JP2011165381A - Method for manufacturing electronic device - Google Patents

Abstract

To increase the bonding strength of a sealing member of an electronic device.
An underlayer (3, 3 ′) is provided on each peripheral portion of a pair of substrates (1, 4) having an electronic element 2 formed on one substrate 1 and provided on one substrate 4. A light absorption layer 6 having a high absorptance with respect to visible light or near-infrared light on the underlayer 3 ′, and a low melting point metal layer 6 on the underlayer 3 provided on the other substrate 1; The light absorbing layer 6 is irradiated with visible light or the near infrared light through the substrate 4 and the base layer 3 ′ to heat and melt the low melting point metal layer 5, and an alloy is formed by the light absorbing layer 6 and the low melting point metal layer 5. Then, the pair of substrates (1, 4) are joined together.
[Selection] Figure 1

Description

  The present invention relates to a method for manufacturing an electronic device in which an electronic element typified by a display medium such as a liquid crystal or a light-emitting medium such as an organic EL is sealed.

  2. Description of the Related Art In recent years, light emitting media such as organic EL elements have been used in electronic devices such as mobile phones and music players, and home appliances, and typically have a structure in which electronic devices are sealed between a pair of substrates. Organic EL elements are vulnerable to moisture and oxidation, and in order to extend their operating time, the elements are sealed off from oxygen and moisture in the air during the manufacturing process, and deterioration due to moisture etc. occurs after manufacturing. In order to suppress it, it is necessary to ensure sufficient moisture resistance (high barrier property).

  Various methods have been proposed as sealing techniques for organic electronic devices that require high barrier properties such as organic EL elements. For example, Patent Document 1 describes a technique in which a resin layer is interposed between an element formation substrate and a sealing substrate so as to cover an organic EL element, and the periphery thereof is sealed with an adhesive. However, in this method, there is moisture permeation from the adhesive-sealed portion around the resin layer, and complete moisture tightness cannot be obtained.

  In order to solve the problem of moisture permeation of the adhesive, Patent Document 2 proposes a method of sealing by laser heating using a frit glass which is an inorganic material as a sealing material. According to this, since the gap between the element formation substrate and the sealing substrate is completely sealed by using an inorganic material, the amount of newly entering water is small, so that the deterioration of the organic EL element is theoretically reduced. It is considered that a device having a small amount of the device can be manufactured. However, the method described in Patent Document 2 has a problem that when the frit pattern is irradiated with a laser, an uncured portion is generated in the frit glass in a portion where the laser energy does not reach. For this reason, moisture permeation actually occurs and complete moisture tightness cannot be obtained.

  In order to solve this, Patent Document 3 proposes a method for preventing incomplete melting and incomplete hardening of a frit pattern by irradiating a laser along at least two or more paths. However, with this method, it is difficult to confirm whether or not there is a completely uncured part, and a redundant design such as increasing the line width of the frit is necessary to reduce the probability. Has a point.

  On the other hand, as another method for eliminating moisture permeation of the adhesive, the applicant has proposed a method of sealing by laser heating using a low melting point metal as a sealing material (Patent Document 4). In this method, in a pair of resin substrates, a light absorption layer is provided on at least one substrate periphery, and a low melting point metal layer is provided on both substrate periphery, and the light absorption layer is heated by laser irradiation. It melts and bonds low melting point metals.

JP 2005-190703 A US Patent Application Publication No. 2004-0207314 JP 2007-220648 A JP 2008-251242 A

  Since the method described in Patent Document 4 can block moisture permeation over time, it is possible to effectively suppress deterioration of the organic EL element. However, in this method, the low melting point metal layers are joined together, and in the case of the kind of the low melting point metal layer, for example, In, an oxide film is formed between the low melting point metal layers at the time of joining. Even if heated, it may not be completely joined. Since it is very difficult to remove this oxide film, there is room for improvement in order to further increase the bonding strength.

  In addition, whether or not complete sealing has a significant effect on manufacturing yield, etc., and there is no way to check whether or not complete sealing has been achieved, a redundant process is used to increase yield. It must be a situation. Therefore, if it can be confirmed whether or not the low melting point metal is melted and completely sealed by laser heating, the manufacturing cost can be greatly reduced.

  The present invention has been made in view of the above circumstances, and it is possible to increase the bonding strength of a sealing member, and preferably an electronic device capable of determining whether an electronic element is completely sealed. An object of the present invention is to provide a device manufacturing method.

  In the electronic device manufacturing method of the present invention, a base layer is provided on each peripheral portion of a pair of substrates having an electronic element formed on one substrate, and visible light is formed on the base layer provided on one of the substrates. Alternatively, a light absorption layer having a high absorptance with respect to near-infrared light, a low melting point metal layer is provided on a base layer provided on the other substrate, and the visible light or the light is transmitted through the substrate and the base layer. Irradiating the light absorption layer with near infrared light to heat and melt the low melting point metal layer, forming an alloy with the light absorption layer and the low melting point metal layer, and bonding the pair of substrates together It is a feature.

  In this case, the reflected light intensity of the visible light or the near infrared light is detected from the substrate side irradiated with the visible light or the near infrared light, and the visible light or the near infrared light is detected based on the detection result of the reflected light intensity. It is preferable to irradiate the visible light or the near infrared light by adjusting the irradiation light intensity of the near infrared light.

  Alternatively, the reflected light intensity of the detection light is detected by irradiating the detection light from one of the substrate sides, and the visible light or the near infrared light is irradiated based on the detection result of the reflected light intensity. It is preferable to adjust the intensity and irradiate the visible light or the near infrared light.

  As another aspect, in the method for manufacturing an electronic device of the present invention, a base layer is provided on each peripheral portion of a pair of substrates in which an electronic element is formed on one substrate, and the base layer provided on the one substrate is provided. A light-absorbing layer having a high absorptance to visible light or near-infrared light and a low-melting point metal layer on the light-absorbing layer, and an alloy on the base layer provided on the other substrate Forming a formation layer, irradiating the light absorption layer with the visible light or the near-infrared light through the substrate and the base layer to heat and melt the low melting point metal layer, to form the alloy formation layer and the low melting point metal; An alloy is formed by the layers, and the pair of substrates are bonded to each other.

  In this case, the detection light is irradiated from one of the substrate sides to detect the reflected light intensity of the detection light, and the visible light or the near infrared light is irradiated based on the detection result of the reflected light intensity. It is preferable to adjust the light intensity and irradiate the visible light or the near infrared light.

  In the method for manufacturing an electronic device according to the present invention, a base layer is provided on each peripheral portion of a pair of substrates on which electronic elements are formed on one substrate, and visible light or light is formed on the base layer provided on one substrate. A light-absorbing layer having a high absorption rate for near-infrared light is provided, a low-melting point metal layer is provided on the base layer provided on the other substrate, and visible light or near-infrared light is transmitted through the substrate and the base layer. The low melting point metal layer is heated and melted by irradiating the absorption layer, and an alloy is formed by the light absorption layer and the low melting point metal layer, so the bonding strength is greatly increased by the alloy formed by the light absorption layer and the low melting point metal layer. In addition, it is possible to block the permeation of moisture over a long period of time, so that deterioration of electronic devices such as organic EL elements can be effectively suppressed.

  When detecting the reflected light intensity of irradiated visible light or near infrared light, or when detecting the reflected light intensity of detection light by irradiating the detection light separately, the light absorbing layer and the low melting point metal Since it is possible to confirm whether an alloy is formed by the layer, visible light or near infrared light is adjusted by adjusting the irradiation light intensity of visible light or near infrared light based on the detection result of reflected light intensity. Irradiation makes it possible to complete the bonding between the light absorption layer and the low-melting-point metal layer, and it is possible to manufacture electronic devices with a high production yield without introducing redundant designs and processes. Costs can be greatly reduced.

  According to another aspect of the method for manufacturing an electronic device of the present invention, a base layer is provided on each peripheral portion of a pair of substrates in which electronic elements are formed on one substrate, and the base layer is provided on the one substrate. A light absorption layer having a high absorptivity with respect to visible light or near-infrared light, a low melting point metal layer on the light absorption layer, and an alloy formation layer on the base layer provided on the other substrate Since the low melting point metal layer is heated and melted by irradiating the light absorbing layer with visible light or near infrared light through the substrate and the base layer, the alloy is formed by the alloy forming layer and the low melting point metal layer. The alloy formed by the formation layer and the low-melting-point metal layer significantly improves the bonding strength and can block the permeation of moisture over a long period of time, effectively preventing the deterioration of electronic devices such as organic EL elements. It is possible to suppress it.

  In addition, by irradiating the detection light separately and detecting the reflected light intensity of the detection light, it can be confirmed whether the alloy is formed by the alloy forming layer and the low melting point metal layer, so the reflected light intensity Based on the detection results, the irradiation light intensity of visible light or near-infrared light is adjusted and irradiated with visible light or near-infrared light. This makes it possible to manufacture electronic devices with a high production yield without introducing redundant designs and processes, thereby greatly reducing manufacturing costs.

It is a schematic diagram which shows the manufacturing method of the organic EL device by 1st embodiment of this invention. It is a schematic diagram which shows the manufacturing method of the organic EL device by 2nd embodiment of this invention. It is a schematic diagram which shows the manufacturing method of the organic EL device by 3rd embodiment of this invention. It is a graph which shows the relationship between the reflected light change rate in case a low melting-point metal layer is In, and a wavelength. It is a schematic diagram which shows the manufacturing method of the organic EL device by 4th embodiment of this invention.

  Hereinafter, an electronic device manufacturing method of the present invention will be described with reference to the drawings, taking an organic EL device as an example. FIG. 1 is a schematic diagram showing a method for manufacturing an organic EL device according to the first embodiment of the present invention. An organic EL element 2 is formed on the element forming substrate 1, and a base layer 3 is provided on the periphery of the element forming substrate 1. Similar to the element forming substrate 1, a base layer 3 'is provided on the peripheral edge of the sealing substrate 4 of the other substrate. In addition, a low melting point metal layer 5 is provided on the base layer 3 at the peripheral portion of the element forming substrate 1, and visible light or near infrared light is provided on the base layer 3 ′ at the peripheral portion of the sealing substrate 4. A light absorption layer 6 having a high absorptance with respect to light (hereinafter also simply referred to as irradiation light) is provided.

  Although not shown in FIG. 1, an extraction electrode for driving the organic EL element 2 is formed across the peripheral underlayer 3 so that electric power can be input from the outside. Is covered with an insulating film so as not to be short-circuited by the base layer 3 or the low melting point metal layer 5 at the peripheral edge.

  A manufacturing procedure of the organic EL device will be described. First, in order to seal the organic EL element 2, the low melting point metal layer 5 of the element forming substrate 1 and the light absorption layer 6 of the sealing substrate 4 are arranged together. As the irradiation light irradiation device, for example, as shown in FIG. 1, an optical fiber 10 connected to a light source (not shown) for irradiation light irradiation, and a collimator lens that collimates light from the optical fiber 10 into parallel light. 11 and a condensing lens 12 that condenses light collimated into parallel light.

  When irradiation light is irradiated from the optical fiber 10 through the sealing substrate 4 and the base layer 3 ′, the irradiated light is collimated into parallel light by the collimating lens 11, and the parallel light is collimated by the condenser lens 12. It is condensed toward By irradiating the condensed irradiation light along the light absorption layer 6 provided on the peripheral edge of the sealing substrate 4, the low melting point metal layer 5 is heated and melted by the light absorption layer 6 to absorb light. An alloy is formed by the layer 6 and the low melting point metal layer 5, the element formation substrate 1 and the sealing substrate 4 are joined, and the organic EL element 2 is sealed by the element formation substrate 1 and the sealing substrate 4. As described above, the alloy formed by the light absorption layer 6 and the low melting point metal layer 5 significantly improves the bonding strength, and can block the permeation of moisture over a long period of time. It can be effectively suppressed.

  In FIG. 1, the low melting point metal layer 5 is provided on the base layer 3 at the peripheral portion of the element forming substrate 1, and the light absorption layer 6 is provided on the base layer 3 ′ at the peripheral portion of the sealing substrate 4. In this embodiment, the light absorption layer 6 is irradiated with irradiation light through the sealing substrate 4 and the base layer 3 ′. The light absorption layer 6 is formed on the base layer 3 at the peripheral edge of the element formation substrate 1. A low melting point metal layer 5 may be provided on the base layer 3 ′ at the peripheral edge of the sealing substrate 4, and the light absorption layer 6 may be irradiated with irradiation light through the element formation substrate 1 and the base layer 3.

  FIG. 2 shows a method for manufacturing an organic EL device according to the second embodiment of the present invention. In FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted unless necessary (the same applies hereinafter). In the electronic device in FIG. 2, the alloy forming layer 7 is provided on the base layer 3 provided on the peripheral portion of the element forming substrate 1, and the base layer 3 ′ on the peripheral portion of the sealing substrate 4 is provided on the base layer 3 ′. The light absorption layer 6 and the low melting point metal layer 5 are provided. In this case, an alloy is formed by the low melting point metal layer 5 heated by the light absorption layer 6 and the alloy forming layer 7, the element forming substrate 1 and the sealing substrate 4 are joined, and the organic EL element 2 is the element. Sealing is performed by the formation substrate 1 and the sealing substrate 4.

  In FIG. 2, the alloy forming layer 7 is formed on the base layer 3 at the peripheral portion of the element forming substrate 1, and the light absorption layer 6 and the low melting point metal layer 5 are formed on the base layer 3 ′ at the peripheral portion of the sealing substrate 4. Is provided, and the light absorbing layer 6 is irradiated with irradiation light through the sealing substrate 4 and the base layer 3 ′. However, the light is applied on the base layer 3 at the peripheral edge of the element forming substrate 1. The absorption layer 6 and the low melting point metal layer 5 are provided with the alloy forming layer 7 on the base layer 3 ′ at the peripheral portion of the sealing substrate 4, and the light absorption layer 6 passes through the element forming substrate 1 and the base layer 3. On the other hand, it is good also as an aspect which irradiates irradiation light.

  FIG. 3 shows a method for manufacturing an organic EL device according to the third embodiment of the present invention. In the embodiment shown in FIG. 3, the detection light is irradiated from the sealing substrate 4 side, the reflected light intensity of the detection light is detected, and the irradiation light is irradiated based on the detection result of the detected reflected light intensity. The light intensity is adjusted as needed (in FIG. 3, the structure of the sealing member of the organic EL device is shown in the same structure as in FIG. 1). That is, the mode shown in FIG. 3 is the irradiation light irradiation device (the optical fiber 10 described in FIG. 1, the collimating lens 11, the condensing lens 12 and the like) shown in the manufacturing method of the organic EL device shown in FIG. In addition to the irradiation light irradiation device configured to include the detection light irradiation device 13 that irradiates the detection light (for example, wavelength 435 nm), the light of the irradiation light (for example, wavelength 405 nm) reflects, and the other light A dichroic mirror 14 that passes through, a half mirror 15 that splits detection light from the detection light irradiation device 13 and reflected light of the detection light, and an imaging device (for example, CCD) 16 that receives the reflected light from the half mirror 15. A detection light irradiation system and a reflected light detection system are added.

  When the irradiation light is irradiated from the optical fiber 10, the irradiated light is collimated into parallel light by the collimator lens 11, and the parallel light is dispersed by the dichroic mirror 14, and the irradiation light is reflected by the dichroic mirror 14 to be a condensing lens. Head to 12. Irradiation light transmitted through the condenser lens 12 is condensed toward the light absorption layer 6. As a result, the low melting point metal layer 5 is heated and melted, an alloy is formed by the light absorption layer 6 and the low melting point metal layer 5, and the element forming substrate 1 and the sealing substrate 4 are joined.

  On the other hand, the detection light emitted from the detection light irradiation device 13 passes through the half mirror 15 and the dichroic mirror 14 and is applied to the low melting point metal layer 5. The irradiated detection light is reflected by the low melting point metal layer 5, passes through the dichroic mirror 14, and is detected by the imaging device 16 by the half mirror 15. The detection signal detected here is configured to be fed back to a control unit (not shown) installed in the light source, and a detection signal in which an alloy is not formed by the low melting point metal layer 5 and the light absorption layer 6. In this case, the irradiation light intensity is controlled based on this detection signal.

  This will be specifically described. FIG. 4 is a graph showing the relationship between the rate of change in reflected light and the wavelength when the low melting point metal layer is In, and the rate of change in reflected light is when the reflected light intensity is 100% when In is not melted. The ratio of reflected light intensity of molten In. It can be seen from this graph that, regardless of the wavelength of the detection light, when In is melted, the intensity of the reflected light is about 20% stronger than In when it is not melted. Therefore, taking the case of In as an example, in the case of a detection signal whose reflected light intensity is less than 120%, a control unit that can be controlled to increase the intensity of light emitted from the light source should be provided in the light source. By feeding back the detection signal to the light source, the irradiation light intensity is automatically increased, and the bonding between the light absorption layer 6 and the low melting point metal layer 5 can be made more complete. This control is not limited to the intensity of irradiation light. For example, in the case of a detection signal in which an alloy is not formed by the low-melting point metal layer 5 and the light absorption layer 6, the irradiation light is irradiated. It is possible to control the scan speed to be slow.

  The graph shown in FIG. 4 is the case where the low melting point metal layer is In, but the low melting point metal used as the low melting point metal layer described below has a higher reflected light intensity after melting than before melting, The wavelength of the detection light can be selected from a wide range. In addition, when the irradiation light and the detection light are irradiated from the same side of the substrate as shown in FIG. 3, by changing the spectral characteristics of the dichroic mirror that transmits and reflects the light at a predetermined wavelength as appropriate, What is necessary is just to select the light for a detection suitably.

  In addition, although the aspect which irradiates the detection light from the sealing substrate 4 side and detects the reflected light intensity of the detection light has been described in FIG. 3, the light absorption layer 6 is irradiated without irradiating the detection light separately. It is good also as an aspect which detects the reflected light intensity of irradiated light using the irradiated light, and adjusts the irradiated light intensity of irradiated light based on the detection result of this reflected light intensity. In this case, the detection light irradiation device 13 shown in FIG. 3 may be omitted.

  FIG. 5 shows a method for manufacturing an organic EL device according to the fourth embodiment of the present invention. The mode shown in FIG. 5 is a mode in which detection light is irradiated from the sealing substrate 4 side. In this way, the irradiation light irradiation system and the detection light irradiation system may be separately arranged on both sides of the substrate. By arranging in this way, it is not necessary to arrange a dichroic mirror.

  In the above description, the case where the intensity of irradiation light is adjusted at any time while confirming whether the low melting point metal layer 5 is melted or not is described. After joining the layer 6 and the low-melting-point metal layer 5, it is confirmed whether the joining is performed by irradiating the detection light, and the joining process is performed again by increasing the irradiation light intensity with respect to the unjoined part. May be performed.

  The material used for each part of the electronic device of the present invention will be described. As the element formation substrate 1 and the sealing substrate 4, resins such as glass, PEN, PET, PES, and PC can be used. The thickness may be a thickness used for a normal electronic device. For example, in the case of a PEN substrate, about 100 μm is preferable.

  Underlying metal layers 3 and 3 ′ are layers for increasing the adhesion between element forming substrate 1 and sealing substrate 4, and depending on the material of the substrate, for example, Cr, Ti, Ni, etc. are preferred. be able to. Although depending on the material of the substrate, for example, in the case of Cr, it can be provided by a vacuum deposition method, a laser transfer method, or the like.

  The low melting point metal layer 5 is a layer made of a metal (including an alloy) having a low melting point (having a melting point of 250 ° C. or lower), and includes, for example, In, Sn, In · Sn alloy, Sn · Bi · Ag alloy, Preferred examples include low melting point metals such as Sn / Ag alloy, Sn / Ag / Cu alloy, Sn / Ag / Cu / Bi alloy, and these include film formation such as vacuum deposition, aerosol deposition, and cold spray. It can be provided by law.

  The light absorbing layer 6 is irradiated with visible light to increase the temperature of the light absorbing layer to such an extent that the preheated low melting point metal layer is melted while keeping the temperature rise of the element forming substrate 1 and the sealing substrate 4 low. Alternatively, it is a layer having a sufficiently high absorption rate for near-infrared light, and preferred examples include colored metals such as Au, Ni, and Cu, Cr, Mo, W, and the like. It can be provided by a film forming method such as an aerosol deposition method or a cold spray method.

  The alloy forming layer 7 is not particularly limited as long as it is a metal that forms an alloy with the low melting point metal layer 5, but for example, Au, Ni, Cu and the like can be preferably mentioned, and these are also vacuum deposition methods, aerosol deposition methods, It can be provided by a film forming method such as a cold spray method.

  The thickness of each layer varies depending on the metal to be used, and may be provided as desired. For example, when the base layer is Cr (film thickness 5 nm) and the light absorption layer is Au (200 nm), the low melting point When In is used as the metal layer, if the thickness of the low melting point metal layer is small, the amount of melting becomes small, and it becomes difficult to fill the gaps due to surface waviness between the substrates and the surface roughness of each layer. For this reason, it is usually appropriate to set it to 2 μm or more. In the case of the structure having the alloy formation layer as shown in FIG. 2, for example, the underlayer is Cr (film thickness 5 nm), the light absorption layer is Au (200 nm), and the alloy formation layer is Au (200 nm). Even in the case of using In as the low melting point metal layer, if the thickness of the low melting point metal layer is small, the amount of melting is reduced, and it becomes difficult to fill the gap due to the surface waviness between the substrates and the surface roughness of each layer. Therefore, it is usually appropriate to set it to 2 μm or more.

  The pattern width of the underlayer, light absorption layer, low melting point metal layer, and alloy formation layer can maintain high barrier properties even if the width is reduced, but the bonding strength decreases, so the size of the device It is preferable to select a suitable pattern width according to the size, for example, in the case of a 21-inch liquid crystal display, it is desirable to set it to about 0.5 mm.

  In order to heat the light-absorbing layer with the irradiation light that irradiates the light-absorbing layer through the substrate, it is necessary to select the wavelength of the irradiation light that is sufficiently small to absorb the substrate, while keeping the temperature rise of the substrate low. However, in order to increase the temperature of the light absorption layer to such an extent that the low melting point metal layer is melted, it is required that the absorption rate of the light absorption layer is sufficiently high at the selected wavelength. In other words, it is desirable that the wavelength of visible light or near-infrared light used for irradiation is approximately twice or more apart between the absorption rate of the substrate and the absorption rate of the light absorption layer at that wavelength. If PEN is selected for the resin substrate and the light absorption layer is Au, the wavelength of the laser beam suitable for irradiation is preferably in the range of approximately 390 nm to 500 nm, and similarly PET and Cu are selected. In this case, it is preferable that the appropriate wavelength range of the laser beam is approximately 350 nm to 600 nm. In addition, when the wavelength of a laser beam is changed, it can respond by changing suitably the spectral characteristic of the said dichroic mirror.

For example, when the base layer exemplified above is Cr (film thickness 5 nm), the light absorption layer is Au (200 nm), and the low melting point metal layer is In (2 μm), the wavelength of the irradiation laser is 405 nm, the laser power is 2 W, and the spot Is a Gaussian beam shape having a 1 / e diameter of 0.3 mm, and this may be irradiated and scanned at a scanning speed of 2 mm / second at the center of the pattern. Note that the scan speed can be increased by increasing the laser power. If the output of a single laser diode is less than the desired laser output, the laser output from a single laser head can be increased by bundling a plurality of optical fibers or using a combined light source. .

DESCRIPTION OF SYMBOLS 1 Element formation board | substrate 2 Organic EL element 3,3 'Base metal layer 4 Sealing board | substrate 5 Low melting-point metal layer 6 Light absorption layer 7 Alloy formation layer 10 Optical fiber 11 Collimate lens 12 Condensing lens 13 Detection light irradiation apparatus 14 Dichroic Mirror 15 Half mirror 16 Imaging device

Claims (5)

  A base layer is provided on each peripheral portion of a pair of substrates on which electronic elements are formed on one substrate, and an absorptivity for visible light or near infrared light on the base layer provided on one of the substrates. A high light absorption layer, a low melting point metal layer is provided on the base layer provided on the other substrate, and the visible light or the near infrared light passes through the substrate and the base layer to the light absorption layer. Irradiating, heating and melting the low melting point metal layer, forming an alloy with the light absorption layer and the low melting point metal layer, and bonding the pair of substrates to each other.   The reflected light intensity of the visible light or the near infrared light is detected from the substrate side irradiated with the visible light or the near infrared light, and the visible light or the near red light is detected based on the detection result of the reflected light intensity. 2. The method of manufacturing an electronic device according to claim 1, wherein the visible light or the near-infrared light is irradiated by adjusting an irradiation light intensity of external light.   The detection light is irradiated from one side of the substrate to detect the reflected light intensity of the detection light. Based on the detection result of the reflected light intensity, the irradiation light intensity of the visible light or the near infrared light is determined. 2. The method of manufacturing an electronic device according to claim 1, wherein the visible light or the near-infrared light is irradiated after adjustment.   A base layer is provided on each peripheral portion of a pair of substrates on which electronic elements are formed on one substrate, and an absorptivity for visible light or near infrared light on the base layer provided on one of the substrates. A light absorption layer having a high thickness and a low melting point metal layer on the light absorption layer, an alloy formation layer on the base layer provided on the other substrate, and the visible light passing through the substrate and the base layer. Alternatively, the light absorbing layer is irradiated with the near infrared light to heat and melt the low melting point metal layer, and an alloy is formed by the alloy forming layer and the low melting point metal layer to bond the pair of substrates together. A method for manufacturing an electronic device.   The detection light is irradiated from one side of the substrate to detect the reflected light intensity of the detection light. Based on the detection result of the reflected light intensity, the irradiation light intensity of the visible light or the near infrared light is determined. 5. The method of manufacturing an electronic device according to claim 4, wherein the visible light or the near infrared light is irradiated after adjustment.

Images