JP5430121B2 - Wiring board and probe card using the same - Google Patents

Description

  The present invention relates to a wiring board used for a semiconductor integrated circuit or the like.

When manufacturing a wiring board in which a wiring conductor is disposed on an insulating substrate, a metal thin film that joins the insulating substrate and the wiring conductor is used as a chemical solution such as a plating solution in the process of forming plating on the surface of the wiring conductor. Corrosion may occur when touched. Therefore, as disclosed in Patent Document 1, a printed circuit board has been proposed in which a protective insulating layer made of a resin is disposed on a base insulating layer so as to seal a side surface of a metal thin film.
JP 2006-66451 A

  As disclosed in Patent Document 1, a protective insulating layer made of a resin is disposed on a base insulating layer so as to seal a side surface of a metal thin film, so that a metal thin film with a chemical solution such as a plating solution can be formed. Side corrosion can be prevented to some extent.

  However, in Patent Document 1, the protective insulating layer is formed by a step of disposing a varnish to be a protective insulating layer over the entire surface of the base insulating layer and a step of patterning the varnish into the shape of the protective insulating layer. Thus, since the protective insulating layer has to be formed by a plurality of steps, the manufacturing cost has increased. In addition, the thickness of the varnish must be adjusted so as to seal the side surfaces of the metal thin film, and the work is complicated. At the same time, the metal thin film may be corroded by contact with the chemical solution.

  The present invention has been made in view of the above problems, and can reduce the possibility of corrosion due to contact with a chemical solution of a metal layer that joins an insulating substrate and a wiring conductor while being easily manufactured. An object of the present invention is to provide a wiring board to be used.

  The wiring board according to the present invention includes an insulating substrate having a main surface, a metal bonding layer disposed on the main surface of the insulating substrate and bonded to the insulating substrate, and disposed on the metal bonding layer. A wiring conductor; a vacuum film-forming layer covering the metal bonding layer and the wiring conductor; and a plating layer disposed on the vacuum film-forming layer. The wiring conductor has a smaller ionization tendency than the main component constituting the metal bonding layer, and has a component having higher electrical conductivity than the main component constituting the metal bonding layer and the vacuum film-forming layer as a main component. Yes. The vacuum film-forming layer is mainly composed of a component having higher corrosion resistance to the plating solution used for forming the plating layer than the main component constituting the metal bonding layer and the wiring conductor.

  According to the wiring board of the present invention, the vacuum film-forming layer is mainly composed of a component having higher corrosion resistance to the plating solution used for forming the plating layer than the main components constituting the metal bonding layer and the wiring conductor. Therefore, since only the vacuum film formation layer comes into contact with the chemical solution such as the plating solution, the galvanic corrosion of the metal bonding layer and the wiring conductor due to the potential difference between the vacuum film forming layer and the metal bonding layer and the wiring conductor. Is suppressed. In addition, since it is not necessary to form the protective insulating layer as described above, the wiring board can be easily manufactured.

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

  As shown in FIGS. 1-3, the wiring board 1 concerning the 1st Embodiment of this invention is arrange | positioned on the insulating substrate 3 which has the main surface 3a, and the main surface 3a of the insulating substrate 3, and is insulated. Metal bonding layer 5 bonded to conductive substrate 3, wiring conductor 7 disposed on metal bonding layer 5, vacuum film-forming layer 9 covering metal bonding layer 5 and wiring conductor 7, and vacuum film-forming layer 9 And a plating layer 11 disposed thereon.

  In addition, the wiring conductor 7 has an ionization tendency smaller than that of the main component constituting the metal bonding layer 5, and a component having higher electrical conductivity than the main component constituting the metal bonding layer 5 and the vacuum film forming layer 9. Yes. Further, the vacuum film-forming layer 9 is mainly composed of a component having higher corrosion resistance to the plating solution used for forming the plating layer 11 than the main components constituting the metal bonding layer 5 and the wiring conductor 7.

  As described above, the wiring board 1 according to the present embodiment has as its main component a component having higher corrosion resistance to the plating solution for forming the plating layer 11 than the main components constituting the metal bonding layer 5 and the wiring conductor 7. The metal bonding layer 5 and the wiring conductor 7 are covered with the vacuum film formation layer 9. Therefore, occurrence of galvanic corrosion of the metal bonding layer 5 and the wiring conductor 7 can be suppressed.

  In addition, since the components constituting the vacuum film-forming layer 9 have high corrosion resistance to the plating solution, the metal bonding layer 5 and the wiring conductor 7 are not only used for the plating solution but also for strongly alkaline chemicals for cleaning the surface of the wiring board 1. The occurrence of galvanic corrosion can also be suppressed.

The insulating substrate 3 in the present embodiment has a main surface 3a on which the metal bonding layer 5, the wiring conductor 7, the vacuum film forming layer 9, and the plating layer 11 are disposed. In the insulating substrate 3 of the present embodiment, a via conductor 13 (first via conductor 13) and a wiring member (not shown) electrically connected to the metal bonding layer 5 are embedded. The metal bonding layer 5 can be energized via the via conductor 13 and the wiring member. As the insulating substrate 3, a member having good electrical insulation may be used. Specifically, a ceramic member such as Al ₂ O ₃ or a resin can be used. For example, Ag, Cu, Mo, and W can be used as the via conductor 13 and the wiring member.

  The wiring board 1 according to the present embodiment includes a metal bonding layer 5 disposed on the main surface 3a. In the present embodiment, the metal bonding layer 5 functions as a metal bonding layer for bonding the insulating substrate 3 and the wiring conductor 7. Therefore, it is preferable to use a metal bonding layer 5 that has good bonding properties to the insulating substrate 3, and specifically, Ti, Cr, TiN, and W can be used. The thickness of the metal bonding layer 5 is preferably 0.1 to 0.5 μm. For example, the metal bonding layer 5 may be separately formed on the main surface 3a of the insulating substrate 3 or may be disposed on the main surface 3a of the insulating substrate 3 by sputtering.

  The wiring board 1 according to the present embodiment includes a wiring conductor 7 disposed on the metal bonding layer 5. The wiring conductor 7 in this embodiment functions as a wiring conductor whose main component is a component having higher electrical conductivity than the main components constituting the metal bonding layer 5 and the vacuum film forming layer 9. As the wiring conductor 7, it is preferable to use one having good electrical conductivity. Moreover, since it is used as a circuit pattern, it is preferable to use a member that has a smaller ionization tendency than the metal bonding layer 5 and is less likely to corrode. Specifically, as the wiring conductor 7, an alloy member of Cu, Ti and Cu can be used. The thickness of the wiring conductor 7 is preferably larger than the thickness of the metal bonding layer 5, specifically 1 to 10 μm. The wiring conductor 7 may be separately formed on the main surface 3a of the insulating substrate 3 like the metal bonding layer 5 or may be disposed on the main surface 3a of the insulating substrate 3 by sputtering. May be.

  Further, as shown in FIG. 4, the width D <b> 2 of the wiring conductor 7 is preferably smaller than the width D <b> 1 of the metal bonding layer 5 in a cross section perpendicular to the longitudinal direction of the wiring conductor 7. Thereby, even if a gap is generated between the vacuum film-forming layer 9 and the plating layer 11 and the insulating substrate 3, the possibility that the wiring conductor 7 is exposed to a chemical solution such as an etching solution or the outside air can be reduced. And it can suppress that the electroconductivity of the wiring conductor 7 falls. The shape of the present embodiment is effective when stable electrical conductivity of the wiring conductor 7 is required.

  The wiring board 1 according to this embodiment includes a vacuum film forming layer 9 that covers the metal bonding layer 5 and the wiring conductor 7. The metal bonding layer 5 and the wiring conductor 7 may be corroded by a process of coating the vacuum film formation layer 9 with plating. Therefore, the vacuum film-forming layer 9 in this embodiment acts as a covering member that suppresses deterioration of the metal bonding layer 5 and the wiring conductor 7 due to corrosion. Therefore, it is preferable to use a component having higher corrosion resistance to the plating solution than the main component constituting the metal bonding layer 5 and the wiring conductor 7 as the vacuum film formation layer 9. Specifically, Cu, Ni, and TiN can be used as the vacuum film formation layer 9. The vacuum film-forming layer 9 can be disposed on the main surface 3a of the insulating substrate 3 by sputtering or vacuum evaporation.

  Further, as shown in FIG. 4, in the cross section perpendicular to the longitudinal direction of the wiring conductor 7, the bonding width L <b> 1 between the insulating substrate 3 and the vacuum film formation layer 9 is larger than the thickness L <b> 2 of the vacuum film formation layer 9. Is preferred. This is because the bondability between the vacuum film formation layer 9 and the insulating substrate 3 can be improved while suppressing an increase in the thickness of the vacuum film formation layer 9.

  In addition, the wiring board 1 of the present embodiment includes a plating layer 11 disposed on the vacuum film formation layer 9. In this embodiment, the plating layer 11 functions as a covering member that suppresses deterioration of the metal bonding layer 5, the wiring conductor 7, and the vacuum film-forming layer 9 due to long-term use. Specifically, Ni and Au can be used as the plating layer 11.

  In addition, when Cu is used as the wiring conductor 7 and Ni plating is used as the plating layer 11, the Ni plating has a smaller thermal expansion coefficient than the wiring conductor 7 made of Cu, and at the same time has a large elastic modulus. Therefore, the stress due to the thermal expansion of copper can be relaxed in the plated layer 11.

  Further, as shown in FIG. 4, the plating layer 11 includes a first plating layer 11a that covers the vacuum film formation layer 9 and a second plating layer 11b that covers the first plating layer 11a. Is preferred. Thus, even if the second plating layer 11b is peeled off by providing the plurality of plating layers 11 such as the first plating layer 11a and the second plating layer 11b, the first plating layer 11a and the second plating layer 11b are provided. Since the plating layer 11a covers the vacuum film formation layer 9, the possibility of corrosion of the metal bonding layer 5, the wiring conductor 7, and the vacuum film formation layer 9 can be reduced. In this case, for example, Ni plating can be used as the first plating layer 11a, and Au plating can be used as the second plating layer 11b.

  The plated layer 11 preferably has a smaller coefficient of thermal expansion than the wiring conductor 7. Even when the wiring conductor 7 generates heat due to energization of the wiring conductor 7, the thermal expansion coefficient of the plating layer 11 is smaller than that of the wiring conductor 7. This is because the possibility of peeling between the vacuum film forming layer 9 and the wiring conductor 7 and between the wiring conductor 7 and the metal bonding layer 5 can be reduced. In the present embodiment, the thermal expansion coefficient of the plating layer 11 is smaller than the thermal expansion coefficient of the wiring conductor 7. The main component constituting the plating layer 11 has a higher thermal expansion than the main component constituting the wiring conductor 7. In other words, it is a member with a low rate.

  Next, the manufacturing method of the wiring board 1 of this invention is demonstrated.

  The wiring substrate 1 according to the present embodiment includes a step of preparing the insulating substrate 3. The insulating substrate 3 can be produced as follows, for example. First, raw material powders such as glass powder and ceramic powder are kneaded together with an organic solvent and a binder. This is formed into a sheet shape to produce a plurality of ceramic green sheets. Next, a conductor paste to be a wiring member is deposited on the main surface of the ceramic green sheet. Further, a ceramic green sheet in which through holes are formed is laminated on the conductor paste. Then, the through-hole is filled with a conductor paste that becomes the via conductor 13. These are fired at a predetermined firing temperature (for example, 1000 ° C.). Thereby, the insulating substrate 3 can be produced.

  Moreover, you may provide the process of surface-processing the main surface 3a of the produced insulating board | substrates 3. FIG. Surface processing by surface grinding is performed to correct the parallelism of the front and back surfaces and the warpage of the substrate, and the damage layer to the porcelain by surface grinding can be reduced by lapping and polishing.

  In addition, a step of disposing the metal bonding layer 5 on the main surface 3a of the insulating substrate 3 is provided. The metal bonding layer 5 can be disposed on the main surface 3a of the insulating substrate 3 by a sputtering method. Further, the metal bonding layer 5 may be disposed by a semi-additive method using an electrolytic plating method.

  In addition, a step of disposing the wiring conductor 7 on the metal bonding layer 5 is provided. The wiring conductor 7 can be formed on the main surface 3a of the insulating substrate 3 by the sputtering method, similarly to the metal bonding layer 5.

  At this time, a plating resist may be disposed on the wiring conductor 7 and plating may be formed by a semi-additive method using an electrolytic plating method. Since the wiring conductor 7 is disposed on the entire metal bonding layer 5 by sputtering, the circuit thickness of the wiring conductor 7 and the like can be increased while preventing the metal bonding layer 5 from being corroded by the plating solution. is there.

  When the metal bonding layer 5 and the wiring conductor 7 are disposed on the main surface 3a of the insulating substrate 3 by using the sputtering method, the metal bonding layer 5 and the wiring conductor 7 other than the portion that becomes the circuit wiring are removed by etching or the like. To do.

  Furthermore, a step of providing a vacuum film-forming layer 9 so as to cover the metal bonding layer 5 and the wiring conductor 7 is provided. The vacuum film formation layer 9 can be formed on the main surface 3a of the insulating substrate 3 by sputtering or the like, similarly to the metal bonding layer 5.

  And the process of arrange | positioning the plating layer 11 so that the vacuum film-forming layer 9 may be coat | covered is provided. As the plating layer 11, for example, a nickel layer and / or a gold layer can be used. The plating layer 11 can be disposed so as to cover the vacuum film-forming layer 9 by, for example, a semi-additive method using an electrolytic plating method.

  Next, a wiring board 1 according to a second embodiment of the present invention will be described.

  As shown in FIGS. 1 to 3, the wiring board 1 according to the present embodiment is disposed on the insulating substrate 3 having the main surface 3 a and the main surface 3 a of the insulating substrate 3, and is bonded to the insulating substrate 3. Metal bonding layer 5, wiring conductor 7 disposed on metal bonding layer 5, vacuum film-forming layer 9 covering metal bonding layer 5 and wiring conductor 7, and vacuum film-forming layer 9. And a plated layer 11.

  In addition, the wiring conductor 7 has an ionization tendency smaller than that of the main component constituting the metal bonding layer 5, and a component having higher electrical conductivity than the main component constituting the metal bonding layer 5 and the vacuum film forming layer 9. Yes. Further, the vacuum film-forming layer 9 is mainly composed of a component having a smaller ionization tendency than the main components constituting the metal bonding layer 5 and the wiring conductor 7.

  Thus, since the vacuum film-forming layer 9 in the wiring board 1 of the present embodiment is mainly composed of a component having a smaller ionization tendency than the main components constituting the metal bonding layer 5 and the wiring conductor 7, the plating layer 11. It is possible to suppress the occurrence of galvanic corrosion of the metal bonding layer 5 and the wiring conductor 7 due to the plating solution used when forming the wire.

  Further, since the main component is a component having a smaller ionization tendency than the main component constituting the metal bonding layer 5 and the wiring conductor 7, the metal is not only a plating solution but also a strongly alkaline chemical solution for cleaning the surface of the wiring substrate 1. Generation of galvanic corrosion of the bonding layer 5 and the wiring conductor 7 can also be suppressed.

  Next, a wiring board 1 according to a third embodiment of the present invention will be described.

  As shown in FIG. 5, the wiring board 1 according to the present embodiment has a cross section perpendicular to the longitudinal direction of the wiring conductor 7 compared to the wiring board 1 according to the first embodiment. The bonding layer 5 is covered.

  Since the wiring conductor 7 covers the metal bonding layer 5 as in the present embodiment, the possibility that the metal bonding layer 5 is corroded by the chemical solution can be further reduced. When it is required to improve the bonding property between the metal bonding layer 5 and the insulating substrate 3, the shape of the present embodiment is effective.

  Next, a wiring board 1 according to a fourth embodiment of the present invention will be described.

  As shown in FIG. 6, the wiring board 1 according to the present embodiment has a smaller coefficient of thermal expansion than the wiring conductor 7 compared with the wiring board 1 according to the first embodiment, and covers the vacuum film formation layer 9. The covering member 15 is further provided.

  Even when the wiring conductor 7 generates heat, the coefficient of thermal expansion of the covering member 15 is smaller than that of the wiring conductor 7, so that the space between the covering member 15 and the vacuum film forming layer 9 and the vacuum film forming layer 9 are the same. This is because the possibility of peeling between the wiring conductor 7 and the wiring conductor 7 can be reduced. In the present embodiment, the coefficient of thermal expansion of the covering member 15 is smaller than the coefficient of thermal expansion of the wiring conductor 7. The main component constituting the covering member 15 is more thermally expanded than the main component constituting the wiring conductor 7. In other words, it is a member with a low rate.

  As the covering member 15, it is preferable to use titanium nitride or chromium nitride having high corrosion resistance.

  Next, a probe card according to an embodiment of the present invention will be described.

  As shown in FIG. 7, the probe card 17 of this embodiment includes a wiring board 1 typified by the above embodiment, a second insulating board 19 laminated on the back surface of the wiring board 1, and a second A second via conductor 21 embedded in the insulating substrate 19 and electrically connected to the first via conductor 13, a measurement terminal 25 disposed on the main surface of the wiring substrate 1, and a second And a connection terminal 27 disposed on the back surface of the insulating substrate 19.

  In the present embodiment, the measurement terminal 25 is electrically connected to the first via conductor 13 via the metal bonding layer 5 and the wiring conductor 7 disposed on the main surface of the wiring board 1. Further, the connection terminal 27 is electrically connected to the first via conductor 13 via the second via conductor 21 that penetrates the second insulating substrate 19.

  In the probe card 17 of this embodiment, the terminal of the semiconductor element that is the object to be measured is electrically connected to the measurement terminal 25, and the semiconductor element is energized. Here, energizing is intended not only to apply a voltage but also to input a signal to a semiconductor element. The quality of the semiconductor element can be determined by measuring the output taken out via the connection terminal 27 and comparing it with the expected value.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

It is a perspective view which shows the wiring board in the 1st and 2nd embodiment of this invention. It is AA sectional drawing in the wiring board shown in FIG. It is an expanded sectional view which shows the area | region A in sectional drawing shown in FIG. It is an expanded sectional view showing a modification of a wiring board in a 1st embodiment of the present invention. It is an expanded sectional view showing a wiring board in a 3rd embodiment of the present invention. It is an expanded sectional view showing a wiring board in a 4th embodiment of the present invention. It is sectional drawing which shows the probe card concerning one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wiring board 3 ... Insulating board 3a ... Main surface 5 ... Metal bonding layer 7 ... Wiring conductor 9 ... Vacuum film-forming layer 11 ... Plating layer 11a ... 1st plating layer 11b ... 2nd plating layer 13 ... Via conductor 15 ... Cover member 17 ... Probe card 19 ... 2nd insulating substrate 21 ... 2nd via Conductor 25 ... Measuring terminal 27 ... Connection terminal

Claims (6)

An insulating substrate having a main surface, a metal bonding layer disposed on the main surface of the insulating substrate and bonded to the insulating substrate, a wiring conductor disposed on the metal bonding layer, and the metal bonding A vacuum film-forming layer covering the layer and the wiring conductor, and a plating layer disposed on the vacuum film-forming layer,
The wiring conductor has a smaller ionization tendency than the main component constituting the metal bonding layer, and has a component having higher electrical conductivity than the main component constituting the metal bonding layer and the vacuum film-forming layer as a main component,
The wiring board according to claim 1, wherein the vacuum film-forming layer includes a component having a smaller ionization tendency as a main component than the main component constituting the metal bonding layer and the wiring conductor. The wiring board according to claim 1, wherein a width of the wiring conductor is smaller than a width of the metal bonding layer in a cross section perpendicular to the longitudinal direction of the wiring conductor . The wiring board according to claim 1 , wherein the wiring conductor covers the metal bonding layer in a cross section perpendicular to the longitudinal direction of the wiring conductor . 2. The wiring according to claim 1 , wherein a bonding width between the insulating substrate and the vacuum film-forming layer is larger than a thickness of the vacuum film-forming layer in a cross section perpendicular to the longitudinal direction of the wiring conductor. substrate. The wiring board according to claim 1, further comprising a covering member that has a smaller coefficient of thermal expansion than the wiring conductor and covers the vacuum film-forming layer . A probe card comprising: the wiring board according to claim 1; a measurement terminal disposed on a main surface side of the wiring board; and a connection terminal disposed on a back surface side of the wiring board.

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