いることができる。 Known types of organic polymers (resins or polymers) can be used, such as ethyl cellulose, cellulose ester, nitrocellulose, polyvinyl butyral, phenol resin, melamine resin, urea resin, xylene resin, alkyd resin, and unsaturated polyester resin. , Acrylic resin, polyimide resin, furan resin, urethane resin, isocyanate compound, heat-curable resin such as cyanate compound, polyethylene, polypropylene, polystyrene, ABS resin, polymethylmethacrylate, polyvinyl chloride, polyvinylidene chloride, polyvinylacetate, Examples thereof include polyvinyl alcohol, polyacetal, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyphenylene oxide, polysulphon, polyimide, polyether sulfone, polyarylate, polyether ether ketone, polytetrafluoroethylene, silicon resin, rosin resin and the like. .. These organic polymers can be used alone or in combination of two or more.
　有機ビヒクルに含まれる有機ポリマーの含有量は、前記銀粉末に対する有機ポリマーの体積比（つまり、有機ポリマー／銀粉末）が０．２５以上０．４０以下となる含有量であればよいが、当該体積比は０．３０以上０．４０以下であることがより好ましい。 The content of the organic polymer contained in the organic vehicle may be such that the volume ratio of the organic polymer to the silver powder (that is, the organic polymer / silver powder) is 0.25 or more and 0.40 or less. The volume ratio is more preferably 0.30 or more and 0.40 or less.
（銅化合物）
　本発明の導電性ペースト組成物は、前記銀粉末、前記ガラス粉末及び前記有機ビヒクルに加えて、必要に応じて銅化合物を含有することが好ましい。 (Copper compound)
The conductive paste composition of the present invention preferably contains a copper compound, if necessary, in addition to the silver powder, the glass powder and the organic vehicle.
　銅化合物を含有する場合には、銅は酸化数（例えば１価又は２価）を有するため、導電性ペースト組成物を用いてパッシベーション膜（及び／又は反射防止膜）を介してシリコン基板の表面に電極を形成する場合において、焼成時にガラス粉末がパッシベーション膜（及び／又は反射防止膜）に対して作用する前に銅化合物と反応し、ガラス粉末によるパッシベーション膜（及び／又は反射防止膜）への作用を緩和し得ると推測される。また、銅化合物を含有する場合には、形成された電極と外部とを電気的接続する際のはんだ付け時に電極とはんだとの合金化の程度を適度に制御し、電極とはんだとの密着強度の向上に寄与するものと推測される。 When a copper compound is contained, since copper has an oxidation number (for example, monovalent or divalent), the surface of the silicon substrate is used through a passivation film (and / or an antireflection film) using a conductive paste composition. In the case of forming an electrode on the surface, the glass powder reacts with the copper compound before acting on the passivation film (and / or the antireflection film) during firing, and the glass powder forms the passivation film (and / or the antireflection film). It is speculated that the action of Further, when a copper compound is contained, the degree of alloying between the electrode and the solder is appropriately controlled at the time of soldering when the formed electrode and the outside are electrically connected, and the adhesion strength between the electrode and the solder is appropriately controlled. It is presumed that it contributes to the improvement of.
　銅化合物としては上記作用が得られるものであれば限定的ではないが、例えば銅（ＩＩ）アセチルアセトナート、ネオデカン酸銅（ＩＩ）、酸化銅（Ｉ）、酸化銅（ＩＩ）、ビス（８－キノリノラト）銅（ＩＩ）、ビス（トリフェニルホスフィン）銅テトラヒドロボレート及びトリフロロメタンスルホン酸銅（ＩＩ）からなる群から選択される少なくとも一種を好適に用いることができる。これらの中でも、銅化合物の導電性ペーストへの分散性の観点からは酸化銅（Ｉ）、酸化銅（ＩＩ）、銅（ＩＩ）アセチルアセトナート等の少なくとも一種が好ましい。 The copper compound is not limited as long as it can obtain the above action, but for example, copper (II) acetylacetonate, copper (II) neodecanoate, copper (I) oxide, copper (II) oxide, bis (8). -At least one selected from the group consisting of quinolinolato) copper (II), bis (triphenylphosphine) copper tetrahydroborate and copper (II) trifluoromethanesulfonate can be preferably used. Among these, at least one of copper (I) oxide, copper (II) oxide, copper (II) acetylacetonate and the like is preferable from the viewpoint of dispersibility of the copper compound in the conductive paste.
　銅化合物の含有量は、上記効果を得る観点から、銀粉末１００質量部に対して０．１質量部以上１．０質量部以下であることが好ましい。 From the viewpoint of obtaining the above effect, the content of the copper compound is preferably 0.1 part by mass or more and 1.0 part by mass or less with respect to 100 parts by mass of the silver powder.
　本発明の導電性ペースト組成物は、結晶系シリコン太陽電池セルの電極形成用の導電性ペースト組成物として有用である。つまり、本発明の導電性ペースト組成物は、例えば、図１に例示されるようにシリコン基板１（シリコン半導体基板１）に任意にパッシベーション膜２（及び／又は反射防止膜２）を積層した後、スクリーン印刷などの手法により本発明の導電性ペースト組成物３を電極形状に印刷し、次いで８００℃程度の大気中で焼成することにより電極４（銀電極４）を形成することができる。シリコン基板、パッシベーション膜（及び／又は反射防止膜）、スクリーン印刷、焼成等の材料及び条件については、結晶系シリコン太陽電池セルの分野において公知又は常用されているものをそのまま使用することができる。本発明は、本発明の導電性ペースト組成物を用いて形成した電極を備えた結晶系シリコン太陽電池セルの発明についても包含する。 The conductive paste composition of the present invention is useful as a conductive paste composition for forming electrodes of crystalline silicon solar cells. That is, in the conductive paste composition of the present invention, for example, after optionally laminating the passivation film 2 (and / or the antireflection film 2) on the silicon substrate 1 (silicon semiconductor substrate 1) as illustrated in FIG. The electrode 4 (silver electrode 4) can be formed by printing the conductive paste composition 3 of the present invention on an electrode shape by a method such as screen printing and then firing in the air at about 800 ° C. As for materials and conditions such as a silicon substrate, a passivation film (and / or an antireflection film), screen printing, and firing, those known or commonly used in the field of crystalline silicon solar cells can be used as they are. The present invention also includes the invention of a crystalline silicon solar cell including an electrode formed by using the conductive paste composition of the present invention.
　以下に実施例及び比較例を示して本発明を具体的に説明する。但し、本発明は実施例に限定されない。 The present invention will be specifically described below with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.
　実施例１
　平均粒子径（Ｄ５０）０．５μｍの銀粉末（球状粉：比重１０．５）１００質量部と、ＰｂＯ－Ｂ２Ｏ３－ＳｉＯ２＝７０／１０／２０（質量％）のガラス粉末１．０質量部とを、エチルセルロース（有機ポリマー：比重１．１２）４．０質量部をターピネオール９５．０質量部に溶解した有機ビヒクルと混合し、既知の分散装置（ディスパー）を用いて導電性ペースト組成物を調製した。なお、実施例１における銀粉末に対する有機ポリマーの体積比は０．３８であった。 Example 1
1. 100 parts by mass of silver powder (spherical powder: specific gravity 10.5) with an average particle diameter (D50) of 0.5 μm and glass powder of PbO-B 2 O 3- SiO 2 = 70/10/20 (mass%). 0 parts by mass was mixed with an organic vehicle in which 4.0 parts by mass of ethyl cellulose (organic polymer: specific gravity 1.12) was dissolved in 95.0 parts by mass of tarpineol, and a conductive paste was prepared using a known disperser. The composition was prepared. The volume ratio of the organic polymer to the silver powder in Example 1 was 0.38.
　評価用の試験体を次のように製作した。 The test body for evaluation was manufactured as follows.
　まず、図１の（Ａ）に示す、ｐ型の単結晶シリコンからなるシリコン基板を準備した（基板：６ｉｎｃｈ、厚み１６０μｍ、抵抗率２Ω・ｃｍ）。 First, a silicon substrate made of p-type single crystal silicon shown in FIG. 1 (A) was prepared (substrate: 6 inches, thickness 160 μm, resistivity 2 Ω · cm).
　次に図１の（Ｂ）に示すように、プラズマＣＶＤ法によって、窒化ケイ素を主成分とする反射防止膜２を形成した。 Next, as shown in FIG. 1B, the antireflection film 2 containing silicon nitride as a main component was formed by the plasma CVD method.
　次に図１の（Ｃ）に示すように、導電性ペースト組成物３を、反射防止膜２を介してシリコン基板１の表面上に、スクリーン印刷機を用いて、印刷幅が１．５ｍｍとなるように印刷した。 Next, as shown in FIG. 1 (C), the conductive paste composition 3 was printed on the surface of the silicon substrate 1 via the antireflection film 2 using a screen printing machine to have a printing width of 1.5 mm. I printed it so that it would be.
　印刷性の評価においては、スクリーン版上における導電性ペースト組成物の展開性を外観観察により評価した。評価基準としては、導電性ペースト組成物をスクリーン上に塗り広げる際に、
かすれが生じ難く均一に広がったものを○
かすれが生じたものを×
と評価した。 In the evaluation of printability, the deployability of the conductive paste composition on the screen plate was evaluated by observing the appearance. As an evaluation standard, when spreading the conductive paste composition on the screen,
○ that is less likely to be blurred and spreads evenly
Those with faintness ×
I evaluated it.
　その後、８００℃に設定した赤外ベルト炉を用いて焼成した。この焼成により、図１の（Ｄ）に示すように、電極４を形成し、引っ張り強度測定用の焼成基板を製作した。 After that, it was fired using an infrared belt furnace set at 800 ° C. By this firing, as shown in (D) of FIG. 1, an electrode 4 was formed, and a firing substrate for measuring tensile strength was produced.
　はんだ付け後の密着強度（引張強度）の評価のために、インターコネクト用の銅リボン（幅１．０ｍｍ）を、予めフラックスを塗布した電極４上に、２７０℃の温度で３秒間はんだ付けすることにより、試験試料を作成した。 In order to evaluate the adhesion strength (tensile strength) after soldering, a copper ribbon (width 1.0 mm) for interconnect is soldered on the electrode 4 to which flux is applied in advance at a temperature of 270 ° C. for 3 seconds. To prepare a test sample.
　引張強度の測定においては、東洋精機社製、ストログラフＶＧＳを用いて、試験試料に対して１８０度方向に１２０ｍｍ／ｍｉｎで引っ張ることで測定を行った。 In the measurement of tensile strength, a Strograph VGS manufactured by Toyo Seiki Co., Ltd. was used, and the measurement was performed by pulling the test sample at 120 mm / min in the 180 degree direction.
　なお、引張強度が２．０Ｎ／ｍｍより大きい場合には、十分に実使用に耐える良好な引張強度であるといえる。 If the tensile strength is greater than 2.0 N / mm, it can be said that the tensile strength is sufficiently good to withstand actual use.
　実施例２
　エチルセルロース（比重１．１２）３．８質量部をターピネオール９５．２質量部に溶解した有機ビヒクルを用いた以外は、実施例１と同様とした。 Example 2
The same procedure as in Example 1 was carried out except that an organic vehicle in which 3.8 parts by mass of ethyl cellulose (specific gravity 1.12) was dissolved in 95.2 parts by mass of tarpineol was used.
　実施例３
　エチルセルロース（比重１．１２）３．２質量部をターピネオール９５．８質量部に溶解した有機ビヒクルを用いた以外は、実施例１と同様とした。 Example 3
The same procedure as in Example 1 was carried out except that an organic vehicle in which 3.2 parts by mass of ethyl cellulose (specific gravity 1.12) was dissolved in 95.8 parts by mass of tarpineol was used.
　実施例４
　エチルセルロース（比重１．１２）２．７質量部をターピネオール９６．３質量部に溶解した有機ビヒクルを用いた以外は、実施例１と同様とした。 Example 4
The same procedure as in Example 1 was carried out except that an organic vehicle in which 2.7 parts by mass of ethyl cellulose (specific gravity 1.12) was dissolved in 96.3 parts by mass of tarpineol was used.
　実施例５
　ポリビニルブチラール（比重１．１０）４．０質量部をターピネオール９５．０質量部に溶解した有機ビヒクルを用いた以外は、実施例１と同様とした。 Example 5
The same procedure as in Example 1 was carried out except that an organic vehicle in which 4.0 parts by mass of polyvinyl butyral (specific gravity 1.10) was dissolved in 95.0 parts by mass of tarpineol was used.
　実施例６
　エチルセルロース（比重１．１２）３．８質量部をターピネオール９４．７質量部に溶解した有機ビヒクルを用い、銅化合物として酸化銅（ＩＩ）を０．５質量部添加した以外は、実施例１と同様とした。 Example 6
Example 1 and Example 1 except that an organic vehicle in which 3.8 parts by mass of ethyl cellulose (specific gravity 1.12) was dissolved in 94.7 parts by mass of tarpineol was used and 0.5 parts by mass of copper (II) oxide was added as a copper compound. The same was true.
　比較例１
　エチルセルロース（比重１．１２）２．５質量部をターピネオール９６．５質量部に溶解した有機ビヒクルを用いた以外は、実施例１と同様とした。 Comparative Example 1
The same procedure as in Example 1 was carried out except that an organic vehicle in which 2.5 parts by mass of ethyl cellulose (specific gravity 1.12) was dissolved in 96.5 parts by mass of tarpineol was used.
　比較例２
　エチルセルロース（比重１．１２）４．５質量部をターピネオール９４．５質量部に溶解した有機ビヒクルを用いた以外は、実施例１と同様とした。 Comparative Example 2
The same procedure as in Example 1 was carried out except that an organic vehicle in which 4.5 parts by mass of ethyl cellulose (specific gravity 1.12) was dissolved in 94.5 parts by mass of tarpineol was used.
　比較例３
　ポリビニルブチラール（比重１．１０）５．０質量部をターピネオール９４．０質量部に溶解した有機ビヒクルを用いた以外は、実施例１と同様とした。 Comparative Example 3
The same procedure as in Example 1 was carried out except that an organic vehicle in which 5.0 parts by mass of polyvinyl butyral (specific gravity 1.10) was dissolved in 94.0 parts by mass of tarpineol was used.
　各実施例及び比較例の条件及び試験結果を下記表１に示す。 Table 1 below shows the conditions and test results of each example and comparative example.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１の結果から分かる通り、銀粉末に対する有機ポリマーの体積比を０．２５以上０．４０以下に設定することにより、良好な印刷性と２Ｎ／ｍｍ以上の引張強度（すなわち、はんだ付け後の良好な密着強度）が両立できることが分かる。 As can be seen from the results in Table 1, by setting the volume ratio of the organic polymer to silver powder to 0.25 or more and 0.40 or less, good printability and tensile strength of 2 N / mm or more (that is, after soldering) It can be seen that (good adhesion strength) can be compatible.
１：シリコン基板
２：パッシベーション膜（及び／又は反射防止膜）
３：ペースト組成物
４：電極 1: Silicon substrate 2: Passivation film (and / or antireflection film)
3: Paste composition 4: Electrode

Claims (6)

  1. 　銀粉末、ガラス粉末及び有機ビヒクルを含有する導電性ペースト組成物であって、
    　前記有機ビヒクルは有機ポリマーと溶剤とを含有し、前記銀粉末に対する前記有機ポリマーの体積比が０．２５以上０．４０以下である、
    ことを特徴とする、導電性ペースト組成物。     A conductive paste composition containing silver powder, glass powder and an organic vehicle.
    The organic vehicle contains an organic polymer and a solvent, and the volume ratio of the organic polymer to the silver powder is 0.25 or more and 0.40 or less.
    A conductive paste composition, characterized in that.
  2. 　銅化合物を更に含有する、請求項１に記載の導電性ペースト組成物。 The conductive paste composition according to claim 1, further containing a copper compound.
  3. 　前記銅化合物は、銅（ＩＩ）アセチルアセトナート、ネオデカン酸銅（ＩＩ）、酸化銅（Ｉ）、酸化銅（ＩＩ）、ビス（８－キノリノラト）銅（ＩＩ）、ビス（トリフェニルホスフィン）銅テトラヒドロボレート及びトリフロロメタンスルホン酸銅（ＩＩ）からなる群から選択される少なくとも一種である、請求項２に記載の導電性ペースト組成物。 The copper compounds include copper (II) acetylacetonate, copper (II) neodecanoate, copper (I) oxide, copper (II) oxide, bis (8-quinolinolato) copper (II), and bis (triphenylphosphine) copper. The conductive paste composition according to claim 2, which is at least one selected from the group consisting of tetrahydrobolate and copper (II) trifluoromethanesulfonate.
  4. 　前記銀粉末１００質量部に対して前記銅化合物を銅換算で０．１質量部以上１．０質量部以下含有する、請求項２又は３に記載の導電性ペースト組成物。 The conductive paste composition according to claim 2 or 3, which contains 0.1 part by mass or more and 1.0 part by mass or less of the copper compound in terms of copper with respect to 100 parts by mass of the silver powder.
  5. 　前記導電性ペースト組成物中の前記銀粉末の含有量が６０質量％以下である、請求項１～４のいずれかに記載の導電性ペースト組成物。 The conductive paste composition according to any one of claims 1 to 4, wherein the content of the silver powder in the conductive paste composition is 60% by mass or less.
  6. 　請求項１～５のいずれかに記載の導電性ペースト組成物を用いて形成した電極を備えた結晶系シリコン太陽電池セル。 A crystalline silicon solar cell having an electrode formed by using the conductive paste composition according to any one of claims 1 to 5.
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JP2001015782A (en) * 1999-06-29 2001-01-19 Kyocera Corp Solar cell element and manufacture thereof
WO2008078374A1 (en) * 2006-12-25 2008-07-03 Namics Corporation Conductive paste for solar cell

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