JP2006005035A - Ceramic package assembly for storing electronic component and ceramic package - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring board assembly and a wiring board or a ceramic package capable of obtaining the ceramic package that can prevent burrs and conductor foreign matters from being generated and can secure a large bonding area for soldering. <P>SOLUTION: The wiring board assembly for manufacturing the ceramic packages stores electronic components having castellations on side walls formed with a conductive film for connecting a conductive portion on the top face, and a conductive portion on the bottom face. The assembly has through holes 6 formed with the conductive film which become the castellations after being divided into individual packages. The conductive film formed on the inner wall of the through holes is continuous inside the through holes, but away from a position from which the wiring board assembly is going to be divided into individual packages in a lower part of the through holes. Moreover, the conductor pattern 8 on the bottom face which become external connection terminals by being connected to the conductive film 4 on the through holes is also away from the position from which the assembly is going to be divided into individual packages. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an assembly of ceramic packages having a wiring board on which electronic components are mounted, and a ceramic package manufactured from the assembly.

  In recent years, ceramic packages for storing electronic components for storing electronic circuit component elements such as semiconductor elements, crystal resonators, and piezoelectric elements have become highly functional in small devices using the electronic component elements, such as mobile phones and notebook personal computers. Accordingly, further downsizing and high reliability are required.

  This ceramic package consists of a wiring board having a conductor pattern, a frame joined to the board, and an upper lid, and an electronic circuit component element connected to the conductor pattern by a conductive wire or the like is housed therein, and the lid The body is joined to the upper part of the frame and hermetically sealed. The conductor pattern on the substrate is connected to an external connection terminal pad through a conductor in a via penetrating the substrate or the like, or a recess (hereinafter also referred to as castellation) on a substrate side wall surface provided with a conductor film. The pad is bonded to a land of an external circuit board such as a mother printed circuit board by solder or the like.

  FIG. 2A shows a schematic diagram of an example of a ceramic package, in which a frame body 2 is bonded to a substrate 1 having a conductor pattern such as an electronic component element connection land 3. Such a wiring board or ceramic package is usually manufactured in the form of a wiring board assembly as shown in FIG. 2B, and is divided into individual packages. FIGS. 3A and 3B show a case where the ceramic package and its assembly are turned upside down and viewed from below.

  FIG. 4 is an example schematically showing a cross section of a castellation portion when an electronic component element is loaded on the ceramic package and joined to a mother printed circuit board by soldering. The electronic component 12 is connected to the conductor pattern 3 on the wiring board. After the lid body 13 is joined and sealed onto the conductor on the upper surface of the frame body 2, the solder 16 is placed on the connection land 15 on the circuit board 14. Be joined. This bonding has the purpose of electrically connecting the electronic component elements inside the package and the mother printed circuit board and also fixing the package to the circuit board.

  FIG. 5 shows an example of a manufacturing process of a wiring board assembly such as a package and a wiring board. First, a through-hole 6 that becomes a castellation 4 is formed in a green sheet formed to a predetermined thickness, and a paste such as tungsten that becomes a conductor film is printed on the inner wall surface of this through-hole by a through-hole printing method. Next, the conductor paste of the connection land pattern is printed on the upper surface so as to be connected to the conductor film. In addition, a conductor pattern as a terminal land for connecting to a mother printed circuit board or the like is also printed on the lower surface of the laminated sheet. When the wiring board has a plurality of layers, the through-hole positions are the same, green sheets each having a different conductor pattern or via for connecting the upper and lower layers are produced, and these are laminated. If necessary, the frame is also crimped.

  After lamination, as shown in FIG. 2B or FIG. 3B, dividing grooves 7 are formed on the upper and lower surfaces at positions orthogonal to the through holes, and integrated firing is performed. After firing, the circuit pattern exposed on the surface and the conductor film on the inner wall of the through hole are subjected to nickel plating and gold plating for improving conductivity. If the wiring board assembly produced in this way is divided along the dividing grooves at the positions of the through holes, the wiring board (ceramic package) shown in FIG. 2 (A) or FIG. 3 (A) is completed. Thereby, the through-hole 6 in which the conductor film is formed on the inner surface becomes the castellation 4 on the side wall of the package or the wiring board.

  At this time, since the substrate material is brittle ceramic such as alumina, it is separated and cut cleanly, but the conductor part is attached with a soft material with high ductility such as nickel and gold by plating, which makes the separation property worse when dividing. Or may generate burrs. This burr may cause a connection failure such as floating the package when soldering to the mother printed circuit board, etc., or it will drop off later and become a conductive foreign object, resulting in a short circuit with other components such as adjacent packages. Cause the quality of the electronic circuit to deteriorate.

In order to suppress the occurrence of such burrs and conductive foreign objects, for example, Patent Document 1 proposes an invention of a substrate in which the side end portion of the conductor pattern on the substrate surface is positioned away from the divided end surface. The invention of Patent Document 1 can be described as a state around the through hole when the wiring board assembly viewed from the bottom side shown in FIG. 3B is divided at the position AA ′. become that way. FIG. 6 is a perspective view with the divided surface at the position AA ′ shown in FIG. 6, and the conductor pattern formed on the lower surface of the wiring board assembly 9 as shown in FIG. If the grooves 7 are connected to each other, burrs are generated from the conductor when divided, which causes soldering defects and miswiring. Therefore, in the wiring board assembly of the invention disclosed in Patent Document 1, as shown in FIG. 6 (B), a shape in which a gap is provided between the side end of the conductor pattern on the board located on the split end face and the split position. It is said.

  In addition, the inner wall of the through-hole that becomes the castellation is coated with a conductive paste by through-hole printing. In this case, a mask for printing with an opening that is larger than the diameter of the through-hole is used. The conductor paste is also printed on the substrate surface. In Patent Document 2, it is assumed that the wraparound of the conductor paste around the through-holes causes deterioration of the partitionability, poor insulation, and short-circuit problems. An invention of a wiring board assembly in which conductor paste is not printed at the groove position is disclosed. According to this method, the conductor film can be eliminated at the dividing position of the end portion of the through hole on the upper surface of the substrate assembly, and the problem of burrs caused by dividing the conductor at this position is eliminated. The film is also divided in the vertical direction.

  Further, Patent Document 3 discloses an invention relating to a wiring board assembly and a wiring board obtained therefrom, in which the conductor films in the through holes connected to the conductor pattern on the surface of the board are separately insulated. Yes.

JP-A-10-313157 Japanese Patent Publication No. 7-67001 Japanese Patent Laid-Open No. 11-26639

  In the manufacture of such a ceramic package or wiring board, the present inventors have made various studies in order to eliminate the occurrence of defects due to burrs generated during assembly division or the inclusion of conductive foreign matter. The burrs and conductor foreign matter are produced by soft nickel plating or gold plating applied on the conductor film made by firing, which is deformed and separated at the time of division. It seemed that the side edge of the conductor pattern should be positioned away from the split end face. However, the effect of reducing burrs and foreign matters was not so great only by implementing such improvement of the substrate surface pattern shape.

  Upon further examination, as shown in FIG. 7, the burrs 18 and the conductive foreign matter are formed on the conductive film 17 around the end of the through-hole that wraps around the surface of the substrate attached during through-hole printing. It has been found that it is mainly generated from plating and gold plating, and in particular, it is likely to occur when dividing grooves are formed after printing a conductor pattern. This is because the conductor is deformed into the concave shape of the groove, so that the adhesion of the plating may be deteriorated, and more plating metal tends to adhere to the convex part at the time of plating. It has been found that this is also caused by the presence of more soft metal in the corners of the holes than in other parts. The generation of burrs due to division or separation of metal pieces is mostly caused by this.

  Therefore, as shown in Patent Document 2 or 3, the castellation was formed without printing the conductor film at the through hole division positions. For example, as shown in FIG. 8A, through-hole printing is performed on a portion of the through hole 6 where the dividing groove 7 is present as a printing mask 19 having a shape to which no conductor paste is applied. In this case, the shape of the conductor film in the through hole is a vertical band like the castellation 4 shown in FIG. 8 (B). There is no conductor plating, and the generation of burrs and foreign conductors can be suppressed.

  However, in the case of a ceramic package, the castellation requires not only an electrical connection but also a fixing function by solder. For example, as can be seen from the diagram schematically showing the cross-section of the castellation portion when the ceramic package of FIG. 4 is joined to a mother printed circuit board by soldering, the castellation 4 together with the terminal pads 8 on the bottom surface of the package wiring board. At the same time, the solder 16 is attached to form a meniscus so that the bonding of the mother printed circuit board 14 to the connection land 15 is further strengthened.

  However, when the shape of the conductor film of the castellation becomes narrow as seen in 4 of FIG. 8B, the solder wet area decreases, and sufficient strength for fixing cannot be secured. Also, in this case, the conductor patterns on the wiring board assembly are all electrically independent, but when performing electroplating on the conductor film, the same through-hole can be used to increase the plating efficiency. The adjacent conductor patterns are preferably connected to each other.

The gist of the present invention is as follows.
(1) A wiring board assembly for producing a ceramic package for storing electronic components having a castellation provided with a conductor film having a conductor film connected to a lower surface on a side wall, the caster A conductive film on the inner wall, the conductive film on the inner wall of the through hole is connected in the through hole, but is separated from the planned division position in the lower part of the through hole, and the through hole conductive film on the lower surface A ceramic package assembly characterized in that a conductor pattern that is connected to and serves as an external connection terminal is separated from a predetermined division position of the assembly.

  (2) The wiring board part consists of two or more layers, and the conductor film on the inner surface of the through-hole that becomes the castellation is on the entire inner wall surface in the upper layer, away from the planned division position in the lowermost layer, and the conductor pattern on the lower surface The ceramic package assembly according to the above (1), wherein the ceramic package assembly is separated from a predetermined dividing position or a dividing groove.

  (3) A ceramic package for storing electronic parts, wherein the ceramic wiring board assembly according to (1) or (2) is divided.

  In the production of a ceramic wiring board on which electronic components are mounted, when the wiring board assembly of the present invention is divided into individual wiring boards, the generation of burrs and conductive foreign matter is suppressed, and the electronic circuit It is effective for improving the quality. Furthermore, a substrate obtained from this assembly or a ceramic package using this substrate can obtain sufficient connection strength when connected and fixed to a mother printed circuit board or the like with solder.

  The wiring substrate assembly for a ceramic package of the present invention has a through-hole having a conductor film that becomes a castellation after division on the inner wall, and the end of the conductor pattern that becomes a terminal pad for external connection on the lower surface is a planned division position of the assembly The conductor film on the inner wall of the through hole connected to the connection terminal of the loaded electronic component or the like is separated from the scheduled division position on the lower surface and connected on the upper portion.

  The wiring substrate assembly of the ceramic package has, for example, a form as shown in FIG. 2B when viewed from the upper surface and as shown in FIG. 3B when viewed from the lower surface, and an electronic circuit is formed on the upper surface of the wiring substrate layer 9. There is a conductor pattern 3 for connecting the component elements, and the conductor pattern is connected to the conductor film 4 on the inner surface of the through hole, and this is connected to the conductor pattern 8 on the lower surface of the wiring board layer 9, that is, the external connection terminal pad. Yes. When this through hole 6 is divided into individual ceramic packages, a castellation 4 is formed to connect a conductor in the package and an external circuit.

The shape of the lower surface conductor pattern and the conductor film on the inner surface of the through-hole connected to the lower surface conductor pattern is as shown in FIG. That is, the end of the conductor pattern 8 on the lower surface is separated from the planned dividing position such as a dividing groove, and the conductor film 4 of the through hole connected to this conductor pattern is formed on the lower surface and the lower portion of the through hole (in FIG. In the upper part, the conductor film on the inner surface is integrated and connected above the through hole (lower part in FIG. 1). By using such a surface conductor pattern and the shape of the conductor film on the inner wall of the through hole, the generation of burrs and the occurrence of conductive foreign objects during division are suppressed.

  Furthermore, the conductive patterns around the through holes are connected to each other, for example, in FIG. 2 (B) or FIG. 3 (B), four or two conductive patterns are connected, thereby facilitating electrolytic plating. In addition, the area of the conductor film portion of the wiring board castellation is increased, and a sufficient fixing land can be provided when connecting and fixing to an external circuit board such as a mother printed circuit with solder.

  In order to form the conductor film on the inner surface of the through hole as shown in FIG. 1, the wiring board is preferably formed of two or more layers. In this case, the first layer 20 on the lower surface side (the upper surface side in FIG. 1) has a conductor on the inner surface of the through hole as a vertical belt as shown in FIG. 8, and the second layer 21 below the first layer 20 A through hole is provided at the same position as the layer, and the through hole has a conductor film printed on the entire inner surface. If the first layer and the second layer are overlapped to form a wiring board, there is no metal conductor at the dividing position on the lower surface of the through hole, the conductor pattern is connected in the through hole, and the caster formed The solder can have a solder land with a sufficient area.

  When the circuit of the wiring board portion has two or more layers, it can be easily formed into the desired shape of the conductor in the through-hole by the above method. In order to make the hole inner conductor, two layers are preferable. In addition, when the circuit of the wiring board has three or more layers, a through-hole is provided in the same position as the first layer and the second layer on the lowermost surface in the third and higher layers, and a conductor is attached to the entire inner wall. However, the conductor on the inner wall of the through hole in the third and higher layers may be omitted as long as the connection and fixing by solder can be sufficiently performed.

  As described above, the shape of the conductor pattern and the conductor in the through hole is such that the end portion of the conductor pattern on the lowermost surface is separated from the division position and no conductor exists at the division position in the lowermost portion near the lower surface of the castellation. The present invention can be applied not only to the lower surface but also to the upper surface.

  FIG. 9 illustrates a case where the lower surface of the package of the present invention is shown upward. When connecting the conductor on the upper surface of the frame to which the lid is bonded and the external connection terminal pad on the lower surface, vias 11 may be provided in the frame as shown on the left side of FIG. As shown as the conductor film 22 in the portion, the conductor in the through hole on the surface of the frame body may be connected by a castellation similar to the case of the lower surface.

FIG. 2 is a perspective view schematically showing a divided surface facing forward in order to show a lower surface conductor pattern and a conductor film shape of an inner wall of a through hole connected to the conductor pattern of a ceramic wiring board assembly according to an embodiment of the present invention. is there. It is the schematic diagram which looked at the ceramic wiring board aggregate | assembly and the wiring board for packages obtained by dividing | segmenting from it from the upper surface. It is the schematic diagram which looked at the ceramic wiring board aggregate | assembly and the wiring board for packages obtained by dividing | segmenting it from the lower surface. It is the figure which showed typically the cross section of the castellation part at the time of joining a ceramic package to a mother printed circuit board etc. with the solder. It is a figure which shows the manufacturing process of a ceramic wiring board. It is a figure explaining the state of the conductor film of the periphery of the through-hole used as the castellation of the ceramic package aggregate | assembly seen from the lower surface. It is a figure explaining generation | occurrence | production of the burr | flash when a wiring board aggregate | assembly is divided | segmented. It is a figure explaining through-hole printing which does not make a conductive paste adhere to a division position. It is the figure which looked at one example of the ceramic package of this invention from the lower surface side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ceramic package board | substrate part 2 Ceramic package frame part 3 Conductor pattern 4 Conductor film in castellation or through-hole 5 Frame body upper surface conductor film 6 Through-hole 7 Dividing groove 8 External connection terminal pad (lower surface conductor pattern)
DESCRIPTION OF SYMBOLS 9 Assembly wiring board layer 10 Assembly frame body layer 11 Via in frame 12 Electronic component element 13 Lid body 14 Mother printed circuit board 15 Circuit board connection land 16 Solder 17 Through-hole edge peripheral conductor film 18 Burr 19 Printing mask 20 First layer 21 for wiring board Second layer for wiring board 22 Conductor film for upper surface conductor connection

Claims (3)

  A wiring board assembly for producing a ceramic package for housing an electronic component having a castellation provided with a conductor film having an upper conductor portion connected to a lower side on a side wall, the conductor film serving as a castellation of a package after division The conductor film on the inner wall of the through hole is connected in the through hole, but is separated from the planned division position in the lower part of the through hole, and connected to the through hole conductor film on the lower surface. A ceramic package assembly characterized in that a conductor pattern serving as an external connection terminal is separated from a scheduled division position of the assembly.   The wiring board part consists of two or more layers, and the conductor film on the inner surface of the through-hole that becomes the castellation is on the entire inner wall surface in the upper layer, away from the planned division position in the lowermost layer, and the conductive pattern on the lower surface is the planned division position 2. The ceramic package assembly according to claim 1, wherein the ceramic package assembly is separated from the dividing groove. A ceramic package for storing electronic components, wherein the ceramic wiring board assembly according to claim 1 or 2 is divided.

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