JP5022322B2 - Inter-chip terminal connection method, circuit board manufactured using the same, and fire detector including the circuit board - Google Patents

Description

  According to the present invention, an optical element chip having at least one of a light receiving surface and a light emitting surface and an integrated circuit chip for an optical element that performs signal processing on the output of the optical element chip are mounted on the same substrate. The present invention relates to an inter-chip terminal connection method for electrically connecting the terminals of the circuit board, a circuit board manufactured using the same, and a fire detector including the circuit board.

Conventionally, in an electronic device module in which an optical element such as a smoke detector and an integrated circuit for an optical element are combined, a semiconductor chip is mounted on a lead frame or the like in either or both of the optical element and the integrated circuit for the optical element. Was assembled in a discrete state. FIG. 19 is a cross-sectional view of a circuit board manufactured by using a conventional interchip terminal connection method, in which a discrete optical element 101 and an optical element integrated circuit 102 are mounted on a single circuit board 100. For example, see Patent Document 1).
JP 2000-12773 A

  In the conventional interchip terminal connection method described above, since discrete components are used for the optical element 101 and the optical element integrated circuit 102, the wiring length L between the optical element 101 and the optical element integrated circuit 102 is reduced. It was long. In general, since the output impedance of the optical element 101 is high impedance, when the wiring length L between the optical element 101 and the optical element integrated circuit 102 is increased, noise is easily superimposed and noise resistance is deteriorated. There was a problem. Further, in order to ensure noise resistance, it is necessary to cover the entire periphery of the optical element 101 and the optical element integrated circuit 102 with the shield case 103. As a result, the entire circuit board becomes large and the material cost increases. was there.

The present invention has been made in view of the above problems, and its object is to improve the noise resistance and to reduce the size of the circuit board and to produce the inter-chip terminal connection method. It is an object of the present invention to provide a fire detector having a circuit board.
There was a thing (for example, refer to patent documents 1).

In the invention of claim 1, the optical device chip provided with the optical element light receiving and emitting unit having at least one of the light receiving surface or the light emitting surface, the output to the output signal or the optical device chip from said optical device chip a chip-terminal connecting method of electrically connecting the electrodes of the optical element for an integrated circuit chip for signal processing the at least one of the signals, the circuit board on which the optical element for an integrated circuit chip is mounted the wiring pattern of the relay is provided around the mounting position of the optical element for an integrated circuit chip, the circuit board opposite to the surface of the optical element for an integrated circuit chip, any of the light receiving surface or the light emitting surface or in a state toward the opposite side of the optical element for an integrated circuit chip, after the optical element chip is mounted and fixed, provided on the circuit board opposite to the surface of the optical element for an integrated circuit chip And poles, connected by wire bonding method and an electrode provided on the surface opposite to the optical element for an integrated circuit chip on the same of the wiring pattern, respectively, in the optical element chip, an integrated circuit chip for the light element, After sealing with a sealing material made of a black epoxy resin having a light shielding property so as not to narrow the directivity angle of the optical element chip, together with the integrated circuit chip for optical elements sealed with the sealing material, Either the light-receiving surface or the light-emitting surface of the optical element chip is sealed with a transparent sealing material having translucency for light from the infrared band to the visible light band .

According to a second aspect of the present invention, in the first aspect of the invention, the underfill resin for sealing the optical element integrated circuit chip is formed on at least a part of the outer periphery of the optical element integrated circuit chip. It is provided so as not to protrude outward from the end face.

The invention of claim 3 is the invention of claim 1 or 2, using an epoxy resin having a light-transmitting property with respect to light from an infrared band to a visible light band as a transparent sealing material having a light-transmitting It is characterized by that.

According to a fourth aspect of the present invention, there is provided a circuit board, which is manufactured using the inter-chip terminal connecting method according to any one of the first to third aspects.

The invention of claim 5 is a fire detector, a labyrinth wall barrier rib to prevent entrance of external light together with allowing the smoke from entering from the outside, emitting smoke chamber surrounded by the labyrinth wall a light emitting side of the optical member for light distribution of the light from the element, and the optical element chip which generates an electrical signal corresponding to the quantity of received light, which is scattered by the smoke which has entered into the smoke chamber from said light emitting element an optical member on the light receiving side for focusing light onto the optical element chip, the optical device chip detection circuit for detecting the occurrence of a fire from an output of the optical element chip includes a light device for an integrated circuit chip output signal processing of When the circuit component of the detection circuit including the optical element for an integrated circuit chip is mounted, and a circuit board which is manufactured using the inter-chip terminal connection method according to any one of claims 1 to 3 Tako The features.

According to the first aspect of the present invention, since the optical element chip is mounted and fixed on the surface of the integrated circuit chip for optical elements, the area required for chip mounting can be reduced, and the integrated circuit chip for optical elements and the optical element By connecting each electrode of the chip to the wiring pattern by wire bonding method, both electrodes are connected through the wiring pattern. Therefore, compared with the conventional inter-chip terminal connection method, the optical element chip and the optical element integration Since the electrodes of the circuit chip can be connected with a short distance, noise is less likely to be applied to the electric circuit connecting the optical element chip and the integrated circuit chip for the optical element, and the noise resistance is improved. . In addition, since the optical element integrated circuit chip is sealed with a black sealing material having a light shielding property so that the directivity angle of the optical element chip is not narrowed, the light hits the optical element integrated circuit chip and noise is generated. Can be prevented. Moreover, the black sealing material having light shielding properties is generally higher in viscosity and higher in thixotropy than the transparent sealing material having translucency, so that the range to be sealed is limited to a necessary range. As a result, the time required for applying the sealing material can be shortened and the productivity can be improved.

According to the invention of claim 2 , in addition to the effect of the invention of claim 1 , there is an effect that the circuit board can be miniaturized by reducing the band to be sealed.

The invention according to claim 3 is the epoxy resin according to claim 1 or 2 , wherein the transparent sealing material having translucency is translucent to light from the infrared band to the visible light band. The present invention has the same effect as the invention of claim 1 or claim 2 .

According to invention of Claim 4 , the small circuit board which improved noise resistance is realizable.

According to the invention of claim 5 , a fire detector with improved noise resistance can be realized.

  Hereinafter, an embodiment in which the inter-chip terminal connection method according to the present invention is applied to a circuit board included in a fire sensor will be described.

(Basic configuration)
First, the basic configuration of the fire detector will be described with reference to FIGS. FIG. 18 shows a circuit configuration of a fire detector. This fire detector is a combined type having both a smoke detection function for detecting smoke and a heat detection function for detecting heat, and a smoke detection chamber described later. A light emitting diode LED that irradiates S with infrared light, a photodiode PD that receives scattered light from the smoke that has entered the smoke sensing chamber S of infrared light irradiated from the light emitting diode LED, a light projecting / receiving circuit 50, A microcomputer (hereinafter referred to as a microcomputer) 60 and a transmission circuit 61 are included.

  The light emitting / receiving circuit 50 includes a light emission current control circuit 51 that controls a current flowing through the light emitting diode LED, and an I / V conversion circuit 52 that converts an output current of the photodiode PD into a voltage signal. The output voltage is amplified with a predetermined gain by the gain switching circuit 53, the voltage level is adjusted by the gain adjustment circuit 54, the offset voltage is further adjusted by the offset adjustment circuit 55, and then output to the microcomputer 60. The microcomputer 60 A / D converts the output of the light projecting / receiving circuit 50 and compares it with a preset threshold level. When the output of the light projecting / receiving circuit 50 exceeds the threshold level, the smoke density is increased. A notification signal indicating that the predetermined concentration has been reached is output to the transmission circuit 61, and the transmission circuit 61 transmits this notification signal to a fire receiver (not shown) by a multiplex transmission signal. The light projecting / receiving circuit 50 includes a sensitivity adjustment control circuit 56 that changes the output of the light emission current control circuit 51 in accordance with a test signal input from the microcomputer 60 and selectively switches the gain of the gain switching circuit 53. ing. Although not shown in FIG. 18, the output of the thermistor 6 is input to the microcomputer 60, and the ambient temperature is monitored from the output of the thermistor 6.

  Next, the structure of the fire detector will be described with reference to FIGS. As shown in FIGS. 7 to 9, the fire detector includes a body 1 attached to a construction surface such as a ceiling surface, a light emitting diode LED made of a printed circuit board, a chip-formed photodiode PD, and a smoke detection circuit described later. The smoke detection chamber S having a substantially circular horizontal cross section surrounded by a circuit board 2 on which the circuit components are mounted and a labyrinth wall 9 that allows intrusion of smoke from the outside and prevents the entrance of external light And an optical base on which the circuit board 2 is mounted on the upper surface with the light emitting diode LED and the photodiode PD facing the optical system components. The base 3 is composed of an insect repellent cover 4 for preventing insects and the like from entering the smoke sensing chamber S provided on the optical base 3, and a protective cover 5.

  The body 1 is formed by integrally forming a substantially disc-shaped main portion 1a and a side wall 1b protruding upward from the outer peripheral edge of the main portion 1a. A round hole 1c is formed at a substantially center of the lower surface of the main portion 1a. The optical base 3 to which the circuit board 2 is fixed and the protective cover 5 holding the insect-proof cover 4 are inserted and fixed in the round hole 1c.

  A light emitting diode LED and a thermistor 6 are mounted on the lower surface of the circuit board 2 with the light emitting surface and the heat sensing part protruding downward, respectively. Further, as shown in FIG. 5A, on the lower surface of the circuit board 2, a photodiode PD (optical element chip) formed as a chip and the above-mentioned I / V conversion circuit 52 and the like are integrated into a chip. A circuit chip IC1 is mounted in proximity. Electrodes are formed on the back surfaces of the photodiode PD and the optical element integrated circuit chip IC1 and are die-bonded to the conductor patterns 2a and 2a formed on the surface of the circuit board 2, respectively. Electrodes (not shown) are respectively formed on the upper surfaces of the photodiode PD and the optical element integrated circuit chip IC1, and a wire 80 made of a thin metal wire such as aluminum or gold is formed between the electrodes by a wire bonding method. Connected directly through. As described above, in this fire detector, the photodiode PD and the optical element integrated circuit chip IC1 which are chipped on the same circuit board 2 are die-bonded, and the electrode of the photodiode PD and the optical element for which the output current is very small. Since the electrodes of the integrated circuit chip IC1 are directly connected by wire bonding, the electrodes can be connected at a short distance compared to the conventional inter-chip terminal connection method, and thus the circuit board can be miniaturized. The noise is less likely to be applied to the bonding wire connecting the two electrodes, and the noise resistance is improved.

  Here, the wire bonding method is roughly classified into two methods, that is, an ultrasonic method and a thermocompression ultrasonic combined method. Needless to say, any method may be used for wire bonding. In this case, it is constructed using a jig (capillary) having a cylindrical shape with a through-hole through which the wire passes and having a conical shape at the tip. In the case of the ultrasonic method, an aluminum wire is mainly used, and in the case of the thermocompression ultrasonic method, a gold wire is mainly used.

  For example, when bonding is performed using a gold wire 80 having a diameter of about 20 μm by the thermocompression ultrasonic method, the first connection (also referred to as “first bonding”) is performed at the tip of the wire 80 with a minute diameter of about 60 μm. After forming the ball and bonding its tip by the thermocompression ultrasonic method, the capillary is moved to the position of the electrode to be connected next (also referred to as 2nd bonding), and the tip of the capillary is pressed against the electrode Then, bonding is performed by a thermocompression ultrasonic combined method. When connecting the electrode on the bare chip and the substrate or the lead frame with a bonding wire, the first bonding is generally performed on the electrode on the bare chip, and the 2nd bonding is mainly performed on the connection destination such as the substrate or the lead frame. In the case of this sensor, it may be first bonded to the electrode of the integrated circuit chip IC1 for optical elements as shown in FIG. 5A, or a photodiode as shown in FIG. 5B. The first bonding may be performed on the PD electrode.

  Further, as shown in FIG. 5C, in the case of bonding by an ultrasonic method using a wire 80 ′ made of an aluminum thin wire, the chip electrode and the electrode on the substrate side are the same, and the bonding is performed although the order of the processes is there. The device itself is not considered as 1st bonding or 2nd bonding. Therefore, in the ultrasonic method, there is no particular regulation regarding the connection method between the electrode of the photodiode PD and the electrode of the integrated circuit chip IC1 for optical elements, and any order in the process may be first.

  When the photodiode PD and the optical element integrated circuit chip IC1 are sealed with resin, if the photodiode PD and the optical element integrated circuit chip IC1 are sealed with different resins, the sealing resin is cured. There is a problem that a tensile stress is applied to the joint portion of the wire 80 due to a difference in thermal stress, but the photodiode PD and the optical element integrated circuit chip IC1 are sealed with one kind of resin having translucency. In this way, it is possible to prevent the thermal stress from being applied to the joint portion of the wire 80 and causing a problem.

  As shown in FIGS. 10 to 12, the optical base 3 is made of a black synthetic resin and has a substantially disc-shaped bottom plate 7, a square frame-like side wall 8 projecting from the top surface of the bottom plate 7, and a bottom plate 7 bottom surface. A labyrinth wall 9 composed of a plurality of partition walls 9a having a substantially square horizontal cross section disposed along the outer peripheral portion is integrally formed.

  The partition wall 9a constituting the labyrinth wall 9 is formed in black so that reflection does not occur, the direction in which the bent portion of the intermediate portion protrudes is the same direction as the adjacent partition wall 9a, and the partition portion where the bent portion of the intermediate portion is adjacent It is arranged at a predetermined interval so as to enter between both ends of 9a. The smoke introduction path formed between the adjacent partition walls 9a has one end communicating with the outside to become a smoke introduction port, the other end communicating with the smoke sensing chamber S, and bending the middle part of the smoke introduction path, External light is less likely to enter the smoke sensing chamber S.

  In the recess 10 surrounded by the bottom plate 7 and the side wall 8 of the optical base 3, the surface on which the light emitting diode LED, photodiode PD, optical element integrated circuit chip IC1 and thermistor 6 are mounted is the bottom plate 7 side. The circuit board 2 is delivered. The base plate 7 of the optical base 3 is provided with projecting portions 19 and 20 projecting downward at portions corresponding to the light emitting diodes LED and the photodiode PD, respectively. Through holes 11 a and 11 b penetrating through 7 are formed. Grooves 19a and 20a are formed in the respective protrusions 19 and 20 so as to be continuous with the through holes 11a and 11b and extend toward the center of the optical base 3, and light is emitted in these grooves 19a and 20a. Prism lenses 12 and 13 as optical members on the side and the light receiving side are attached. Here, the prism lenses 12 and 13 are attached to the optical base 3 with one surface facing the through holes 11a and 11b and the other surface directed toward the center of the smoke sensing chamber S. The upper side and the left and right sides of 13 are covered with the projecting parts 19 and 20. That is, the prism lenses 12 and 13 are arranged such that the optical axes L1 and L2 face the center direction of the smoke sensing chamber S and intersect at a predetermined angle as shown in FIG.

  As described above, the prism lenses 12 and 13 face the light emitting surface of the light emitting diode LED and the light receiving surface of the photodiode PD, respectively, and the light emitted from the light emitting diode LED is condensed by the prism lens 12 and irradiated to the smoke sensing chamber S. Is done. When smoke enters the smoke sensing chamber S, the light irradiated from the prism lens 12 is scattered by the smoke particles and enters the prism lens 13. Since the light incident on the prism lens 13 is condensed on the light receiving surface of the photodiode PD by the prism lens 13, the intrusion of smoke can be detected from the increase in the output of the photodiode PD. Since the prism lenses 12 and 13 are arranged so that the optical axes L1 and L2 intersect at a predetermined angle, the light of the light emitting diode LED irradiated from the prism lens 12 is directly incident on the prism lens 13. There is nothing.

  Incidentally, since the output current from the photodiode PD is very small and weak against external noise such as electrostatic noise, it is necessary to shield the photodiode PD from such external noise. Therefore, in this sensor, a box-shaped shield cover 14 having an opening on one surface is insert-molded at the site of the optical base 3 facing the photodiode PD, and when the circuit board 2 is placed in the recess 10, A shield cover 14 covers the photodiode PD and the smoke detection circuit mounted on the circuit board 2 so as to electrostatically shield the photodiode PD and the smoke detection circuit. The shield cover 14 is provided with a ground pin 14a that protrudes toward the circuit board 2. The ground pin 14a is inserted into a through hole provided in the circuit board 2 and is connected to a ground line (not shown) of the circuit board 2. Soldered. The shield cover 14 is formed with a communication hole 14b that communicates with the through hole 11b, and the light collected by the prism lens 13 through the communication hole 14b is applied to the light receiving surface of the photodiode PD. .

  In addition, four terminal pins 15 are insert-molded in the optical base 3, and each terminal pin 15 is inserted into a through hole (not shown) provided in the circuit board 2 and soldered. Each terminal pin 15 is electrically connected to the wiring pattern of the circuit board 2, and the tip portion of each terminal pin 15 protruding from the circuit board 2 to the opposite side serves as an external connection terminal. Further, the circuit board 2 is held on the optical base 3 by soldering the terminal pins 15 insert-molded on the optical base 3 to the circuit board 2.

  Here, the manufacturing process of the optical base 3 will be briefly described with reference to FIGS. First, as shown in FIG. 13, a hoop material 40 formed in a strip shape with a metal material is punched, and the hatched portion in FIG. 13 is bent to the heel side of the paper, and shown in FIGS. 14 (a) and 14 (b). Thus, the shield cover 14 is formed in a box shape, and the terminal pins 15 are projected in a direction substantially orthogonal to the plane direction of the hoop material 40. After that, as shown in FIGS. 15 (a) and 15 (b), the base part composed of the bottom plate 7 and the side wall 8 is insert-molded (primary molding) in the hoop material 40, and the labyrinth as shown in FIGS. 16 (a) and 16 (b). After the wall 9 is secondarily formed, the frame portion is cut to form a shape as shown in FIGS. Needless to say, the base portion composed of the bottom plate 7 and the side wall 8 and the labyrinth wall 9 may be insert-molded on the hoop material 40 at a time.

  Thus, since the shield cover 14 and the terminal pin 15 and the optical base 3 are integrated by simultaneous molding (insert molding), the number of parts can be reduced and the workability of the assembly work can be improved. . In addition, the optical base 3 and the labyrinth wall 9 are integrated to improve the assembly workability by reducing the number of parts, and the positioning accuracy between the labyrinth wall 9 and the optical base 3 is increased, so that stray light can be prevented. Occurrence can be suppressed. Moreover, since the shield cover 14 and the terminal pin 15 are formed by punching one sheet metal and bending it, the process of processing the shield cover 14 and the terminal pin 15 can be easily automated. Manufacturing cost can be reduced.

  Moreover, the insect-proof cover 4 is formed in bottomed cylindrical shape with the synthetic resin which has insulation, as shown in FIGS. The bottom plate 4a of the insect-proof cover 4 communicates with an insertion hole 11c provided in the optical base 3, and is formed with a through hole 4d through which the thermistor 6 mounted on the circuit board 2 is inserted, and the peripheral wall 4b has a plurality of holes. The mesh part 4c which is opened in a lattice shape is formed. The insect cover 4 is attached to the optical base 3 with the lower end portion of the optical base 3 inserted into the cylinder, and the labyrinth wall 9 is covered with a peripheral wall 4b on which a mesh portion 4c is formed. Thus, foreign matter such as insects can be prevented from entering the smoke sensing chamber S surrounded by the labyrinth wall 9. Further, as shown in FIG. 9, the bottom plate 4 a of the insect-proof cover 4 is directed upward (on the side of the optical base 3) to a portion facing the protrusions 19 and 20 provided on the bottom plate 7 of the optical base 3. Lids 21 and 22 that protrude and fit into grooves 19a and 20a provided in the protrusions 19 and 20 are integrally formed. Thus, when the insect base cover 4 is put on the optical base 3, the lid portions 21 and 22 provided on the insect base cover 4 are fitted into the grooves 19a and 20a provided on the optical base 3, respectively, and the emission of the prism lens 12 is performed. Since the surface and the incident surface of the prism lens 13 are surrounded by the projecting portions 19 and 20 and the lid portions 21 and 22, it can be optically sealed, so that extra light such as external light enters. Can be prevented from malfunctioning.

  Further, the protective cover 5 is formed of a synthetic resin in a bottomed cylindrical shape, and an engaging claw 16 that protrudes outwardly protrudes from the upper end portion of the peripheral wall 5a, and in the circumferential direction in a substantially lower half of the peripheral wall 5a. A plurality of strip-shaped openings 17 extending along the bottom surface 5b, projecting upward from the bottom plate 5b, and projecting a plurality of ribs 18 whose tips are in contact with the bottom plate 4a of the insect-proof cover 4. In the assembled state of the fire detector, the thermistor 6 protrudes downward from the through hole 4 d of the insect-proof cover 4, and the tip of the thermistor 6 is disposed between the bottom plate 4 a of the insect-proof cover 4 and the bottom plate 5 b of the protective cover 5. The The plurality of ribs 18 are arranged radially about the thermistor 6 and rectify the air flow so that the air flowing into the inside from the opening 5 c hits the heat sensitive part of the thermistor 6.

  When assembling this fire detector, circuit components such as a light emitting diode LED, a photodiode PD, an optical element integrated circuit chip IC1, a thermistor 6 and a smoke detection circuit are first mounted on the circuit board 2, and the circuit board 2 is mounted on the optical substrate. The ground pin 14 a and the terminal pin 15 of the shield cover 14 are soldered to the circuit board 2 by being inserted into the recess 10 of the base 3, and the circuit board 2 is fixed to the optical base 3. Next, after inserting the insect-proof cover 4 and the optical base 3 to which the circuit board 2 is attached into the cylinder of the protective cover 5 and holding the insect-proof cover 4 and the optical base 3 on the protective cover 5, When the upper end portion of the protective cover 5 is inserted into the round hole 1c of the body 1, the engaging claw 16 protruding from the upper end portion of the protective cover 5 and the engaging step portion 1d formed on the inner peripheral surface of the round hole 1c. Are engaged with each other, and the protective cover 5 is coupled to the body 1.

  By the way, as shown in FIG. 6A, the optical element integrated circuit chip IC1 is made of a light-blocking substantially black sealing material (hereinafter referred to as a light-blocking sealing agent) 71 so as not to disturb the directivity angle of the photodiode PD. After sealing, the light-receiving surface of the photodiode PD together with the optical element integrated circuit chip IC1 after sealing is a substantially transparent sealing material having translucency with respect to light from the infrared band to the visible light band (hereinafter, referred to as a sealing material). It is also preferable to seal with 72). In addition, since structures other than the light-shielding sealant 71 and the translucent resin 72 are the same as those of the above-described fire detector, the same components are denoted by the same reference numerals, and description thereof is omitted.

  Here, as the light-shielding sealant 71, an epoxy resin usually used for sealing a semiconductor bare chip may be used. For example, a thermosetting liquid epoxy resin (model number CV5181D manufactured by Matsushita Electric Works Co., Ltd.) is used. Yes. In addition, in order to reduce the mounting area determined by the range of resin sealing, it is preferable to use a resin with high viscosity and high thixotropy, so the viscosity and thixotropy are adjusted by fillers typified by silica in the resin. is doing.

  Moreover, as the translucent resin 72, an epoxy resin that is usually used for sealing a semiconductor bare chip may be used. For example, a thermosetting epoxy resin (model number CV5130A manufactured by Matsushita Electric Works Co., Ltd.) is used. This epoxy resin has translucency with respect to light in the infrared band to the visible light band, and is a two-component type composed of a main agent and a curing agent.

  The procedure for resin sealing will be briefly described below. First, a substantially black light-blocking sealant 71 is applied around the integrated circuit chip IC1 for optical elements. Here, since the light-shielding sealant 71 is a resin having a high viscosity and a high thixotropy, it is possible to seal only a minimum range of a connection portion between the electrode of the integrated circuit chip IC1 for optical elements and the wire 80. it can. This is to improve productivity in a liquid resin coating method called a resin extrusion (dispensing method) by air pressure with a small coating amount per unit time. In addition, once formed into a solid, and then heated to make it temporarily liquid, then use a well-known sealing agent of a type that is cured again, and after protecting with a mask except for the part to be sealed The whole substrate is heated, and this substrate is placed in an airtight container with an open top, and a sealing resin is placed on the opening while the air is being stirred in the airtight container. A method of adhering a resin only to a necessary part by melting and adhering a resin in the form of heat, or a method of sealing only a necessary part by transfer molding using a mold as shown in FIG. 6B It may be sealed with.

  As described above, the substantially black light-shielding sealant 71 is applied around the integrated circuit chip IC1 for optical elements, heated and cured, and then the substantially transparent sealant 72 is used to include the optical element chip. By covering the chip and the input / output terminals of the integrated circuit chip for the optical element, the exposed portion of the wiring pattern on the substrate corresponding thereto, and the bonding wire described above, it does not interfere with the directivity angle of the optical element chip. The optical element chip and the bonding wire can be protected. The dark black light-blocking sealant 71 may be applied so as to be exposed from the substantially transparent sealant 72.

(Reference Example 1)
Reference Example 1 of the present invention will be described with reference to FIGS. In the basic configuration described above, the photodiode PD and the optical element integrated circuit chip IC1 are mounted face-up on the circuit board 2. In this reference example, the photodiode PD and the optical element integrated circuit chip IC1 are mounted. It is mounted on the circuit board 2 in a face-down state. In addition, since it is the same as that of the fire detector of basic composition except the mounting method of photodiode PD and integrated circuit chip | tip IC1 for optical elements, the same code | symbol is attached | subjected to the same component and the description is abbreviate | omitted.

  In this reference example, the circuit board 2 is provided with a through hole 2c that penetrates the circuit board 2 in the thickness direction, and the photodiode PD is arranged so that the light receiving surface of the photodiode PD faces the through hole 2c. Bump 73 provided on the electrode on the same surface as that of the surface is flip-chip bonded to a substrate-side electrode (not shown) formed on the circuit board 2, thereby electrically connecting the electrode of the photodiode PD and the circuit board 2. Connect. As shown in FIG. 2B, the photodiode PD has electrodes formed at four corners of the same surface as the light receiving surface, and bumps 73 are formed on each electrode. In this state, the parallelism with respect to the circuit board 2 can be ensured.

  Bumps 74 are also formed on the mounting surface of the integrated circuit chip IC1 for optical elements, and the bumps 74 are flip-chip bonded to substrate-side electrodes (not shown) formed on the circuit board 2, thereby providing an optical element. The electrode of the integrated circuit chip IC1 and the circuit board 2 are electrically connected. Here, the wiring pattern 2a for electrically connecting the photodiode PD and the optical element integrated circuit chip IC1 is the shortest distance between the electrode of the photodiode PD and the electrode of the optical element integrated circuit chip IC1. Patterned to connect.

  In addition, light is prevented from being inserted into the light receiving surface through the gap between the circuit board 2 and the photodiode PD on which flip chip mounting is performed, and the bonding strength between the bumps 73 and 74 and the substrate side electrode is maintained and reliable. In order to improve the performance, underfill resin 75 is injected into the gap between the flip-chip mounted photodiode PD and the optical element integrated circuit chip IC1 and the circuit board 2 and cured. As shown in FIG. 2 (c), a photodiode PD and an optical element integrated circuit in which an underfill resin 75 is applied to the upper surface of the circuit board 2 before flip chip mounting and thereafter bumps 73 and 74 are formed, respectively. The chip IC1 may be pressed against the circuit board 2 and the resin may be heat-cured in a state where the chip IC1 is in contact with the board-side electrode (pre-coating method).

  Here, since it is necessary for light to enter the optical element, a transparent resin is used as the underfill resin for protecting the light receiving surface or light emitting surface of the optical element, and a dark black light shielding resin is applied from the outside. Then, the incidence of light from the outside may be blocked. Further, it is applied to the flip chip portion of the optical element integrated circuit chip IC1 mounted adjacent to the photodiode PD, and a photo is covered with a part of the dark black light shielding resin for sealing the optical element integrated circuit chip IC1. A sealant that seals the outside of the transparent sealant of the diode PD may also be used. The resin that covers the bump and the connection terminal on the circuit board 2 side in the above configuration may be a substantially black light shielding resin or a transparent resin.

(Reference Example 2)
In Reference Example 1 described above, a liquid underfill resin 75 is applied to the surface of the circuit board 2, and the photodiode PD and the optical element integrated circuit chip IC 1 are pressed against the circuit board 2 to come into contact with the electrodes of the circuit board 2. In this state, the resin is sealed with a film type underfill resin 76 as shown in FIGS. 3A and 3B. In the case of a film type, the underfill resin 76 is formed in a predetermined shape in advance, so that the sealing band can be limited to the minimum band. In FIGS. The integrated circuit chip IC1 is formed in a shape that covers substantially the entire lower surface of the integrated circuit chip IC1 and only the bonding portion of the photodiode PD. In addition, since it is the same as that of the reference example 1 except the underfill resin 76, the same code | symbol is attached | subjected to the same component and the description is abbreviate | omitted.

  Here, the film type underfill resin 76 is an insulating resin or an anisotropic conductive resin, and the film type underfill resin 76 is placed on the wiring pattern 2a of the circuit board 2 as shown in FIG. The bumps 73, 74, 74, 74, 74, 74 are formed by aligning the photodiode PD and the optical element integrated circuit chip IC 1 on which the bumps 73, 74 are formed with the wiring pattern 2 a of the circuit board 2, and applying pressure and heating. 74 and the substrate side electrode are joined.

  When the underfill resin 76 is an insulating resin, the film-like underfill resin 76 is softened by heating, and further, the photodiode PD and the optical element integrated circuit chip IC1 are pressed against the circuit board 2 to thereby provide the photodiode. Bumps 73 and 74 provided on the PD and the optical element integrated circuit chip IC1 penetrate the underfill resin 76, reach the wiring pattern 2a on the circuit board 2, and make electrical contact therewith. When the film-like underfill resin 76 is cured in this state, the underfill resin 76 is cured and contracted at room temperature, so that the electrical connection between the bumps 73 and 74 and the electrodes of the circuit board 2 is maintained. Can be secured.

  Further, when the underfill resin 76 is an anisotropic conductive resin, the conductive particles are dispersed in the insulating resin. Therefore, the photodiode PD and the optical element integrated circuit are formed with the underfill resin 76 softened by heating. By pressing the circuit chip IC1 against the circuit board 2, the bumps 73 and 74 formed on the photodiode PD and the optical element integrated circuit chip IC1 pass through the film-like underfill resin 76 and come into contact with the electrodes of the circuit board 2. Alternatively, it is electrically connected to the electrode of the circuit board 2 through the conductive particles, thereby conducting with the electrode of the circuit board 2. When the film-like underfill resin 76 is cured in this state, the electrical connection between the bumps 73 and 74 and the electrodes of the circuit board 2 is caused by the conduction through the conductive particles and the curing and shrinkage of the underfill resin 76. It is maintained and conduction can be secured.

  By the way, in this reference example, as shown in FIG. 3 (c), a substantially transparent sealing agent 77 having translucency from the infrared band to the visible light band is filled in the through hole 2 c formed in the circuit board 2. Thus, the light receiving surface of the photodiode PD may be sealed to protect the light receiving surface of the photodiode PD. In this case, it is desirable that a hole (for example, a square hole) that exposes the light receiving surface of the photodiode PD is formed in the underfill resin 76 to form a frame, and the underfill resin 76 causes the sealant 77 to flow out. Can be prevented.

(Reference Example 3)
Reference Example 3 of the present invention will be described with reference to FIG. In the reference example 1 described above, the photodiode PD and the optical element integrated circuit chip IC1 are flip-chip mounted on the upper surface of the circuit board 2, whereas in the present reference example, the optical element integrated circuit is mounted on the circuit board 2. The chip IC1 is fixed in an embedded state, the photodiode PD is flip-chip mounted on the circuit board 2, and the bumps 73 of the photodiode PD are directly connected to the electrodes of the integrated circuit chip IC1 for optical elements. In addition, since it is the same as that of the reference example 1 except the mounting method of integrated circuit chip IC1 for optical elements, the same code | symbol is attached | subjected to the same component and the description is abbreviate | omitted.

  In this reference example, a through hole 2c is formed through the circuit board 2, and a recess 2d for fixing the integrated circuit chip IC1 for optical elements in an embedded state is formed in advance adjacent to the through hole 2c. . Then, the integrated circuit chip IC1 for optical elements is embedded in the recess 2d, and fixed with, for example, an adhesive 78 so that the upper surface on which the connection terminal with the photodiode PD is formed is substantially flush with the surface of the circuit board 2. To do. Thereafter, the bump 73 provided on the photodiode PD is electrically connected to the wiring pattern 2a on the circuit board 2 and the electrode (not shown) of the integrated circuit chip IC1 for optical elements by flip chip bonding. Although not shown in FIG. 3, in order to protect the photodiode PD and the flip chip mounting portion of the optical element integrated circuit chip IC1 and the light receiving surface of the photodiode PD, the same method as in Reference Example 1 is used. An underfill resin 75 may be applied.

(Embodiment)
An embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the photodiode PD is die-bonded on the upper surface of the optical element integrated circuit chip IC1 mounted face-up on the circuit board 2 with the light receiving surface facing upward, and the upper surface of the optical element integrated circuit chip IC1. The electrode formed on the electrode PD and the electrode formed on the upper surface of the photodiode PD are connected to the wiring pattern 2a of the circuit board 2 by wire bonding. In addition, since it is the same as that of a basic structure except the mounting method of photodiode PD and integrated circuit chip IC1 for optical elements, the same code | symbol is attached | subjected to the same component and the description is abbreviate | omitted.

  Here, when the photodiode PD is die-bonded to the upper surface of the optical element integrated circuit chip IC1, the die-bonding is performed so as to cover a circuit portion where it is necessary to avoid the incidence of light. However, since it is necessary to connect the electrode formed on the upper surface of the integrated circuit chip IC1 for optical elements and the electrode of the circuit board 2 by wire bonding, the circuit area may be covered when the photodiode PD is die-bonded. However, it is necessary not to enter the bonding area in the vicinity.

  Then, the electrode of the integrated circuit chip IC1 for optical elements and the electrode of the photodiode PD are connected to the wiring pattern 2a of the circuit board 2 by wire bonding, and the bonding portion is sealed so as not to cover the light receiving surface of the photodiode PD. After sealing with the agent 71, a translucent sealant 72 is applied so as to cover the light receiving surface of the photodiode PD. At this time, in order to prevent the translucent sealing agent 72 applied to the light receiving surface of the photodiode PD from flowing out, a frame that protrudes above the upper surface of the photodiode and surrounds the photodiode PD is formed. A light blocking sealant 71 may be applied. In the present embodiment, the electrodes of the optical element integrated circuit chip IC1 and the photodiode PD are connected to the wiring pattern 2a of the circuit board 2 by wire bonding, and both electrodes are connected via the wiring pattern 2a. The electrode of the integrated circuit chip IC1 for optical elements and the electrode of the photodiode PD may be directly connected by a wire bonding method.

  In the present embodiment, the photodiode PD and the optical element integrated circuit chip IC1 are die-bonded while being superposed on the circuit board 2 in a face-up state. However, as shown in FIG. The semiconductor integrated circuit chip IC1 is die-bonded in a face-down state, the photodiode PD is die-bonded on the upper surface of the optical element integrated circuit chip IC1, and the electrode of the photodiode PD and the wiring pattern 2a of the circuit board 2 are bonded. And the electrodes of the integrated circuit chip IC1 for optical elements and the photodiode PD may be electrically connected via the wiring pattern 2a. Here, the integrated circuit chip IC1 for optical elements is flip-chip mounted on the upper surface of the circuit board 2, and the substrate electrodes and the bumps 74 of the integrated circuit chip IC1 for optical elements are electrically connected. An underfill resin 75 is applied to the surface of the film to protect it from the external environment and light incidence. The photodiode PD is die-bonded to the back surface (upper surface) of the optical element integrated circuit chip IC1 with the light receiving surface facing upward, and the chip electrode and the wiring pattern 2a of the circuit board 2 are connected by a wire bonding method. Thereafter, the photodiode PD and the substrate-side electrode are covered with a light-transmitting sealant 72 so as to cover the photodiode PD and the substrate side electrode.

  When sealing the integrated circuit chip IC1 for optical elements, it may be sealed with a film type underfill resin 76 as shown in FIG. By forming it in a predetermined shape in advance, it is possible to prevent the underfill resin 76 from protruding outside the integrated circuit chip IC1 for optical elements, and between the chip electrode and the substrate electrode of the photodiode PD. When wire bonding is performed, the underfill resin 76 for sealing the integrated circuit chip IC1 for optical elements does not get in the way, and the electrodes on the circuit board 2 side can be arranged closer to each other.

In the above-described embodiment, the photodiode PD having the light receiving surface and the optical element integrated circuit chip IC1 for processing the output of the photodiode PD are described as an example, but the optical element chip is described. Is not limited to a light receiving element such as a photodiode PD, but may be a light emitting element such as an LED chip having a light emitting surface.
Also, an optical element chip including an optical element light emitting / receiving unit having at least one of a light receiving surface and a light emitting surface, and at least one of an output signal from the optical element chip or an output signal to the optical element chip An optical device integrated circuit chip for signal processing of either one is mounted close to the same circuit board, and an inter-chip terminal connection method for electrically connecting electrodes of both chips, the integrated circuit for optical devices An electrode is provided on the surface opposite to the mounting surface of the chip, with either the light receiving surface or the light emitting surface facing away from the optical element integrated circuit chip at a predetermined position on the surface of the optical element integrated circuit chip. It is also preferable that after the optical element chip is mounted and fixed, the electrode of the optical element chip and the electrode of the integrated circuit chip for optical element are directly connected by a wire bonding method. As a result, since the optical element chip is mounted and fixed on the surface of the optical element integrated circuit chip, the area required for chip mounting can be reduced, and the electrodes of the optical element integrated circuit chip, the electrodes of the optical element chip, Can be connected at a short distance between the electrodes of the optical element chip and the integrated circuit chip for the optical element, compared to the conventional inter-chip terminal connection method. Noise is less likely to be applied to the electric circuit connecting the integrated circuit chip for optical elements, and noise resistance is improved.

(A)-(c) is sectional drawing of the circuit board explaining the inter-chip terminal connection method of this embodiment. (A) is sectional drawing of the circuit board produced by the interchip terminal connection method of the reference example 1, (b) is a bottom view of an optical element chip, (c) (d) is sectional drawing explaining a manufacturing process. (A)-(c) is sectional drawing of the circuit board explaining the inter-chip terminal connection method of the reference example 2. FIG. It is sectional drawing of the circuit board explaining the inter-chip terminal connection method of the reference example 3. FIG. (A)-(c) is sectional drawing of the circuit board explaining the reference example of the inter-chip terminal connection method. (A) (b) is sectional drawing of the circuit board explaining the other reference example of the inter-chip terminal connection method. It is sectional drawing of the state before assembling the fire detector which comprises the circuit board produced using the same chip connection method same as the above. It is an exploded perspective view same as the above. It is sectional drawing same as the above. The optical base same as the above is shown, (a) is a plan view, and (b) is a cross-sectional view along A-A ′. It is a reverse view of an optical base same as the above. FIG. 11 is an enlarged view of a C part in FIG. 10, showing the optical base same as above. It is explanatory drawing explaining the manufacturing process of an optical base same as the above. (A) (b) is explanatory drawing explaining another manufacturing process of the optical base same as the above. (A) (b) is explanatory drawing explaining another manufacturing process of the optical base same as the above. (A) (b) is explanatory drawing explaining another manufacturing process of the optical base same as the above. (A) (b) is explanatory drawing explaining another manufacturing process of the optical base same as the above. It is a circuit block diagram same as the above. It is sectional drawing of the circuit board produced using the conventional interchip terminal connection method.

Explanation of symbols

2 circuit board 2a wiring pattern 80 wire PD photodiode IC1 integrated circuit chip for optical elements

Claims (5)

And the optical element chip provided with the optical element light receiving and emitting unit having at least one of the light receiving surface or the light emitting surface, at least one of the output signals or output signal to the optical device chip from said optical device chip An inter-chip terminal connection method for electrically connecting electrodes with an integrated circuit chip for an optical element that processes one of the signals,
A circuit board on which the optical element integrated circuit chip is mounted is provided with a relay wiring pattern around the mounting position of the optical element integrated circuit chip,
The optical element chip is mounted on the surface of the integrated circuit chip for optical elements opposite to the circuit board with either the light receiving surface or the light emitting surface facing the opposite side of the integrated circuit chip for optical elements. After fixing,
The electrode provided on the surface opposite to the circuit board in the integrated circuit chip for optical elements and the electrode provided on the surface opposite to the integrated circuit chip for optical elements in the optical element chip are the same. Connect to the wiring pattern by wire bonding method ,
After sealing the integrated circuit chip for optical elements with a sealing material made of a black epoxy resin having a light shielding property so as not to narrow the directivity angle of the optical element chip,
The optical element integrated circuit chip sealed with the sealing material and the light receiving surface or the light emitting surface of the optical element chip are transparent with respect to light from the infrared band to the visible light band. A method for connecting terminals between chips, which is sealed with a sealing material . The underfill resin for sealing the IC chip for optical elements, at least part of the outer periphery of the optical element for an integrated circuit chip, provided from the end face of the optical element for an integrated circuit chip so as not protrude outwardly The inter-chip terminal connection method according to claim 1. 3. The inter-chip terminal connection according to claim 1 , wherein an epoxy resin having translucency with respect to light from an infrared band to a visible light band is used as the transparent sealing material having translucency. Method. A circuit board manufactured using the inter-chip terminal connection method according to claim 1. A labyrinth wall in which a partition wall is formed that allows intrusion of smoke from outside and prevents external light from entering, and a light emitting side optical member that distributes light from the light emitting element to a smoke sensing chamber surrounded by the labyrinth wall And an optical element chip that generates an electrical signal corresponding to the amount of received light, and a light receiving side that condenses the light from the light emitting element scattered by the smoke that has entered the smoke sensing chamber onto the optical element chip. An optical member, an optical element integrated circuit chip that performs signal processing on the output of the optical element chip, a detection circuit that detects the occurrence of a fire from the output of the optical element chip, and the detection that includes the optical element integrated circuit chip A fire sensor, comprising: a circuit board on which circuit components of a circuit are mounted; and a circuit board manufactured by using the inter-chip terminal connection method according to any one of claims 1 to 3.

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