JP4455352B2 - Manufacturing method of substrate for electronic device - Google Patents

Description

This invention relates to a semiconductor acceleration sensor or a plurality of IC chips, a method of manufacturing a substrate for an electronic device, such as other modules with electronic components.

  Conventionally, when making a sensor element such as a pressure sensor or an acceleration sensor, a glass substrate that is stably bonded to silicon is used as the sensor element substrate. In order to extract a signal from the sensor element, electrical wiring from the inside of the sensor to the outside is required. As this wiring method, as shown in Patent Document 1, there is an electronic element substrate having a structure in which wiring is provided in the thickness direction of the substrate. The electronic element substrate is formed by laminating a semiconductor thin plate such as silicon having a predetermined electrode shape on an insulating substrate such as a glass plate, and from the side opposite to the laminated surface of the semiconductor thin plate of the substrate, A plurality of through holes reaching the semiconductor thin plate are formed in the substrate. And the back surface electrode which touches the inside of the said through-hole and the said semiconductor thin plate is formed in the back surface side of the said board | substrate with the metal thin film. In this method for manufacturing an electronic device substrate, a plurality of through holes are formed by sandblasting or the like so that the semiconductor thin plate is exposed in the thickness direction of the substrate from the opposite side of the laminated surface of the semiconductor thin plates, and then the transparent substrate is formed. The back electrode in contact with the exposed semiconductor thin plate in the hole is formed of an aluminum metal thin film or the like.

Moreover, as shown in Patent Document 2, a conductor pattern such as an electrode or wiring is formed on the surface of a glass insulating substrate, and a lead electrode connected to the conductor pattern is provided on the surface, and silicon is formed on the surface of the insulating substrate. Also proposed is a sensor body joined by the above.
JP 2003-152162 A JP 2004-309306 A

  In the former case of the above prior art, the metal thin film may be cracked at the boundary between the glass substrate and the through-hole, which may cause poor connection and the like, and a higher electrical connection reliability is required. It was. Further, in the latter case of the above conventional technique, since the lead electrode is formed on the surface of the glass substrate, in an electronic element that requires airtightness, it is necessary to fill the gap between the joint portion with the silicon body, There were problems such as complicated manufacturing processes.

The present invention, said been made in view of the problems of the prior art, it is possible to obtain a conductive in the thickness direction of the substrate by a simple process, electrical reliability high manufacturing method of an electronic device substrate The purpose is to provide.

  According to the present invention, a bottomed hole having a bottom having a small diameter is formed by sandblasting at a predetermined position on a surface on one side of an insulating substrate, and the substrate surface on the side where the hole is formed and Forming a metal thin film on the inner surface of the hole, and then forming a hole to the extent that the metal thin film is exposed by sandblasting from the surface opposite to the side of the substrate on which the hole is formed; A substantially drum-shaped through-hole is formed in the substrate, the through-hole is partitioned by the metal thin film at a small-diameter portion of the through-hole, and other than the opening portions of the hole on both surfaces of the substrate are covered with a protective film, In this method of manufacturing an electronic device substrate, the inside of a through hole is filled with a plating metal such as copper, and then the protective film is removed.

  The plating metal grows plating in the through hole from both sides of the metal thin film in the through hole formed in the substrate.

  In removing the protective film, the metal thin film is left in a predetermined pattern shape to form a conductor pattern on the substrate surface.

  According to the present invention, electrical conduction between the front and back sides of the substrate can be ensured, and the conductor formed of the plated metal is filled in the substantially drum-shaped through-hole, so that it does not come out and has high electrical reliability. In addition, since the through holes are formed by sandblasting, the material of the substrate is not selected, the application range is wide, and it is possible to flexibly cope with design changes such as pattern changes. Furthermore, it is possible to easily provide a surface mountable substrate. This greatly contributes to downsizing of electronic devices and improvement of mounting density.

  Hereinafter, an electronic device substrate according to an embodiment of the present invention will be described with reference to FIGS. The substrate 10 for an electronic element of this embodiment has an insulating substrate 11 at a predetermined electrode drawing position of the insulating substrate 11 such as a Pyrex (registered trademark) glass or a glass plate that is an adjustment glass whose linear expansion coefficient is close to that of silicon. A through-hole 12 formed in the thickness direction is formed. The through-hole 12 is formed in a drum shape, and a metal thin film 14 is provided in a truncated cone shape on the inner surface on one side of the small diameter portion of the drum shape. The metal thin film 14 is made of a metal such as Cr, Ni, Au, etc., by a vacuum thin film forming technique such as vapor deposition or sputtering. Further, the inside of the through hole 12 is filled with copper plating 16 in the inside of the truncated conical metal thin film 14 and the truncated cone portion on the opposite side of the through hole 12. The metal thin film 14 and the copper plating 16 in the through hole 12 are connected to a conductor pattern 18 such as an electrode or a wiring formed by the metal thin film 14 formed on the surface of the insulating substrate 11.

  As shown in FIG. 2 (a), the manufacturing method of the electronic device substrate 10 of this embodiment is as follows. First, as shown in FIG. 2 (b), an insulating substrate 11 which is a glass plate having an appropriate thickness is used. A frustoconical hole 12a for the through hole 12 is formed by sandblasting. The hole 12a is stopped substantially at the center so as not to penetrate the insulating substrate 11. Thereafter, as shown in FIG. 2C, a metal thin film 14 made of Cr, Ni, Au or the like is provided on the surface of the insulating substrate 11 on the side where the holes 12a are formed and the inner surface of the holes 12a by vapor deposition or sputtering. . Then, as shown in FIG. 2D, a photosensitive plating-resistant protective film 20 is applied to the surface side of the metal thin film 14 of the insulating substrate 11.

  Next, as shown in FIG. 2 (e), a truncated cone-shaped hole 12 b for the through hole 12 is formed by sandblasting at a position corresponding to the hole 12 a on the opposite surface of the insulating substrate 11. The hole 12b has substantially the same shape as the hole 12a. The bottom of the hole 12b is formed so as to reach the metal thin film 14 at the bottom of the hole 12a, and the metal thin film 14 is exposed in the hole 12b. A plating-resistant protective film 20 is applied to the entire surface of the insulating substrate 11 on the side where the holes 12b are formed.

  Next, as shown in FIG. 3 (a), a photomask (not shown) is applied, the portion where the through holes 12 are formed is exposed with ultraviolet rays, developed, and the exposed portion of the plating-resistant protective film 20 is removed. To do. For the exposure, the hole 12a is exposed to a diameter that is approximately equal to or slightly larger than the diameter of the opening of the hole 12a, and the hole 12b is exposed to a diameter that is larger than the opening. Try to remove it. Then, as shown in FIG. 3 (b), the holes 12 a and 12 b of the through hole 12 are filled with copper plating 16. At this time, the metal thin film 14 is connected to the negative electrode side, and the copper plating 16 is grown using the metal thin film 14 as a plating base. Also on the hole 12b side of the through hole 12, the copper thin film 16 grows based on the metal thin film 14 exposed at the small diameter portion, and fills the hole 12b.

  Next, the plating-resistant protective film 20 is again exposed to ultraviolet rays to remove it as shown in FIG. At this time, exposure is performed by leaving a portion corresponding to the conductor pattern 18 such as an electrode and wiring by a predetermined photomask, and the metal thin film 14 of the portion is left. Then, as shown in FIG. 3D, the unnecessary metal thin film 14 and copper plating 16 on the insulating substrate 11 are removed by etching. Further, the shape is adjusted by adjusting the etching time so that the copper plating 16 does not protrude greatly from the surface of the insulating substrate 11. Thereafter, as shown in FIG. 3E, the plating-resistant protective film 20 on the conductor pattern 18 such as electrodes and wiring is removed, and the surface is washed to form the electronic element substrate 10.

  As an electronic element using the electronic element substrate 10 of this embodiment, for example, there is a semiconductor acceleration sensor. Hereinafter, the acceleration sensor 22 using the electronic element substrate 10 will be described. As shown in FIG. 1, the semiconductor acceleration sensor is provided with a sensor body 21 formed by etching silicon on a substrate 10 for electronic elements. The sensor body 21 includes a rectangular frame portion 24, a weight portion 26 provided at an inner central portion thereof, and integrally extends from four corners of the frame portion 24 and is integrally connected to the weight portion 26. It consists of a held beam portion 28 and a thin plate-like electrode portion 29 extending symmetrically from the weight portion 26 in all directions. The frame portion 24 is joined to the peripheral portion of the electronic element substrate 10 in an airtight state by anodic bonding or the like. Further, on the front and back surfaces of the electronic element substrate 10, electrodes connected to the copper plating 16 of the through holes 12, electrodes that form capacitance with the electrode portion 29 of the semiconductor acceleration sensor 22, and other circuit boards A conductive pattern 18 such as an electrode to be connected is formed by the metal thin film 14. A glass plate 32 is bonded to the surface side of the frame portion 24.

  In the manufacturing method of the acceleration sensor 22 of this embodiment, the silicon substrate forming the sensor body 21 is etched, and the weight portion 26, the beam portion 28, and the electrode portion 29 are integrally formed. Next, the sensor body 21, the glass plate 32, and the electronic element substrate 10 are joined. As a bonding method, anodic bonding (about 400 ° C.), Au brazing, high-temperature solder, or a method of tight bonding using low-melting glass is appropriately selected. The inside of the acceleration sensor 22 can be evacuated by performing this joining operation in a vacuum state.

  The electronic element substrate 10 of the present invention and the acceleration sensor 22 which is an electronic element using the substrate 10 can easily and reliably perform hermetic sealing in the sensor, have a simple manufacturing process, and reduce manufacturing costs. be able to. In addition, the electronic device mounted on the surface by using the electronic device substrate 10 can easily keep the inside of the electronic device in an airtight state, can be less affected by thermal distortion, and the like. Can be improved.

  The electronic device substrate of the present invention is not limited to the above embodiment, and the plating growth in the through holes may be performed separately on the front and back surfaces of the substrate. Moreover, a metal thin film may be formed in the through-holes from both the front and back sides of the substrate, and in that case, a conductor pattern made of the metal thin film may be formed on both surfaces of the substrate. Moreover, in order to form a through-hole, processing / formation by sandblasting is the most realistic means from the viewpoint of production efficiency, but it goes without saying that processing / formation by a drill or the like is also possible.

  Furthermore, the electronic device substrate of the present invention can be used particularly effectively for electronic devices that need to maintain an airtight state, such as a gyro sensor and a pressure sensor other than an acceleration sensor. As the insulating substrate, silicon, ceramics, or the like may be used depending on the application in addition to the glass-based material. Moreover, you may comprise a back surface electrode with conductors other than a metal thin film.

It is a perspective view which shows the semiconductor acceleration sensor using the board | substrate for electronic devices of one Embodiment of this invention. It is a longitudinal cross-sectional view which shows a part of schematic manufacturing process of the board | substrate for electronic devices of one Embodiment of this invention. It is a longitudinal cross-sectional view which shows the next general manufacturing process of the board | substrate for electronic devices of one Embodiment of this invention.

DESCRIPTION OF SYMBOLS 10 Substrate for electronic devices 11 Insulating substrate 12 Through-hole 12a, 12b Hole 14 Metal thin film 16 Copper plating 18 Conductive pattern 20 Plating-resistant protective film 22 Acceleration sensor

Claims (3)

  A bottomed hole with a bottom having a small diameter is formed by sandblasting at a predetermined position on the surface on one side of the insulating substrate, and a metal is formed on the substrate surface on the side where the hole is formed and on the inner surface of the hole. After forming a thin film, a hole is formed in the substrate surface from the surface opposite to the side where the hole is formed by sandblasting to the extent that the metal thin film is exposed, and the substrate is substantially A drum-shaped through-hole is formed, and the through-hole is partitioned by the metal thin film at the small-diameter portion of the through-hole, and the openings other than the openings of the holes on both sides of the substrate are covered with a protective film, and the inside of the through-hole is formed A method for producing a substrate for an electronic device, comprising filling with a plating metal and thereafter removing the protective film.   The method for manufacturing a substrate for an electronic device according to claim 1, wherein plating is grown in the through-hole from both sides of the metal thin film in the through-hole formed in the substrate.   2. The method of manufacturing a substrate for an electronic device according to claim 1, wherein when the protective film is removed, the conductive pattern on the surface of the substrate is formed while leaving the metal thin film in a predetermined pattern shape.

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