TWI784291B - Cover member for light-emitting device, manufacturing method of cover member, and light-emitting device - Google Patents

Abstract

A light-emitting device (10). An LED chip (13) is accommodated in an empty chamber (111) of a ceramic packaging body (11), and the opening of the empty chamber (111) is sealed by a crystal cover (12). The cover (20) before sealing is structured such that a crystal cover (12) is used as a cover main body, and a first metallized film (41) is formed on the sealing surface of the crystal cover (12). The first metallized film (41) comprises a first metal layer (411) directly formed on the crystal cover (12) and an alloy layer ( 43). The first metal layer (411) has a single-layer structure composed of a titanium film with a film thickness of 20-700 nm.

Description

Cover member for light-emitting device, manufacturing method of cover member, and light-emitting device

The present invention relates to a cover used in a light-emitting device including an LED (Light Emitting Diode), a method for manufacturing the cover, and a light-emitting device.

In a light-emitting device using an LED, a structure in which the LED is encapsulated in a package to improve reliability is widely known. A specific structural example includes a structure in which an LED is housed in a cavity of a package base (for example, a ceramic package), and the opening of the cavity of the package base is sealed with a lid.

In such a structure, the cover needs to have translucency with respect to the irradiation light of LED. In the case where the LED is a deep ultraviolet LED emitting deep ultraviolet light, quartz glass has been used as a cover in many conventional cases (for example, Patent Document 1).

However, in the case of using quartz glass as the cover, the number of processes in the manufacturing process of the elements in the light emitting device will increase. In this case, if a crystal is used as the cover, it has the advantage of reducing the number of manufacturing processes.

When sealing the ceramic package with a crystal cap, gold-tin (Au-Sn) alloy can be used as a solder material. Since the adhesion between crystal and gold-tin alloy is low, a base film for improving adhesion is required. Moreover, such a base film is also required when quartz glass is used as the cover. Therefore, when sealing a ceramic package with a cover, it is generally used on the bonding surface of the cover and the package. A lid member (lid and base film) with a base film formed in advance. In addition, in such a lid member, a solder material may be fused (bonded by heating) to the base film in advance.

However, the inventors of the present application found that, in the cap material using the crystal cap, there were problems such as peeling of the cap and poor airtightness due to the formation conditions of the base film. That is, if the base film is formed under the same conditions as in the case of using quartz glass as the cover, the adhesiveness will be significantly lowered, and the conditions need to be greatly changed.

It goes without saying that even when quartz glass is used as the cover, if the adhesion to the gold-tin alloy can be further improved, the reliability of the light-emitting device can be improved. Adopt quartz glass as the prior art of lid, generally use chromium (Cr) film as the base film that is used to obtain the adhesion between gold-tin alloy, but, in this case, gold-tin alloy diffuses to base film easily, From the viewpoint of film peeling and adhesion, there is still sufficient room for improvement.

[Patent Document 1]: Japanese Patent No. 6294417

In view of the above-mentioned technical problems, an object of the present invention is to provide a cover having an excellent base film that does not cause peeling of the cover or poor airtightness for a light-emitting device configured by arranging LEDs inside a package and sealing them with a cover. A method for manufacturing a member and a cover member, and a light emitting device.

In order to solve the above-mentioned technical problems, the cover member as the first aspect of the present invention is a cover member used for a light-emitting device configured by sealing an LED in a package, and is characterized in that it includes a light-transmitting material with respect to the irradiated light of the LED. A permanent cover main body and a first metallized film formed on the sealing surface of the cover main body, the first metallized film includes a first layer formed directly on the cover main body and on the first layer The second layer formed, the first layer comprising a titanium film with a film thickness of 20-700nm The second layer has an alloy film containing nickel (Ni), titanium (Ti), gold (Au) and tin (Sn).

With the above configuration, in a light-emitting device in which LEDs are arranged inside a package and sealed with a lid, a lid having an excellent base film that does not cause peeling of the lid or poor airtightness can be obtained.

In addition, in the above cover member, the titanium film contained in the first layer may be a titanium film having a film thickness of 200 to 300 nm.

In addition, in the above cover member, the first layer may have a structure in which an oxide film made of titanium oxide is formed on the surface.

In addition, in the above cover member, the first layer may have a buffer film composed of a gold film and another titanium film stacked in order from the side closer to the titanium film on the titanium film.

In addition, in the above-mentioned cover member, the second layer may be configured to have a nickel alloy film on its inner peripheral side and outer peripheral side, and a layer containing nickel, titanium, gold, and tin is formed between these nickel alloy films. The structure of the alloy film.

In addition, in the above-mentioned cover material, a structure in which the cover main body is a crystal may be adopted.

In addition, in order to solve the above-mentioned technical problems, a method of manufacturing a cover member as a second aspect of the present invention is a method of manufacturing a cover member used in a light-emitting device configured by sealing an LED in a package, and is characterized in that: The process of forming the base film on the sealing surface of the cover main body where the irradiation light of the LED is translucent includes forming a first layer comprising a titanium film with a film thickness of 20 to 700 nm on the sealing surface of the cover main body. A process; a second process of oxidizing the titanium film on the uppermost layer of the first layer formed in the first process to form an oxide film made of titanium oxide on the surface; after the second process A third process of forming a second layer comprising a nickel alloy film and a gold film sequentially laminated from the side close to the first layer on the first layer; melting the solder material constituted as a gold-tin preform a fourth process on the gold film formed in the third process.

In addition, in the above method of manufacturing the lid member, the titanium film formed in the first process may have a film thickness of 200 to 300 nm.

In addition, in the manufacturing method of the above-mentioned cover member, in the first process, a gold film and other titanium films that are sequentially stacked from the side close to the titanium film may be formed on the titanium film. buffer film.

In addition, in the manufacturing method of the above-mentioned lid member, in the base film, the upper layer portion including any film other than the lowermost film may have a retracted structure, and in the retracted structure, the retracted structure may have a The inner peripheral edge of the included film is retracted to the outside than the inner peripheral edge of the other film, and the outer peripheral edge of the film included in the retracted structure is retracted to the inner side than the outer peripheral edge of the other film.

Moreover, in the manufacturing method of the said cover material, the said cover main body may be a crystal.

In addition, in order to solve the above-mentioned technical problems, a light-emitting device according to a third aspect of the present invention is a light-emitting device configured by sealing an LED in a package, and is characterized in that the package includes the LED and accommodates the LED in a cavity. A body base and a cover for sealing the cavity opening of the package base, the cover is the cover as described above.

In addition, in the above-mentioned light-emitting device, a structure in which the package base is made of aluminum nitride may be employed.

In addition, in the above-mentioned light-emitting device, a configuration may be adopted in which the LEDs are LEDs for deep ultraviolet.

The present invention has an effect that, in a light-emitting device in which LEDs are arranged inside a package and sealed with a cover, a cover having an excellent base film that does not cause peeling of the cover or poor airtightness can be obtained.

10: Lighting device

10': Lighting device

11: Ceramic package

11': ceramic base

11A: sealing surface

12: Crystal cover, cover body

12': Crystal cover

13: LED chip

14: Bonding layer

20: cover

21: cover

22: cover

30: Packaging components

41: The first metallized film

41A: basement membrane

41B: Welding materials

42: Second metallized film

43: alloy layer, the second layer

51: The first metallized film

51A: basement membrane

61: The first metallized film

61A: basement membrane

111: empty room

112: Mounting pad

113: External connection terminal

411: first metal layer, first layer

412: second metal layer, second layer

421: nickel plating layer

422: nickel-tin alloy layer

511: the first metal layer, the first layer

612: second metal layer, second layer

4121: Nickel-titanium film

4122: gold film

5111: titanium film

5112: gold film

5113: titanium film

6121: nickel-titanium film

6122: gold film

d1: inside retraction width

d2: Retraction width on the outside

Fig. 1 is a cross-sectional view showing an example of a basic structure of a light emitting device according to the present invention.

FIG. 2 is a cross-sectional view schematically showing a method of manufacturing the light emitting device of FIG. 1 .

Fig. 3 is a bottom view of the cover.

4 is a partial cross-sectional view showing the structure of a base film formed in the film-forming process of the lid member according to the first embodiment.

Fig. 5 is a cross-sectional view showing a fusion process of the lid member according to the first embodiment.

Fig. 6 is a SEM photograph obtained by photographing a part of the cross-section of the bonding layer in the sealed light-emitting device.

Fig. 7 is a cross-sectional view showing a fusion process of the lid member according to the second embodiment.

FIG. 8 is a partial cross-sectional view showing the structure of a base film formed in a film-forming process of a lid member according to a second embodiment.

Fig. 9 is a cross-sectional view showing a fusion process of the lid member according to the third embodiment.

FIG. 10 is a partial cross-sectional view showing the structure of a base film formed in a film-forming process of a lid member according to a third embodiment.

11 is a partial cross-sectional view showing the structure of the first metallized film of the lid member according to the third embodiment.

12 is a partial cross-sectional view showing another structure of the base film in the lid of the third embodiment.

Fig. 13 is a cross-sectional view showing another example of the basic structure of a light emitting device according to the present invention.

Fig. 14 is a cross-sectional view showing still another example of the basic structure of a light-emitting device according to the present invention.

<First Embodiment>

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Basic structure of light emitting device]

First, the basic configuration of a light emitting device 10 according to the present invention will be described with reference to FIG. 1 . As shown in FIG. 1 , a light emitting device 10 is mainly composed of a ceramic package 11 , a crystal cover (cover main body) 12 and an LED chip 13 . That is, the light emitting device 10 is configured by accommodating the LED chip 13 in the cavity 111 of the ceramic package 11 and sealing the opening of the cavity 111 with the crystal cover 12 .

The ceramic package 11 is a substantially rectangular parallelepiped package base, the top surface has an opening of the cavity 111 , and the periphery of the opening is a sealing surface 11A joined to the crystal cover 12 . In addition, mounting pads 112 for mounting the LED chip 13 are formed on the inner bottom surface of the cavity 111 , and external connection terminals 113 are formed on the lower bottom surface of the ceramic package 11 . The mounting pad 112 is electrically connected to the external connection terminal 113 through a through hole not shown. In addition, in order to release the heat generated by the LED chip 13 , it is preferable that the ceramic package body 11 is made of a material with high thermal conductivity, and aluminum nitride is more suitable. In addition, here, a case where a ceramic substrate is used as the package base of the light-emitting device 10 is exemplified, but the package base may also be a crystal substrate.

The crystal cover 12 is a rectangular crystal plate having substantially the same size as the ceramic package 11 in plan view. The crystal cover 12 is bonded to the sealing surface 11A of the ceramic package 11 through the bonding layer 14 .

In the light emitting device 10 shown in FIG. 1 , an LED chip 13 is mounted on a ceramic package 11 by FCB (Flip Chip Bonding, flip-chip bonding). However, the present invention is not limited thereto, and the LED chip 13 can also be mounted on the ceramic package 11 by wire bonding.

Preferably, the LED chip 13 is a deep ultraviolet LED emitting deep ultraviolet. Deep ultraviolet rays refer to ultraviolet rays with shorter wavelengths in ultraviolet rays, which are mainly used for sterilization, disinfection and other purposes. Since the crystal cover 12 has translucency with respect to deep ultraviolet rays, it can be used when the LED chip 13 is an LED for deep ultraviolet rays. However, as long as the LED chip 13 is an LED chip that emits light within the wavelength range transmitted by crystal, it is not limited to LEDs for deep ultraviolet.

In addition, there is also conventionally used quartz glass as a material having translucency to deep ultraviolet rays, but if quartz glass is used as the cover of the light-emitting device 10, the number of test processes in the airtight test may increase. The use of the crystal cover 12 in the light-emitting device 10 has the advantage of reducing the number of test processes during the airtight test and making it easier to perform the airtight test.

[Manufacturing method of light-emitting device]

Next, a method of manufacturing the light emitting device 10 shown in FIG. 1 will be described. FIG. 2 is a cross-sectional view schematically showing a method of manufacturing the light emitting device 10 .

As shown in FIG. 2 , the light emitting device 10 is manufactured by bonding the cover 20 and the package member 30 via a bonding member. Here, the cover 20 is constituted by forming the first metallized film 41 on the bottom surface (joint surface) of the crystal cover 12 . As shown in FIG. 3 , the first metallized film 41 is formed in a ring shape corresponding to the shape of the crystal cover 12 on the bottom surface of the crystal cover 12 . The first metallized film 41 is formed by melting the solder material 41B (see FIG. 5 ) on the base film 41A (see FIGS. 4 and 5 ) for improving the adhesion between the crystal cover 12 and the bonding layer 14 . constituted. In addition, the specific structure of the first metallized film 41 will be described later.

In addition, the package member 30 is constituted by forming the second metallization film 42 on the sealing surface 11A of the ceramic package 11 on which the LED chip 13 is mounted. Second Metallized Film 42 It is formed into a ring shape corresponding to the shape of the sealing surface 11A so that it can be superimposed on the first metallized film 41 when the cover 20 and the package member 30 face each other. The second metallized film 42 is a base film for improving the adhesion between the ceramic package 11 and the bonding layer 14 . As the second metallization film 42, it is preferable to use a nickel alloy/gold film (or nickel/gold film) formed on the top of a metallization material such as tungsten or molybdenum when the package base is a ceramic substrate. etc. In addition, it is preferable that the film thickness of the second metallization film 42 is in the range of 150 to 700 nm. Further, when the package base is a crystal substrate, the second metallization film 42 may also be a titanium alloy/gold film (or titanium/gold film).

In the manufacture of the light-emitting device 10 , as shown in FIG. 2 , the lid 20 and the sealing member 30 are stacked, and the lid 20 and the sealing member 30 are heated while applying a load to achieve bonding between the members. That is, the first metallized film 41 and the second metallized film 42 are heated and melted, and thereafter, they are cooled while applying a load. After the melted first metallized film 41 and second metallized film 42 are cooled and solidified, the bonding layer 14 shown in FIG. 1 is formed.

[Structure and Manufacturing Method of Cover]

Next, the structure and manufacturing method of the cover member 20 will be described.

As described above, the cover member 20 is constituted by forming the first metallized film 41 on the bottom surface of the crystal cover 12, and the first metallized film 41 is formed by fusing the solder material 41B on the base film 41A. . The first metallized film 41 is formed by a film-forming process of the base film 41A and a fusion process of the solder material 41B. First, the structure of the base film 41A formed by the film formation process will be described with reference to FIG. 4 .

As shown in FIG. 4 , base film 41A of first metallization film 41 is configured to include first metal layer 411 and second metal layer 412 .

The first metal layer 411 formed directly on the crystal cover 12 has a single-layer structure composed of a titanium film. The second metal layer 412 is formed on the first metal layer 411 and has a stacked structure including a nickel-titanium film 4121 and a gold film 4122 in order from the side close to the first metal layer 411 . In addition, preferably, the film thickness of the nickel-titanium film 4121 in the second metal layer 412 is in the range of 50-1000 nm. In addition, the nickel-titanium film 4121 may be replaced with another nickel alloy film.

As a method of manufacturing the base film 41A in the cover member 20, first, a titanium film as the first metal layer 411 is formed by physical vapor deposition on one surface of the crystal cover 12 (the surface facing the package member 30). . After the titanium film is formed, it is temporarily taken out from the film forming apparatus, and the surface of the titanium film is exposed to the air. As a result, an oxide film made of titanium oxide is formed on the surface of the titanium film. Thereafter, a nickel-titanium film 4121 is formed by physical vapor deposition on the titanium film as the first metal layer 411, and a gold film 4122 is formed on the nickel-titanium film 4121 by physical vapor deposition. That is, the second metal layer 412 has a stacked structure of a nickel-titanium film 4121 and a gold film 4122 .

In addition, the method of oxidizing the titanium film to form an oxide film on the surface is not limited to the above-mentioned method of exposing the surface of the titanium film to air. For example, a method of forming a titanium oxide film by introducing oxygen gas when the titanium film is formed by sputtering, or a method of promoting oxidation of the surface of the formed titanium film by using oxygen plasma may also be employed.

After the base film 41A is formed, next, the solder material 41B is fused on the base film 41A by a fusion process. In this fusion process, as shown in FIG. 5, the solder material 41B is placed on the base film 41A and subjected to heat treatment (baking in a heating furnace). By this heat treatment, the base film 41A and the solder material 41B are integrated to form the first metallized film 41 . In addition, the solder material 41B before fusion is formed by preforming gold tin (Au—Sn) used as a solder material into a ring shape substantially the same as that of the base film 41A. Preferably, the thickness of the prefabricated welding material 41B is in the range of 10-20 μm.

In the first metallized film 41 after the fusion process, the stacked structure of the second metal layer 412 (the stacked structure of the nickel-titanium film 4121 and the gold film 4122 ) in the base film 41A before heating disappears. Specifically, through the heating of the fusion process, the second metal layer 412 and the solder material 41B Melting and alloying (formation of eutectic bonding) form the alloy layer 43 (see FIG. 6 ). On the other hand, the first metal layer 411 still maintains a layered shape after the fusion process, and no eutectic bonding is formed.

FIG. 6 is a SEM (scanning electron microscope, scanning electron microscope) photograph obtained by photographing a part of the cross section of the bonding layer 14 in the sealed light emitting device 10 . As shown in FIG. 6 , the bonding layer 14 has a first metal layer 411 , an alloy layer 43 , a nickel-tin alloy layer 422 and a nickel plating layer 421 sequentially from the side close to the crystal cover 12 . In addition, since the oxide film on the surface of the first metal layer 411 as the titanium film is extremely thin, it cannot be visually recognized as a clear layer in the SEM photograph of FIG. 6 . However, the first metal layer 411 which is a titanium film maintains a layered form without forming a eutectic bond because the oxide film on the surface of the titanium film exists as a barrier film.

The alloy layer 43 is a layer obtained by melting the second metal layer 412 and the solder material 41B in the base film 41A before heating to form eutectic bonding. In the alloy layer 43, in addition to the "gold-tin δ' phase" and the "gold-tin δ phase" in gold tin (Au-Sn) as the solder material 41B, it also contains the second metal layer 412 and the solder material 41B. Mixed "nickel-tin alloy" and "titanium-tin alloy". That is, the alloy layer 43 is an alloy layer containing nickel, titanium, gold, and tin.

The nickel plating layer 421 is a layer included in the second metallization film 42 of the package member 30 . In addition, the nickel-tin alloy layer 422 is a layer formed by alloying the joint portion of the first metallized film 41 and the second metallized film 42 . That is, the nickel-tin alloy layer 422 is an alloy layer containing nickel, titanium, gold, and tin, like the alloy layer 43 . More specifically, in the nickel-tin alloy layer 422 formed by soldering the cover 20 to the package member 30, the nickel plating layer on the package member 30 side is combined with the tin of the gold-tin alloy on the cover 20 side to form nickel. - tin layer. Therefore, the gold-tin alloy becomes a non-eutectic state. After the lid member 20 and the packaging member 30 are soldered, the non-eutectic state of such gold-tin alloy is better.

In addition, when the packaging member 30 of the light emitting device 10 is a crystal substrate and the first metallization film 41 is a titanium/gold film, a titanium-tin layer may be formed instead of the nickel-tin alloy layer 422 . That is, the titanium plating layer on the package member 30 side is combined with the tin of the gold-tin alloy on the lid member 20 side to form a titanium-tin layer.

In addition, the SEM photo of FIG. 6 is obtained by photographing the cross-section of the bonding layer 14 in the sealed light-emitting device 10, and the first metallized film 41 in the cover member 20 before bonding already includes the first metal layer (the first metal layer). One layer) 411 and alloy layer (second layer) 43.

[Conditions for forming the first metallized film]

In the cover member 20 described above, it has been confirmed that in order to obtain good adhesion of the crystal cover 12 in the light emitting device 10 , it is necessary to control the film thickness of the first metallized film 41 . In particular, it is necessary to control the film thickness of the titanium film serving as the first metal layer 411 within an appropriate range. Hereinafter, consideration will be made based on experiments.

Here, the film thickness of the first metal layer 411 was changed as a parameter, and the light-emitting device 10 was manufactured by the above-mentioned manufacturing method, and the appearance evaluation and air-tightness test (helium gas leak test) of the manufactured light-emitting device 10 were performed. Airtight evaluation. In the appearance evaluation, discoloration of the metallized film seen from the side of the crystal cover 12 and whether the crystal cover 12 was cracked were confirmed visually. In addition, in each light-emitting device 10 manufactured, the film thicknesses of the nickel-titanium film 4121 and the gold film 4122 of the second metal layer 412 were fixed at 300 nm and 50 nm, respectively. In addition, the thickness of the gold-tin preform as the solder material 41B is fixed at 15 μm, and the second metallization film 42 uses a nickel alloy/gold film, and its film thickness is fixed at a total of 5 μm. The experimental results are shown in Table 1 below.

【Table 1】

Regarding discoloration, discoloration occurred in a wide range under conditions 1 and 2 (film thickness 7 nm, 10 nm), and the evaluation was "x". In addition, in conditions 3~6, 10~15 (film thickness 20nm, 50nm, 100nm, 150nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm), a small amount of discoloration occurred, and the evaluation was "○". Moreover, in conditions 7-9 (film thickness 200 nm, 250 nm, 300 nm), discoloration hardly occurred, and it evaluated as "⊚".

This discoloration indicates that peeling has occurred between the crystal cover 12 and the metallized film serving as the bonding layer 14 . That is, it is considered that when the film thickness of the first metal layer 411 is insufficient, gold and tin diffuse from the bonding member to the contact surface between the titanium film as the first metal layer 411 and the crystal cover 12, causing The adhesion between the first metal layer 411 and the crystal cover 12 is reduced and peeling (ie, discoloration) occurs. The large-scale discoloration occurred under conditions 1 and 2 where the film thickness of the first metal layer 411 is relatively thin also illustrates the above-mentioned problem. Actually, in condition 1 in which the film thickness of the first metal layer 411 was the thinnest, the airtightness evaluation was "x" (poor airtightness occurred). In addition, in Condition 2, no airtightness failure was detected at the stage of airtightness evaluation, and the evaluation was "○", but since the discoloration range is wide, it is difficult to think that the airtightness can be maintained for a long time. Therefore, in terms of conditions 1 and 2, the overall evaluation was "x".

When the film thickness of the first metal layer 411 becomes thicker, the diffusion of gold and tin in the titanium film as the first metal layer 411 is suppressed, thereby improving the adhesion between the crystal cover 12 and the metallized film as the bonding layer 14. improve. In conditions 3 to 6, the evaluation on discoloration was "◯", and on conditions 7 to 9, the evaluation on discoloration was "⊚". The airtightness evaluation was also "◯" in conditions 3 to 9, so the overall evaluation was "◯" in conditions 3 to 6, and "⊚" in conditions 7 to 9.

In Conditions 10 to 15, the film thickness of the first metal layer 411 was further increased, but the evaluation on discoloration was “◯”, which was lower than the evaluation of Conditions 7 to 9. However, this does not mean that the adhesiveness of the crystal cover 12 of the conditions 10-15 is lower than the adhesiveness of the crystal cover 12 of the conditions 7-9. It is considered that the evaluation of discoloration in Conditions 10 to 15 is "◯" because of the following reason.

In the light emitting device 10 , since the materials of the ceramic package 11 and the crystal cover 12 are different, the coefficients of thermal expansion are also different. In addition, it can be considered that under conditions 10 to 15, since the film thickness of the first metal layer 411 is thick and the adhesion is high, bending occurs due to the difference in thermal expansion between the ceramic package 11 and the crystal cover 12, and the bending occurs due to this bending. peel off. That is, it can be considered that conditions 7-9 and condition 10 ~15 is lower in adhesion, so even if there is a difference in thermal expansion between the ceramic package 11 and the crystal cover 12, a dislocation will occur between the first metal layer 411 and the crystal cover 12 to absorb the difference in thermal expansion, so that the suppression factor can be exerted. The effect of peeling due to bending. In fact, cracking of the crystal cover 12 also occurred under conditions 14 and 15, and it is considered that the cracking of the crystal is caused by bending caused by a difference in thermal expansion.

In addition, when the material of the ceramic package 11 is aluminum nitride, the difference in thermal expansion coefficient between crystal and aluminum nitride is larger than the difference in thermal expansion coefficient between quartz glass and aluminum nitride. Therefore, when the crystal cover 12 is used, warping due to thermal expansion difference is more likely to occur than in the conventional structure using a quartz glass cover, so it is necessary to consider such warping.

Regarding the airtight evaluation of conditions 10 to 15, conditions 10 to 13 were "○", and conditions 14 and 15 were "x". This is because, in Conditions 14 and 15, the airtightness was broken due to cracking of the crystal cover 12 . Therefore, in conditions 10 to 13, the comprehensive evaluation is "○"; in conditions 14 and 15, the comprehensive evaluation is "×".

As described above, in the cover member 20 according to this embodiment, whether the film thickness of the first metal layer 411 is too thin or too thick, reliable airtightness of the light emitting device 10 cannot be obtained. It can be known from the above results in Table 1 that the film thickness of the first metal layer 411 is preferably in the range of 20-700 nm, more preferably in the range of 200-300 nm.

<Second Embodiment>

[Structure and Manufacturing Method of Cover]

In the above-mentioned first embodiment, the cover member 20 has the first metallized film 41 as the base film, and the adhesion degree of the first metallized film 41 to the crystal is high. The case of an excellent base film where peeling or poor airtightness occurs is described. However, the first metallized film 41 in the first embodiment sometimes has a problem of cracking the cover of the light emitting device 10 due to its high degree of adhesion. In particular, when the sealing load is large (for example, 100 gf or more) or in a thermal shock test, etc., the cap tends to be easily cracked. In this second embodiment, for Covers that can prevent cracking of the cover under the condition of large sealing load or thermal shock test are described.

As shown in FIG. 5, the first metallization film 41 in the cover member 20 is formed by fusing the solder material 41B on the base film 41A. In this regard, as shown in FIG. 7, the cover member 21 related to the second embodiment is constituted by replacing the first metallized film 41 of the cover member 20 with a first metallized film 51. The first metallized film 51 is formed by fusing the solder material 41B to the base film 51A.

FIG. 8 is a partial cross-sectional view showing the structure of a base film 51A in the cover member 21 according to the second embodiment. Here, as shown in FIG. 8 , the base film 51A is configured to include a first metal layer (first layer) 511 and a second metal layer (second layer) 412 . That is, the base film 51A in the cover 21 is configured by changing the first metal layer 411 in the base film 41A of the cover 20 according to the first embodiment to the first metal layer 511 .

The first metal layer 411 of the first embodiment has a single-layer structure composed of only titanium films, while the first metal layer 511 has a stacked structure composed of titanium films 5111 , gold films 5112 and titanium films 5113 . Here, the titanium film 5111 corresponds to the titanium film constituting the first metal layer 411 of the first embodiment. That is, the titanium film 5111 is the same as the titanium film of the first metal layer 411 , preferably, the film thickness is 20-700 nm; more preferably, the film thickness is 200-300 nm.

The gold film 5112 and the titanium film 5113 in the first metal layer 511 are formed as buffer films for preventing cracking of the cap under a large sealing load or in a thermal shock test. As described in the above-mentioned first embodiment, since the materials of the ceramic package 11 and the crystal cover 12 in the light emitting device 10 are different, the coefficients of thermal expansion are also different. As a result, warping occurs due to the difference in thermal expansion between the ceramic package 11 and the crystal cover 12 , and this warping may become a factor of crystal cracking. In this regard, it is considered that in the light-emitting device 10 using the cover member 21, the buffer film (that is, the gold film 5 112 and the titanium film 5113) can absorb the difference in thermal expansion between the ceramic package 11 and the crystal cover 12, and as a result, can reduce bending and suppress cracking of the crystal.

As a method of manufacturing the cover member 21, a titanium film 5111 as the first metal layer 511, a gold film 5112, and Titanium film 5113. After the first metal layer 511 is formed, it is temporarily taken out from the film forming apparatus, so that the surface of the uppermost titanium film 5113 is exposed to the air. As a result, an oxide film made of titanium oxide is formed on the surface of the titanium film 5113 .

In addition, in the first embodiment, an oxide film made of titanium oxide was formed on the surface of the first metal layer 411. In the second embodiment, the titanium film 5111 corresponds to the titanium layer of the first metal layer 411 in the first embodiment. membrane. However, since the oxide film made of titanium oxide forms the boundary between the first metal layer and the second metal layer, in the lid member 21 according to the second embodiment, the oxide film made of titanium oxide is not formed on the titanium oxide layer. film 5111, but formed on the surface of the titanium film 5113 that is the uppermost layer of the first metal layer 511. In addition, the method of forming an oxide film on the surface of the titanium film 5113 is the same as the first embodiment, and a method of introducing oxygen gas to form a titanium oxide film when forming a titanium film by sputtering, or a method of forming a titanium oxide film by oxygen plasma body to promote the oxidation of the titanium film surface after film formation. After the first metal layer 511 is formed, the method of forming the second metal layer 412 is the same as that described in the first embodiment. By forming the first metal layer 511 and the second metal layer 412 , the base film 51A is formed on the crystal cover 12 .

After the base film 51A is formed, the solder material 41B is fused on the base film 51A through a subsequent fusion process. In this fusion process, as shown in FIG. 7, the solder material 41B is placed on the base film 51A and subjected to heat treatment (baking in a heating furnace). By this heat treatment, the base film 51A and the solder material 41B are integrated to form the first metallized film 51 .

[Conditions for forming the first metallized film]

In the cover member 21 described above, it was confirmed that controlling the film thickness of the base film is effective in order to obtain good adhesion of the crystal cover 12 in the light emitting device 10 and the effect of preventing cracking of the crystal. In particular, it is effective to control the film thickness of the gold film 5112 in the first metal layer 511 within an appropriate range. Hereinafter, consideration will be made based on experiments.

Here, the film thicknesses of the titanium film 5111, the gold film 5112, and the titanium film 5113 in the first metal layer 511 were changed as parameters, and the light emitting device 10 was manufactured by the above-mentioned manufacturing method, and the manufactured light emitting device 10 was tested. Appearance evaluation and airtightness evaluation based on airtightness test (helium gas leak test). In the appearance evaluation, discoloration of the metallized film seen from the side of the crystal cover 12 and whether the crystal cover 12 was cracked were confirmed visually. In addition, in each light-emitting device 10 manufactured, the film thicknesses of the nickel-titanium film 4121 and the gold film 4122 of the second metal layer 412 were fixed at 300 nm and 50 nm, respectively. In addition, the thickness of the gold-tin preform as the joining member was fixed at 15 μm, and the second metallization film 42 used a nickel alloy/gold film, and its film thickness was fixed at 5 μm in total. The experimental results are shown in Table 2 below. Among the film thicknesses of the first metal layer in Table 2, the titanium film thickness in the left column shows the film thickness of the titanium film 5111 , and the titanium film thickness in the right column shows the film thickness of the titanium film 5113 .

【Table 2】

Conditions 16 to 18 in Table 2 do not have the gold film 5112 and the titanium film 5113 as the buffer film, but the thicker the titanium film 5111, the better the result. In addition, the overall evaluation was also "◯" for the film thickness of the titanium film 5111 of 250 nm (condition 3), which was considered to be in the appropriate range in the first embodiment.

On the other hand, the overall evaluation of any of the conditions 18 to 25 having the gold film 5112 and the titanium film 5113 as the buffer film was "◯" or higher, and the overall evaluation of conditions 21 to 24 was "⊚". In Conditions 21 to 24, since the discoloration evaluation was "⊚", it was found that the adhesion of the crystal cover 12 in the light emitting device 10 was further improved. It can be considered that in the light-emitting device 10, the buffer film (namely, the gold film 5112 and the titanium film 5113) absorbs the The difference in thermal expansion between 11 and crystal cover 12 reduces warping and, as a result, reduces cover peeling. In addition, the effect can be improved by appropriately controlling the thickness of the gold film 5112, and the thickness of the gold film 5112 is preferably in the range of 100-700 nm, more preferably in the range of 300-600 nm.

In addition, conditions 26 to 27 in Table 2 have a cushion film, but the airtight evaluation was "x" (the overall evaluation was also "x"). In addition, in condition 27, the evaluation of crystal cracking was "x". These results are the result of the buffer film being too thick, and it is considered that the total film thickness of the base film was increased and the problem occurred due to the influence of stress. That is, it is considered that if the total film thickness of the base film is increased, the film thickness of the entire base film will be uneven, and the stress applied to the crystal cover 12 will increase due to the uneven film thickness, thereby causing cracks in the crystal. This shows that there is an upper limit to the film thickness of the buffer film.

<Third Embodiment>

〔Structure of the cover part〕

In the above-mentioned first and second embodiments, the nickel-titanium film 4121 and the gold film 4122 included in the second metal layer 412 are configured such that the film formation width (metallization width) of the nickel-titanium film 4121 and the gold film 4122 is Same (gold film 4122 completely overlaid on nickel-titanium film 4121). However, in this case, due to the manufacturing conditions of the light-emitting device 10 and the like, there are technical problems in that the cover is peeled off and the airtightness is poor in the evaluation stage. In the present third embodiment, a cap material capable of more reliably preventing cap peeling and airtight failure will be described.

As shown in FIG. 9, the cover member 22 related to the third embodiment is constituted by replacing the first metallized film 51 of the cover member 21 with a first metallized film 61. The first metallized film 61 is made of The solder material 41B is formed by melting on the base film 61A.

FIG. 10 is a partial cross-sectional view showing the structure of the base film 61A in the cover member 22 according to the third embodiment. As shown in FIG. 10 , base film 61A is configured to include a first metal layer (first layer) 511 and a second metal layer (second layer) 612 . However, the third embodiment The relevant cover part 22 is characterized by the structure of the second metal layer. Therefore, in the cover member 22 of FIG. 6, although the first metal layer has the same structure as the first metal layer 511 of the cover member 21, the first metal layer may also have the same structure.

The second metal layer 612 has a laminated structure including a nickel-titanium film 6121 formed on the first metal layer 511 and a gold film 6122 formed on the nickel-titanium film 6121 . The nickel-titanium film 6121 may be the same film as the nickel-titanium film 4121 in the lid members 20 and 21 . In addition, the gold film 6122 is different from the gold film 4122 in the lid members 20 and 21 only in the film formation width.

That is, in the base film 61A, the gold film 6122 is formed to have a width narrower than that of the nickel-titanium film 6121 . More specifically, the gold film 6122 has an inner periphery of the gold film 6122 retracted further outside than an inner periphery of the nickel-titanium film 6121, and an outer periphery of the gold film 6122 retracted further than the outer periphery of the nickel-titanium film 6121. A retracted structure at the inner side (a structure in which there is a space between the peripheral portion of the gold film 6122 and the peripheral portion of the nickel-titanium film 6121). In addition, the "inner side" and "outer side" here mean the "inner side" and "outer side" seen from the center of the cover material 22. As shown in FIG. In addition, the shrinkage width of the gold film 6122 does not have to be the same on the inner side and the outer side of the base film 61A. As shown in FIG. 10, the inner shrinkage width [μm] is d1, and the outer shrinkage width is d2.

As described in the first embodiment, when the solder material 41B is fused to the base film 61A and when the lid member 22 is bonded to the sealing member 30 to manufacture the light-emitting device 10 , originally only the second layer of the base film 61A is used. The metal layer 412 melts to form a eutectic bond with the solder material 41B. However, under certain manufacturing conditions (for example, if the sealing load at the time of bonding is large), alloys (alloys containing nickel, titanium, gold, and tin) formed by eutectic bonding may dislodge from the side of the bonding layer 14. detour to the first metal layer 411 . In this case, it is considered that the components of gold or tin reaching the alloy of the first metal layer 411 permeate into the first metal layer 411 so that the first metal layer 411 and the crystal cover are separated. The adhesion between 12 is reduced, which becomes the main cause of peeling of the cover and poor airtightness. The same problem also occurs when the light-emitting device 10 is manufactured by bonding the cover 21 to the package member 30 .

In contrast, in the case of manufacturing the light emitting device 10 by bonding the lid member 22 and the package member 30 , the eutectic bonding is formed only in a region that substantially overlaps with the formation region of the gold film 6122 . This is because gold cannot be lacking in the formation of eutectic bonding. In the cover member 22, since the gold film 6122 has a retracted structure relative to the nickel-titanium film 6121, it is possible to prevent the alloy formed by eutectic bonding from detouring from the side surface of the bonding layer 14 to the first metal layer 511 (or 411). , As a result, peeling of the cover and poor airtightness can be prevented.

More specifically, the eutectic bonding when the solder material 41B is fused to the base film 61A is formed in a region substantially corresponding to the formation region of the gold film 6122 , and is not formed in the peripheral region where the gold film 6122 is retracted. That is, as shown in FIG. 11 , the alloy layer 43 formed by melting the second metal layer 412 and the solder material 41B has a nickel alloy film (nickel alloy film remaining in a non-eutectic bonding state) in the inner and outer peripheral portions thereof. -Titanium film 6121) An alloy film containing nickel, titanium, gold, and tin (alloy film after eutectic bonding) is formed between these nickel alloy films. In this way, since the nickel alloy film remaining without eutectic bonding exists in the peripheral portion of the alloy layer 43, the alloy formed by the eutectic bonding can be prevented from detouring from the side surface of the bonding layer 14 to the first metal layer 511 (or 411).

[Conditions for forming the first metallized film]

In the above-mentioned cover member 22 , it was confirmed that it is effective to control the formation width of the gold film 6122 in the second metal layer 612 in order to obtain good adhesion of the crystal cover 12 in the light emitting device 10 . Hereinafter, consideration will be made based on experiments.

Here, the respective film thicknesses of the titanium film 5111, the gold film 5112, and the titanium film 5113 in the first metal layer 511 are fixed at 250 nm, 500 nm, and 50 nm, respectively. In addition, the respective film thicknesses of the nickel-titanium film 6121 and the gold film 6122 in the second metal layer 612 were fixed at 300nm and 50nm, respectively. Then, the shrinkage width of the gold film 6122 is used as a parameter to make As a variation, the light-emitting device 10 was manufactured by the above-mentioned manufacturing method, and the appearance evaluation and air-tightness evaluation based on an airtight test (helium gas leak test) were performed on the manufactured light-emitting device 10 . In the appearance evaluation, discoloration of the metallized film seen from the side of the crystal cover 12 and whether the crystal cover 12 was cracked were confirmed visually. In addition, the thickness of the gold-tin preform as the joining member was fixed at 15 μm, and the second metallization film 42 used a nickel alloy/gold film, and its film thickness was fixed at 5 μm in total. The experimental results are shown in Table 3 below.

【table 3】

Based on the comparison of conditions 28 to 30 in Table 3, it can be seen that discoloration occurs in condition 28 without shrinkage structure, and the airtightness evaluation is "×" (the overall evaluation is also "×"), while conditions 29 and 30 with shrinkage structure , and the airtight evaluation was "◯" (the overall evaluation was also "◯"). It can be seen that the retracted structure of the gold film 6122 in the cover 22 is effective in reducing the peeling of the cover and poor airtightness caused by the detour of the alloy formed by the eutectic bonding. In addition, it can be seen that the effect can be exhibited as long as the shrinkage width in the shrinkage structure is at least 25 μm or more.

In addition, based on the comparison of conditions 30 to 35 in Table 3, it can be seen that the evaluation of discoloration differs depending on the metallization width of the gold film 6122 . That is, in Conditions 31 and 32, the appearance evaluation of discoloration was "⊚" (the overall evaluation was also "⊚"), but in Condition 30 in which the metallization width of the gold film 6122 was wider than this, the appearance evaluation of discoloration was "◯" " (Comprehensive evaluation is also "○"). It can be considered that the reason is that the widening of the metallization width of the gold film 6122 increases the area of the base film where the adhesion is strong, so that until the outer area of the light emitting device 10, the crystal cover 12 and the ceramic package body 11 are joined with high adhesion. That is, it is considered that in the light-emitting device 10, since the area bonded with high adhesive force becomes wider, it is easily affected by the difference in thermal expansion between the crystal cover 12 and the ceramic package 11. As a result, Condition 30 is stronger than Condition 31, 32 is more prone to discoloration.

In addition, in conditions 33-35 where the metallization width of the gold film 6122 is narrower than conditions 31 and 32, the narrower the metallization width is, the lower the discoloration appearance evaluation is, and the overall evaluation is also lower. Can It is considered that the reason is that if the metallization width of the gold film 6122 is too narrow, the area of the base film with higher adhesion becomes smaller, which cannot sufficiently withstand the thermal expansion difference between the crystal cover 12 and the ceramic package body 11, thereby easily Lid peeling occurs.

Furthermore, based on the comparison of conditions 31 to 34 and conditions 36 to 39 in Table 3, it can be seen that in the case where the shrinkage width of the gold film 6122 is different on the inner side and the outer side, the inner shrinkage width is larger than the outer side. Inward mode (Conditions 31 to 34) in which the retraction width on the outside is larger than that on the inside is better than the other modes (Conditions 36 to 39). That is, it became clear that crystal cracking by the thermal shock test is more likely to occur in the external mode than in the internal mode. The reason for this is considered to be that if the crystal cover 12 and the ceramic package 11 are bonded with high adhesive force in a relatively outer region of the light emitting device 10, it is likely to be affected by the difference in thermal expansion between the crystal cover 12 and the ceramic package 11. , As a result, crystal cracking caused by thermal and thermal shock tests is prone to occur.

In addition, in the above description in the present third embodiment, the case where only the gold film 6122 positioned on the uppermost layer of the base film 61A has the retracted structure was exemplified. However, the present invention is not limited thereto, and a setback structure may be employed in the upper layer portion including any film other than the lowermost film (ie, the titanium film 5111 ) of the base film 61A. For example, as shown in FIG. 12 , a retracted structure may also be used in the upper layer including the gold film 5112 .

The embodiments disclosed this time are examples for various aspects, and are not the basis for a limited interpretation. Therefore, the technical scope of the present invention is not interpreted only based on the above-mentioned embodiments, but is defined by the description of the claims. In addition, all modifications within the meaning and range equivalent to the claims are included.

For example, in the above description, the case where the crystal cover 12 is used as the cover main body among the covers 20 to 22 of the light emitting device 10 is exemplified. However, the present invention is not limited thereto, and quartz glass may also be used as the cover body. That is, in the conventional cover member using quartz glass, a chromium (Cr) film is used as the base film, but in the case of using quartz glass as the cover main body, as long as the above-mentioned base film 41A, 51A or 61A is used as the base film, the The fact that excellent performance can be obtained in terms of film peeling and adhesion results in confirm. The reason for this is considered to be that by changing the base film from the chromium film to the base film 41A, 51A, or 61A, diffusion of gold and tin which are solder materials can be suppressed.

In addition, in the light-emitting device 10 described above, the bonding layer 14 for bonding the ceramic package 11 and the crystal cover 12 is formed on almost the entire surface of the frame-shaped bonding surface of the ceramic package 11 and the crystal cover 12 (with respect to the width of the frame). direction is not skewed). However, the present invention is not limited thereto. As shown in FIG. 13 , the bonding layer 14 may be formed on the inner peripheral portion of the frame-shaped bonding surface of the ceramic package 11 and the crystal cover 12 . In this way, when the bonding layer 14 is formed on the inner peripheral portion of the bonding surface, the influence of the stress caused by the thermal expansion difference between the ceramic package 11 and the crystal cover 12 can be reduced, so that cracking of the cover is less likely to occur. Wait.

”字形狀，水晶蓋12被構成為平板形狀。然而，本發明不局限於此，也可以如圖14所示的發光裝置10’那樣，將平板形狀的陶瓷基底11’與截面為”

”字形狀的水晶蓋12’組合，而構成將LED13封裝的封裝體。在此情況下，將陶瓷基底11’與截面為”

”字形狀的水晶蓋12’接合的接合層14可以採用與上述說明過的發光裝置10中的相同的結構。 Further, in the light-emitting device 10 described above, in order to package the LED 13 in the package, the ceramic package 11 is configured such that the cross section is "

” shape, the crystal cover 12 is formed into a flat plate shape. However, the present invention is not limited thereto, and it is also possible to combine a flat plate-shaped ceramic substrate 11 ′ with a cross-section of “

"The shape of the crystal cover 12' is combined to form a package that encapsulates the LED13. In this case, the ceramic substrate 11' and the cross-section are"

The bonding layer 14 to which the ""-shaped crystal cover 12' is bonded can have the same structure as that of the light emitting device 10 described above.

12: Crystal cover, cover body

14: Bonding layer

43: alloy layer, the second layer

411: first metal layer, first layer

421: nickel plating layer

422: nickel-tin alloy layer

Claims (16)

A cover, which is used for a light-emitting device configured by sealing an LED in a package, is characterized in that it includes a cover main body that is transparent to the light irradiated by the LED, and a cover body on the cover main body. The first metallized film formed on the sealing surface, the first metallized film includes a first layer formed directly on the cover body and a second layer formed on the first layer, the first The layer is a layer including a titanium film with a film thickness of 20 to 700 nm, and the second layer has an alloy film in which nickel, titanium, gold, and tin are alloyed through eutectic bonding. The cover member according to claim 1, wherein the titanium film contained in the first layer is a titanium film with a film thickness of 200-300 nm. The cover member according to claim 1 or 2, wherein the first layer has an oxide film made of titanium oxide on the surface. The cover member according to claim 1 or 2, wherein the first layer is composed of a gold film and other titanium films stacked sequentially on the titanium film from a side close to the titanium film. buffer film. The cover member according to claim 1 or 2, wherein the second layer is formed to have a nickel alloy film on its inner peripheral side and outer peripheral side, and a layer containing nickel is formed between these nickel alloy films. , titanium, gold, and tin alloy film. The cover according to claim 1 or 2 is characterized in that: the cover main body is crystal. A method for manufacturing a cover, which is a method for manufacturing a cover used in a light-emitting device formed by sealing an LED in a package, and is characterized in that: The process of forming a base film on the sealing surface of the cover main body which is light-transmissive to the light irradiated by the LED includes forming a second titanium film with a film thickness of 20 to 700 nm on the sealing surface of the cover main body. the first process of one layer; the second process of oxidizing the titanium film on the uppermost layer of the first layer formed in the first process to form an oxide film made of titanium oxide on the surface; The third process of forming a second layer comprising a nickel alloy film and a gold film stacked sequentially from the side close to the first layer on the first layer after the second process; and making it as a gold-tin preform The formed solder material is fused to the fourth process on the gold film formed in the third process. The method for manufacturing a cover according to Claim 7, wherein the titanium film formed in the first process has a film thickness of 200-300 nm. The method for manufacturing a cover according to claim 7 or 8, wherein in the first process, a gold film and a gold film stacked sequentially from the side close to the titanium film are formed on the titanium film. Other buffer films made of titanium films. The method for manufacturing a cover according to claim 7 or 8, wherein the base film has a retracted structure in the upper layer including any film except the lowermost film, and in the retracted structure , the inner periphery of the film contained in the retraction structure retracts to the outside than the inner periphery of other films; the outer periphery of the film contained in the retraction structure retracts to the inside than the outer periphery of other films . The manufacturing method of the cover according to claim 7 or 8 is characterized in that: the cover main body is crystal. A light-emitting device is a light-emitting device configured by sealing an LED in a package, and is characterized in that it includes the LED, a package base for accommodating the LED in a cavity, and a cavity for enclosing the package base. A cover for sealing a chamber opening, the cover being the cover of any one of claims 1 to 6. The light-emitting device according to claim 12, wherein the package base is made of aluminum nitride. The light emitting device according to claim 12 or 13, wherein the LED is a deep ultraviolet LED. The light-emitting device according to claim 12 or 13, wherein the package base and the cover are bonded via a bonding layer, and the bonding layer has layers in order from the side close to the cover main body. The first layer, the second layer, the third layer, and the fourth layer are formed, the first layer is directly formed on the cover main body, and includes a titanium film layer with a film thickness of 20 to 700 nm; The second layer is an alloy layer containing nickel, titanium, gold, and tin; the third layer is an alloy layer containing nickel, titanium, gold, and tin, but the content of gold is less than that of the second layer; The fourth layer is nickel plating. The light-emitting device according to claim 15, wherein the second layer is an alloy layer in a eutectic state, and the third layer is an alloy layer in a non-eutectic state.

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