KR20070095665A - Semiconductor package and method of manufacturing thereof - Google Patents

Abstract

A semiconductor package and its manufacturing method are provided to accurately seize a reference point by using distinguishable inclined angles between first and second inclined portions, thereby easily judging good products and bad products. LED chips(42) are mounted on a lower substrate(30), and an upper substrate(36) is placed on the lower substrate. The upper substrate has two upper and lower ceramic sheet layers(32,34). A cavity(first inclined portion) is formed on a center portion of the lower ceramic sheet layer at a right angle, and is filled with a silicon or phosphor and an epoxy(46). A cavity(second inclined portion) is formed on a center portion of the upper ceramic sheet layer at an obtuse angle, and is filled with a silicon or an epoxy(48).

Description

Semiconductor package and method of manufacturing thereof

1 to 4 is a cross-sectional view showing the structure of a typical LED package,

5 is a view adopted to explain a problem in a general LED package,

6 is a cross-sectional view showing the structure of a typical LED package,

7 is a cross-sectional view of a semiconductor package according to an embodiment of the present invention.

<Description of Symbols for Major Parts of Drawings>

30: lower substrate 36: upper substrate

38, 40: pattern electrode 42: LED chip

44: wire 50: reflector

The present invention relates to a semiconductor package and a method for manufacturing the same, and more particularly, to a semiconductor package and a method for manufacturing the same so that the phosphor coating of the light emitting device used in the lighting fixture and the like can be made uniform.

A light emitting diode (hereinafter, referred to as an LED) is a semiconductor device capable of realizing various colors by configuring a light emitting source by changing compound semiconductor materials such as GaAs, AlGaAs, GaN, InGaN, and AlGaInP. Say. At present, many such semiconductor devices have been adopted in the form of packages in electronic components.

In general, a method of realizing a white LED employed in a luminaire or the like includes a method of combining a blue LED chip having a wavelength of 430 nm to 470 nm with a YAG-based phosphor (for example, yellow phosphor) in a visible light region, and a UV LED chip. There is a method of combining red / green / blue phosphors, and a method of combining red / green / blue LED chips.

Among the above methods, the first method is mainly used due to the reason that a white LED can be implemented inexpensively and the light efficiency is high.

When the white LED is implemented by combining the blue LED chip with a YAG-based phosphor (eg, yellow phosphor), the structure is illustrated in FIGS. 1 to 4.

1 to 4, the LED package shown in common, the LED chip 10; A lower substrate 12 on which the LED chip 10 is mounted; An upper substrate 14 disposed on the lower substrate 12 and having a cavity having a predetermined inclination angle in a region corresponding to the region where the LED chip 10 is mounted; Pattern electrodes 16 and 18 formed in the lower substrate 12 in a predetermined shape and connected to the LED chip 10 through wires 20; A reflector 24 installed in close contact with the inner surface of the cavity of the upper substrate 14 to surround the LED chip 10; And a phosphor layer 22 formed by potting the YAG-based phosphor (eg, yellow phosphor) and silicon (or epoxy) according to a predetermined compounding ratio to cover the LED chip 10. do. In FIG. 3 and FIG. 4, reference numeral 26 denotes a coating layer made of silicon or epoxy.

The light directing angle by the LED package of FIG. 1 is about 120 degrees to about 130 degrees, and the light directing angle by the LED package of FIG. 2 is about 80 degrees to about 110 degrees, and by the LED package of FIGS. The light directivity angle is about 60 to 70 degrees.

Of course, other series of phosphors other than YAG-based phosphors may be used, and white LEDs may be realized by employing LEDs of other colors than blue LEDs.

According to the LED package employing the cavity having the same inclination angle as in FIGS. 1 to 4, it is difficult to uniformly coat the phosphor on the LED chip and difficult to precisely adjust the light directivity angle according to the inclination angle of the LED package due to the scattering effect of the phosphor. Do. That is, in FIG. 1, the light directing angle is fixed to 120 degrees to 130 degrees regardless of the inclination angle of the cavity depending on the presence or absence of coating of the phosphor. In the case of Figure 2, the light directivity control is changed according to the height of the fluorescent material layer. 3 and 4, if the coating of the phosphor is uniform, as shown in Figure 5 (b), but the coating of the fluorescent material layer is uneven because it is difficult to coat a uniform fluorescent material layer on the LED chip. There are many. In particular, when the coating accuracy of the phosphor is low in Figures 3 and 4 as shown in Figure 5 (a) or (c) it becomes difficult to implement the white light due to the yellow band phenomenon occurs at the edge of the light.

In addition, in order to narrow the light directing angle of the LED package structure of FIG. 2, a structure in which a silicon layer or an epoxy layer 26 is formed on the fluorescent material layer 22 is proposed as in FIG. 6. This structure reacts with the silicon or epoxy and the ceramic or metal part of the surface of the inclined surface of the cavity when the phosphor layer 22 is coated and cured. Therefore, as shown in FIG. 6, the portion of the fluorescent material layer 22 in contact with the inclined surface of the cavity rises up the wall surface of the inclined surface, so that the desired light directivity angle cannot be obtained properly.

The present invention has been proposed to solve the above-mentioned conventional problems, and an object thereof is to provide a semiconductor package and a method of manufacturing the same, which facilitate the uniform coating of phosphors.

In order to achieve the above object, a semiconductor package according to a preferred embodiment of the present invention is a semiconductor package including a substrate having a cavity,

The cavity is characterized by having at least two inclined portions formed at different inclination angles.

The inclination part includes a first inclination part formed at a right angle inclination angle and a second inclination part formed at an obtuse angle inclination angle formed on an upper portion of the first inclination part.

The light emitting device chip is mounted on the cavity portion surrounded by the first inclined portion, and the phosphor is filled, and a reflecting plate is formed on the inner surface of the second inclined portion.

Alternatively, the semiconductor package according to the embodiment of the present invention is a semiconductor package including a substrate,

The substrate includes a first sheet layer having a hole having a first inclination angle in the center, and a second sheet layer having a hole having a second inclination angle in the center, wherein the second sheet layer is formed of the first sheet layer. It is characterized in that stacked on top.

The first inclination angle of the first sheet layer is a right angle, and the second inclination angle of the second sheet layer is an obtuse angle.

The hole of the first sheet layer is not only mounted with a light emitting device chip, but also filled with a phosphor, and a reflecting plate is formed on an inner surface of the hole of the second sheet layer.

Meanwhile, the method of manufacturing a semiconductor package according to the embodiment of the present invention is a method of manufacturing a semiconductor package including a lower substrate and an upper substrate.

A first step of preparing a first sheet layer having a hole having a first inclination angle in a center thereof; A second process of preparing a second sheet layer having a hole having a second inclination angle in a center thereof; And laminating the first sheet layer and the second sheet layer as the upper substrate on the lower substrate, wherein the first sheet layer is laminated on the lower substrate, and the second sheet layer is laminated thereon. It is characterized by including three processes.

The first inclination angle in the first process is formed at a right angle, and the second inclination angle in the second process is formed at an obtuse angle.

The fourth step of mounting the light emitting device chip in the hole of the first sheet layer and the fifth step of filling the phosphor in the hole of the first sheet layer may be further provided.

Hereinafter, a semiconductor package and a method of manufacturing the same according to an embodiment of the present invention will be described with reference to the accompanying drawings.

7 is a cross-sectional view of a semiconductor package according to an embodiment of the present invention.

The semiconductor package of the present invention, the LED chip 42; A lower substrate 30 on which the LED chip 42 is mounted; An upper substrate 36 disposed on the lower substrate 30 and having a cavity having predetermined first and second inclination angles in a region corresponding to the region where the LED chip 42 is mounted; Pattern electrodes 38 and 40 formed on the lower substrate 30 and connected to the LED chip 42 through wires 44; And a reflecting plate 50 installed along the inner surface of the cavity of the upper substrate 36 to surround the LED chip 42.

The lower substrate 30 can be any substrate as long as the LED chip 42 can be mounted at a high density. For example, the lower substrate 30 may include alumina, quartz, calcium zirconate, forsterite, SiC, graphite, fusedsilica, and mullite. ), Cordierite, zirconia, beryllia, aluminum nitride, low temperature co-fired ceramic (LTCC), and the like. Therefore, the material of the lower substrate 30 is not particularly limited, but in the embodiment of the present invention, a ceramic is used. The ceramic can be used as a multi-layer ceramic package (MLP) through the firing process by forming a metal conductor wiring pattern thereon. The upper substrate 36 may also be considered to be the same as the material of the lower substrate 30 described above.

The upper substrate 36 is composed of two ceramic sheet layers 32 and 34. A cavity (hole) (which becomes a first inclined portion) having a first angle of inclination (θL) at right angles is formed in the central portion of the lower ceramic sheet layer 32, and an obtuse angle is formed in the central portion of the upper ceramic sheet layer 34. A cavity (hole) (which becomes a second inclined portion) having a two inclination angle θT is formed. The upper opening surface of the cavity (hole) formed in the lower ceramic sheet layer 32 is in contact with the lower opening surface of the cavity (hole) formed in the upper ceramic sheet layer 34, but the diameters of the joint portions same.

In the specification of the present invention, the first inclined portion includes a space inclined by the inclined surface of the right angle θL and the inclined surface thereof. The second inclined portion includes an inclined surface of the obtuse angle θT and a space surrounded by the inclined surface of the obtuse angle.

Cavities (holes) are formed in the lower ceramic sheet layer 32 and the upper ceramic sheet layer 34 by adopting a conventional method, which is well known. It is easy to see.

In the cavity (hole) of the lower ceramic sheet layer 32, phosphor and silicon or phosphor and epoxy 46 are blended in a predetermined compounding ratio and then filled. The height of the filled phosphor and silicon (or epoxy) 46 is a0 to a1. Then, the level is maintained at the height of a1.

On the other hand, the cavity (hole) of the upper ceramic sheet layer 34 is filled with silicon or epoxy 48. Of course, no material may be filled in the cavity (hole) of the upper ceramic sheet layer 34. The height of the silicon or epoxy 48 to be filled is a1 to a2. And it is filled so that it may remain horizontal at the height of a2. Of course, it may be filled in a dome shape.

As such, when the cavity (hole) of the lower ceramic sheet layer 32 is filled to maintain the horizontal at the height of a1, it is possible to solve the problem caused by the phosphor filling that has occurred in the conventional structure. . That is, assuming that a plurality of semiconductor packages are filled with phosphors and the semiconductor packages filled with the phosphors are viewed from the top to the bottom, in the case of FIGS. 1, 2, and 6, each phosphor is charged on each LED chip. Since the inclined surface of the cavity is set at an angle, it is difficult to determine whether the heights of the phosphors charged on the respective LED chips are the same, so that it is difficult to determine good or bad. However, the semiconductor package can be accurately identified because the structural features of the present invention, i.e., the inclination angles of the first and second inclined portions, can accurately determine the reference point (the filling completion point of the phosphor; a1) (or referred to as the reference height). When viewed from the top down, when the filling height of the phosphor exceeds its reference point a1, it is easily grasped to facilitate the determination of good or bad. In particular, while FIG. 3 and FIG. 4 have a very difficult structure of uniform filling of the phosphor, the present invention can perform uniform filling of the phosphor much more easily than in FIGS. 3 and 4.

Furthermore, when the reflecting plate 50 is provided only on the inner wall of the upper ceramic sheet layer 34 as described below, the bottom surface of the reflecting plate 50 prevents the phosphor from rising on the inner wall during curing after phosphor filling. Done. Therefore, the desired phosphor shape can be maintained even after curing after phosphor filling. This effect aids in forming the desired brightness and / or light directivity angle.

In FIG. 7, the reflecting plate 50 is provided only on the inner wall of the upper ceramic sheet layer 34, but may be provided up to the inner wall of the lower ceramic sheet layer 32 as necessary. In this case, the reflector 50 may be connected to at least one of the pattern electrodes formed on the lower substrate 30 (eg, the anode electrode 38).

Here, the reflecting plate 50 may be formed separately from the above-described conventional metal reflecting plate and provided separately on the inner wall surface of the cavity (hole) of the upper ceramic sheet layer 34 by a silicon-based bonding material. Alternatively, the reflective plate 50 may be formed using a low temperature co-fired ceramic method. In the case of using this low temperature simultaneous firing ceramic method, the upper ceramic sheet layer 34 is processed at an angle to obtain a desired light directivity angle using an inclination angle former (also referred to as an orientation angle former) (not shown), and then the inside thereof. After printing conductive metal such as Ag of 20 ~ 20 micron on the wall and sintering by Low Temperature Co-fired Ceramic method, 2 ~ 20 micron of Ni is plated on the sintered surface. It is produced by plating micron Ag (Au) again. When sintering by low temperature co-fired ceramic method, it starts at 25 ℃ and increases by 2 ℃ / min and reaches 830 ~ 900 ℃. It keeps about 20 minutes and then drops by 2 ℃ / min and reaches 25 ℃. do. The above mentioned plating and firing conditions are general and may vary slightly depending on the composition and additives.

In the semiconductor package of the present invention described above, the light directing angle is different depending on the height of the reflecting plate 50 and the cavity inclination angle of the upper ceramic sheet layer 34. Of course, the light directing angle is also different depending on the difference in reflectance of the reflecting plate 50. The following table exemplarily shows changes in the view angle and lumen value according to the height h and the inclination angle (that is, the inclination angle of the second inclined portion) of the semiconductor package according to the embodiment of the present invention. It is shown. In the present invention, the inclination angle of the second inclined portion is an obtuse angle and is represented by θT in FIG. 7. In the following table, the inclination angle of the second inclined portion is represented by θ1 + θ2 in FIG. 7 for convenience.

(table)

Tilt angle of the second slope Optical characteristic value Height of reflector (height from a1 to a2) 1.2mm (h = 1.6mm) 1.6mm (h = 2.0mm) 1.8mm (h = 2.2mm) 120 degrees (θ1 + θ2) (θ1 = 60 degrees, θ2 = 60 degrees) Optical orientation 86 59.5 52 lumen 20.3 27.3 27.4 90 degrees (θ1 + θ2) (θ1 = 45 degrees, θ2 = 45 degrees) Optical orientation 102 74 68 lumen 18 22 24

In other words, the above table is a data experiment assuming that the reflectance of the reflector 50 is all the same, as can be seen from the above table, the light inclination angle is adjusted by the inclination angle of the second inclined portion and the height of the reflector 50 Able to know. Of course, although not shown in the table, changing the reflectance of the reflecting plate 50 adjusts the light directivity angle and lumen described in the table. In the above table, the ratio of the height (h1 to a2) of the reflector 50 to the height h of the semiconductor package is high, which is to obtain the light directing angle adjustment effect by the reflector 50. The height h of the semiconductor package described in the above table and the height of the reflector 50 (a1 to a2) are just one example, and the height of the reflector 50 is the size of the semiconductor package and the size and cavity of the LED chip. Is optimized according to the size of the (viewed from top to bottom) and so on.

In order to manufacture the semiconductor package according to the exemplary embodiment of the present invention configured as described above, the lower substrate 30 and the upper substrate 36 may be manufactured, respectively, after lamination and simultaneous firing. Of course, there are other detailed processes such as forming the pattern electrodes 38 and 40, mounting the LED chips 42, bonding the wires, and forming the reflecting plate 50. These processes may be performed by well-known manufacturing processes. The description is omitted.

The lower substrate 30 and the upper substrate 36 differ in the presence or absence of a cavity forming process, and are basically the same in that they are manufactured by laminating ceramic sheets. In order to manufacture the lower substrate 30 and the upper substrate 36, first, a ceramic sheet must be manufactured.

The manufacturing method of this ceramic sheet is as follows.

A glass ceramic powder having a predetermined weight is prepared, and PVB-based binder is weighed by a predetermined weight part with respect to the glass ceramic powder, and then dissolved in toluene / alcohol-based solvent and blended together in the glass ceramic powder. .

Then, the blended glass ceramic powder is placed in a container and rotated to mix uniformly. For example, a glass ceramic powder having a desired particle size is obtained through a ball mill at 50 rpm for about 20 hours. The above 50 rpm and 20 hours are just examples and vary depending on the diameter and amount of the balls in the ball mill, the amount of solvent and binder, and the like.

When milling in the ball mill, the first blended glass ceramic powder is discharged in the form of a slurry. Since the discharged slurry has some bubbles, it is degassed to remove bubbles in the discharged slurry. Is carried out. In order to prevent the slurry surface from drying rapidly during defoaming, the slurry is kept under vacuum for a predetermined time while stirring.

The mixed raw material (ie, in the form of a slurry) subjected to the defoaming process is formed into a sheet. That is, after installing the film and the blade (blade) on the tape caster, while slowly transferring the film, the degassed slurry is introduced, and the slurry passed through the blade is dried to produce a ceramic having a desired thickness (for example, 20 to 150 μm on the film). It is wound on a roll in the form of a sheet (green sheet).

Then, the ceramic sheet wound on the roll is cut to a certain size (dimension) so that it can be easily worked in a later process.

When a ceramic sheet having a predetermined size is manufactured in this way, via holes are formed in the cut ceramic sheet, and the via holes are filled with a conductor paste. The via hole serves to connect the interlayer circuits. Then, conductive pastes such as Ag, Pt, and Pd are formed on the ceramic sheet by a thin film manufacturing method such as screen printing, or a thin film manufacturing method such as sputtering, evaporation, vapor chemical vapor deposition, and sol-gel coating to form an internal circuit suitable for each layer. A patterned ceramic sheet is produced.

When the ceramic sheet printed with the internal circuit pattern is manufactured as described above, the lower substrate 30 and the upper substrate 36 are manufactured using the respective ceramic sheets.

That is, in the case of the lower substrate 30 and the upper substrate 36, after the respective ceramic sheets are dried, the respective ceramic sheets are collectively laminated so as to form a desired molded body. Then, the laminated ceramic sheet is pressurized at a pressure of about 3000 psi and a temperature of 80 to 100 ° C. to form a molded body. The pressure of about 3000 psi and the temperature of 80 to 100 ° C. are just one example and may vary depending on the situation.

In this way, manufacture of the lower substrate 30 is completed, and the upper substrate 36 may just form a cavity additionally in the molded object by which the ceramic sheet was laminated | stacked. Here, when the cavity is formed on the upper substrate 36, the cavity (hole) (first inclined portion) having the first inclination angle (θL) at right angles and the second inclination angle (θT) at the obtuse angle, as shown in FIG. If it is possible to form the holes (second inclined portion) at once, it is possible to do so, but it is better to form each because it is difficult to form them all at once.

That is, as can be seen in Figure 7, the upper substrate 36 is roughly divided into the lower ceramic sheet layer 32 and the upper ceramic sheet layer 34, the first perpendicular to the lower ceramic sheet layer 32 A cavity (first inclined portion) having an inclination angle θL is formed, and a cavity (hole) having a second oblique angle (θT) of an obtuse angle is formed in the upper ceramic sheet layer 34. To form. For example, in the case of the lower ceramic sheet layer 32, a cavity having a right angle of inclination is formed using a conventional punching process. In the case of the upper ceramic sheet layer 34, a cavity having an obtuse inclination angle is formed by using an inclination angle former (not shown). On the other hand, the upper ceramic sheet layer 34 may be manufactured through a conventional manufacturing process in which a plurality of ceramic sheets with holes having different diameters are sequentially stacked, pressed and fired.

As described above, after the lower substrate 30, the upper substrate 36 (the lower ceramic sheet layer 32 and the upper ceramic sheet layer 34) are manufactured, the upper substrate (on the lower substrate 30) is formed. When the lower ceramic sheet layer 32 in 36 is laminated and the upper ceramic sheet layer 34 is laminated thereon, and then fired, a semiconductor package having the structure as shown in FIG. 7 is completed.

As described in detail above, according to the present invention, the reference point can be accurately identified due to the significantly different inclination angles of the first and second inclined portions, thereby making it easier to determine whether the phosphor is filled uniformly or non-uniformly. It becomes easy.

In addition, when the first and second inclined portions have inclined angles that are significantly different from each other, and particularly, the inclined surface of the first inclined portion has a right angled inclination angle, the phosphor is filled in a plurality of arrayed semiconductor packages, compared with the conventional case. The height can be made uniform, eliminating the occurrence of differences in the light directivity angles.

Furthermore, in the case where the reflector is installed only on the inner wall of the upper ceramic sheet layer, the bottom surface of the reflector prevents the phosphor from rising on the inner wall during curing after the filling of the phosphor. It becomes possible. Therefore, the desired light directivity angle and color coordinates can be obtained, and there is an effect of improving the production yield.

On the other hand, the present invention is not limited only to the above-described embodiment, but can be modified and modified within the scope not departing from the gist of the present invention, the technical idea to which such modifications and variations are also applied to the claims Must see

Claims (18)

A semiconductor package comprising a substrate with a cavity, And the cavity has at least two inclined portions formed at different inclination angles. The method of claim 1, The inclined portion includes a first inclined portion formed at an inclined angle at a right angle and a second inclined portion formed at an obtuse inclination angle formed on an upper portion of the first inclined portion. The method of claim 2, The semiconductor package, characterized in that the light emitting device chip is mounted in the cavity portion surrounded by the first inclined portion. The method of claim 2 or 3, The cavity package surrounded by the first inclined portion is a semiconductor package characterized in that the phosphor is filled. The method of claim 3, wherein The light emitting device chip is a semiconductor package, characterized in that consisting of the LED chip. The method of claim 2, A semiconductor package, characterized in that the reflection plate is formed on the inner side of the second inclined portion. A semiconductor package comprising a substrate, The substrate includes a first sheet layer having a hole having a first inclination angle in the center, and a second sheet layer having a hole having a second inclination angle in the center, And the second sheet layer is stacked on top of the first sheet layer. The method of claim 7, wherein The first inclination angle of the first sheet layer is a semiconductor package, characterized in that the right angle. The method according to claim 7 or 8, And a second inclination angle of the second sheet layer is an obtuse angle. The method of claim 9, A light emitting device chip is mounted in the hole of the first sheet layer. The method of claim 10, The hole of the first sheet layer is a semiconductor package, characterized in that the phosphor filled. The method of claim 10, The light emitting device chip is a semiconductor package, characterized in that consisting of the LED chip. The method of claim 9, A semiconductor package, characterized in that the reflection plate is formed on the inner surface of the hole of the second sheet layer. A method of manufacturing a semiconductor package comprising a lower substrate and an upper substrate, A first step of preparing a first sheet layer having a hole having a first inclination angle in a center thereof; A second process of preparing a second sheet layer having a hole having a second inclination angle in a center thereof; And A third process of laminating the first sheet layer and the second sheet layer as the upper substrate on the lower substrate, laminating the first sheet layer on the lower substrate, and laminating the second sheet layer thereon; Method of manufacturing a semiconductor package comprising a. The method of claim 14, A method of manufacturing a semiconductor package, characterized in that to form a first inclination angle in the first process at a right angle. The method according to claim 14 or 15, A method of manufacturing a semiconductor package, characterized in that to form a second oblique angle in the second process at an obtuse angle. The method of claim 16, And a fourth process of mounting the light emitting device chip in the hole of the first sheet layer. The method of claim 17, And a fifth process of filling the holes of the first sheet layer with phosphors.

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