Patent Document

BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to a sensing module, especially relates to a reflective sensing module having a light chip and a sensor chip mounted on a top glass substrate. 
         [0003]    2. Description of Related Art 
         [0004]      FIG. 1  show a prior art 
         [0005]      FIG. 1  shows a prior art US 20140231635 publication which discloses an optical device  110 - 1  configured in a first cavity  108 - 1  and a sensor die  110 - 3  configured in a second cavity  108 - 3  of a carrier substrate  104 . 
         [0006]      FIG. 1  illustrates a silicon carrier substrate  104  having cavities  108 - 1 ,  108 - 3 . An optical device  110 - 1  disposed within the cavity  108 - 1  and a sensor die  128  disposed within the cavities  108 - 3 . A cover  112  is disposed on top of the carrier substrate  104 . Lens  114 - 1 .  114 - 2  may be configured on top of the dies  110 - 1 ,  110 - 3 . Through-substrate-vias (TSV)  116 - 1 ,  116 - 2  extends through the carrier substrate  104  to corresponding contact pads  118  on the bottom surface of cavity  108 - 1 . Solder bumps  120  electrically connect the optical device  110 - 1  and pad  118 . Through-substrate-vias (TSV)  116 - 3 ,  116 - 4  extends through the carrier substrate  104  to the redistribution circuit  122  on the bottom surface of cavity  108 - 3 . The sensor die  110 - 3  stacks on a top of a processor die  128 . Through-substrate-vias (TSV)  126  extends through the processor die  128  for an electrical connection among the sensor die  110 - 3 , processor die  128  and redistribution circuit  122 . The disadvantages of the prior art is that two cavities needs to be made in the carrier substrate  104 . The cavities&#39; forming process is complicated. A simpler device or process is desired to be developed in the sensing module industry. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  show a prior art. 
           [0008]      FIG. 2A-2G  shows a fabrication process for a first embodiment according to the present invention. 
           [0009]      FIG. 3A-3G  shows a fabrication process for a second embodiment according to the present invention. 
           [0010]      FIG. 4  shows a modified version of the embodiments according to the present invention. 
           [0011]      FIG. 5  shows a wristband embedding the reflective sensing module according to the present invention. 
           [0012]      FIG. 6  shows a wristband wearing on a wrist according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0013]      FIG. 2A-2G  shows a fabrication process for a first embodiment according to the present invention. 
         [0014]      FIG. 2A  shows a transparent top cover such as a glass  23  is prepared. A bottom circuitry  24  is configured on a bottom surface of the top glass  23 . 
         [0015]      FIG. 2B  shows a light chip  21  electrically coupled to the bottom circuitry  24 ; wherein the light chip  21  has a plurality of top electrodes  211  electrically coupled to the bottom circuitry  24  of the top glass  23  through solder ball  212 ; and a sensor chip electrically coupled to the bottom circuitry  24 ; wherein the sensor chip  22  has a plurality of top electrodes  221  electrically coupled to the bottom circuitry  24  of the top glass  23  through solder ball  222 . 
         [0016]    The light chip  21  used in the present invention can be one of light emitting diode, laser diode, vertical cavity surface emitting laser (VCSEL) or the like. Different underfill material can be chosen for a specific light chip  21 . For example, an infrared (IR) light transparent underfill material such as silicone or benzocyclobutene (BCB) can be used to fill in the gap between the light chip  21  and the top glass  23  for a module where an IR light chip is used. 
         [0017]      FIG. 2C  shows a molding compound  26  is applied to enclose the light chip  21  and the sensor chip  22 . 
         [0018]      FIG. 2D  shows a plurality of holes  26 H are made through the molding compound  26  to expose predetermined areas of the bottom circuitry  24 . 
         [0019]      FIG. 2E  shows metal plated or filled in each hole  26 H so that a plurality of via metals  261  are formed passing through the molding compound  26 . A top of the via metal  261  electrically couples to the bottom circuitry  24  of the top glass  23 . A bottom circuitry  262  is formed on a bottom surface of the molding compound  26 . The bottom circuitry  262  is electrically coupled to a bottom of the via metal  261 . 
         [0020]      FIG. 2F  shows a redistribution layer  27  formed on bottom of the bottom circuitry  262  of the molding compound  26 . The redistribution layer  27  includes redistribution circuitry  271 , dielectric layer  273  and a plurality of bottom pads  272 . The redistribution circuit  271  is embedded in the dielectric layer  273 , and a plurality of bottom pads  272  are formed on a bottom of the dielectric layer  273 . Each bottom pad  272  is electrically coupled to the redistribution circuity  271 . 
         [0021]      FIG. 2G  shows a plurality of solder balls  281 , each solder ball  281  is configured on one corresponding bottom pad  272 . The light chip  21  is able to emit a plurality of light beams upwards passing through the top glass  23  to an object (not shown) on top. The sensor chip  22  detects reflective light beams downwards passing through the top glass  23  for a further processing. 
         [0022]      FIG. 3A-3G  shows a fabrication process for a second embodiment according to the present invention. 
         [0023]      FIG. 3A  shows a top glass  23  is prepared; and a bottom circuitry  24  is configured on a bottom surface of the top glass  23 . 
         [0024]      FIG. 3B  shows a light chip  21  electrically coupled to the bottom circuitry  24 ; wherein the light chip  21  has a plurality of top electrodes  211  electrically coupled to the bottom circuitry  24  of the top glass  23  through solder ball  212 ; and a sensor chip electrically coupled to the bottom circuitry  24 ; wherein the sensor chip  22  has a plurality of top electrodes  221  electrically coupled to the bottom circuitry  24  of the top glass  23  through solder ball  222 . 
         [0025]      FIG. 3C  shows a molding compound  26  is applied to enclose the light chip  21  and the sensor chip  22 . 
         [0026]      FIG. 3D  shows a thinning process is applied from bottom to expose a bottom surface of the light chip  21  and the sensor chip  22 . A flat bottom  265  is formed where the bottom surface of the molding compound  26 , the bottom surface of the light chip  21 , and the bottom surface of the sensor chip  22  are made coplanar. 
         [0027]      FIG. 3E  shows a plurality of holes  26 H are made through the molding compound  26  to expose predetermined areas of the bottom circuitry  24 . 
         [0028]      FIG. 3F  shows metal filled or plated in each hole  26 H so that a plurality of via metals  261  are formed passing through the molding compound  26 . A top end of the via metal  261  is electrically couple to the bottom circuitry  24  of the top glass  23 . A bottom circuitry or bottom pad  362  is formed on a bottom surface of the molding compound  26 . The bottom pad  362  is electrically coupled to a bottom end of the via metals  261 . 
         [0029]      FIG. 3G  shows a plurality of solder balls  381 , each solder ball  381  is configured on one corresponding bottom pad  362 . The light chip  21  is able to emit a plurality of light beams upwards passing through the top glass  23  to an object (not shown) on top. The sensor chip  22  detects reflective light beams downwards passing through the top glass  23  for a further processing. 
         [0030]      FIG. 4  shows a modified version of the embodiments according to the present invention. 
         [0031]      FIG. 4  shows a modified version  400  of the reflective sensing module. A first Fresnel lens  351  is configured on top of the light chip  21 ; and a second Fresnel lens  352  is configured on top of the sensor chip  22 . The first Fresnel lens  351  focuses the plurality of light beams L 1  from the light chip  21  into a detecting area  38  where an object (not shown) to be detected is configured. A plurality of reflective light beams L 2  reflected from the object (not shown) is detected by the sensor chip  22  for a further process. 
         [0032]      FIG. 5  shows a wristband embedding the reflective sensing module according to the present invention. 
         [0033]      FIG. 5  shows a wristband  500  embedding the reflective sensing module  400  according to the present invention. A flexible circuit board  43  is prepared and electrically coupled to the reflective sensing module  400 . A control chip  41  is configured and electrically coupled to the flexible circuit board  43 , and a flexible molding compound  44  encloses the reflective sensing module  400  and the control chip  41 . A transceiver (not shown) can be integrated in the control chip  41  for an information exchange. A battery  42  can also be prepared and embedded in the molding compound  44  to provide the power needed for the control chip  41 . 
         [0034]      FIG. 6  shows a wristband wearing on a wrist according to the present invention. 
         [0035]      FIG. 6  shows a flexible wristband  500  worn on a wrist. The plurality of light beams L 1  emitted from the light chip  21  detects health information such as pulse rate of blood vessels. The health information detected by the sensor chip  22  is transmitted to a mobile phone  48  through the transducer in the control chip  41 . The mobile phone  48  is then connected to interne for transmitting the health information to a predetermined host computer, for example, located in a hospital where the information can be retrieved for a reference, or transmitted to a mobile phone of a doctor for the doctor&#39;s reference. 
         [0036]    While several embodiments have been described by way of example, it will be apparent to those skilled in the art that various modifications may be configured without departs from the spirit of the present invention. Such modifications are all within the scope of the present invention, as defined by the appended claims.

Technology Category: 1