JP2007035779A - Leadless hollow package and manufacturing method thereof - Google Patents

Abstract

An inexpensive leadless hollow package that encloses a light receiving element and / or a light receiving / emitting element without using an expensive mold and a method for manufacturing the same.
An individual package corresponding to an IC chip is not manufactured in advance, and a collective substrate is manufactured by a known printed wiring board manufacturing technique. A plurality of IC chips are mounted thereon, and then a viscous adhesive is applied so as to surround the IC chips to form “dams”. Next, a glass plate having substantially the same dimensions as the wiring board is placed on the dam, cured, and then the glass plate, the adhesive, and the substrate are cut at the same time so that each IC chip is sealed. Get the package. As a result, an IC chip is mounted.
Efficiency can be improved because the wiring process can be concentrated. Furthermore, an expensive metal mold is not required, and it can be easily and inexpensively adapted to the production of various types.
[Selection] Figure 1

Description

  The present invention relates to a package for a semiconductor light emitting / receiving element.

  A solid-state imaging device used for a digital camera, a video camera, and the like is formed by forming a light receiving element on a surface of a silicon single crystal thin plate (hereinafter referred to as a silicon wafer) by a known semiconductor process, and then soldering it to a printed wiring board. Enclosing in a package for this purpose.

  This package must have characteristics such as transmitting light from the imaging lens to the light receiving element without loss, protecting the semiconductor from moisture in the air, corrosive gas, etc., and withstanding the heat of soldering. I must. Therefore, it is common to provide a translucent cover such as glass on the light incident surface of the package. Here, when a microlens for improving the light collection efficiency is formed on the surface of the light receiving element, it is advantageous to form an air layer between the translucent cover and the microlens. That is, since the microlens is generally made of a resin having a refractive index of about 1.5 to 1.6, if a resin having an equivalent refractive index is filled, the light condensing power is impaired.

  Since the package body is required to have airtightness, heat resistance and the like as described above, a composite material of an epoxy resin or a ceramic and a metal terminal is widely used.

  The above example is shown in FIG.

  Reference numeral 1 denotes an IC chip obtained by cutting a silicon wafer, on which a light receiving element 1a, a microlens 1b, an electrode 1c, and the like are formed by a known semiconductor process technology.

  The IC chip 1 is bonded to the package 3 using an adhesive 4. The fine metal wire (wire) 2 electrically connects the IC electrode 1c and the surface 7a of the terminal 7 provided on the package by a known wire bonding technique.

  The glass 5 that is a translucent cover is hermetically bonded to the package 3 by an adhesive 6.

In order to connect such a solid-state imaging device to the printed wiring board 10, it is common to solder the terminal 7b of the package and the wiring pattern 10a.
JP-A-7-307408 JP-A-8-107161

  The package technology described above has been widely used, but is reaching its limit in the face of demand for lower costs.

  The package 3 and the terminal 7 are produced by injecting an epoxy resin or a ceramic material into a mold (not shown) and curing it. Although the molding operation can be performed relatively efficiently, the mold is generally expensive. Further, since the bonding operation of the IC chip and the glass plate has to be performed one by one, the improvement of the processing efficiency has been hindered.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is an inexpensive leadless hollow package that encloses a light receiving element and / or a light receiving / emitting element without using an expensive mold and a method for manufacturing the same. Is to provide.

  In order to achieve the above object, according to the present invention, an individual package corresponding to an IC chip is not manufactured in advance, and a collective substrate is manufactured by a known printed wiring board manufacturing technique. A plurality of IC chips are mounted thereon, and then a viscous adhesive is applied so as to surround the IC chips to form “dams”.

Next, a glass plate having substantially the same dimensions as the wiring board is placed on the dam, cured, and then the glass plate, the adhesive, and the substrate are cut at the same time so that each IC chip is sealed. Get the package. As a result, an IC chip is mounted.
Efficiency can be improved because the wiring process can be concentrated. Furthermore, an expensive metal mold is not required, and it can be easily and inexpensively adapted to the production of various types.

  ADVANTAGE OF THE INVENTION According to this invention, an inexpensive hollow package which encloses a light receiving element and / or a light receiving / emitting element without using an expensive metal mold | die can be provided.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
FIG. 1 is a cross-sectional view showing the steps of Embodiment 1 of the present invention, and FIG. 2 is a perspective view thereof. In FIGS. 1 and 2, the light receiving element 1a, the microlens 1b, the electrode 1c, and the adhesive 4 shown in FIG. 6 are omitted for convenience.

  FIGS. 1a) and 2a) are printed wiring boards (hereinafter referred to as substrates) provided with through-holes in a grid or row. This is used for the known COB (Chip On Board) mounting, and the material is based on BT (bismaleimide / triazine) or polyimide made by Mitsubishi Gas Chemical Co., Ltd., which is superior in heat resistance in addition to glass epoxy. A flexible printed board (FPC) may be used. A plurality of through holes 107 are provided in the substrate 103, and virtual center lines 108a connecting the center lines 108 are arranged in a lattice shape or a row shape.

  Electrodes 107a and 107b that are electrically connected through a through hole 107 are provided on the front surface 103a and the back surface 103b of the substrate 103. These are formed by patterning a copper foil attached to the substrate 103 by a photolithography technique. Those subjected to surface treatment are generally used. Note that this surface treatment is performed by gold plating so as to be suitable for wire bonding or soldering, more preferably, nickel plating is applied on the copper foil, and electrolytic gold plating is further applied.

  Next, as shown in FIGS. 1b) and 2b), a plurality of IC chips are assembled on a substrate using a known COB technique. That is, the IC chip 1 is bonded to the substrate surface 103a, and then the IC chip electrode 1c and the substrate electrode 107a are connected by the wire 2 by a known wire bonding technique. In general, a thin gold wire having a diameter of about 0.03 mm is used for this wire.

  In FIGS. 1 c) and 2 c), a viscous adhesive 106 is applied with a dispenser 300 at the position of the virtual center line 108 a of the through hole 107 to form a “dam”. The adhesive 106 is suitably one having a viscosity of 100 Pa · s (Pascal · second) or more at normal temperature and being cured by ultraviolet rays and / or heat. Furthermore, it is necessary not to allow moisture permeation after curing and to be insulating. As satisfying these requirements, for example, XV6841 (trade name: viscosity is about 800 Pa · s) manufactured by NAMICS Co., Ltd. is desirable. Since the above adhesive is viscous, it does not leak immediately to the back side even if it is applied from above the through hole.

  As a known technique for applying a sealing resin to a printed circuit board provided with a through hole and preventing the resin from leaking to the back surface, for example, JP-A-7-307408 (Patent Document 1), As disclosed in JP-A-8-107161 (Patent Document 2) and the like, a metal that can be soldered is filled in the through-hole hole, or a film is sometimes attached to the surface of the hole.

  However, this has the disadvantage that the manufacturing process of the printed circuit board becomes complicated and the price increases.

  In addition, Japanese Patent Application Laid-Open No. 8-107161 (Patent Document 2) also discloses a technique in which a silicone rubber plate or the like is adhered or adhered to the back surface of the substrate. In this process, the sealing resin is dried and cured. This rubber cannot be separated from the substrate until it is finished. Not only is the process complicated, but when siloxy acid generated from silicone rubber adheres to the electrode portion of the substrate, there is a possibility that a defect may occur in solderability after the package is completed.

  In order to avoid the above inconvenience, as shown in FIGS. 1 and 2d), when the ultraviolet ray 200 is irradiated from the back surface 103b side during and / or after the application of the adhesive, only the adhesive 106 immediately above the through hole 107 is cured. Thus, a lid can be formed and filling the through hole 107 can be prevented.

  The thickness of the dam needs to be larger than the maximum height of the wire 2. Since the thickness of the IC chip 1 is usually around 0.7 mm and the loop of the wire 2 is further about 0.2 mm, at least 1 mm is necessary. If the required thickness cannot be obtained at one time, it may be applied in several times.

  The glass plate 104 shown in FIGS. 1 and 2f) is placed on the substrate 103 on which the dam has been applied as shown in FIGS. 1 and 2d), and then the ultraviolet ray 201 is irradiated to cure the adhesive 106. If necessary, it can be further cured by heating.

  Although the process is slightly complicated, as shown in FIG. 1 e), an adhesive 106 may be applied to the opposing surfaces of the substrate 103 and the glass plate 104 and bonded together.

  In place of the glass plate 104, a crystal plate, a plastic plate, an infrared absorbing glass plate, an optical low-pass filter obtained by laminating and bonding them, or a plate on which an optical element such as a hologram element or a diffraction grating is formed may be used. it can.

  Finally, as shown in FIGS. 1 and 2g), the glass plate 104, the adhesive 106, and the substrate 103 are simultaneously cut using a cutting grindstone (not shown) thinner than the inner diameter of the through hole 107 to complete individual packages. By cutting along the virtual center line 108a, the inner surface of the through hole 107 plated with gold is exposed to the package end surface and can be used as a soldering terminal.

  Through the above-described steps, a hollow package with air above the IC chip can be efficiently produced.

<Embodiment 2>
FIG. 3 shows a second embodiment.

  When the glass plate 104 is placed, the ultraviolet curable adhesive 106 cannot enter the irradiated surface by irradiating the ultraviolet rays 201 through the mask 203. Thereby, the micro lens 1b can be selectively made hollow.

<Embodiment 3>
FIG. 4 shows a third embodiment of the present invention.

  In the case of using the ultraviolet / thermal curing type for the adhesive 106, the above-described mask 03 can be printed in advance on the front or back surface of the glass plate 04 (104a in FIG. 4). In this case, the adhesive 106 is finally cured by heating.

<Embodiment 4>
FIG. 5 shows a fourth embodiment of the present invention.

  In addition to the IC chip 1 in which a light receiving element is formed in one package, a light emitting element 109 such as an LED is also enclosed, so that a photo interrupter, an optical encoder element, and the like can be manufactured. At this time, it is effective to provide a light shielding dam 110 between the light receiving element and the light emitting element.

  That is, a part of the light 210 emitted from the light emitting element 109 is reflected by, for example, the encoder scale 211 and reaches the light receiving element, but the provision of the light shielding dam 110 prevents other unnecessary light from reaching the light receiving element. can do.

It is sectional drawing which shows the process example of Embodiment 1 of this invention. FIG. 2 is a perspective view corresponding to FIG. 1. It is sectional drawing which shows Embodiment 2 of this invention. It is sectional drawing which shows Embodiment 3 of this invention. It is sectional drawing which shows Embodiment 4 of this invention. It is sectional drawing of the conventional hollow package.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 IC chip 2 Wire 3 Package 4 Adhesive 5,104 Cover glass 6 Adhesive 103 Substrate 106 Viscose adhesive 107 Through hole 108 Center line of through hole 109 Light emitting element 110 Light shielding dam 200, 201 Ultraviolet ray 203 Mask 210 Light 211 Encoder Scale 300 dispenser

Claims (8)

A package containing at least one IC chip having a photoelectric conversion function,
A substrate having a plurality of electrodes in the periphery, a translucent cover having the same projection shape as the substrate, a space between the substrate and the translucent cover, and the photoelectric conversion portion of the IC chip and the translucency A leadless hollow package comprising an adhesive that does not fill between covers.   The leadless hollow package according to claim 1, wherein the electrode is formed by cutting a through hole.   The leadless hollow package according to claim 1, wherein the outer peripheral side surface of the adhesive is formed to have the same projection size as that of the substrate and the translucent cover.   The leadless hollow package according to claim 1, wherein the translucent cover is a glass plate, a crystal plate, an infrared cut filter, a hologram element, a diffraction grating, and / or a laminated plate obtained by bonding them.   A plurality of IC chips having a photoelectric conversion function are mounted on a substrate in which a plurality of through holes are arranged in a straight line or a lattice pattern, and a viscous insulating adhesive is applied on the through holes. A method for manufacturing a leadless hollow package, comprising: mounting a translucent cover having a size; and curing the adhesive, and cutting and dividing the adhesive along a center line connecting the centers of the through holes.   6. The method for producing a leadless hollow package according to claim 5, wherein the ultraviolet curable viscous adhesive applied on the through hole is irradiated with ultraviolet rays from below through the through hole to be partially cured.   6. The method of manufacturing a leadless hollow package according to claim 5, wherein when the translucent cover is mounted, ultraviolet rays are irradiated locally on the upper part of the IC chip.   The method for producing a leadless hollow package according to claim 6 or 7, wherein the viscosity of the adhesive is approximately 100 Pa · s (Pascal · second) or more.

Images