Ceramic part for packaging and manufacturing method thereof

Abstract

The invention provides a ceramic part for packaging and a manufacturing method thereof, the main body of the ceramic part for packaging is a circular or polygon-prism-shaped ceramic cylinder, the center of the ceramic cylinder is provided with a cavity, the inner side wall of the cavity and the outer side wall of the ceramic cylinder are coated with metallization layers, the outer diameter of the ceramic cylinder is between 1mm and 5mm, and the thickness of the inner metallization layer and the outer metallization layer is between 0.05 mm and 0.1 mm. The ceramic part is manufactured by adopting a multi-layer co-fired ceramic production technology and a method of punching and filling step by step and finally cutting a ceramic green body, a continuous and surrounding metallization layer can be formed outside a ceramic cylinder, batch production of the ceramic part can be realized, and the problems of low efficiency, poor product consistency and the like caused by a traditional die casting technical route are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic packaging, in particular to a ceramic piece for packaging and a manufacturing method thereof. BACKGROUND

[0002] In an electronic ceramic packaging shell, a transistor package (TO package) is a common packaging structure, in which a coaxial ceramic piece is a key component for connecting a chip and an external circuit. The main structure is a circular or square column ceramic with a coaxial cavity. The inner and outer side walls are covered with a metal layer, and the metal layers are insulated from each other. The inner side wall metal layer is welded with a lead to provide current and signal transmission for the device. The outer side wall metal layer is welded with a metal frame to provide sealing and fixing protection for the device. This type of ceramic piece is mainly used in various circuit devices such as transistors. It has a simple structure, small size, and large market demand.

[0003] The current mainstream coaxial ceramic piece manufacturing technology route is as follows: ceramic powder is mixed with sintering aids, forming aids, and other powders or organic binders to obtain a coaxial cavity ceramic column green body by pressure casting. After sintering and polishing, a coaxial cavity ceramic column is obtained. Then, the inner and outer side wall metal layers are coated one by one according to the requirements. After sintering and polishing, the ceramic piece is obtained. This technology route has two sintering processes, and the inner and outer side wall metal layers need to be coated one by one, which is labor-intensive and low in production efficiency. In addition, due to the one-by-one processing operation, the consistency of appearance, size, and performance is poor, which makes it difficult to meet the demand of batch production.

[0004] CN 120186895 A discloses a low-temperature co-fired ceramic substrate cavity side wall metallization method. The method adopts punching, metal paste filling, cutting, and sintering to manufacture a ceramic substrate with cavity side wall metallization. In this scheme, there are many non-metallized gaps in the inner side wall metallization. As a signal transmission, it limits the stability of signal transmission. As a welding structure, it affects the welding strength and the air tightness of the device. SUMMARY

[0005] The purpose of the present application is to provide a packaging ceramic piece that avoids electromagnetic wave radiation escape. Another purpose of the present application is to provide a preparation method for a packaging ceramic piece, which improves production efficiency and the consistency of appearance and performance.

[0006] Technical solution: The packaging ceramic piece disclosed by the present application comprises a ceramic column, a continuous metal layer is arranged on the outer side wall of the ceramic column, and a first cavity coaxial with the ceramic column is arranged in the center of the ceramic column.

[0007] Preferably, the inner wall of the first cavity is provided with a metal layer.

[0008] Preferably, the top and bottom of the ceramic column are provided with a metallization layer.

[0009] Preferably, the first cavity and the ceramic column are a cylinder or a polygonal column, the outer diameter of the ceramic column is 1-5 mm, and the thickness of the metallization layer is 0.05-0.1 mm.

[0010] The method for preparing the aforementioned packaging ceramic piece comprises the following steps:

[0011] (1) Forming a plurality of second cavities on the ceramic green body and filling the second cavities with metal paste;

[0012] (2) Continuing to form third cavities on the ceramic green body, the third cavities being capable of being spliced with the second cavities to form a closed ring, and filling the third cavities with metal paste;

[0013] (3) Stacking and compacting a plurality of ceramic green bodies, cutting between the inner ring side and the outer ring side of the closed ring, taking the central part, and sintering to obtain a ceramic column with a metallization layer on the outer sidewall.

[0014] Preferably, the second cavities and the third cavities are each independently at least one of an arc shape, an L shape, and a strip shape.

[0015] Preferably, the second cavities and the third cavities are arranged in a circumferential array.

[0016] Preferably, a first cavity is continuously formed at the center of the closed ring, or a first cavity is first formed on the ceramic green body, and a plurality of second cavities are formed with the first cavity as the center.

[0017] Preferably, the first cavity is filled with metal paste to form a metallization layer.

[0018] Preferably, the ceramic green body is in the form of a sheet and is prepared by tape casting, cutting, and blanking of a ceramic paste, and the ceramic green body is at least one of an alumina green body and an aluminum nitride green body. The alumina or aluminum nitride accounts for 92%-95% by mass in the ceramic paste, the total proportion of clay, talc powder, and calcium carbonate accounts for 3%-6% by mass, and the proportion of PVB accounts for 4-10% by mass.

[0019] Preferably, in step (3), the first cavity is used as a positioning cavity during stacking to ensure that the upper and lower ends of the first cavity are aligned.

[0020] Preferably, in step (3), a pressure of 200-3000 psi is applied during compaction to ensure tight bonding between the layers.

[0021] Preferably, the metal paste contains one or more of tungsten, molybdenum, copper. The metal powder in the metal paste accounts for 70-95% by mass, the inorganic binder accounts for 1-10%, and the organic medium accounts for 4-20%. The metal powder is at least one of molybdenum powder, copper powder, and tungsten powder. The metal powder is a conductor, the inorganic binder tightly binds the metal powder and the ceramic green body during sintering, and the organic medium enables the metal powder and the inorganic binder to be printed onto the ceramic green body.

[0022] Preferably, in order to improve the density and ensure the interface bonding strength between the metal paste and the ceramic green body, in step (3), the sintering step is: heating to 1700-1800℃ at a heating rate of 5-10℃ / min in a nitrogen or hydrogen atmosphere, and holding for 1-2h.

[0023] Advantages: Compared with the prior art, the present application has the following advantages: 1. Avoiding electromagnetic wave radiation escape: The metallized layer outside the ceramic green body is a continuous / seamless structure, which can prevent electromagnetic wave radiation from escaping and ensure the airtightness during welding; 2. Using multi-layer ceramic processing, when using a conventional eight-inch ceramic green body as a raw material, using multi-layer ceramic metallization filling and side wall metallization technology, 1000-10000 annular continuous metallization filling areas, coaxial cavities and inner side wall metallization layers can be obtained on a single stack. After multi-layer alignment lamination and compaction, the coaxial ceramic green body is obtained by batch cutting, and the coaxial ceramic part is obtained by one-time sintering. Compared with the current die casting manufacturing technology, the present application overcomes the shortcomings of the prior art, such as the need for single die casting processing and single side metallization, improves production efficiency, and has batch production capacity. At the same time, by one-time co-sintering of ceramic and metallization, the present application overcomes the shortcomings of the prior art, such as the need for two-time sintering. Therefore, the present application can solve the problem of low production efficiency in the prior art, and improve the consistency of the appearance and performance of the ceramic part; 3. Ensuring the interface bonding strength between the metallized layer and the ceramic column. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 Structure diagram of the cylindrical ceramic part for packaging described in the first embodiment of the present application;

[0025] Figure 2 Structure diagram of the four-prism ceramic part for packaging described in the first embodiment of the present application;

[0026] Figure 3 Preparation flowchart of the metallized layer of the second embodiment of the present application;

[0027] Figure 4 Preparation flowchart of the metallized layer of the third embodiment of the present application. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0029] Example 1: As Figure 1 As shown, the ceramic component for packaging disclosed in this invention is mainly composed of a ceramic column 1 and a continuous metallization layer 2 covering the outer wall of the ceramic column 1. The ceramic column 1 can be a cylinder, or a polyprismatic structure such as a quadrangular prism or a pentagonal prism. A cavity A3 is opened in the center of the ceramic column 1. The cavity A3 is consistent with the outer contour structure of the ceramic column 1 and the two are coaxial.

[0030] The outer diameter of the ceramic column 1 is between 1 mm and 5 mm, the thickness of the metallization layer is between 0.05 mm and 0.1 mm, the inner wall of the cavity A3 is covered with a metallization layer 2, and the height of the metallization layer 2 on the inner and outer walls is not greater than the height of the ceramic column 1. The top and bottom surfaces of the ceramic column 1 can also be covered with the metallization layer 2.

[0031] Example 2: This example provides a method for preparing the ceramic part for packaging described in Example 1, including the following steps:

[0032] S101: Ceramic slurry is cast, cut, and blanked to obtain sheet-shaped ceramic green bodies. The ceramic slurry can be purchased directly or prepared by oneself, for example, according to the scheme described in CN 105347777 A: by mass, 92%~95% alumina or aluminum nitride, 3%~6% clay, talc powder and calcium carbonate are mixed to form an inorganic powder; a binder solution containing PVB, anhydrous ethanol and plasticizer is prepared; the inorganic powder and binder solution are ball-milled to form a ceramic slurry;

[0033] S102: A cavity is drilled in the ceramic green body to obtain a hollow cavity A1 that penetrates the ceramic green body. In this embodiment, the cavity A1 is arc-shaped and distributed in a circumferential array. The cavity A1 on a single ceramic green body is as follows: Figure 2 As shown in part b;

[0034] S103: Fill cavity A1 with metal slurry to obtain metal-filled area B1. The metal-filled area B1 on a single ceramic green body is as follows: Figure 2 As shown in section c. The metal paste can be purchased directly or prepared according to the scheme described in CN 102314957 A, for example, by ball milling 70-95% tungsten, molybdenum, or copper powder and 1-10% inorganic binder mixture to form a thick film conductor metallization powder, and then dispersing the thick film conductor metallization powder in 4-20% organic medium to form a metal paste.

[0035] S201: punch a cavity on the ceramic green body prepared in S103 (remove the ceramic green body between the metal filling area B1) to form a hollow cavity A2 penetrating the ceramic green body. The cavity A2 is also arc-shaped and can be spliced with the cavity A1 to form a complete (closed) circular ring. The cavity A2 on the single ceramic green body is shown in part d of Figure 2 ;

[0036] S202: fill the cavity A2 with metal slurry, connect with the metal filling area B1 obtained in S103, and obtain a ring-shaped metal filling area B2. The metal filling area B2 on the single ceramic green body is shown in part e of Figure 2 ;

[0037] S301: punch a cavity at the center of the metal filling area B2 to obtain a hollow cavity A3 penetrating the ceramic green body and having the same center as the metal filling area B2, as shown in part f of Figure 2 . The metal filling area B2 is in the shape of a circular ring, so the cavity A3 is circular, and the outer diameter of the cavity A3 is smaller than the inner diameter of the metal filling area B2;

[0038] S302: fill the cavity A3 with metal slurry, and metalize the inner wall of the cavity A3;

[0039] S400: stack multiple ceramic green bodies obtained in S302, apply a pressure of 200-3000 psi for compaction (when stacking, the cavities A3 of the upper and lower ceramic green bodies need to be aligned), and cut along the metal filling area B2 ring (i.e., the cutting track is located between the outer ring side and the inner ring side of the metal filling area B2 to ensure that the outer sidewall of the ceramic green body after cutting forms a complete / continuous metalized layer), to obtain a ceramic green body.

[0040] S500: sinter the ceramic green body under a nitrogen or hydrogen atmosphere at a heating rate of 5-10 ℃ / min to 1700-1800 ℃, and keep the temperature for 1-2 h to obtain a packaging ceramic part.

[0041] Example 3: The steps of this example are the same as those of Example 2, except that the hollow cavities A1 and A2 are different in shape, as shown in Figure 3 . The hollow cavity A1 is L-shaped, the hollow cavity A2 is strip-shaped, the hollow cavity A1 can be spliced with the hollow cavity A2 to form a complete / closed rectangular ring, and the metal filling area B2 is a rectangular ring. Punch a cavity at the intersection of the diagonal lines of the metal filling area B2 to obtain a cavity A3.

[0042] Embodiment 4: The difference between this embodiment and Embodiment 2 is that step S200 is advanced to before step S101, that is, the cavity A3 is first formed on the ceramic green body, the metal paste is used to fill A3, and the metal layer is formed on the inner side wall of A3; then the cavity A3 is taken as the center, and the arc-shaped hollow cavities A1, A2 and the metal filling area B2 are formed by step-by-step punching and filling outside the hollow cavity A3.

Claims

1. A ceramic member for packaging, characterized by, The ceramic column is surrounded by a metal layer on the outside wall, and a first cavity is arranged in the center of the ceramic column.

2. The ceramic package of Claim 1, wherein The first cavity and the ceramic column are cylindrical or polygonal, the outer diameter of the ceramic column is 1-5 mm, and the thickness of the metal layer is 0.05-0.1 mm.

3. The ceramic package of Claim 1, wherein The inner wall of the first cavity is provided with a metal layer.

4. The method of producing a ceramic package according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: (1) Forming a plurality of second cavities on the ceramic green body and filling metal slurry into the second cavities; (2) Forming a third cavity on the ceramic green body, the third cavity being capable of being spliced with the second cavity to form a closed ring, and filling metal slurry into the third cavity; (3) Stacking and compacting a plurality of ceramic green bodies, cutting between the inner ring side and the outer ring side of the closed ring, taking the center part, and sintering to obtain a ceramic column surrounded by a metal layer on the outside wall.

5. The preparation method according to claim 4, characterized in that, The second cavity and the third cavity are each independently selected from at least one of an arc shape, an L shape, and a strip shape, and the second cavity and the third cavity are arranged in a circular array.

6. The preparation method according to claim 4, characterized in that, A first cavity is formed at the center of the closed ring, or a first cavity is formed on the ceramic green body, and a plurality of second cavities are formed with the first cavity as the center.

7. The production method according to claim 6, characterized by, The first cavity is filled with metal slurry to form a metal layer.

8. The preparation method according to claim 4, characterized in that, The metal slurry contains one or more of tungsten, molybdenum, and copper.

9. The preparation method according to claim 4, characterized in that, The ceramic green body is in the form of a sheet, and the pressure of the compacting step in step (3) is 200-3000 psi.

10. The method of claim 4, wherein, In step (3), the sintering step is: heating to 1700-1800℃ at a heating rate of 5-10℃ / min in a nitrogen or hydrogen atmosphere, and holding for 1-2h.

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