Abstract:
A light irradiating device ( 68 ) having the good radiation characteristic comprises a plurality of conductive paths ( 51 ) that are electrically separated, a photo semiconductor chips ( 65 ) fixed onto desired conductive path ( 51 ), and a resin ( 67 ) for covering the photo semiconductor chips ( 65 ) to support the conductive paths ( 51 ) integrally.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a light irradiating device, manufacturing method thereof and lighting apparatus using the light irradiating device, more particularly, the technology of achieving the improvement in the light irradiation efficiency and the improvement in the reliability of the device.  
           [0002]    First, in case the light must be irradiated in great quantities, normally the electric lamp, etc. are employed. However, for the purpose of the reduction in weight, thickness, and size and the saving of electricity, sometimes the light emitting elements  2  are mounted on the printed circuit board  1 , as showing FIG. 19.  
           [0003]    The light emitting diode formed of the semiconductor is mainly employed as this light emitting element. But the semiconductor laser, etc. may also be employed.  
           [0004]    The light emitting diode  2  has two leads  3 ,  4 . One lead  3  is adhered to the back surface of the light emitting diode chip  5  (the anode electrode or the cathode electrode) with the solder, etc., while the other lead  4  is electrically connected to the electrode on the chip surface (the cathode electrode or the anode electrode) via the metal thin wire  6 . Also, the transparent resin sealing member  7  for sealing the leads  3 ,  4 , the chip  5 , and the metal thin wire  6  is formed to be used as a lens.  
           [0005]    Meanwhile, the electrodes  8 ,  9  for supplying the power supply to the light emitting diode  2  are provided to the printed circuit board  1 . The above leads  3 ,  4  are inserted into the through holes provided in the printed circuit board  1 , and the light emitting diode  2  is fixed/mounted onto the printed circuit board  1  via the solder, etc.  
           [0006]    For example, the light irradiating device employing the light emitting diodes is explained in Japanese Patent Application Publication No. H09-252651.  
           [0007]    However, since the above light emitting diode  2  is formed as the package into which the resin sealing member  7 , the leads  3 ,  4 , etc. are incorporated, there is the drawback such that the size of the packaged substrate  1  is increased. Also, since the radiating characteristic of the substrate itself is inferior, there is the problem such that the temperature rise is brought about as a whole. Therefore, there are the problems such that the temperature rise of the semiconductor chip itself is caused and thus the driving capability is lowered.  
           [0008]    In addition, the light emitting diode chip  5  also emits the light from its side surface of the chip. Thus, there exists the light that is directed toward the substrate  1 . However, since the substrate  1  is formed of the printed circuit board, there is the problem such that the highly effective emission in which all the lights are emitted upward cannot be achieved.  
         SUMMARY OF THE INVENTION  
         [0009]    The present invention has been made in light of the above subjects, and provides a light irradiating device having the good radiation characteristic, that comprises a plurality of conductive paths that are electrically separated, photo semiconductor chips that are fixed onto desired conductive paths, and a resin for covering the photo semiconductor chips and serving as a lens to support the conductive paths integrally.  
           [0010]    Also, there is provided a light irradiating device that comprises a plurality of conductive paths that are electrically separated by isolation trenches, photo semiconductor chips that are fixed onto desired conductive paths, and a resin for covering the photo semiconductor chips to fill the isolation trenches between the conductive paths and serving as a lens to support the conductive paths integrally while exposing only back surfaces of the conductive paths. Therefore, back surfaces of the conductive paths can be connected to the outside to eliminate through holes and thus the above subjects can be overcome.  
           [0011]    In addition, there is provided a light irradiating device manufacturing method that comprises the steps of preparing a conductive foil and then forming conductive paths by forming isolation trenches, which are shallower than a thickness of the conductive foil, in the conductive foil except at least areas serving as the conductive paths, adhering respective photo semiconductor chips onto desired conductive paths, molding a resin serving as a lens to cover respective photo semiconductor chips and to fill the isolation trenches, and removing the conductive foil on a side on which the isolation trenches are not provided. Therefore, since the conductive foil to form the conductive paths is employed as the starting material, the conductive foil has the supporting function until the resin is molded, and the resin has the supporting function after the molding, the supporting substrate can be omitted and thus the above subjects can be overcome.  
           [0012]    Further, there is provided a light irradiating device manufacturing method that comprises the steps of preparing a conductive foil and then forming a plurality of conductive paths by forming isolation trenches, which are shallower than a thickness of the conductive foil, in the conductive foil except at least areas serving as the conductive paths, adhering a plurality of photo semiconductor chips onto desired conductive paths, forming connecting means for electrically connecting electrodes of the photo semiconductor chips and desired conductive paths, molding a resin to cover the plurality of photo semiconductor chips and to fill the isolation trenches, removing the conductive foil having a thickness portion, on which the isolation trenches are not provided, and separating the photo semiconductor chips into an individual photo semiconductor chip by cutting the resin. Therefore, a large number of light irradiating devices can be mass-produced and thus the above subjects can be overcome.  
           [0013]    Also, if the corrosion-resistant conductive film is formed in at least the areas, which serve as the conductive paths, of the surface of the conductive foil, this conductive film is left on the upper surface of the conductive foil like the visor when the isolation trenches are formed in the conductive foil. Therefore, the adhesiveness between the conductive foil and the resin can be improved when each light irradiating device is covered with the resin.  
           [0014]    In addition, when the conductive foil is bent to surround at least the areas, to which the photo semiconductor chips are fixed respectively, of the conductive foil, such conductive foil is bent to have an inclination angle that enables the light emitted from the photo semiconductor chip to reflect upwardly. Therefore, the irradiation efficiency can be improved.  
           [0015]    Further, the conductive foil is bent in the situation that the corrosion-resistant conductive film is formed on the conductive paths. Therefore, the gloss appears on the conductive film, and thus the irradiation efficiency can be much more improved.  
           [0016]    Also, there are provided the step of removing the conductive foil on the side, in which the isolation trenches are not provided, up to a predetermined position after the light irradiating devices are covered with the resin to fill the isolation trenches, and then the step of separating the light irradiating devices that are covered with the resin. Therefore, respective light irradiating devices are not separated up to the final stage, and accordingly the conductive foil can be provided to respective steps as one sheet, and thus the workability becomes good.  
           [0017]    Further, the resin is fixed by the transfer molding using the mold. Therefore, the workability can be improved and also the proper shape can be formed. Particularly, it is suitable for forming a lens shape.  
           [0018]    Also, in the case that the individual light irradiating devices that are sealed with the resin are separated by the press machine, the process of removing the flash generated on the end portions of the light irradiating devices is not needed and thus the productivity can be improved.  
           [0019]    Further, if the adhesiveness between the material of the conductive film and that of the insulating resin is lower than the adhesiveness between the material of the conductive foil and that of the insulating resin, the conductive film is formed on the conductive foil in the area smaller than the area served as at least the conductive path. Therefore, the area on the conductive foil where the conductive film does not covered, becomes large. Therefore, the adhesiveness between the conductive foil and the resin can be improved when light irradiating device is covered with the resin. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    [0020]FIG. 1 is a sectional view showing a light irradiating device manufacturing method of the first embodiment;  
         [0021]    [0021]FIG. 2 is a sectional view showing a light irradiating device manufacturing method of the first embodiment;  
         [0022]    [0022]FIG. 3 is a sectional view showing a light irradiating device manufacturing method of the first embodiment;  
         [0023]    [0023]FIG. 4 is a sectional view showing a light irradiating device manufacturing method of the first embodiment;  
         [0024]    [0024]FIG. 5 is a sectional view showing a light irradiating device manufacturing method of the first embodiment;  
         [0025]    [0025]FIG. 6 is a sectional view showing a light irradiating device manufacturing method of the first embodiment;  
         [0026]    [0026]FIG. 7 is a sectional view showing a light irradiating device manufacturing method of the first embodiment;  
         [0027]    [0027]FIG. 8 is a plan view of a light irradiating device of the first embodiment;  
         [0028]    [0028]FIG. 9 is a view showing a lighting apparatus using the light irradiating device of the first embodiment;  
         [0029]    [0029]FIG. 10 is a sectional view showing a light irradiating device manufacturing method of the second embodiment;  
         [0030]    [0030]FIG. 11 is a sectional view showing a light irradiating device manufacturing method of the second embodiment;  
         [0031]    [0031]FIG. 12 is a sectional view showing a light irradiating device manufacturing method of the second embodiment;  
         [0032]    [0032]FIG. 13 is a sectional view showing a light irradiating device manufacturing method of the second embodiment;  
         [0033]    [0033]FIG. 14 is a sectional view showing a light irradiating device manufacturing method of the second embodiment;  
         [0034]    [0034]FIG. 15 is a sectional view showing a light irradiating device manufacturing method of the second embodiment;  
         [0035]    [0035]FIG. 16 is a sectional view showing a light irradiating device manufacturing method of the second embodiment;  
         [0036]    [0036]FIG. 17 is a plan view of a light irradiating device of the second embodiment;  
         [0037]    [0037]FIG. 18 is a view showing a lighting apparatus using the light irradiating device of the second embodiment; and  
         [0038]    [0038]FIG. 19 is a view showing a light irradiating device in the conventional art. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0039]    (Embodiment 1)  
         [0040]    Embodiments of a light irradiating device and a method of manufacturing the same according to the first embodiment of the present invention will be explained with reference to the accompanying drawings hereinafter.  
         [0041]    In FIG. 1, 61 is a sheet-like conductive foil. The  8  material is selected with regard to the adhesive property, the bonding property, and the plating property of the brazing material. The conductive foil containing Cu (copper) as main material, the conductive foil containing Al (aluminum) as main material, the conductive foil formed of the alloy such as Fe—Ni (iron-nickel), Cu—Al (copper-aluminum), Al—Cu—Al (aluminum-copper-aluminum) etc., or the like may be employed.  
         [0042]    It is preferable that a thickness of the conductive foil should be set to about 10 μm to 300 μm in light of the later etching. Here the copper foil of 100 μm thickness is employed. But basically the thickness of more than 300 μm or less than 10 μm may be employed. As described later, any thickness may be selected if isolation trenches  64  that is shallower than the thickness of the conductive foil  61  can be formed in the conductive foil.  
         [0043]    In this case, the sheet-like conductive foil  61  that is wound on a roller to have a predetermined width may be prepared and then be carried to respective steps described later, otherwise the conductive foil that is cut into a predetermined size may be prepared and then be carried to respective steps described later.  
         [0044]    Then, the plating process is applied to predetermined areas of the front surface and the back surface of the conductive foil  61  respectively. In the present embodiment, a film formed of Ag (silver) (referred to as an “Ag film  62 ” hereinafter) is formed as the conductive film  62 , but the conductive film is not limited to this. For example, there are Au (gold), Ni (nickel), Pd (palladium), Al (aluminum), or the like, as other materials. In addition, these corrosion-resistant conductive films have the feature that they can be practically employed as the die pad or the bonding pad as they are. Further, the Ag film  62  formed only on the front surface of the conductive foil  61  may be employed.  
         [0045]    For example, the above Ag film  62  adheres to not only Au but also the brazing material. Therefore, if the Au film is coated on the back surface of the chip, the chip can be bonded to the Ag film  62  on a conductive path  51  by the thermo compression bonding as it is, and also the chip can be fixed via the brazing material such as the solder, etc. Further, since the Au thin wire can adhere to the Ag conductive film, it is also possible to apply the wire bonding.  
         [0046]    Then, in FIG. 2, predetermined area of the conductive foil  61  are formed as an upwardly convex portion by applying the pressing process to the conductive foil  61 , which is subjected to the plating process, thereby forming a convex portion  63 . In this case, a photo semiconductor chip  65  described later is mounted in the photo semiconductor chip mounting portion of the sectional cup-shaped area formed by the convex portion  63 . Then, the light emitted from the photo semiconductor chip  65  can be reflected by inclined portion formed by the convex portion  63  and the periphery of the inclined portion, and thus the irradiation efficiency can be improved. Further, if the pressing process is applied to the conductive foil  61  after the Ag film  62  is coated on the conductive foil  61 , the gloss appears in the area pressed and bent (head portion of the convex portion  63 ) other than remaining areas. Thus, there can be achieved the advantage such that the reflection efficiency of the light emitted from the photo semiconductor chip, described later, can be improved.  
         [0047]    It is of course that the conductive film may be formed after the press working. Further, the photo semiconductor chip may be formed on the conductive foil that is not subjected to the press working.  
         [0048]    In this case, as described above, the gloss can be given to the Ag film  62  by not bending the conductive foil  61  but applying the pressure to the conductive foil  61  (and the Ag film  62 ) by the press, etc. in the situation that the Ag film  62  is formed, and thus the improvement of the irradiation efficiency can be achieved.  
         [0049]    In turn, in FIG. 3, if the half-etching process is applied to the surface of the conductive foil  61  while using the Ag film  62  as a mask in a state that the back surface of the conductive foil  61  is masked by a photoregist film (not shown), areas which are not subjected to the plating process are half-etched and then isolation trenches  64  are formed. In this case, a depth of the isolation trench  64  formed by this etching is 50 μm, for example, and the adhesiveness to a resin  67  which can transmit a light, described later, can be improved since side surfaces of the trench become a rough surface. A resist film may be formed on the Ag film  62  and then the half-etching process may be applied by using the resist film as a mask. In addition, the Ag film  62  may be formed after the half-etching is carried out.  
         [0050]    Also, the side wall sectional shape of this isolation trench  64  has a different structure according to the removing method. As this removing method, the wet etching, the dry etching, the laser evaporation, the dicing, etc. maybe employed.  
         [0051]    For example, in the case of the wet etching, the iron (II) chloride or the copper (II) chloride is employed mainly as the etchant. The conductive foil  61  is dipped into this etchant or is showered with this etchant. Since normally the conductive foil is anti-anisotropically etched by the wet etching, the side surface of the etched portion has a curved structure. At this time, since the conductive film  62  adhering to the conductive foil  61  is located over the isolation trench  64  like a visor, the adhesiveness can be improved when the photo semiconductor chip  65  is covered with the resin  67 , described later. In the present embodiment, the wet etching process is applied.  
         [0052]    Also, in the case of the dry etching, the anisotropic etching or the anti-anisotropic etching may be carried out. It is said at present that Cu cannot be removed by the reactive ion etching, but Cu can be removed by the sputtering. Also, the anisotropic etching or the anti-anisotropic etching can be carried out depending upon the conditions of the sputtering.  
         [0053]    In addition, in the case of the laser evaporation, the isolation trench  64  can be formed by irradiating directly the laser beam. In this case, the side surface of the isolation trench  64  is rather formed as a flat surface.  
         [0054]    Further, in the case of the dicing, it is impossible to form a complicated curved pattern, but it is possible to form the lattice isolation trench.  
         [0055]    In the steps shown in FIG. 3, a photoresist film is coated selectively in place of the conductive film, and then the conductive foil  61  may be half-etched by using the photoresist film as a mask.  
         [0056]    Then, in FIG. 4, the photo semiconductor chip  65  is electrically connected to the conductive foil  61  in which the isolation trenches  64  are formed. Here the light emitting diode is employed as the photo semiconductor chip  65 . The photo semiconductor chip  65  is bonded onto a first electrode  51 A, described later, by the die bonding, and also the front surface of the photo semiconductor chip  65  and a second electrode  51 B are bonded by the wire bonding via a metal thin wire  66  (see FIG. 6).  
         [0057]    Then, in FIG. 5, the conductive foil  61  containing the photo semiconductor chips  65  is covered with the insulating resin  67  that can transmit the light emitted from the photo semiconductor chip  65 . In this step, the conductive foil  61  having the photo semiconductor chips  65  and the isolation trenches  64  is sealed with the thermosetting silicon resin or epoxy resin by virtue of the transfer molding using the mold (not shown). As described above, the resin  67  may be any resin which can transmit the light, and thus the so-called transparent resin or the opaque resin can transmit the light of a predetermined wavelength may be employed.  
         [0058]    Here, in order to collect the light from the photo semiconductor chips  65  as much as possible and emit it upward, the resin  67  has a convex lens shape. Accordingly, if viewed from the top, the lens has a substantially circular shape, as shown in FIG. 8. A thickness of the resin  67  (lens) coated on the surface of the conductive foil  61  can be set thick or thin with regard to the strength.  
         [0059]    The feature of the present step is that the conductive foil  61  acts as the supporting substrate until the insulating resin  67  serving as the lens is coated. Then, since the good radiation characteristic is obtained rather than the structure in which the light emitting diodes  2  are mounted onto the printed circuit board  1  like the related art (see FIG. 19), the driving capability can be improved.  
         [0060]    Further, since the conductive foil  61 , used as the supporting substrate in the present invention, is the material that is necessary for the electrode material. Therefore, the present invention has the advantage such that the constituent material can be omitted to the utmost and can also achieve the reduction in cost.  
         [0061]    Also, since the isolation trench  64  is formed shallower than the thickness of the conductive foil  61 , the conductive foil  61  is not individually separated as the conductive paths  51 . Accordingly, there is the advantage such that, when the sheet-like conductive foil  61  must be exchanged as a whole and then the resin  67  must be molded, the carrying operation to the mold and the fitting operation into the mold can be very simplified.  
         [0062]    When the photo semiconductor chip  65  is sealed with the resin, the potting resin maybe coated on the photo semiconductor chip  65  instead of the employment of the mold so as to form the lens shape.  
         [0063]    However, in this case, since both the silicon resin and the epoxy resin has small viscosity at the time of the heat curing, there is the problem such that the resin cannot be stably formed into the hemispherical shape that is preferable as the lens. In contrast, there is the advantage such that, if the above lens forming method using the mold is employed, the stable lens shape can be constructed. In case that the lens shape is not needed, the insulating resin  67  may be relatively thin, further, other than transfer molding using the mold may be used.  
         [0064]    In turn, in FIG. 6, there is the step that the conductive foil  61  is separated as the conductive paths  51  by removing the back surface of the conductive foil  61  chemically and/or physically. Here this removing step is carried out by the polishing, the grinding, the etching, the metal evaporation by the laser, etc.  
         [0065]    In the present embodiment, the conductive foil  61  under the isolation trench  64  is deleted by wet-etching the conductive foil  61  while using the Ag film  62 , that adheres onto the back surface of the conductive foil  61 , as a mask. Thus, the resin  67  is exposed to separate the conductive paths respectively. Accordingly, there can be obtained such a structure that surfaces of conductive paths  51 A,  51 B (a first electrode and a second electrode) are exposed from the resin  67 .  
         [0066]    At this time, the resin  67  may be exposed from the isolation trench  64  by scraping the back surface of the conductive foil  61  by about 50-60 μm by virtue of the polishing machine, the grinding machine, or the like. In this case, the conductive foil  61  is separated as the conductive paths having a thickness of about 40 μm. Also, the resin  67  maybe exposed by wet-etching the entire surface of the conductive foil  61  to the extent not to expose the resin  67 , and then scraping the overall surface by virtue of the polishing or grinding machine. In this case, the flat light irradiating device, in which the conductive paths  51  are buried in the resin  67  and the back surface of the resin  67  coincides in level with the back surface of the conductive paths  51 , can be implemented.  
         [0067]    Further, if the conductive paths  51  are separated by scraping the back surface of the conductive foil  61  by virtue of the polishing machine, the grinding machine, or the like, the oxidation inhibiting process of the conductive paths  51  may be applied by depositing the conductive material such as the solder, etc. onto the exposed conductive paths  51 , as occasion demands.  
         [0068]    Finally, there is the step of separating the neighboring light irradiating devices individually to complete the light irradiating device.  
         [0069]    This separating step can be carried out by the dicing, the cutting, the chocolate break, etc. If the chocolate break is employed, copper pieces  69  are stripped off from both end portions of the resin  67 , that covers the light irradiating devices  68 , by the press machine indicated by a dot-dash line in FIG. 7, whereby respective light irradiating devices  68  are separated. In this case, there can be achieved the advantage that, since the flash removing process of the back surface can be omitted unlike the dicing, the cutting, etc., the good workability can be achieved.  
         [0070]    The feature of the present manufacturing method resides in that the separating operation of the conductive paths  51  can be attained while practically using the resin  67  as the supporting substrate. The resin  67  is the material necessary to fill the conductive paths  51 , and the substrate used only for the supporting is not needed during the manufacturing steps. Accordingly, the present invention has the feature such that the light irradiating device can be manufactured by the minimum material and thus the reduction in cost can be accomplished.  
         [0071]    The thickness of the resin from the surface of the conductive paths  51  can be adjusted when the resin is adhered in the preceding step. Therefore, the present invention has the feature such that the thickness of the light irradiating device  68  can be set thick or thin although such thickness is different according to the packaged photo semiconductor chip. The light irradiating device in which the conductive paths  51  of 40 μm thickness and the photo semiconductor chips are buried in the resin  67  of 400 μm thickness is obtained herein (see FIG. 7 and FIG. 8 as for the above).  
         [0072]    [0072]FIG. 9 shows a lighting apparatus  40  in which the light irradiating devices  68  (light emitting diodes) are connected in series between an electrode  30  and an electrode  31  to make constant the current value that flows through the light irradiating devices  68 .  
         [0073]    Ten sheets of electrodes are formed between the electrode  30  and the electrode  31 . The back surface of the chip serving as the cathode electrode (or the anode electrode) of the light irradiating device  68  is fixed to an electrode  32 , and the anode electrode (or the cathode electrode) and the electrode  30  are connected by a metal thin wire  66 . Also, the back surface of the chip of the second light irradiating device  68  is fixed to an electrode  33 , and the electrode on the surface of the chip and the electrode  32  are connected by the metal thin wire  66 . That is, the electrode to which the back surface of the chip serving as the cathode electrode (or the anode electrode) is fixed is connected to the metal thin wire extended from the anode electrode (or the cathode electrode) of the succeeding light irradiating device  68 . The series connection can be completed by repeating this connection mode. The light irradiating devices are arranged on the predetermined portion of the electrodes by a robot having movable arm with respect to X-Y-Z (lengthwise direction—crosswise direction—up and down direction), or the like.  
         [0074]    Also, in order to form the electrode formed of the copper foil as a reflection plate, Ni is coated on the surface of the electrode. Then, in order to form the all area of the substrate as a substantial reflection plate, the electrodes are patterned such that the overall area of the substrate is covered substantially completely with 12 electrodes from the right electrode  30  to the left electrode  31 .  
         [0075]    According to the lighting apparatus  40 , there can be achieved the advantage such that, since the heat generated from the light irradiating device  68  can be radiated via a metal substrate  11 , the driving current of the light irradiating devices  68  can be set large.  
         [0076]    Although the illustration is omitted, even if the light irradiating devices  68  are connected in parallel, or the light irradiating devices  68  are connected so that serial connections and parallel connections are combined, similarly the lighting apparatus  40  that have the good radiation characteristic can be accomplished.  
         [0077]    The lighting apparatus  40  may be used to traffic light etc., for example.  
         [0078]    (Embodiment 2)  
         [0079]    Second embodiment of the invention will be explained with reference to the accompanying drawings hereinafter.  
         [0080]    First, the difference between the first embodiment and the second embodiment will be described. In the first embodiment, as shown in FIG. 3, at the time of forming the isolation trench  64  by half-etching the conductive foil  61  using the conductive film  62  as a mask, the etching process is applied so that the diameter of an opening portion of the isolation trench  64  is larger than that of the conductive film. Then, the conductive film  62  remains on the isolation trench  64  like a visor. Therefore, the adhesiveness between the conductive foil  61  and insulating resin  67  is improved by the visor.  
         [0081]    On the contrary, in the second embodiment, as shown in FIG. 11, a conductive film  162  is formed on a conductive foil  161  as small area as possible (smaller than that of the first embodiment), then, a larger area of the conductive foil is exposed. Therefore, the adhesiveness between the conductive foil  161  and the insulating resin  167  is improved. That is, for example, when the conductive foil  161  is formed of Cu and the conductive film  162  is formed of Ag, the adhesiveness of Au to the insulating resin  167  is inferior to that of Cu. In this case, if the forming area of the conductive film  162  is as small as possible as described above, thus increasing the exposing area of the conductive foil  161  that has better adhesiveness to the insulating resin  167 . Therefore, the adhesiveness of the conductive film  162  to the insulating resin  167  is improved.  
         [0082]    The second embodiment will be described, the structure other than reducing the forming area of the conductive film  162  is substantially same as the structure of the first embodiment. In order to avoid repeating the same explanation, the description is simplified, regarding same structure, with reference to the numerals wherein 100 is added to the numerals in the first embodiment.  
         [0083]    In FIG. 10, 161 represents a sheet-like conductive foil. The material is selected with regard to the adhesive property, the bonding property, and the plating property of the brazing material. The conductive foil containing Cu as main material, the conductive foil containing Al as main material, the conductive foil formed of the alloy such as Fe—Ni, Cu—Al, Al—Cu—Al etc., or the like may be employed.  
         [0084]    It is preferable that a thickness of the conductive foil should be set to about 10 μm to 30 μm in light of the later etching. Here the copper foil of 100 μm thickness is employed. But basically the thickness of more than 300 μm or less than 10 μm may be employed. As described later, any thickness may be selected if isolation trenches  164  that is shallower than the thickness of the conductive foil  161  can be formed in the conductive foil.  
         [0085]    In this case, the sheet-like conductive foil  161  that is wound on a roller to have a predetermined width may be prepared and then be carried to respective steps described later, otherwise the conductive foil that is cut into a predetermined size may be prepared and then be carried to respective steps described later.  
         [0086]    Then, if the half-etching process is applied to the conductive foil  161  while using the photoregist film  160  as a mask in a state that the back surface of the conductive foil  161  is masked by a photoregist film (not shown), predetermined areas are half-etched and then isolation trenches  164  are formed. In this case, a depth of the isolation trench  164  formed by this etching is 50 μm, for example, and the adhesiveness to a resin  167 , described later, can be improved since side surfaces of the trench become a rough surface.  
         [0087]    The half-etching process may be applied by using the photoresist film as a mask formed to entirely cover an Ag film  162  described later, after forming the Ag film  162  on the conductive foil  161 .  
         [0088]    Also, the side wall sectional shape of this isolation trench  164  has a different structure according to the removing method. As this removing method, the wet etching, the dry etching, the laser evaporation, the dicing, etc. maybe employed.  
         [0089]    For example, in the case of the wet etching, the iron (II) chloride or the copper (II) chloride is employed mainly as the etchant. The conductive foil  161  is dipped into this etchant or is showered with this etchant. Since normally the conductive foil is anti-anisotropically etched by the wet etching, the side surface of the etched portion has a curved structure.  
         [0090]    Also, in the case of the dry etching, the anisotropic etching or the anti-anisotropic etching may be carried out. It is said at present that Cu cannot be removed by the reactive ion etching, but Cu can be removed by the sputtering. Also, the anisotropic etching or the anti-anisotropic etching can be carried out depending upon the conditions of the sputtering.  
         [0091]    In addition, in the case of the laser evaporation, the isolation trench  164  can be formed by irradiating directly the laser beam. In this case, the side surface of the isolation trench  164  is rather formed as a flat surface.  
         [0092]    Further, in the case of the dicing, it is impossible to form a complicated curved pattern, but it is possible to form the lattice isolation trench.  
         [0093]    Then, in FIG. 11, the plating process is applied to predetermined areas of the front surface and the back surface of the conductive foil  161  respectively. In the present embodiment, a film formed of Ag (referred to as an “Ag film  162 ” hereinafter) is formed as the conductive film  162 , but the conductive film is not limited to this. For example, there are Au, Ni, Pd, Al, or the like, as other materials. In addition, these corrosion-resistant conductive films have the feature that they can be practically employed as the die pad or the bonding pad as they are. Further, the Ag film  162  formed only on the front surface of the conductive foil  161  maybe employed.  
         [0094]    For example, the above Ag film  162  adheres to not only Au but also the brazing material. Therefore, if the Au film is coated on the back surface of the chip, the chip can be bonded to the Ag film  162  on a conductive path  151  by the thermo compression bonding as it is, and also the chip can be fixed via the brazing material such as the solder, etc. Further, since the Au thin wire can be fixed to the Ag conductive film, it is also possible to apply the wire bonding.  
         [0095]    Then, a forming area of the Ag film  162  formed on the conductive foil  161 , as a feature of the second embodiment, is smaller as compared with the forming area of Ag film  62  according to the first embodiment. That is, in the second embodiment, it may be enough for the forming area of the Ag film  162  to have at least a reflecting surface of the inclined portion formed by a convex portion  163  described later for reflecting the light irradiated from the photo semiconductor chip  165 , e.g., only the surface of a cup-shaped photo semi conductor chip mounting portion formed by the convex portion  163  which is formed by applying the press process to the conductive foil  161 , and a metal thin line connecting portion (second electrode  151 B described later) where the photo semiconductor chip  165  is wire-bonded.  
         [0096]    By the above structure, since the area where the conductive foil  161  contacts the insulating resin  167  increases as compared with the first embodiment, the adhesiveness between the conductive foil  161  and insulating resin  167  is improved. (see FIG. 12 to FIG. 14).  
         [0097]    Then, in FIG. 12, predetermined area of the conductive foil  161  are formed as an upwardly convex portion by applying the pressing process to the conductive foil  161 , which is subjected to the plating process, thereby a convex portion  163  is formed. In this case, a photo semiconductor chip  165  described later is mounted in the photo semiconductor chip mounting portion of the sectional cup-shaped area formed by the convex portion  163 . Then, the light emitted from the photo semiconductor chip  165  can be reflected by a inclined portion formed by the convex portion  163  and the periphery of the inclined portion, and thus the irradiation efficiency can be improved. Further, if the pressing process is applied to the conductive foil  161  after the Ag film  162  is coated on the conductive foil  161 , the gloss appears in the area pressed and bent (head portion of the convex portion  163 ) other than remaining areas. Thus, there can be achieved the advantage such that the reflection efficiency of the light emitted from the photo semiconductor chip, described later, can be improved.  
         [0098]    It is of course that the conductive film may be formed after the press working. Further, the photo semiconductor chip may be formed on the conductive foil that is not subjected to the press working.  
         [0099]    In this case, as described above, the gloss can be given to the Ag film  162  by not bending the conductive foil  61  but applying the pressure to the conductive foil  161  (and the Ag film  162 ) by the press, etc. in the situation that the Ag film  162  is formed, and thus the improvement of the irradiation efficiency can be achieved.  
         [0100]    Then, in FIG. 13, the photo semiconductor chip  165  is electrically connected to the conductive foil  161  in which the isolation trenches  164  are formed. Here the light emitting diode is employed as the photo semiconductor chip  165 . The photo semiconductor chip  165  is bonded onto a first electrode  151 A, described later, by the die bonding, and also the front surface of the photo semiconductor chip  165  and a second electrode  151 B are bonded by the wire bonding via a metal thin wire  166  (see FIG. 15).  
         [0101]    Then, in FIG. 14, the conductive foil  161  containing the photo semiconductor chips  165  is covered with the insulating resin  167  that can transmit the light emitted from the photo semiconductor chip  165 . In this step, the conductive foil  161  having the photo semiconductor chips  165  and the isolation trenches  164  is sealed with the thermosetting silicon resin or epoxy resin by virtue of the transfer molding using the mold (not shown). As described above, the resin  67  may be any resin which can transmit the light, and thus the so-called transparent resin or the opaque resin can transmit the light of a predetermined wavelength may be employed.  
         [0102]    Here, in order to collect the light from the photo semiconductor chips  165  as much as possible and emit it upward, the resin  167  has a convex lens shape. Accordingly, if viewed from the top, the lens has a substantially circular shape, as shown in FIG. 17. A thickness of the resin  167  (lens) coated on the surface of the conductive foil  161  can be set thick or thin with regard to the strength.  
         [0103]    The feature of the present step is that the conductive foil  161  acts as the supporting substrate until the light resin  167  serving as the lens is coated. Then, since the good radiation characteristic is obtained rather than the structure in which the light emitting diodes  2  are mounted onto the printed circuit board  1  like the related art (see FIG. 19), the driving capability can be improved.  
         [0104]    Further, since the conductive foil  161 , used as the supporting substrate in the present invention, is the material that is necessary for the electrode material. Therefore, the present invention has the advantage such that the constituent material can be omitted to the utmost and can also achieve the reduction in cost.  
         [0105]    Also, since the isolation trench  164  is formed shallower than the thickness of the conductive foil  161 , the conductive foil  161  is not individually separated as the conductive paths  151 . Accordingly, there is the advantage such that, when the sheet-like conductive foil  161  must be exchanged as a whole and then the resin  167  must be molded, the carrying operation to the mold and the fitting operation into the mold can be very simplified.  
         [0106]    When the photo semiconductor chip  165  is sealed with the resin, the potting resin may be coated on the photo semiconductor chip  165  instead of the employment of the mold so as to form the lens shape.  
         [0107]    However, in this case, since both the silicon resin and the epoxy resin has small viscosity at the time of the heat curing, there is the problem such that the resin cannot be stably formed into the hemispherical shape that is preferable as the lens. In contrast, there is the advantage such that, if the above lens forming method using the mold is employed, the stable lens shape can be constructed. When the lens shape is not needed, the insulating resin  167  may be somewhat thin, further, others than transfer molding using the mold may be used.  
         [0108]    In turn, in FIG. 15, there is the step that the conductive foil  161  is separated as the conductive paths  151  by removing the back surface of the conductive foil  161  chemically and/or physically. Here this removing step is carried out by the polishing, the grinding, the etching, the metal evaporation by the laser, etc.  
         [0109]    In the present embodiment, the conductive foil  161  under the isolation trench  164  is deleted by wet-etching the conductive foil  161  while using the Ag film  162 , that adheres onto the back surface of the conductive foil  161 , as a mask. Thus, the resin  167  is exposed to separate the conductive paths respectively. Accordingly, there can be obtained such a structure that surfaces of conductive paths  151 A,  151 B (a first electrode and a second electrode) are exposed from the resin  167 .  
         [0110]    At this time, the resin  167  may be exposed from the isolation trench  164  by scraping the back surface of the conductive foil  161  by about 50-60 μm by virtue of the polishing machine, the grinding machine, or the like. In this case, the conductive foil  161  is separated as the conductive paths having a thickness of about 40 μm. Also, the resin  167  may be exposed by wet-etching the entire surface of the conductive foil  161  to the extent not to expose the resin  167 , and then scraping the overall surface by virtue of the polishing or grinding machine. In this case, the flat light irradiating device, in which the conductive paths  151  are buried in the resin  167  and the back surface of the resin  167  coincides in level with the back surface of the conductive paths  151 , can be implemented.  
         [0111]    Further, if the conductive paths  151  are separated by scraping the back surface of the conductive foil  161  by virtue of the polishing machine, the grinding machine, or the like, the oxidation inhibiting process of the conductive paths  151  may be applied by depositing the conductive material such as the solder, etc. onto the exposed conductive paths  151 , as occasion demands.  
         [0112]    Finally, there is the step of separating the neighboring light irradiating devices individually to complete the light irradiating device.  
         [0113]    This separating step can be carried out by the dicing, the cutting, the chocolate break, etc. If the chocolate break is employed, copper pieces  169  are stripped off from both end portions of the resin  167 , that covers the light irradiating devices  168 , by the press machine indicated by a dot-dash line in FIG. 16, whereby respective light irradiating devices  168  are separated. In this case, there can be achieved the advantage that, since the flash removing process of the back surface can be omitted unlike the dicing, the cutting, etc., the good workability can be achieved.  
         [0114]    The feature of the present manufacturing method resides in that the separating operation of the conductive paths  151  can be attained while practically using the resin  167  as the supporting substrate. The resin  167  is the material necessary to fill the conductive paths  151 , and the substrate used only for the supporting is not needed during the manufacturing steps. Accordingly, the present invention has the feature such that the light irradiating device can be manufactured by the minimum material and thus the reduction in cost can be accomplished.  
         [0115]    The thickness of the resin from the surface of the conductive paths  151  can be adjusted when the resin is adhered in the preceding step. Therefore, the present invention has the feature such that the thickness of the light irradiating device  168  can be set thick or thin although such thickness is different according to the packaged photo semiconductor chip. The light irradiating device in which the conductive paths  151  of 40 μm thickness and the photo semiconductor chips are buried in the resin  167  of 400 μm thickness is obtained herein (see FIG. 16 and FIG. 17 as for the above).  
         [0116]    [0116]FIG. 18 shows a lighting apparatus  168  in which the light irradiating devices  168  (light emitting diodes) are connected in series between an electrode  130  and an electrode  131  to make constant the current value that flows through the light irradiating devices  168 .  
         [0117]    Ten sheets of electrodes are formed between the electrode  130  and the electrode  131 . The back surface of the chip serving as the cathode electrode (or the anode electrode) of the light irradiating device  168  is fixed to an electrode  132 , and the anode electrode (or the cathode electrode) and the electrode  130  are connected by a metal thin wire  166 . Also, the back surface of the chip of the second light irradiating device  168  is fixed to an electrode  133 , and the electrode on the surface of the chip and the electrode  132  are connected by the metal thin wire  166 . That is, the electrode to which the back surface of the chip serving as the cathode electrode (or the anode electrode) is fixed is connected to the metal thin wire extended from the anode electrode (or the cathode electrode) of the succeeding light irradiating device  168 . The series connection can be completed by repeating this connection mode. The light irradiating devices are arranged on the predetermined portion of the electrodes by a robot having movable arm with respect to X-Y-Z (lengthwise direction—crosswise direction—up and down direction) The lighting apparatus  140  may be used to traffic light etc., for example.  
         [0118]    Also, in order to form the electrode formed of the copper foil as a reflection plate, Ni is coated on the surface of the electrode. Then, in order to form the all area of the substrate as a substantial reflection plate, the electrodes are patterned such that the overall area of the substrate is covered substantially completely with  12  electrodes from the right electrode  130  to the left electrode  131 .  
         [0119]    According to the lighting apparatus  140 , there can be achieved the advantage such that, since the heat generated from the light irradiating device  168  can be radiated via a metal substrate  111 , the driving current of the light irradiating devices  168  can be set large.  
         [0120]    Although the illustration is omitted, even if the light irradiating devices  168  are connected in parallel, or the light irradiating devices  168  are connected so that serial connections and parallel connections are combined, similarly the lighting apparatus  140  that have the good radiation characteristic can be accomplished.  
         [0121]    Further, as a means for improving the adhesiveness between the conductive foil  61 ,  161  and the insulating resin  67 ,  167 , the surface of the conductive foil  61 ,  161  may be oxidized to form a copper oxide film (CuO, or Cu 2 O). This improves the adhesiveness without forming conductive film  62 ,  162 .  
         [0122]    In addition, according to the inventors, it is found that the better adhesiveness is obtained when the state of the surface of the conductive film  61 ,  161  is Cu 2 O state rather than CuO state, that is, lower oxidization rate the better adhesiveness can be obtained.  
         [0123]    As apparent from the above explanation, in the present invention, it is possible to accomplish the light irradiating device that can be constructed by the required minimum elements including the photo semiconductor chip, the conductive paths (conductive electrodes), and the resin serving as the lens and that can save waste of the resource. Accordingly, it is possible to accomplish the light irradiating device in which no extra element is needed until the completion and the cost can be reduced considerably. Also, the very small, thin, and lightweight light irradiating device can be accomplished by setting the coated thickness of the resin and the thickness of the conductive foil to their optimum values.  
         [0124]    Further, since only the back surfaces of the conductive paths are exposed from the resin, the present invention has the advantage such that the back surfaces of the conductive paths can be immediately connected to the outside and thus the back surface electrodes and the through holes in the conventional structure can be omitted. Also, the radiation characteristic can be improved rather than the structure in which the photo semiconductor chips are mounted on the printed circuit board in the related art, and thus the driving capability of the photo semiconductor chips can be increased.  
         [0125]    Also, if the conductive film is formed at least in the areas of the surface of the conductive foil as the conductive paths, this conductive film is left on the upper surface of the conductive foil like the visor when the isolation trenches are formed in the conductive foil. Therefore, the adhesiveness between the conductive foil and the resin can be improved when the light irradiating device is covered with the resin.  
         [0126]    Further, if the conductive foil is bent to have an inclination angle that enables the light emitted from the photo semiconductor chip to reflect upwardly when such conductive foil is bent to surround at least the areas of the conductive foil to which the photo semiconductor chips are fixed, the irradiation efficiency can be improved.  
         [0127]    If the conductive foil is bent by a press in the situation that the conductive film is formed on the conductive paths, the gloss appears on the conductive film and thus the irradiation efficiency can be improved further.  
         [0128]    Also, after the light irradiating devices are covered with the resin to fill the isolation trenches, there are provided the step of removing the conductive foil on the side, in which the isolation trenches are not provided, up to a predetermined position and then the step of separating the light irradiating devices that are covered with the resin. Therefore, respective light irradiating devices are not separated up to the final stage, and accordingly the conductive foil can be provided to respective steps as one sheet and thus the workability becomes good.  
         [0129]    Further, since the resin is adhered by the transfer molding employing the mold, the workability becomes good and the proper shape can be formed. Particularly, it is suitable for forming a lens shape.  
         [0130]    Also, in case the light irradiating devices that are sealed with the resin are separated individually by the press machine, the process of removing the flash generated on the end portions of the light irradiating devices is not needed and thus the productivity can be improved.