Abstract:
The present invention relates to an electro-static discharge (ESD) protection device with a low temperature co-fire ceramic (LTCC) and a manufacturing method thereof. The ESD protection device comprises a low temperature co-fire ceramic film having a first patterned conductive electrode material layer and a second patterned conductive electrode material layer therein. The low temperature co-fire ceramic film has at least one via exposing a portion of the first patterned conductive electrode material layer and a portion of the second patterned conductive electrode material layer simultaneously.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to an electro-static discharge (ESD) protection device and a manufacturing method thereof, in particular, to an ESD protection device with a low temperature co-fire ceramic (LTCC) and a manufacturing method thereof. 
       DESCRIPTION OF THE PRIOR ART 
       [0002]    Over-voltage protection or discharge protection elements have been widely used in circuits of various electronic products for protection or to protect the elements in the electronic products from being damaged by an abnormal voltage or electro-static discharge (ESD), so as to avoid the failure or the shortening of the service life of the electronic products. ESD protection design has become a basic requirement for electronic products. 
         [0003]    In order to enable the electronic products to meet the requirements for withstanding ESD, this industry has developed various ESD protection elements, for example, transient voltage suppress diode (TVSD) and multi-layer varistor (MLV), that protect the circuit. Furthermore, in the circuit design, the industry has developed various means for solving the problem of ESD protection design by utilizing, for example, shielding protection, gap discharge, or capacitor charge/discharge. In the Japanese Patent Publication No. JP1995-245878, an over-voltage protection device is disclosed which has a micro gap used for discharging to protect electronic products. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention is directed to an ESD protection device. The ESD protection device includes an LTCC film. The LTCC film has a first patterned conductive electrode material layer, a second patterned conductive electrode material layer, and at least one via for exposing a portion of the first patterned conductive electrode material layer and a portion of the second patterned conductive electrode material layer simultaneously. 
         [0005]    The present invention is also directed to a manufacturing method for an ESD protection device. The method includes the following steps: providing a first LTCC film having a first patterned conductive electrode material layer; providing a second LTCC film having at least one via; disposing the second LTCC film on the first LTCC film; filling the at least one via with a volatile material; providing a third LTCC film having a second patterned conductive electrode material layer; disposing the third LTCC film on the second LTCC film; and co-firing the first LTCC film, the second LTCC film, and the third LTCC film to volatilize the volatile material, so as to form at least one air gap for exposing a portion of the first patterned conductive electrode material layer and a portion of the second patterned conductive electrode material layer. 
         [0006]    According to an embodiment of the present invention, the ESD protection device of the present invention can easily control an electrode spacing so that it falls in the range of 5 μm-30 μm. 
         [0007]    According to another embodiment of the present invention, the air gap of the ESD protection device of the present invention exposes one end of a first patterned conductive electrode and one end of a second patterned conductive electrode. A length (L 1 ) of the air gap is greater than a length (L 2 ) of one end of the first patterned conductive electrode, and is greater than a length (not shown) of one end of the second patterned conductive electrode. Meanwhile, a width (W 1 ) of the air gap is greater than a width (W 2 ) of one end of the first patterned conductive electrode, and is greater than a width (not shown) of one end of the second patterned conductive electrode. Such electrodes can discharge in the air gap, so as to protect the electronic products. 
         [0008]    According to another embodiment of the present invention, the ESD protection device of the present invention can change a pattern of the first patterned conductive electrode material layer and a pattern of the second patterned conductive electrode material layer, so as to meet different size design requirements. 
         [0009]    According to another embodiment of the present invention, the size of the air gap of the ESD protection device is very small, so that a breakdown voltage can be effectively reduced. This simple structure provides a design meeting the ESD low-voltage protection requirement. 
         [0010]    To make the features and functions of the present invention more comprehensible, the present invention will be illustrated below in detail with reference to the following embodiments and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIGS. 1A and 1B  are respectively a top view and a cross-sectional view of a first LTCC film formed according to a first embodiment of the present invention. 
           [0012]      FIGS. 2A and 2B  are respectively a top view and a side cross-sectional view of a second LTCC film formed according to the first embodiment of the present invention. 
           [0013]      FIGS. 3A and 3B  are respectively a top view and a side cross-sectional view of the first LTCC film with the second LTCC film disposed thereon after a via is filled with a volatile material according to the first embodiment of the present invention. 
           [0014]      FIGS. 4A and 4B  are respectively a top view and a side cross-sectional view of the second LTCC film with a third LTCC film disposed thereon according to the first embodiment of the present invention. 
           [0015]      FIGS. 5A and 5B  are respectively a top view and a side cross-sectional view of a chip of an ESD protection device formed according to the first embodiment of the present invention. 
           [0016]      FIGS. 6A and 6B  are respectively a top view and a front view of at least one first terminal electrode and at least one second terminal electrode according to the first embodiment of the present invention. 
           [0017]      FIGS. 7A and 7B  are respectively a top view and a side cross-sectional view of a first LTCC film formed according to a second embodiment of the present invention. 
           [0018]      FIGS. 8A and 8B  are respectively a top view and a side cross-sectional view of a second LTCC film formed according to the second embodiment of the present invention. 
           [0019]      FIGS. 9A and 9B  are respectively a top view and a side cross-sectional view of the first LTCC film with the second LTCC film covered thereon after a via is filled by a volatile material according to the second embodiment of the present invention. 
           [0020]      FIGS. 10A and 10B  are respectively a top view and a side cross-sectional view of the second LTCC film with a third LTCC film disposed thereon according to the second embodiment of the present invention. 
           [0021]      FIGS. 11A and 11B  are respectively a top view and a side cross-sectional view of a chip of an ESD protection device formed according to the second embodiment of the present invention. 
           [0022]      FIGS. 12A and 12B  are respectively a top view and a front view of at least one first terminal electrode and at least one second terminal electrode formed according to the second embodiment of the present invention. 
           [0023]      FIGS. 13A and 13B  are respectively enlarged diagrams of an air gap of an ESD protection device formed according to the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]      FIGS. 1A to 6B  are schematic views of an ESD protection device according to a first embodiment of the present invention. As shown in  FIGS. 1A and 1B , the ESD protection device includes a first LTCC film  100 . The first LTCC film  100  has a first patterned conductive electrode material layer  101  thereon. The first patterned conductive electrode material layer  101  may be printed on the first LTCC film  100 , and the first patterned conductive electrode material layer  101  is disposed in a first direction. As shown in  FIGS. 2A and 2B , a second LTCC film  102  is further provided. The second LTCC film  102  has at least one via  103 . The at least one via  103  may be formed by perforating the film with a punch machine, and meanwhile, the second LTCC film  102  is disposed on the first LTCC film  100 . The first LTCC film  100  and the second LTCC film  102  may be aligned with each other and laminated together. As shown in  FIGS. 3A and 3B , the at least one via  103  is filled with a volatile material  104 . As shown in  FIGS. 4A and 4B , a third LTCC film  105  is provided. The third LTCC film  105  has a second patterned conductive electrode material layer  106  thereon. The second patterned conductive electrode material layer  106  may be printed on the third LTCC film  105 . The second patterned conductive electrode material layer  106  is disposed in a second direction that is the same as the first direction. Meanwhile, the third LTCC film  105  is disposed on the second LTCC film  102 . The second LTCC film  102  and the third LTCC film  105  may be aligned with each other and laminated together. The first LTCC film  100 , the second LTCC film  102 , and the third LTCC film  105  may be bonded together tightly by utilizing water pressure. As shown in  FIGS. 5A and 5B , a formed film structure is cut into a plurality of chip configurations, and the chips are co-fired after being formed. During the sintering process, the volatile material  104  is fired out, so as to form an air gap  108 . The air gap  108  is completely enclosed by the film structure, and a portion of the first patterned conductive electrode material layer  101  and a portion of the second patterned conductive electrode material layer  106  are exposed. As shown in  FIGS. 6A and 6B , at least one first terminal electrode  107   a  for contacting the first patterned conductive electrode material layer  101  and at least one second terminal electrode  107   b  for contacting the second patterned conductive electrode material layer are formed at two sides of the chip by electroplating. The ESD protection device can be finished by forming at least one tin solder boundary layer (not shown) on the at least one first terminal electrode  107   a  and on the at least one second terminal electrode  107   b.    
         [0025]      FIGS. 7A to 12B  are schematic views of an ESD protection device structure formed according to a second embodiment of the present invention. As shown in  FIGS. 7A and 7B , the ESD protection device includes a first LTCC film  200 . The first LTCC film  200  has a first patterned conductive electrode material layer  201  thereon. The first patterned conductive electrode material layer  201  may be printed on the first LTCC film  200 , and the first patterned conductive electrode material layer  201  is disposed in a first direction. As shown in  FIGS. 8A and 8B , a second LTCC film  202  is further provided. The second LTCC film  202  has at least one via  203 . The at least one via  203  may be formed by perforating the film with a punch machine. Meanwhile, the second LTCC film  202  is disposed on the first LTCC film  200 . The first LTCC film  200  and the second LTCC film  202  may be aligned with each other and laminated together. As shown in  FIGS. 9A and 9B , the at least one via  203  is filled with a volatile material  204 . As shown in  FIGS. 10A and 10B , a third LTCC film  205  is provided. The third LTCC film  205  has a second patterned conductive electrode material layer  206  thereon. The second patterned conductive electrode material layer  206  may be printed on the third LTCC film  205 . The second patterned conductive electrode material layer  206  is disposed in a second direction that is different from the first direction. Meanwhile, the third LTCC film  205  is disposed on the second LTCC film  202 . The second LTCC film  202  and the third LTCC film  205  may be aligned with each other and laminated together. The first LTCC film  200 , the second LTCC film  202 , and the third LTCC film  205  may be bonded together tightly by utilizing water pressure. As shown in  FIGS. 11A and 11B , a film structure formed by the above steps is cut into a plurality of chip configurations, and the chips are co-fired after being formed. During the sintering process, the volatile material  204  is fired out, so as to form an air gap  208 . The air gap  208  is completely enclosed by the film structure, and a portion of the first patterned conductive electrode material layer  201  and a portion of the second patterned conductive electrode material layer  206  are exposed. As shown in  FIGS. 12A and 12B , at least one first terminal electrode  207   a  for contacting the first patterned conductive electrode material layer  201  and at least one second terminal electrode  207   b  for contacting the second patterned conductive electrode material layer  206  may be formed at two sides of the chip by electroplating. The ESD protection device can be finished by forming at least one tin solder boundary layer (not shown) on the at least one first terminal electrode  207   a  and on the at least one second terminal electrode  207   b.    
         [0026]    The ESD protection device of the present invention can easily control the electrode spacing in the range of 5 μm-30 μm. 
         [0027]      FIGS. 13A and 13B  are respectively enlarged diagrams of an air gap of an ESD protection device formed according to the present invention. As shown in  FIG. 13A , the air gap ( 308 ) exposes one end of a first patterned conductive electrode and one end of a second patterned conductive electrode. A length (L 1 ) of the air gap  308  is greater than a length (L 2 ) of one end of the first patterned conductive electrode and is greater than a length (not shown) of one end of the second patterned conductive electrode. Meanwhile, as shown in  FIG. 13B , a width (W 1 ) of the air gap  308  is greater than a width (W 2 ) of one end of the first patterned conductive electrode and is greater than a width (not shown) of one end of the second patterned conductive electrode. 
         [0028]    The ESD protection device of the present invention can change a pattern of the first patterned conductive electrode material layer and a pattern of the second patterned conductive electrode material layer, so as to meet different size design requirements. 
         [0029]    Meanwhile, the size of the air gap of the ESD protection device formed in the present invention is very small, so that a breakdown voltage can be effectively reduced. This simple structure provides a design meeting the ESD low-voltage protection requirement. 
         [0030]    The above embodiments are merely preferred embodiments of the present invention, but do not limit the scope of the present invention. It is intended that the present invention cover modifications and variations of this invention, provided that they fall within the scope of the following claims and their equivalents.