Patent Publication Number: US-2013250990-A1

Title: Laser emitting chip package

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to package structures and, particularly, to a laser emitting chip package. 
     2. Description of Related Art 
     With the development of the optical communication technology, Vertical Cavity Surface-Emitting Lasers (VCSEL) are widely used in a variety of optical communication devices. In related art, the VCSEL includes a laser emitting chip, a circuit board, and other electronic components. The laser emitting chip is electrically connected to and supported on the circuit board using flip-chip package method. For example, explanting a gold ball on a chip-pad area of the laser emitting chip, then flipping the laser emitting chip, finally fixing the laser emitting chip on the circuit board with the gold ball as a sandwich filling bonded on a substrate-pad area of the circuit board. 
     However, the circuit boards of related art only provide one substrate-pad area. The substrate-pad area is much smaller than the area of the laser emitting chip. During the flip-chip packaging process, the laser emitting chip, supported on the substrate-pad area only through the gold ball, will be prone to tilting or collapsing. 
     Therefore, it is desirable to provide a laser emitting chip package which can overcome the above-mentioned limitations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. 
         FIG. 1  is an assembled, isometric view of a laser emitting chip package, according to a first exemplary embodiment. 
         FIG. 2  is an exploded, isometric view of the laser emitting chip package of  FIG. 1 . 
         FIG. 3  is an exploded, isometric view of a laser emitting chip package, according to a second exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1-2  illustrate a laser emitting chip package  100 , according to a first exemplary embodiment. The laser emitting chip package  100  includes a circuit board  10  and a laser emitting chip  20  electrically and mechanically connected to the circuit board  10 . The laser emitting chip  20  is configured for emitting laser beams. 
     The circuit board  10  includes a supporting surface  101  and a bottom surface  102  facing away from the supporting surface  101 . In the embodiment, the circuit board  10  is substantially cuboid, and includes four substrate-pad areas  12  respectively formed on the four corners of the supporting surface  101 . The circuit board  10  defines a circuit through hole  110  in a center of the supporting surface  101 . The through hole  110  passes through both the supporting surface  101  and the bottom surface  102 . The four substrate-pad areas  12  surround the through hole  110 . 
     The laser emitting chip  20  includes a first surface  21  opposite to the supporting surface  101  of the circuit board  10 . The first surface  21  forms four chip-pad areas  22 , and each chip-pad area  22  spatially corresponds to a respective one of the substrate-pad areas  12 . A gold ball  14  is explanted on each of the chip-pad areas  22 . In other words, the gold balls  14  are in a square arrangement on the chip-pad areas  22 . In the embodiment, the four gold balls  14  have essentially identical height. The four gold balls  14  act as supports for the laser emitting chip  20  on the supporting surface  101  of the circuit board  10 . The laser emitting chip  20  is electrically connected to the circuit board  10  through the four gold balls  14 . The laser emitting chip  20  also includes a laser emitting portion  24  formed on the first surface  21  and aligned with the through hole  110 . Laser beams emitted by the laser emitting portion  24  exits through the through hole  110 . 
     Unlike a laser emitting chip package of related art, the laser emitting chip  20  of the laser emitting chip package  100  of the present embodiment is supported on the circuit board  10  through the four gold balls  14  each being connected to a respective one of the four substrate-pad areas  12 , and since the four substrate-pad areas  12  are at the corners of the supporting surface  101 , this provides a stable platform and prevents the laser emitting chip  20  from tilting or collapsing. 
       FIG. 3  illustrates a laser emitting chip package  200 , in accordance with a second exemplary embodiment. The laser emitting chip package  200  is essentially similar to the laser emitting chip package  100  in the first embodiment, except that the circuit board  30  includes only two substrate-pad areas  32 ; and the chip pad area  42  utilizes three gold balls  34 . In the embodiment, both the two substrate-pad areas  32  are substantially a strip and are opposite to each other. The first surface  41  of the laser emitting chip  20  forms two strip-like chip-pad areas  42  each spatially corresponding to a respective one of the substrate-pad areas  32 . One of the three gold balls  34  is explanted on one chip-pad area  42 , while the other two gold balls  34  are explanted on the other chip-pad area  42 , in other words, the gold balls  34  are in a triangular arrangement on the chip-pad areas  42 . 
     In another embodiment, the four sides of the first surface  41  can have three sides each forming a strip-like chip-pad area  42 . At least one gold ball  42  is explanted on each one of the chip-pad areas  42 . 
     It will be understood that the above particular embodiments are shown and described by way of illustration only. The principles and the features of the present disclosure may be employed in various and numerous embodiments thereof without departing from the scope of the disclosure as claimed. The above-described embodiments illustrate the scope of the disclosure but do not restrict the scope of the disclosure.