JP4484543B2 - Multiple wiring board - Google Patents

Description

  In the present invention, a large number of wiring board regions, each of which is a small wiring board for mounting electronic components such as a semiconductor element and a crystal resonator, are arranged in a central portion of a large-area mother board in a vertical and horizontal arrangement. This relates to a multi-piece wiring board.

  Conventionally, for example, a small wiring board used for an electronic component storage package for storing an electronic component such as a semiconductor element or a crystal resonator is made of a ceramic material such as an aluminum oxide sintered body, and has a wiring conductor on the surface. In this structure, a plurality of formed rectangular flat ceramic insulating layers are stacked one above the other. An electronic device is formed by housing an electronic component on the wiring board and electrically connecting the electrode of the electronic component to an exposed portion of the wiring conductor via solder, a bonding wire, or the like.

  By the way, with the recent demand for miniaturization of electronic devices, the size of such wiring boards has become extremely small, about several millimeters square, and the thickness has become as thin as 1 mm or less. ing. In order to facilitate handling of such a small number of wiring boards and to efficiently manufacture the wiring board and the electronic device, a large number of mother boards made of a single large-area ceramic material or the like are used. The circuit board is manufactured in the form of a so-called multi-cavity wiring board in which a plurality of wiring boards are obtained simultaneously and collectively.

  An example of such a multi-piece wiring board is shown in FIG.

  The multi-cavity wiring board includes a mother board 31 in which a plurality of rectangular wiring board areas 33 are formed in a matrix, a plurality of wiring conductors (not shown) formed in each wiring board area 33, and a mother board 31. It is the structure which comprised the frame-shaped discard margin area | region 37 formed in the outer periphery.

  A mounting portion (not shown) for mounting electronic components is formed on the upper surface of each wiring board region 33, and a part of the wiring conductor is a mounting portion on the upper surface of the wiring substrate region 33 or its periphery. And the other part is formed so as to be led out to the lower surface and side surfaces of the wiring substrate region 33.

  An electronic component (not shown) is mounted and fixed on the mounting portion of the wiring board region 33, and the electrodes of the electronic component are exposed to the mounting portion or its periphery via an electrical connection means such as a bonding wire or solder. It is electrically connected to the wiring conductor, and a lid made of metal, glass or the like is joined to the upper surface of the wiring board region 33 so as to close the mounting portion, or an electronic component on the mounting portion is made of resin made of epoxy resin or the like By covering with the filler, the electronic components are housed in an airtight manner on the mounting portion, so that a large number of electronic devices are formed in a multi-piece state in which the devices are arranged vertically and horizontally. Thereafter, the electronic device in a multi-piece state is divided into individual wiring board regions 33, whereby electronic devices as a large number of products are formed. The electronic component may be mounted on the wiring board area 33 after the multi-piece wiring board is divided into the individual wiring board areas 33.

  In such multi-cavity wiring boards, nickel or gold is usually applied to the surface of the previously exposed wiring conductor in order to prevent oxidative corrosion, improve the wettability of solder, and improve the bonding property of bonding wires. Etc. are plated.

  In order to plate the wiring conductor, a multi-piece wiring board is immersed in a plating solution such as nickel or gold, and a predetermined plating current is supplied to the wiring conductor. A plating conduction pattern 34 is formed on a pair of opposing sides of the mother board 31 so as to be electrically connected to the wiring conductor, and a conduction terminal provided on a plating jig (rack). (Not shown) is brought into contact with the plating conduction pattern 34, and the conduction terminal 34 and the plating conduction pattern 34 are connected from the power source by sandwiching the plating conduction pattern 34 from above and below between the pair of ends of the conduction terminal. Through this, a current for plating is supplied to the wiring conductor.

  As shown in FIG. 2, the plating conduction pattern 34 is formed by applying a conductor layer such as a metallized layer on the inner surface of an elliptical arc-shaped or arc-shaped cutout 36 formed on a pair of opposed end surfaces of the mother substrate 31. It is formed by wearing.

  In this case, in general, in the electroplating method, the wiring conductor closer to the outer peripheral portion of the wiring board region 33 has a higher current density and a higher current density. Is fast and the plating thickness is known to increase.

  Therefore, in order to make the thickness of the plating such as nickel or gold deposited on the wiring conductor of the wiring board region 33 uniform, the main surface of the discard margin region 37 of the mother board 31 has a frame-shaped outer peripheral metallization. The layer 38 is formed in electrical connection with the plating conduction pattern 34 and the wiring conductor.

  The outer peripheral metallization layer 38 is a so-called auxiliary that suppresses variations in the plating thickness of the wiring conductor by attracting a plating metal such as nickel or gold to be deposited on the inner wiring conductor and depositing it on the outer peripheral metallization layer 38 itself. It functions as a cathode and prevents the plating thickness deposited on the wiring conductor in the inner wiring board region 33 from increasing.

  A through conductor 35 is formed on the boundary between the adjacent wiring board regions 33, and the through conductors 35 electrically connect the wiring conductors of the adjacent wiring board regions 33 and upper and lower wiring conductors. Thus, when divided into individual wiring board regions 33, they are vertically divided to become side conductors (castellation conductors) located on the side faces of the wiring board.

For example, if the mother board 31 is made of a ceramic material, such a multi-cavity wiring board is prepared with a plurality of green sheets, a region to be the wiring substrate region 33, and a predetermined position of the boundary of the region. A through hole is formed in the green sheet, and then a pair of end faces of the green sheet are punched out into a semicircle or semi-elliptical shape to form a cutout portion 36, and then the metal paste is formed on the surface of the green sheet. The entire inner surface of the portion 36 and the inside of the through hole are printed and filled, and then a metal paste is printed and coated on the surface of the green sheet in a pattern such as a predetermined wiring conductor, outer peripheral metallized layer 38, and plating conduction pattern 34. Finally, the green sheets are laminated to form a laminated body and fired.
JP 2000-340898 A

  However, in recent years, small-sized wiring boards used for electronic component storage packages and the like have been required to be further reduced in size, in particular, to be thinner due to the demand for low-profile electronic devices. For example, the mother board 31 has become very thin, for example, with a thickness of 0.5 mm or less.

  When the mother substrate 31 is thinned in this way, the metal paste that becomes the outer metallized layer 38 and the green sheet that becomes the mother substrate 31 have different shrinkage rates at the time of firing. A large stress over the entire length of each side acts in one direction, and when the mother substrate 31 warps in a concave shape or a convex shape due to this stress, each wiring substrate region 33 is divided into individual pieces. 33, and the boundary line between the wiring board region 33 and the disposal margin area 37 is distorted, so that there is a problem that cracks and burrs are generated in each wiring board. Further, when mounting electronic parts such as semiconductor elements without dividing the mother board 31, the mounting portion is deformed, mounting accuracy is deteriorated, and mounting defects frequently occur.

  The present invention has been devised in view of such problems, and an object of the present invention is to provide a mother board in a multi-cavity wiring board in which a large number of wiring boards 33 that are further miniaturized, in particular thinned, are arranged. Even if the outer peripheral metallization layer 38 for preventing the variation in the plating thickness is provided on the main surface of the disposal margin region 37 on the outer periphery of the outer periphery 31, it is possible to prevent the occurrence of problems such as warpage in the mother substrate 31. As a result, it is possible to prevent the occurrence of cracks and burrs when dividing each wiring board region 33 into individual pieces, and to apply a good plating layer to the surface of the wiring conductor. The object is to provide a single-piece wiring board.

The multi-cavity wiring board according to the present invention includes a rectangular mother board in which wiring board areas are vertically and horizontally arranged at the center of the main surface and a margin area is formed on the outer periphery, and each of the wiring board areas. The outer peripheral metallization layer formed so as to surround the wiring substrate region on the main surface of the discard margin region, and the outer peripheral metallization layer is formed on each of the mother substrates. so that discontinuities in the central portion of the sides have to have a non-forming portion, said non-formed part, the direction of the length along said outer peripheral metallized layer of the wiring substrate area whose length is adjacent to the non-formation portion and it is characterized in der Rukoto than is.

  In the multi-piece wiring board of the present invention, it is preferable that the outer peripheral metallization layer is formed on at least a pair of opposing sides of the mother board from both sides of the non-formed part to the outer peripheral edge of the mother board. Each of the extended plating conduction patterns is formed.

  In the multi-cavity wiring board of the present invention, a metallization layer for connection that connects the outer peripheral metallization layers of the pair of opposing sides is formed between each row or each column of the wiring board region of the main surface. The wiring conductor in each wiring board region is electrically connected to the connection metallization layer.

  According to the multi-cavity wiring board of the present invention, the outer peripheral metallized layer has a non-formed portion so as to be discontinuous at the center of each side of the mother substrate. Even if stress is generated due to the difference in shrinkage rate during firing, the stress is generated intermittently for each part delimited by each non-formed part. A large stress does not act in the direction, and it is possible to prevent the mother substrate from warping.

  Thereby, cracks and burrs can be prevented from occurring when each wiring board region is divided into individual pieces. Further, when mounting electronic parts such as semiconductor elements without dividing the mother board, it is possible to effectively prevent deterioration of mounting accuracy and effectively prevent mounting defects.

According to the multi-cavity wiring board of the present invention, each non- formed portion has a length equal to or greater than the length in the direction along the outer peripheral metallization layer of the wiring board region adjacent to the non-formed portion. since it is possible to interconnect conductors take integrally electrical conduction in the region, securing a sufficient length of the non-forming portion can be made stress discontinuity and securely intermittently, effective In addition, it is possible to prevent the mother substrate from warping due to a difference in porcelain shrinkage during firing between the outer peripheral metallized layer and the mother substrate.

  Further, according to the multi-piece wiring board of the present invention, preferably, the outer peripheral metallized layer extends from both sides of the non-formed part to the outer peripheral end of the mother board in at least a pair of opposing sides of the mother board. Since the plating conduction patterns to be formed are respectively formed, the plating conduction patterns formed on the pair of opposing sides of the mother board are connected with the conduction terminals provided on the plating jig (rack). By sandwiching from above and below, the electrical connection between the plating conduction pattern and the conduction terminal can be made easy and reliable, and the current for plating can be supplied to the wiring conductor more reliably, and the uniform thickness can be obtained. The plating layer can be more reliably formed on the wiring conductor.

  Moreover, according to the multi-cavity wiring board of the present invention, preferably, a connection for connecting a pair of outer peripheral metallized layers on opposite sides between each row or each column of the wiring board region of the main surface. Since the metallized layer is formed and the wiring conductor of each wiring board region is electrically connected to the connecting metallized layer, the wiring conductors formed in all the wiring board regions and the main surface of the mother board The outer peripheral metallization layer and the connection metallization layer formed on each other can be directly electrically connected without going through the wiring board region, so that the current flowing through each wiring conductor becomes even more uniform and the mother board with a large area The thickness of the plating layer deposited on the wiring conductor in the main surface of the wiring board region formed in a plurality of rows and columns can be made more uniform and stable.

  As a result, it is possible to provide a multi-piece wiring board capable of producing a wiring board having excellent electrical connection reliability.

  Next, a multi-piece wiring board according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a plan view showing an example of an embodiment of a multi-piece wiring board according to the present invention. In the figure, 1 is a mother board, 3 is a wiring board region, 4 is a pattern for plating conduction, and 8 is an outer metallization layer. In addition, although the wiring conductor is formed in each wiring board area | region 3, the wiring conductor is abbreviate | omitted in order to make drawing easy to see.

  The mother board 1, the wiring board region 3, the wiring conductor, and the outer peripheral metallized layer 8 constitute the multi-piece wiring board of the present invention.

  Here, the mother substrate 1 is formed by laminating ceramic layers made of a ceramic material such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, or a glass ceramic. Moreover, each wiring board area | region 3 is the square shape whose length of one side is about 2-20 mm and thickness is about 0.2-2 mm, for example. A mounting portion (not shown) for storing and mounting electronic components is provided at the center of the upper surface of each wiring board region 3.

  If such a mother substrate 1 is made of, for example, an aluminum oxide sintered body, a plurality of green sheets obtained by forming a raw material powder such as aluminum oxide into a sheet shape are prepared, and the substrate is partitioned vertically and horizontally. Next, a part of the green sheet is subjected to an appropriate punching process, and then laminated and fired.

  A wiring conductor (not shown) is formed in each wiring board region 3. The wiring conductor functions as a conductive path for electrically connecting the electrodes of the electronic components mounted on the mounting portion via bonding wires, solder, or the like and leading them to the lower surface or side surface of the wiring board region 3. .

  The wiring conductor is made of a metal material such as tungsten, molybdenum, copper, or silver. For example, when the wiring conductor is made of tungsten, a metal paste of tungsten is printed on a green sheet as the mother substrate 1 in a predetermined wiring conductor pattern. It is formed by keeping.

  On the surface of the wiring conductor, a plating layer (such as nickel or gold) is used to prevent oxidative corrosion and to improve characteristics such as solder wettability when bonding solder and bonding wires and bonding wire bonding properties. (Not shown) is attached.

  This plating layer is formed by supplying a plating current to the surface of the wiring conductor which is a portion to be plated in the plating solution, and performing electrolytic plating.

  The outer peripheral metallized layer 8 is for reducing and making uniform the plating layer deposited at this time. In other words, the outer peripheral metallization layer 8 functions as a so-called auxiliary cathode, thereby preventing the plating layer deposited on the wiring conductor in the inner wiring board region 3 from becoming thick and causing variations in the plating layer thickness. is doing.

  The outer peripheral metallized layer 8 is preferably formed with a width of 2 mm or more in order to prevent variation in the plating thickness of the wiring conductor. In this case, it is not necessary to have the same width over the entire circumference of the outer peripheral metallized layer 8. For example, the width on the outer side of each corner portion of the wiring substrate region 3 where the current density for plating is particularly high is made wider than the width at other portions, so that variations in plating thickness can be prevented more reliably. Also good.

  The outer peripheral metallization layer 8 is formed by printing and applying a metal paste similar to that for forming the wiring conductor in a frame shape on the main surface of the disposal margin region 7 on the outer periphery of the green sheet. The outer peripheral metallization layer 8 is preferably formed of the same material as the wiring conductor in consideration of productivity and the like.

  In the multi-piece wiring board of the present invention, the outer peripheral metallized layer 8 has a non-formed part 10 so as to be discontinuous at the center part of each side of the mother board 1.

  With this configuration, even if a stress is generated between the outer peripheral metallized layer 8 and the mother substrate 1 due to a difference in shrinkage rate during firing, the stress is intermittent for each part delimited by each non-forming portion 10. Therefore, a large stress does not act in one direction over the entire length of each side of the mother board 1, and it is possible to prevent the mother board 1 from warping.

  As a result, it is possible to prevent cracks and burrs from occurring when the respective wiring board regions 3 are divided into individual pieces. In addition, when mounting electronic components such as semiconductor elements without dividing the mother board 1, mounting accuracy can be prevented from being deteriorated and mounting defects can be prevented.

  In this case, the non-forming part 10 is preferably provided at the central part of each side of the mother board 1. When the non-forming portion 10 is provided in the central portion of each side portion, it is possible to more effectively prevent stress from being concentrated in one direction over the entire length of each side, and warping or the like on the mother substrate 1 can be prevented. It is possible to more reliably prevent the deformation from occurring. Further, as described above, the plating current is increased at the corners of the wiring substrate regions 3 arranged. Therefore, if the non-forming portion 10 is provided at the corner, it is possible to effectively prevent variations in the plating thickness. May be difficult.

Also, multiple patterning wiring board of the present invention, the non-formation portion 10, Ru der direction than the length along the outer peripheral metallized layer 8 of the wiring substrate region 3 whose length is adjacent to the non-formation portion 10.

  Thereby, since the length of the non-forming part 10 can be sufficiently secured and the stress can be made more discontinuous and intermittent, the outer peripheral metallized layer 8 and the mother substrate 1 can be fired more effectively. It is possible to prevent warping of the mother board 1 due to the difference in porcelain contraction at the time.

In this case, if the length of the non-formed portion 10 exceeds 30% with respect to the length of each side of the mother substrate 1, the effect of preventing variation in the plating thickness becomes insufficient. Therefore, the length of the non-formed portion 10 is more preferably set to be not less than the length of the adjacent wiring board region 3 and not more than 30% of the length of each side of the mother board 1 . In addition, in the example of FIG. 1, one non-forming portion 10 is provided on each side, but a plurality of non-forming portions 10 may be provided on each side.

  Further, in the multi-piece wiring board of the present invention, the outer peripheral metallized layer 8 extends from both sides of the non-formed part 10 to the outer peripheral end of the mother board 1 in each of at least a pair of opposing sides of the mother board 1. It is preferable that the plating conduction patterns 4 are respectively formed.

  The plating conduction pattern 4 is electrically connected to the wiring conductor of the wiring board region 3 through the outer peripheral metallized layer 8.

  With this configuration, the plating conduction patterns 4 formed on the pair of opposing sides of the mother board 1 are sandwiched from above and below by the conduction terminals provided on the plating jig (rack), so that the plating conduction is performed. The electrical connection between the common pattern 4 and the conduction terminal can be made easy and reliable, and the current for plating is supplied to the wiring conductor more reliably, and the plating layer of uniform thickness is more reliably wired. It can be formed on a conductor.

  The metal pin of the rack conduction terminal is fitted and brought into contact with the plating conduction pattern 4, and plating is applied to the wiring conductor in each wiring board region 3 from the conduction terminal via the plating conduction pattern 4 in the plating solution. By supplying an electric current, metal components (nickel, gold, etc.) in the plating solution are deposited, and the wiring conductor is plated.

  In addition, the multi-piece wiring board of the present invention has a metallization layer 2 for connection that connects a pair of outer peripheral metallization layers 8 on each side between the rows or columns of the wiring board region 3 on the main surface. It is preferable that the wiring conductor of each wiring board region 3 is electrically connected to the connection metallization layer 2.

With this configuration, the wiring conductor (not shown) formed in all the wiring board regions 3, the outer peripheral metallization layer 8 as the lead wiring conductor formed on the main surface of the mother board 1, and the connection metallization layer 2 are provided. Since direct electrical conduction can be achieved without going through the wiring board region 3,
The current flowing through each wiring conductor 3 is also made more uniform, and the thickness of the plating layer deposited on the wiring conductor in the main surface of the wiring board region 3 formed in a plurality of rows and columns of the large-sized mother board 1 is made more uniform. It can be stable.

  The connection metallization layer 2 does not have to be formed between all the columns (or between the rows) as shown in FIG. 1, and the connection metallization layer 2 is appropriately selected according to the external dimensions and number of wiring board regions 3. Columns or rows in which no can be formed may be provided. However, it is preferable that the intervals between the connection metallization layers 2 be equal to each other in terms of uniform supply of current.

  Note that the metallization layer 2 for connection and the pattern 4 for plating conduction are formed in advance on the main surface and sides of the disposal margin region 7 on the outer periphery of the green sheet by using the same metal paste as that for forming the wiring conductor. It is formed, for example, by printing on the inner surface of the cutout portion 6.

  In this case, the outer peripheral metallization layer 8, the connection metallization layer 2, and the plating conduction pattern 4, for example, have a thickness of 10 to 30 μm. It is preferable in terms of effective prevention.

  As a result, according to the present invention, it is possible to provide a multi-piece wiring board capable of producing a wiring board excellent in electrical connection reliability.

  It should be noted that the present invention is not limited to the above embodiments, and various modifications may be made without departing from the gist of the present invention. For example, in this example, the mother board 1 is constituted by 50 wiring board regions 3 of 5 rows × 10 columns. However, it goes without saying that the mother board 1 may be constituted by other arrangement numbers of mother boards.

It is a top view which shows an example of embodiment of the multi-cavity wiring board of this invention. It is a top view of the conventional multi-piece wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mother board | substrate 2 ... Connection metallization layer 3 ... Wiring board area | region 4 ... Plating conduction | electrical_connection pattern 7 ... Discard allowance area | region 8 ... Outer periphery metallization layer 10 .... non-formation part

Claims (3)

A wiring board region is formed in the central portion of the main surface in vertical and horizontal directions, and a rectangular mother board in which a margin area is formed on the outer periphery, wiring conductors formed in each wiring board region, and the discarding An outer peripheral metallization layer formed so as to surround the wiring substrate region is provided on the main surface of the substitute region, and the outer peripheral metallization layer is discontinuous at the center of each side of the mother substrate. have have a non-forming portion, the non-forming portion, the length and wherein the outer peripheral metallized layer der Rukoto direction or length along the wiring substrate region adjacent to the non-formation portion Multi-piece wiring board. The outer peripheral metallized layer is formed with a plating conduction pattern extending from both sides of the non-formed portion to the outer peripheral end of the mother substrate at each of at least a pair of opposing sides of the mother substrate. multiple patterning wiring board according to claim 1 Symbol mounting features. In the mother board, a connection metallization layer that connects the outer peripheral metallization layers of each of the pair of opposing sides is formed between each row or each column of the wiring board region of the main surface, 3. The multi-piece wiring board according to claim 2 , wherein the wiring conductor in each wiring board region is electrically connected to the connection metallization layer.

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