JP4429115B2 - Lid and optical element storage package using the same - Google Patents

Description

  The present invention relates to a lid for protecting an optical element from external mechanical shock, vibration, or moisture intrusion, and an optical element storage package, and more particularly to an imaging element such as a CCD or CMOS, an optical switch, a mirror device, etc. The present invention relates to a lid for protecting optical elements such as LD and PD for MEMS, CD, and DVD, and an optical element storage package using the lid.

  A conventional lid and an optical element storage package using the same are shown in FIG. In FIG. 2, 11 is a window, 12 is a sealing material, 13 is a metal frame, 14 is a lid, and 15 is a base.

The window 11 is a substance having a thermal expansion coefficient of 5.0 to 8.0 × 10 ⁻⁶ / ° C. and a Young's modulus of 45 to 100 GPa, and is mainly made of borosilicate glass. The sealing material 12 is made of a bonding glass having a thermal expansion coefficient of 5.0 to 8.0 × 10 ⁻⁶ / ° C., a Young's modulus of 45 to 100 GPa, and a sealing temperature of 300 to 500 ° C. The metal frame 13 is made of a metal material such as an iron (Fe) -nickel (Ni) -cobalt (Co) alloy having a thermal expansion coefficient of about 5.0 to 7.0 × 10 ⁻⁶ / ° C. and a Young's modulus of 100 to 220 GPa. Thus, the lid body 14 is made of three materials having different physical property values.

Such an optical element storage package (hereinafter also referred to as a package) includes a metal frame 13 having an opening for transmitting light, and a transparent member bonded through a sealing material 12 so as to cover the opening. It is composed of a flat lid 14 made of a light window 11 and a base body 15 having a recess for receiving and mounting an optical element on an upper surface made of a metal material capable of machining such as cutting and pressing. The lid body 14 and the base body 15 are joined by seam welding or the like.
JP 2002-33407 A

However, when materials having different coefficients of thermal expansion are joined by applying heat, warping occurs. For example, in the lid 14 shown in FIG. 2, the window 11 has a thermal expansion coefficient of 7.0 × 10 ⁻⁶ / ° C. and a thickness of 0.4 mm, and the sealing material 12 has a thermal expansion coefficient of 7.2 × 10 ⁻⁶ / ° C. In the case where the thermal expansion coefficient of 13 is composed of 10.0 × 10 ⁻⁶ / ° C. and a thickness of 0.55 mm, the sealing material 12 is used to perform glass bonding with a heat of 300 to 500 ° C. after the sealing process. At this time, since each component member contracts in proportion to the thermal expansion coefficient, due to the difference in contraction rate, the lid body 14 is deformed into a convex shape having a high center and a low end, and 30 to 30 A warp of 150 μm occurs. When the lid 14 having the warp and the base body 15 are joined by seam welding, a stress is applied to the lid body 14 so as to deform in the direction opposite to the warp, so that the lid body conforms to the shape of the base body 15. The lid body 14 and the base body 15 are joined while deforming 14. That is, the lid body 14 is joined to the base body 15 in a short time required for seam welding while receiving a stress that deforms in a direction opposite to the warp by pressing the seam welding electrode roller from the top surface of the lid body 14. Therefore, this stress cannot be dispersed and a very large residual stress is generated.

  Residual stress due to this bonding is also generated in the window body 11, and the window body 11 is easily broken to cause cracks, or the bonding strength between the window body 11 and the sealing material 12 is weakened to cause interface peeling. To do. Further, the hermetic sealing of the package is broken from these parts, and there is a problem that the optical element housed and mounted inside cannot be operated normally and stably over a long period of time.

  In addition, during seam welding, a large amount of heat is instantaneously generated at the joint surface between the lid body 14 and the base body 15, but the heat from this welding is also transmitted to the sealing material 12 and the window body 11, and the sealing material 12 The thermal stress is generated from the difference in thermal expansion coefficient between the window 11 and the window 11. This thermal stress may also cause cracks in the window 11, cause interface peeling between the window 11 and the sealing material 12, and cause a decrease in bonding strength, and the hermetic sealing of the package is broken from these parts. Therefore, there is a problem that the optical element housed and mounted inside cannot be operated normally and stably over a long period of time.

  Furthermore, when the thermal conductivity of the metal frame 13 is high, the amount of heat generated during seam welding is easily transferred to the sealing material 12 and the window 11, while the temperature gradient when cooled is increased. Since the thermal stress caused by the difference in thermal expansion coefficient becomes very large, the above problem becomes more prominent.

  In addition, the thermal expansion coefficient of each component is not constant but temperature-dependent, and considering the thermal conductivity, the thermal conductivity and thermal expansion coefficient of each component are approximated to prevent warping and peeling due to thermal stress. It is practically difficult to do this, and it is also practically difficult to control the shape and joints so that the warpage of each component becomes equal.

  Therefore, the present invention has been devised in view of such conventional problems, and its purpose is to crack or bond window bodies due to residual stress or thermal stress generated due to deformation or heat during seam welding. The lid can be effectively prevented from being broken and has high airtight reliability. In particular, an object of the present invention is to provide an optical element storage package that can reduce residual stress generated in a window.

The lid of the present invention covers a first frame body having a recess on the lower surface and an opening for transmitting light penetrating between the upper surface and the bottom surface of the recess, and the opening. the outer peripheral portion of the upper main surface is bonded through a first sealing member around said opening of said recess, a first lid body consisting placed glass window member in the recess The lower surface of the first frame body of the first lid is formed through the second sealing material on the upper surface of the inner peripheral portion around the opening, the opening being formed in the central portion and being thicker than the outer peripheral portion. And a second frame joined to each other.

  In the lid of the present invention, preferably, the first frame is thicker than the second frame, and the Young's modulus of the first frame is Young's of the second frame. It is characterized by being greater than the rate.

  In the lid of the present invention, preferably, the first frame body has a thermal conductivity smaller than that of the second frame body.

  An optical element storage package of the present invention includes a base body having a recess for storing an optical element on an upper surface thereof, and the lid body of the present invention joined to the upper surface of the base body so as to close the recess. It is characterized by that.

The lid of the present invention includes a first frame body having a recess on the lower surface and an opening for transmitting light penetrating between the upper surface and the bottom surface of the recess, and an upper side so as to cover the opening. The outer peripheral portion of the main surface is joined to the periphery of the opening in the recess through a first sealing material, and the first lid is formed of a glass window disposed in the recess, and the central portion opens. A second frame in which the lower surface of the first frame of the first lid is bonded to the upper surface of the inner peripheral portion around the opening thicker than the outer peripheral portion via the second sealing material The second frame greatly deforms the residual stress and thermal stress generated when the lid is seam welded with deformation so as to follow the shape of the base body. Can absorb and disperse, so that the first lid to which the window is joined is effectively strained and warped by stress. To be suppressed.

  Further, since the window body is joined to the second frame body via the first frame body, the first sealing material, and the second sealing material, heat due to seam welding is hardly transmitted to the window body. The deformation of the window and the first frame itself due to heat and the generation of stress due to the deformation can be effectively suppressed.

Further, since the window body is joined around the opening in the recess of the first frame body and disposed in the recess, the window body in the recess is protected by the first frame body, and the package is manufactured. It is possible to protect the window body from the occurrence of scratches or falling off due to external factors such as collision or contact during time or use.

  In the lid of the present invention, preferably, the first frame is thicker than the second frame, and the Young's modulus of the first frame is larger than the Young's modulus of the second frame. Residual stress and thermal stress generated during seam welding can be effectively absorbed and dispersed by deformation of the second frame. By doing so, it becomes difficult for the first frame to be deformed, so that external force applied to the window and the first sealing material can be suppressed. As a result, the occurrence of stress and warpage of the relatively weak window body and the first sealing material can be reduced, so that cracks in the window body and destruction of the sealing portion between the window body and the first sealing material can be prevented. A lid that can be effectively prevented and has high hermetic reliability can be realized.

  The lid of the present invention preferably has a heat conductivity generated in the second frame during seam welding because the first frame has a thermal conductivity smaller than that of the second frame. However, since it is difficult to transmit from the second frame to the first frame, thermal stress is further prevented from occurring in the window and the first sealing material, and a lid with higher hermetic reliability is realized. can do.

  An optical element storage package of the present invention includes a base body having a recess for storing an optical element on the upper surface, and a lid body of the present invention joined to the upper surface of the base so as to close the recess. Therefore, it is possible to effectively suppress the occurrence of stress and warpage in the lid due to residual stress and thermal stress generated during seam welding. Since it is possible to effectively prevent the occurrence of cracks and bond breakage, it is possible to provide an optical element storage package with stable optical characteristics over a long period of time.

  Next, a lid of the present invention and an optical element storage package (hereinafter also referred to as a package) using the same will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing an example of an embodiment of a lid of the present invention and an optical element storage package using the same. In FIG. 1, reference numeral 1 denotes a glass window on which an antireflection film is formed, and reference numeral 2 denotes a first member that joins the outer periphery of the upper main surface of the window 1 and the periphery of the opening 3 a in the recess 3 b of the frame 3. One sealing material, 3 is a first frame body, 4 is a first lid body, 5 is a lower surface of the first frame body 3 of the first lid body 4, and an opening 6a of the second frame body 6. 2nd sealing material which joins the circumference | surroundings, 6 is the 2nd frame, 7 is the 1st cover body 4 and the 2nd frame 6 joined via the 2nd sealing material 5. The lid body 8 of the present invention indicates a base body having a recess for mounting an optical element on the upper surface. The first lid body 4 is mainly composed of the window body 1, the first sealing material 2, and the first frame body 3. The lid 7 of the present invention is constituted by the first lid 4, the second sealing material 5, and the second frame 6, and the optical element housing of the present invention is further constituted by the lid 7 and the base body 8. A package is configured.

  Although the material of the window body 1 will not be restrict | limited especially if it is a translucent glass material, For example, hard glass materials, such as borosilicate glass, soda glass, and sapphire glass, are employable. The window body 1 is generally manufactured by forming these materials into a plate-shaped wafer, polishing the wafer surface, and then cutting it into individual pieces.

Note that an antireflection film is preferably applied to the wafer to be the window body 1 by coating or vapor deposition in order to improve light transmission. The antireflection film is formed by laminating titania (TiO ₂ ), alumina (SiO ₂ ), zirconia (ZrO ₂ ), magnesium fluoride (MgF ₂ ), etc. in a multilayer manner by vacuum deposition, high-frequency ion plating, sputtering, or the like. It is formed. The number of layers and the thickness of each layer vary depending on the required optical characteristics, but the total thickness of the antireflection film is 0.1 to 5.0 μm, and the heat resistance of the antireflection film and the low melting point that becomes the first sealing material 2 It is preferable when ensuring adhesion with glass.

  To cut the window 1 from the wafer into individual pieces, first, for example, a vinyl chloride having a thickness of 90 μm and a wafer having a diameter of 6 inches and a thickness of 0.5 to 1 mm bonded to a stainless steel (SUS) frame plate. A window member with a circular blade rotation speed of 20,000 rpm or more and a circular blade feed speed of 20 mm / second by a dicing machine that is adhered to the center of the film made and then set with a circular blade with a diameter of 80 mm and a thickness of 0.15 mm Is cut into pieces of 20 to 25 mm × 10 to 15 mm, for example. The individual pieces cut out from the wafer are more preferable from the viewpoint of stress relaxation with the first sealing material 2 because the sealing area can be increased by chamfering the end face corners.

The first sealing material 2 and the second sealing material 5 are not particularly limited as long as they are low-melting glass. For example, lead borate glass (PbO—B ₂ O ₃ system), borate glass (B ₂ O ₃ system, Li ₂ O—B ₂ O ₃ system, Na ₂ O—B ₂ O ₃ system, etc.), lead silicate glass (PbO—SiO ₂ system, PbO—B ₂ O ₃ —SiO ₂₎ Etc.), phosphate glass (Na ₂ O—P ₂ O ₅ series, B ₂ O ₃ —P ₂ O ₅ series, etc.), tin zinc phosphate glass (P ₂ O ₅ —SnO—ZnO series), etc. From the viewpoint of the global environment, lead-free glass such as borate glass, phosphate glass, and tin zinc phosphate glass is preferable.

  The first sealing material 2 and the second sealing material 5 are made of a mixed paste obtained by adding and mixing an inorganic filler, an organic solvent, a plastic material, and the like with low melting point glass powder. The first frame 3 is applied to the first frame 3 or the second frame 6 by screen printing or a dispenser so as to have a thickness of about 300 μm, and melted in the atmosphere at a temperature of about 350 to 470 ° C. And the window body 1 and the 1st window body 4 and the 2nd frame 6 are joined.

  The width of the glass sealing portion at the outer peripheral portion of the window body 1 to which the first sealing material 2 is applied is preferably 0.5 to 2 mm. When the width is less than 0.5 mm, the amount of the first sealing material 2 is insufficient, and when the window body 1 is joined to the first frame 3, an airtight failure occurs or the joining strength decreases. There is a tendency to cause the window body to peel off. If the width exceeds 2 mm, the sealing width becomes excessively wide, and it is necessary to increase the amount of the first sealing material 2 in order to seal a wide width. As a result, the first frame 3 has a window. When the body 1 is joined, the first sealing material 2 flows out to the lower main surface of the window body 1, that is, the main surface on the base body 8 side, or flows into the side wall of the frame to transmit light. The region is narrowed, and the light transmittance of the window body 1 tends to deteriorate.

  Further, in the first frame 3 and the second frame 6, an area where the first sealing material 2 and the second sealing material 5 are not attached is used to prevent corrosion and the second frame. Various plating layers may be formed for seam welding between the outer peripheral lower surface of the body 6 and the base 8. This plating layer is preferably formed by applying nickel (Ni) plating to a thickness of 1 to 5 μm and then applying gold (Au) plating to a thickness of 1 to 2 μm.

The first frame 3 has a recess 3b on the lower surface, the opening 3a for transmitting light penetrating between the bottom surface of the top surface and the recess 3b in the central portion is withdrawn Chi hit by punching mold fabricated into the shape, the plate or the like made of a metal material, is manufactured by Nuku striking Chi openings 6a in punching mold for transmitting light in the center.

  Examples of the material of the first frame 3 and the second frame 6 include iron (Fe) -nickel (Ni) -cobalt (Co) that can be machined such as cutting and pressing as the first frame 3. ) Fe (55%)-Ni (29%)-Co (16%) alloy (Young's modulus: 130 GPa, thermal conductivity: 16.7 W / mK) which is an alloy, and copper (Young's modulus: A combination of metal materials such as 125 GPa and thermal conductivity: 421 W / mK), alumina ceramics (Young's modulus: 250 to 400 GPa, thermal conductivity: 10 to 100 W / mK) as the first frame 3, second As the frame body 6, a Fe (55%)-Ni (29%)-Co (16%) alloy (Young's modulus: 130 GPa, thermal conductivity: 16.7 W / mK) or the like, such as Fe-Ni-Co alloy or 42 alloy ( Fe (48%)-Ni (42%) alloy, Young's modulus: 147 GPa, thermal conductivity: 15.0 W / mK, 50 alloy (Fe (50%)-Ni (5 (0%) Alloys, Young's modulus: 160 GPa, thermal conductivity: 19.0 W / mK) and metal materials such as copper (Young's modulus: 125 GPa, thermal conductivity: 421 W / mK) may be combined.

  Further, the thickness t1 of the first frame 3 is preferably larger than the thickness t2 of the second frame 6 and has a larger Young's modulus. As a result, the second frame 6 can be made to be more easily deformable than the first frame 3, so that residual stress and thermal stress generated during seam welding can be reduced by deformation of the second frame 6. The second frame 6 can effectively absorb the external force applied to the second sealing material 5 and the first lid 4. Furthermore, since the first frame 3 itself is not easily deformed, the external force applied to the window body 1 and the first sealing material 2 is suppressed. Due to these synergistic effects, the window 1 attached to the first frame 3 and the external force generated by the stress and warpage generated during seam welding on the first sealing member 2 joining the window 1 are joined. It can be very effectively deterred.

  Furthermore, the first frame 3 preferably has a thermal conductivity smaller than that of the second frame 6. Since the thermal conductivity of the first frame 3 is smaller than the thermal conductivity of the second frame 6, heat generated during seam welding is transferred from the second frame 6 to the first frame 3. Since it is difficult to transmit, the first frame 3 is less likely to be deformed or thermally stressed by the transmitted heat, and the window 1 and the first frame 3 attached to the first frame 3 It is possible to effectively prevent the sealing material 2 from being cracked or bonded. Therefore, selecting a material having a small thermal conductivity for the second frame 6 and selecting a material having a thermal conductivity of the first frame 3 smaller than that of the second frame 6 is as follows. It is preferable in order not to generate cracks and joint breakage in the window body 1 and the first sealing material 2.

  Moreover, it is preferable that thickness t1 of the junction part with the 1st sealing material 2 of the 1st frame 3 shall be the range of 0.1 thru | or 0.7 mm. If the thickness of the joint portion between the first frame 3 and the first sealing material 2 is less than 0.1 mm, the residual stress of the lid 7 generated when the lid 7 and the base body 8 are seam welded. As cracks and strength decrease of the window body 1 occur, residual stress acts on the first sealing material 2, and interface peeling between the first sealing material 2 and the window body 1 and the first frame body 3 occurs. The bonding strength is reduced. On the other hand, when the thickness t1 of the first frame 3 exceeds 0.7 mm, the distance from the upper surface of the window body 1 to the upper surface of the first frame 3 increases, so that light generated by the optical element passes through the window body 1. Then, since the probability of being blocked by the opening side wall of the first frame 3 is increased, the light transmittance may be reduced, and the optical characteristics of the package as a product may be deteriorated. Therefore, the thickness of the first frame 3 is preferably 0.1 to 0.7 mm.

  Furthermore, the thickness t2 of the second frame 6 is preferably in the range of 0.1 to 0.2 mm. If the thickness of the seam welded portion of the second frame 6 is less than 0.1 mm, the thermal history in the step of joining the first lid 4 to the second frame 6 via the second sealing material 5 and the like The second frame 6 may be greatly deformed by the influence of the above. On the other hand, if the thickness of the second frame 6 exceeds 0.2 mm, the heat of the welding is easily escaped in the seam welding process, and if a large amount of current is not passed through the seam welded portion, the second frame 6 of the seam welded portion. In some cases, Ni deposited on the lower surface of the substrate does not sufficiently melt, and it becomes difficult to hermetically seal the lid 7 and the base 8.

Second frame 6, the thickness t2 of the peripheral portion to be seam welded of the second frame 6 is thinner than the inner circumferential portion is of a shape as shown in FIG. With the shape as shown in FIG. 1, becomes the second frame 6 backlash Wami structure easy, the residual stress and thermal stress generated during seam welding effectively by the deformation of the second frame 6 Can be absorbed and dispersed. By doing so, the first frame 3 is less likely to be deformed, so that an external force applied to the window body 1 and the first sealing material 2 can be suppressed. As a result, stress and warpage generated in the window body 1 and the first sealing material 2 having relatively low strength can be reduced, so that cracks in the window body 1 and sealing between the window body 1 and the first sealing material 2 can be achieved. The lid can be effectively prevented from being broken and a highly airtight and reliable lid can be realized.

  The substrate 8 is made of alumina ceramic, iron (Fe) -nickel (Ni) -cobalt (Co) alloy, copper (Cu) -tungsten (W) alloy, or the like, and has a recess 8a for accommodating an optical element on the upper surface. It is formed by cutting or the like. A wiring conductor (not shown) is led out from the periphery of the optical element in the recess 8a to the outside of the base 8.

  First, when the material of the base 8 is made of alumina ceramic, for example, a wiring layer serving as a wiring conductor for conducting the inside and outside of the base 8 is formed on the wall surface or bottom surface of the base 8. Further, since the metal body cannot be seam welded around the recess 8a on the upper surface of the base body 8 because the base body 8 is made of an insulator such as alumina ceramics, it is metalized on the joint surface of the base body 8 with the lid body 7. A layer 9 made of Fe—Ni—Co alloy or the like is joined to the metallized layer with a silver brazing material having a melting point of about 700 ° C.

  When the material of the substrate 8 is made of a metal material such as Fe—Ni—Co alloy or Cu—W alloy, a lead pin for wiring made of Fe—Ni—Co alloy or the like is provided in the through hole provided on the wall surface or bottom surface. For example, they are joined by being inserted into the through-holes through a joining material made of a high melting point glass such as boric acid glass having a melting point of about 900 degrees.

  Then, the optical element is mounted in the recess 8a of the base 8 with a low melting point metal brazing material such as an Au—Sn alloy or an Au—Si alloy, and the electrode of the optical element is formed at one end in the recess 8a of the wiring conductor with Al or the like. After connecting by wire bonding of Au or the like, the lid body 7 of the present invention is placed on the upper surface of the base body 8 so as to close the recess 8a, and a seam welding roller is pressed against the upper surface of the outer peripheral portion of the lid body 7 By applying a current of 80 to 130 mA, the lid body 7 is welded to the base body 8, and the optical element storage package of the present invention is completed.

  The optical device can be optically excited by supplying a drive signal from the outside of the package via a wiring conductor or a wiring lead pin, and the excited light can be output to the outside through the window body 1. . Alternatively, an optical device that inputs an optical signal from the outside from the window body 1, converts the optical signal into an electrical signal by the optical element of the recess 8a, and outputs the electrical signal to the outside through a wiring conductor or a wiring lead pin. can do.

  According to the package of the present invention, the substrate 8 having the recess 8a for accommodating the optical element on the upper surface, and the lid body 7 of the present invention joined to the upper surface of the substrate 8 so as to close the recess 8a. Therefore, it is possible to effectively prevent the lid body 7 from being stressed or warped due to residual stress or thermal stress generated during seam welding. Since it is possible to effectively prevent the occurrence of cracks and joint breakage of the sealing portion between the first sealing material 2 and the first sealing material 2, it is possible to provide an optical element storage package with stable optical characteristics over a long period of time. it can.

  The package of the present invention includes, for example, an image sensor such as a CCD and a CMOS, an MEMS such as an optical switch and a mirror device, an LD (laser diode) for reading or writing a CD or DVD, a PD (photodiode), etc. It is suitable for accommodating an optical element that performs optical signal conversion.

Examples of the optical element storage package of the present invention will be described below.
In manufacturing the package as shown in FIG. 1, borosilicate glass having an outer shape of 21.40 mm long × 13.20 mm wide × 1.00 mm thick was prepared as the window body 1.

  Next, the outer dimensions are 27.75 mm in length × 16.75 mm in width × 2.00 mm in height, and the size of the recess 3b for accommodating the window body 1 made of borate glass described above is 22.40 mm in length × 14.40 mm in width × height. (2.00-t1) mm, the dimension of the opening 3a is 17.30 mm in length × 9.20 mm in width, and two kinds of materials, an alumina ceramic having a Young's modulus of about 310 GPa and an Fe—Ni—Co alloy having a Young's modulus of about 145 GPa, are used. The first frame 3 used was prepared. The first frame 3 made of an Fe—Ni—Co alloy was sequentially plated with a nickel layer having a thickness of 5.0 μm and a gold layer having a thickness of 2.0 μm on the surface thereof.

  A first sealing material 2 made of lead borate glass, which is a low-melting glass having a melting point of about 320 ° C., is applied around the opening 3a of the recess 3b of the first frame 3, and is applied to the heater block. The outer peripheral portion of the upper main surface of the window body 1 is melted by being heated to 350 ° C. around the opening 3 a in the recess 3 b of the first frame 3 via the first sealing material 2. The joined first lid 4 was produced.

  Next, the outer dimensions are 31.20 mm long x 20.20 mm wide x 0.5 mm thick, the seam weld thickness is t2 mm, the dimensions of the opening 6a are 17.30 mm long x 19.20 mm wide, and a nickel layer with a thickness of 5.0 μm on the surface And a second frame 6 using two kinds of materials consisting of a Fe-Ni-Co alloy having a Young's modulus of approximately 145 GPa and copper having a Young's modulus of approximately 125 GPa, in which a gold layer having a thickness of 2.0 μm is sequentially plated. Got ready. The second sealing material 5 made of the same lead borate glass as that of the first sealing material 2 is applied to the periphery of the opening 6a on the upper surface of the second frame 6, and 350 ° C. is applied by a heater block. The lid body 7 of the present invention in which the lower surface of the first frame body 3 of the first lid body 4 was joined via the second sealing material 5 was produced by heating to ° C. and melting.

  Furthermore, a metal composed of an Fe-Ni-Co alloy with a Young's modulus of about 145 GPa, measuring 31.20 mm long x 20.20 mm wide x 0.7 mm thick, seam weld thickness 0.1 mm, opening dimensions 17.30 mm long x 19.20 mm wide A conventional lid 14 in which a nickel layer having a thickness of 5.0 μm and a gold layer having a thickness of 2 μm were sequentially plated on the surface of the frame 13 was prepared.

  Then, a base body 8 made of alumina ceramics having outer dimensions as shown in FIG. 1 of length 28.75 mm × width 17.75 mm × thickness 12.0 mm, and the size of the recess 8 a is length 24.75 mm × width 13.75 mm × height 10.0 mm, Silver brazing material with a melting point of about 700 ° C consisting of a seal ring frame 9 made of an Fe-Ni-Co alloy with outer dimensions of 27.75 mm long x 16.75 mm wide x 0.50 mm thick and an opening dimension of 26.75 mm long x 15.75 mm wide A base 8 joined by the above method was prepared, and the lid 7 and the base 8 were joined by seam welding (NAW-1099 manufactured by Nippon Avionics Co., Ltd.) as an evaluation sample.

  It should be noted that the thickness t1 of the joint portion between the first frame 3 and the first sealing material 2 is 0.1 mm, 0.3 mm, and 0.7 mm, and the thickness t2 of the seam welded portion of the second frame 6 is Two types of 0.1 mm and 0.2 mm, two types of first frames 3 made of two types of materials as described above, and two types of second frames 6 made of two types of materials, A total of 19 types obtained by adding the lid 14 of the conventional product to 18 types of evaluation samples among the combinations of the above were used as evaluation samples.

  The evaluation was performed by seaming the lid body 7 and the base body 8 after seam welding, measuring the temperature of the constituent members, and further performing the appearance test and the airtightness test again after the thermal shock test. Each test was conducted by the following method.

  In the appearance test of the window body 1 and the first sealing material 2, the presence or absence of cracks in the window body 1 and the first sealing material 2 and the presence or absence of peeling of the joint portion were confirmed with a 20-fold microscope. If there was no pass, it was judged as acceptable (◯), and if it was present, it was rejected (x).

In the airtightness test, the one that passed the appearance test was judged to pass or fail according to the standard of MIL-STD-883 METHOD 1014.10 SEAL using a fine leak device (Helium Leak Detector Model 305 manufactured by HELIOT ULVAC), and 1.0 × 10 ⁻ If it was less than ⁹ Pa · m ³ / sec, it was judged as acceptable (◯), and if it was more than that, it was judged as unacceptable (x).

  Then, after repeating the thermal shock test in which the sample was left in a thermostatic chamber at 0 ° C. for 5 minutes and then left in a thermostatic layer at 100 ° C. for 5 minutes, the same appearance test and airtightness test were performed again, and both passed. Pass (◯), otherwise it was rejected (x).

  Moreover, in order to judge the magnitude | size of the residual stress of the window body 1, the difference between the height of the highest part of the window body 1 and the height of the lowest part is measured when it cools after seam welding and returns to normal temperature, This was the warp of the window body 1. Since the residual stress is smaller when the warpage of the window body 1 is smaller, it can be determined that the airtight reliability is more excellent.

  Further, the residual temperature generated in the window body 1 and the first sealing material 2 when the temperature of the member (the window body 1 and the first sealing material 2) immediately after seam welding is cooled and returned to room temperature. Since it is greatly related to stress, the temperature of the upper surface of the window body 1 and the first sealing material 2 is measured by attaching a thermocouple with heat-resistant tape and using a temperature profile meter (manufactured by Keyence) during seam welding. did.

  The temperature of the window body 1 and the first sealing material 2 was measured in the case of seven types in which a conventional product was added to six types of evaluation samples in which the thickness t1 of the first frame 3 was 0.1 mm. Note that the thermal conductivities of the Fe—Ni—Co alloy, alumina ceramic, and copper used in the evaluation are 16.7 W / mK, 16.0 W / mK, and 421.0 W / mK, respectively.

  If the thermal conductivity of the first frame 3 is smaller than the thermal conductivity of the second frame 6 due to the warpage of the window body 1 and the temperature measurement result of the member immediately after seam welding, Since the temperature of the member becomes lower and the warp of the window body 1 becomes smaller and the bonding property of the first sealing material 2 can be secured, it can be judged that the airtight reliability is more excellent.

The results of the above evaluation are summarized in Table 1.

  As can be seen from the appearance test and the airtightness test in Table 1, the optical element storage package including the lid body 7 of the present invention has no cracks in the window body 1 and has good airtightness compared to the conventional product. there were.

  It was also found that the warping of the lid 7 can be further suppressed by using a material having a Young's modulus greater than that of the second frame 6 for the first frame 3. Further, the thickness t1 of the joint portion between the first frame 3 and the first sealing material 2 is set to be larger than the thickness t2 of the seam welded portion of the second frame 6, thereby causing the window body 1 to warp. It was found that there is a more suppressing effect.

  Further, in the first frames 3 having the same thickness t1 of the first frames 3, a material having a small thermal conductivity such as an Fe—Ni—Co alloy is selected for the second frame 6. When a material whose thermal conductivity of the first frame 3 is smaller than that of the second frame 6 is selected, the temperature of the window body 1 and the first sealing material 2 becomes lower. It has been found that the generation of thermal stress is further suppressed by reducing the warpage of the window body.

It is sectional drawing which shows an example of embodiment of the cover body of this invention, and the package for optical element accommodation using the same. It is sectional drawing which shows the example of the conventional cover body and the package for optical element accommodation using the same.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Window body 2 ... 1st sealing material 3 ... 1st frame 3a ... Opening part 3b ... Recessed part 4 ... 1st cover body 5 ... 2nd Sealing material 6 ... Second frame 6a ... Opening 7 ... Lid 8 ... Base 8a ... Recess

Claims (4)

A first frame having a recess on the lower surface and an opening for transmitting light passing between the upper surface and the bottom surface of the recess, and an outer peripheral portion of the upper main surface so as to cover the opening Is bonded to the periphery of the opening in the recess via a first sealing material, and an opening is formed in the center portion, which is made of a glass window disposed in the recess. And the lower surface of the first frame body of the first lid is joined to the upper surface of the inner peripheral portion around the opening having a thickness greater than the outer peripheral portion via a second sealing material. A lid body comprising a frame body.   The first frame is thicker than the second frame, and the Young's modulus of the first frame is larger than the Young's modulus of the second frame. The lid according to 1.   The lid according to claim 1, wherein the first frame body has a thermal conductivity smaller than that of the second frame body.   A base having a recess for accommodating an optical element on the upper surface, and a lid according to any one of claims 1 to 3 joined to the upper surface of the base so as to close the recess. Optical element storage package.

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