KR20090121193A - Method of manufacturing circuit substrate - Google Patents

Abstract

PURPOSE: A method of manufacturing a circuit substrate is provided to detect a defect such as exfoliation and broken of a resistor layer or a defect in a pin hole by pressing the circuit board and measuring a pressure change. CONSTITUTION: A method of manufacturing a circuit substrate is comprised of the steps: arranging a plurality of mounting areas for a circuit device on a circuit board(1); forming a through hole electrode around the mounting areas; covering at least one end of the through hole electrode(16) with a resist layer; pressuring the circuit board and measuring a pressure change; and detecting exfoliation and broken of a resistor layer or a defect in a pin hole which is continued from the through hole electrode.

Description

Method of manufacturing a circuit board {METHOD OF MANUFACTURING CIRCUIT SUBSTRATE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a circuit board, and in particular, a plurality of circuit element placement regions are formed on a circuit board, a plurality of through hole electrodes are formed around each circuit element placement region, and one end of the through hole electrode is formed. To the circuit board, and pressurizes the circuit board to measure the pressure change, examines whether there is a pinhole or the like in the resist layer continuous to the through-hole electrode, and then attaches the protective resin layer to the circuit board. It is about a method.

In recent years, as a manufacturing method of a circuit board, the material-saving manufacturing method which has integrated circuit elements, such as many semiconductor elements, closely mold | disconnects, and dices and divides them into a protective resin has become the mainstream.

As a test method of such a circuit board, the method by visual inspection is common, The method of detecting defects, such as a pinhole and a burr, on the board | substrate, visually seeing the pattern shape of a board | substrate through a magnifying glass, or illuminating a light source to the whole board | substrate, or pinhole. The method of detecting a defect with or without the light leaking out from the defect part of this etc. is mainly performed.

There is also an optical pattern inspection method for inspecting the presence or absence of a defect while matching a pattern of a good product registered in advance.

Patent Document 1 discloses a foreign material and a defect inspection device that irradiate light onto a substrate to detect foreign matter, defects (pinholes), and the like on the substrate. The foreign material and defect inspection apparatus includes a light source for irradiating incident light having an optical axis tilted with respect to a substrate, an objective lens for collecting reflected light from the substrate, a pinhole disposed at a position optically conjugated with a reflection point on the substrate surface, and the pinhole. The optical detection element which detects the reflected light which passed, and the mechanism which scans incident light or moves a board | substrate to the X-axis direction which is the direction which inclined the optical axis with respect to the normal line of a board | substrate. The incident light from the light source is irradiated onto the substrate while moving in the X-axis direction, and the reflected light reflected by the foreign matter or defect present on the substrate is detected by the optical detection element to detect the foreign matter or the defect.

[Patent Document 1] Japanese Patent Application Laid-Open No. 2005-300395

However, in the inspection method of the circuit board in the conventional manufacturing method of the circuit board, inspection omission occurs because it is a human inspection by visual observation. In addition, there is a problem that the work time increases due to the miniaturization and complexity of the inspection target, and the work efficiency decreases.

In addition, in the optical pattern inspection method, the above-mentioned problem can be solved, but it is necessary to register a pattern of good products in advance, and there is a problem that the labor of pre-processing increases as the kind of inspection object increases.

In addition, since the foreign material and defect inspection apparatus moves while irradiating the substrate and detects and recognizes the reflected light caused by the foreign matter or defect, there is a problem that the reflected light cannot be detected in the case of a minute pinhole that does not reflect light. .

And since the defect of a circuit board is not detected reliably, when putting a protective resin layer incorporating a circuit element, a protective resin flows in to the back electrode side of a circuit apparatus, adheres to a back electrode, it cannot connect and can not be soldered It was causing a defect.

In particular, with the miniaturization of circuit elements, the number of elements to be mounted on a circuit board has increased dramatically, and a method capable of reliably inspecting the quality of a circuit board in a short time regardless of the size of the circuit board to be inspected is desired. It was.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a plurality of circuit element placing regions are arranged on a circuit board, a plurality of through hole electrodes are formed around the circuit element placing region, and at least one end of the through hole electrodes is resisted. Covering the layer, pressurizing the circuit board to measure the change in pressure, detecting the presence of defects such as peeling, cracking, or pinhole continuous to the through hole electrode of the resist layer, the circuit without the defect This is solved by embedding a circuit element in a substrate, attaching a protective resin layer covering the circuit element, and preventing the protective resin from flowing into the through hole electrode from the resist layer.

In the present invention, when measuring the change in the pressure, the upper and lower surfaces of the circuit board are sandwiched to form an airtight chamber, and the air pressurized from the upper side of the airtight chamber is kept for a certain time, and the upper and lower sides of the airtight chamber are It is characterized by measuring the differential pressure on the lower side.

Moreover, in this invention, it is determined by the good goods that the leak pressure from the upper side of the said airtight chamber to the lower side of the said airtight chamber is 5 kPa or less.

In the present invention, a light receiving element is used as the circuit element, and a transparent epoxy resin is used as the protective resin layer.

According to the present invention, a resist continuous to the through-hole electrode by covering at least one end of the plurality of through-hole electrodes around the circuit element placement region formed on the circuit board with a resist layer and pressing the circuit board to measure the change in pressure. It is possible to detect whether the layer is flawed, cracked, or has a defect such as a pinhole. Thereby, the presence or absence of a defect of a circuit board can be reliably examined in a short time, and since the protective resin layer which coat | covers a circuit element is affixed only after a circuit element is built in only a circuit board with no defect, it is possible to carry out the defect of a resist layer. It is possible to prevent the protective resin layer from flowing into the hall electrode.

In addition, even a minute pinhole of 10 µm or less that could not be detected by the method of inspecting the pinhole by the reflection of light can be easily detected, and the process of matching the optical pattern inspection method is unnecessary, so the pattern needs to be registered in advance. There is an advantage that the labor of work is reduced.

In addition, the measurement of the change of pressure forms the airtight chamber by clamping the upper surface and the lower surface of a circuit board, and sends the pressurized air from the upper side of the airtight chamber, and measures the differential pressure of the upper side and the lower side of the airtight chamber after hold | maintaining for a fixed time. Thereby, the presence or absence of the defect of the resist layer adhering on the many through-hole electrodes can be checked in an instant, and the goodness of the circuit board which provided the several circuit element mounting area can be reliably examined by one measurement. There is an advantage.

Moreover, the board | substrate whose leak pressure from the upper side of an airtight chamber to the lower side of an airtight chamber is 5 kPa or less can be judged as good products. As a result, even the smallest defects of 10 μm or less formed on the circuit board are reliably detected, so that in the process of attaching the protective resin layer covering the circuit element, the protective resin layer flows into the through-hole electrode and adheres to the external electrode to prevent defects. It can be prevented beforehand.

Moreover, in the manufacturing method of this invention, a light receiving element is used as a circuit element, and a transparent epoxy resin can be used as a protective resin layer. As a result, in the conventional manufacturing method, no defects such as pinholes are found and no transparent epoxy resin introduced from the defect portion at the time of coating cannot be found. By using the manufacturing method, it is possible to manufacture light-receiving elements using only good-quality circuit boards, and there is no fear of inflow from defects even when a transparent epoxy resin having good translucency is used for the protective resin layer, so only good-quality light-receiving elements are provided. can do.

EMBODIMENT OF THE INVENTION Below, embodiment of this invention is described with reference to FIGS.

First, the circuit board by the manufacturing method of this invention is shown to FIG. 1 and FIG. FIG. 1 is a top view thereof, FIG. 2A is a partially enlarged view of the surface, and FIG. 2B is a partially enlarged view of the back surface.

The circuit board 1 of the present embodiment includes an insulating substrate 10, a conductive pattern 13, a bonding pad 14, a circuit element placing region 15, a through hole electrode 16, and a resist. It consists of the layer 18 and the protective resin layer 20.

The insulated substrate 10 is a substrate which consists of FR4 (epoxide fabric glass cloth), BT (bismaleimide triazine) resin, a glass epoxy substrate, a glass polyimide substrate, etc. In this embodiment, the board | substrate which consists of BT resin is used as an example. The thickness of the insulating substrate 10 is, for example, about 0.5 mm.

The first conductive foil 11 and the second conductive foil 12 are pressed and bonded to both surfaces of the insulating substrate 10 by an adhesive. As the 1st conductive foil 11 and the 2nd conductive foil 12, what is necessary is just a metal which can be etched. In this embodiment, the metal foil which consists of copper was employ | adopted. These constitute part of the wiring.

That is, as these film thicknesses, the thickness required as wiring is selected. The thickness of the wiring can be arbitrarily determined by the current capacity of the circuit element to be mounted. The film thickness of the 1st conductive foil 11 and the 2nd conductive foil 12 is equivalent, for example, it is selected in the range of 9 micrometers-35 micrometers, and is 18 micrometers here.

The conductive pattern 13 is formed by etching the first conductive foil 11 and the second conductive foil 12 into a predetermined shape, and forms a circuit element placing region 15 in the center thereof. Bonding pads 14 are formed close to each side so as to surround 15, and wiring paths 13a are formed to extend from the bonding pads 14 to the through-hole electrodes 16 described later.

The through-hole electrodes 16 are arranged in the periphery of the individual circuit device 21 including the circuit element placement region 15 arranged in a plurality of matrix shapes on the insulating substrate 10. The through hole electrode 16 is formed to form a through hole in the insulating substrate 10 and through-hole plate its inner surface to connect the first conductive foil 11 and the second conductive foil 12 to each other. Constitutes an external electrode. In addition, as shown in the figure, the individual circuit device 21 refers to the inner side surrounded by the through-hole electrode 16 including the circuit element mounting region 15.

The resist layer 18 is attached to cover the top of the through hole electrode 16 and has a role of preventing the inflow of resin or the like into the through hole electrode. As the resist layer 18, a dry film resistor is used.

On the circuit element mounting region 15, circuit elements 19 such as light receiving elements are fixed, and a plurality of circuit elements 19 are arranged at predetermined positions on the insulating substrate 10.

The protective resin layer 20 is attached to the whole insulated substrate 10 in order to protect the circuit element 19 and the bonding wire. In addition, when forming a light receiving element, as the protective resin layer 20, transparent epoxy resin etc. are used so that light may pass.

Next, the pattern of a mounting board is demonstrated.

As the circuit board 1 shown in FIG. 1, the glass epoxy substrate 10 of 150 mm x 100 mm is used specifically. A plurality of alignment holes 2 are formed in the periphery, and a plurality of individual circuit devices are arranged in a matrix form inside.

In this embodiment, as an example, the individual circuit devices 21 are arranged in a matrix form of 13 rows x 12 columns. Thus, in one circuit board 1,

12 × 13 = 156

Can take individual circuit devices. In addition, the through-hole electrodes 16 are arranged in seven vertically and eight horizontally with respect to one individual circuit device. Thereby, in the row direction of one circuit board 1

(7 × 12) × (13 rows + 1)) = 1,176

Through-hole electrodes 16 are arranged, and in the column direction

(8 × 13) × (12 rows + 1)) = 1,352

Through-hole electrodes 16 are arranged, and a total of 2,528 through-hole electrodes are arranged. In addition, in FIG. 1, the number is simplified rather than the actual number.

Next, the enlarged view of the surface of the circuit board 1 is shown to FIG. 2 (A). The size of each individual circuit device 21 is very small, for example, 8 mm x 6 mm. The through hole electrode 16 is shared with each adjacent individual circuit device 21.

The bonding pad 14 surrounds each side of the circuit element placing region 15 in close proximity and is formed wider than the wiring path 13a.

The conductive pattern 13 consists of the bonding pad 14 and the wiring path 13a extended by bending from the bonding pad 14 to the through-hole electrode 16.

Although the circuit element mounting area 15 is designed suitably according to the circuit element 19 to be mounted, it is formed in 3.5 mm x 3.5 mm, for example.

The through hole electrode 16 is formed surrounding the periphery of the individual circuit device including the circuit element placing region 15. The through hole electrode 16 is formed to a diameter of 0.5 mm by a router or the like.

The resist layer 18 surrounds the circuit element placing region 15 and is bonded to the through hole electrode 16. The first conductive foil 11 and the second conductive foil 12 are covered with a resist layer 18, and the first conductive foil 11 is exposed and developed with the pattern shown in FIG. Etching is performed using the layer as a mask. For example, the width of the resist layer 18 is 1.5 mm and the thickness is 55 탆. In addition, when fine dust etc. exist in an exposure surface at the time of exposure image development, it becomes a cause of a pinhole. In the case of the pinhole of 10 micrometers or less, since even light does not pass, the conventional inspection method could not find a pinhole and missed the defect.

2B is an enlarged view of the back surface of the circuit board 1. The insulating substrate 10 is exposed, leaving a part of the conductive pattern 13 serving as the through hole electrode 16 and the back electrode connected to the through hole electrode.

Next, with reference to FIG. 3, the test method of the circuit board used for the manufacturing method of the circuit board of this invention is demonstrated.

3 is a cross-sectional view of a tester for inspecting a circuit board of the present invention.

The tester 30 constitutes an airtight chamber 33 with the upper case 31 and the lower case 32, sandwiches the circuit board 1 between the two, and seals the airtight with the gasket 34 provided to face the two. Keep it. A press hole is formed in the upper case 31, and pressurized air is supplied to the upper side of the airtight chamber 33. As shown in FIG. The differential pressure between the upper side and the lower side of the airtight chamber 33 is measured by the differential pressure gauge 35.

In the tester 30, the end portion of the circuit board 1 is sandwiched between the tester with the circuit board 1 facing the through-hole electrode 16 covered with the resist layer 18 downward. After all the individual circuit devices on the circuit board 1 are stored in the hermetic chamber 33 of the tester 30, the pressurized air is sent from the upper side of the hermetic chamber 33, and the pressure of the upper side of the hermetic chamber 33 rises. In addition, since the lower side of the hermetic chamber 33 is interrupted by the circuit board 1, it is not pressurized, but the predetermined | prescribed air pressure difference is maintained at the upper side and the lower side of the hermetic chamber 33, and this is measured by the differential pressure gauge 35. As shown in FIG.

By the way, when defects, such as peeling, a crack, a pinhole, etc. exist in the resist layer 18 continuous to the through-hole electrode 16, air leaks below the airtight chamber 33 from those defect parts. Therefore, since the air of the upper side of the airtight chamber 33 flows into the lower side of the airtight chamber 33 at once through the defect part, the pressure difference of the upper side and the lower side of the airtight chamber 33 falls rapidly. Thereby, the minute defect which does not pass even light can be reliably detected instantly.

Specifically, after maintaining the pressurized state on the upper side of the hermetic chamber 33 for a certain time, the differential pressure between the upper side and the lower side of the hermetic chamber 33 is measured by the differential pressure gauge 35. If the differential pressure is 200 kPa (Pascal) and there is a leak of 5 kPa or more for 30 seconds, the circuit board 1 is determined to be defective because the resist layer 18 is obviously defective, and at all subsequent steps are used. It doesn't work.

On the other hand, when the leak is 5 kPa or less in 30 seconds, it is determined that the good quality circuit board 1 has no defect in the resist layer 18.

Subsequently, the manufacturing method of the circuit board of this invention is demonstrated with reference to FIG. 4 and FIG.

In the manufacturing method of the present invention, a plurality of circuit element placing regions are arranged on a circuit board, a plurality of through hole electrodes are formed around the circuit element placing region, and at least one end of the through hole electrodes is covered with a resist layer, Pressurizing the circuit board to measure a change in pressure, detecting the presence of defects such as peeling, cracking, or pinhole continuous to the through-hole electrode of the resist layer, and detecting the defect on the circuit board without the defect. And a protective resin layer covering the circuit element, and preventing the inflow of the protective resin from the resist layer to the through-hole electrode.

In the first step of the present invention, as shown in Fig. 4A, an insulating substrate 10 having a first conductive foil 11 such as copper and a second conductive foil 12 adhered to both surfaces thereof is prepared. do.

It is preferable to use a glass epoxy substrate or a glass polyimide substrate as the insulating substrate 10, but in some cases, a fluorine substrate, a glass PPO substrate, a ceramic substrate, or the like may be employed. Moreover, a flexible sheet, a film, etc. may be sufficient. In this embodiment, a glass epoxy substrate having a thickness of 0.5 mm was employed.

As the 1st conductive foil 11 and the 2nd conductive foil 12, what is necessary is just a metal which can be etched. In this aspect, the metal foil which consists of copper is employ | adopted, and these comprise a part of wiring. That is, the thickness of the wiring can be arbitrarily determined by the current capacity of the circuit element to be mounted. The film thickness of the 1st conductive foil 11 and the 2nd conductive foil 12 is equivalent, and is about 18 micrometers, for example.

As shown in FIG. 4B, the second step of the present invention is to form a through hole penetrating the insulating substrate and the conductive foil at a predetermined position.

In this step, the through hole 16a for forming the through hole electrode 16 is a first conductive foil 11, a second conductive foil 12, and an insulating substrate 10 by a drill or the like using an NC machine tool. It penetrates through. A plurality of through holes 16a is disposed in the periphery of the individual circuit device including the circuit element placing region 15 shown in Fig. 2A, and for example, the diameter of the through holes is formed to be 0.5 mm.

Specifically, 1,176 in the row direction and 1,352 in the column direction are arranged, and a total of 2,528 through-hole electrodes 16 are formed on one circuit board 1.

A third step of the present invention is to form a through hole electrode that electrically connects the through hole by through hole plating, as shown in Fig. 4C.

In this step, the whole is immersed in a palladium solution, and the inner wall of the through hole 16a is subjected to electroless plating and electroplating on the inner wall of the through hole 16a using the first conductive foil 11 and the second conductive foil 12 as electrodes. Through-hole electrodes 16 having a film thickness of 11 to 15 mu m are formed.

In the fourth step of the present invention, as shown in FIG. 4D, the first conductive foil and the second conductive foil are etched to form a plurality of circuit element placing regions on which each circuit element is placed.

In this step, the first conductive foil 11 and the second conductive foil 12 of the insulating substrate 10 are covered with a resist layer (not shown), and the patterns shown in FIGS. 2A and 2B are illustrated. , The first conductive foil 11 and the second conductive foil 12 are etched using the remaining resist layer as a mask. Thereby, the circuit element mounting area | region 15 in which each circuit element 19 is mounted is formed in large number in matrix form. When the first conductive foil 11 and the second conductive foil 12 are copper, ferric chloride is used as the etching solution. Subsequently, peeling removal of a resist layer is performed. Since the shape of the pattern of each cell has already been described with reference to FIGS. 2A and 2B, the description thereof is omitted here.

As shown in Fig. 4E, the fifth step of the present invention is to attach a conductive metal layer that can be bonded to the surface of the through-hole electrode, the conductive pattern, and the bonding pad by plating.

In this step, the conductive metal layer 17 is laminated on the first electrically conductive foil 11, the second conductive foil 12, and the through hole electrode 16 that are electrically connected. That is, the conductive metal layer 17 which can be bonded to the conductive pattern 13 and the bonding pad 14 is attached by electroplating. As the conductive metal layer 17, either gold or nickel is selected. In the case of gold plating, a gold plating layer of 0.5 mu m to 1 mu m is formed, and in the case of nickel, a nickel layer of 5 to 15 mu m is formed to enable bonding of the bonding wire. In the case of dissipating heat, the conductive metal layer 17 may be attached to the surface of the circuit element mounting region 15 by electroplating.

In the sixth step of the present invention, as shown in Fig. 4F, one end of the through-hole electrode is covered with a resist layer.

In this step, the resist layer 18 is adhered to one end of the through hole electrode 16. The resist layer 18 is for preventing the protection resin from flowing into the through hole electrode 16 and may be wider than the opening width of the through hole electrode 16. In this embodiment, the dry film register is used for the resist layer 18. Specifically, the resist layer 18 has a width of 1.5 mm and a thickness of 55 μm.

In addition, after this process, the inspection of the tester 30 shown in FIG. 3 is carried out the test | inspection of the presence or absence of defects, such as a pinhole, to the resist layer 18 which is continuous with the through-hole electrode 16 of the circuit board 1. Do it.

Specifically, 2,528 through-hole electrodes 16 are formed in the circuit board 1 altogether. The first conductive foil and the second conductive foil are covered with a resist layer, and a pattern is formed by exposure development. If there is dust or the like at the time of exposure development, it causes the formation of a pinhole of 10 mu m or less in the resist layer. Although light does not pass through the pinhole of 10 micrometers or less, the inspection machine 30 of this process can test 2000 or more inspection objects in an instant, and can detect even the pinhole of 10 micrometers or less reliably. Since the inspection method has already been described with reference to FIG. 3, it will be omitted here.

In the seventh step of the present invention, as shown in Fig. 5A, the circuit element is fixed on the circuit element placement region of each individual circuit device.

In this step, the chip of the circuit element 19 is fixed to the circuit element placing region 15 with an adhesive such as an insulating epoxy resin. The upper surface of the circuit element 19 has an anode and a cathode electrode, and the bottom surface is fixed. A chip mounter is used for fixing the circuit element 16.

8th process of this invention is to connect the electrode of the circuit element 19, and the bonding pad 14 by bonding of a bonding wire, as shown to FIG.

In this step, the electrodes of the circuit element 19, the through-hole electrode 16, and the conductive pattern 13 are connected by ultrasonic thermocompression while pattern recognition of the position of the electrode with the bonder using gold bonding wires. The conductive metal layer on the bonding pad 14 is connected.

A ninth step of the present invention is to coat the circuit element 19 and the bonding wire with the protective resin layer 20, as shown in Fig. 5B.

In this step, the circuit element 19 and the bonding wire are covered with the protective resin layer 20 by putting to protect it from the outside air, and in the case of the light emitting element, it also functions as a convex lens for extracting light. In this embodiment, a transparent epoxy resin is used as the protective resin layer 20.

In the present step, the put protective liquid resin layer 20 is prevented from flowing into the through hole electrode 16 by the resist layer 18, and is transferred from the back surface of the circuit board 1 to each through hole electrode 16. Entering back can be completely prevented. As a result, since the transparent protective resin layer 20 does not adhere to all the through-hole electrodes 16, it can be kept in a solderable state.

The tenth step of the present invention is to dice the through-hole electrode 16 (not shown) and to divide each of the individual circuit devices 21 separately.

In this step, a plurality of individual circuit devices 21 arranged in a matrix on the insulating substrate 10 are diced on the through-hole electrodes 16 and separated into individual circuit devices 21 completed individually. The through-hole electrodes divided into two become respective external electrodes.

An eleventh step of the present invention is to attach an individual circuit device to a conductive pattern on a printed board by soldering.

In this step, the through-hole electrode 16 of the individual circuit device 21 serves as an external electrode and is placed on the conductive pattern 24 on the printed circuit board 23, and then connected by solder 22.

In this step, since there is no adhesion of the protective resin layer 20 which becomes an insulator on the surface of the through-hole electrode 16, favorable soldering can be performed.

1 is a top view of a circuit board completed by the manufacturing method of the present invention.

2 is an enlarged view (A) of the surface of the circuit board completed by the manufacturing method of the present invention, and (B) an enlarged view of the back surface.

3 is a cross-sectional view illustrating the manufacturing method of the present invention.

4 (A) to (D) are cross-sectional views illustrating the manufacturing method of the present invention.

5 (A) to (C) are cross-sectional views illustrating the manufacturing method of the present invention.

<Explanation of symbols for the main parts of the drawings>

1: circuit board

2: position alignment hole

10: insulated substrate

11: first conductive foil

12: 2nd conductive foil

13: challenge pattern

13a: by wiring

14: bonding pad

15: circuit element mounting area

16: Through Hole Electrode

16a: through hole

17: conductive metal layer

18: resist layer

19: circuit element

20: protective resin layer

21: individual circuit device

22: solder

23: printed board

24: challenge pattern

30: checker

31: upper case

32: lower case

33: confidential room

34: gasket

35: differential pressure gauge

Claims (4)

Arranging a plurality of circuit element placing regions on a circuit board, and forming a plurality of through hole electrodes around the circuit element placing region; Covering at least one end of the through hole electrode with a resist layer, Pressurizing the circuit board to measure a change in pressure, detecting the presence or absence of defects such as peeling, cracking or pinhole continuous to the through hole electrode of the resist layer; A circuit which embeds the circuit element on the circuit board without the defect and attaches a protective resin layer covering the circuit element, and prevents the inflow of the protective resin from the resist layer to the through-hole electrode. Method of manufacturing a substrate. The method of claim 1, When measuring the change in pressure, the upper and lower surfaces of the circuit board are sandwiched to form an airtight chamber, and the pressurized air is sent from the upper side of the airtight chamber to be maintained for a certain time, and the pressure difference between the upper and lower sides of the airtight chamber is measured. The manufacturing method of the circuit board characterized by the above-mentioned. The method of claim 2, A method for manufacturing a circuit board comprising determining that a leak pressure from an upper side of the hermetic chamber to a lower side of the hermetic chamber is 5 kPa or less. The method of claim 1, A light receiving element is used as the circuit element, and a transparent epoxy resin is used as the protective resin layer.

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