Patent Publication Number: US-2016239699-A1

Title: Chip scale sensing chip package and a manufacturing method thereof

Description:
This application claims the benefit of U.S. Provisional Application No. 62/116,909, filed on Feb. 16, 2015, and U.S. Provisional Application No. 62/165,710, filed on May 22, 2015, and the entirety of which are incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a sensing chip package module, and in particular relates to a chip scale sensing chip package module and a manufacturing method thereof. 
     2. Description of the Related Art 
     A conventional chip package having sensing functions, such as a fingerprint-recognition chip package, is easily contaminated or damaged during the manufacturing processes which results in decreasing both the yield and liability of conventional chip package having sensing functions. In order to meet the tendency of size-miniaturization of electronic components, it is an import subject to minimize the thickness of a substrate for carrying a semiconductor chip to be packaged. However, if a thin substrate for carrying a semiconductor chip to be packaged is utilized, the yield will be reduced owing to the thin substrate is bended or damaged during the package process. 
     Moreover, the touch panel or the panel having sensing functions, for example biometric identification, are current trends of technology. However, the touch devices are easily out of orders owing to frequently pressing onto the panel by users. In order to resolve abovementioned defects, a scratch-resistance material having a hardness higher than 9, for example sapphire, is selected as the touch pad of the touch panel to protect the semiconductor devices under the touch panel. Currently, the sapphire substrate used to protect the touch devices or biometric sensing devices has a thickness about 200 μm, and the signals of the touch panel or the sensing panel with biometric identification functions are transmitted by the change of touch pad&#39;s capacitance. The capacitance of a parallel plate capacitor is well-known as following formula: C=ε*A/d, wherein C is the capacitance of a parallel plate capacitor, E is the capacitance permittivity of the dielectric material between parallel plates, A is the area of overlap of parallel plates, and d is the distance between the plates. As the capacitance formula of a parallel plate shown, the capacitance is inversely proportional to the distance between the parallel plates when ε and A keep constant. Therefore, the increase of thickness of parallel plates will result in increase of d which leads to decrease of C. 
     This present invention is achieved by so-called wafer level package processes, which can not only precisely place the thin touch pad on the sensing chip, but also decrease the thickness of the adhesive sandwiched between the touch plate wafer and the wafer with sensing devices by means of spin coating. 
     Therefore, a low-K material for increasing the capacitance is not necessary and can be replaced by medium-K or low-K materials. Accordingly, the production costs can be reduced, and a chip scale sensing chip package module with higher efficiency are provided. Moreover, the mismatch of the sensing chip and the touch pad occurring in the conventional technologies can be avoided because the touch pad and the chip are of the same chip scale by bonding the touch pad to the sensing chip during the semiconductor process. 
     SUMMARY OF THE INVENTION 
     An embodiment of this invention provide a chip scale sensing chip package module, comprising a chip scale sensing chip package and a print circuit board placed under the chip scale sensing chip package by bonding the conductive structure of the chip scale sensing chip package to the print circuit board. The chip scale sensing chip package comprises a sensing chip with a first top substrate and a first bottom substrate opposite to the first top substrate, wherein the sensing chip has a sensing device and a plurality of conductive pads adjacent to the first top substrate, and a plurality of conductive structures connected to the conductive pads by a re-distribution layer adjacent to the first bottom surface; a touch plate having a color layer comprising a base and a spacer formed on the base, wherein the spacer has a cavity with a bottom wall exposing part of the surface of the base and a side wall surrounding the bottom wall; and a first adhesive layer sandwiched between the sensing chip and the touch plate to adjoin the first top surface of the sensing chip to the bottom wall of the cavity of the touch plate and surround the sensing chip by the side wall of the cavity. The print circuit board is placed under the chip scale sensing chip package by bonding the conductive structure of the chip scale sensing chip package to the print circuit board. 
     An embodiment of this invention provides another chip scale sensing chip package module, wherein the area of the touch plate is greater than that of the sensing chip. 
     An embodiment of this invention provides another chip scale sensing chip package module, wherein the top-viewing profile of the cavity is rectangular and the top-viewing profile of the touch plate is circular. 
     An embodiment of this invention provides another chip scale sensing chip package module, wherein the thickness of the spacer is 10-folds of that of the base. 
     An embodiment of this invention provides another chip scale sensing chip package module, wherein the color layer is coated on the side wall and the bottom wall of the cavity. 
     An embodiment of this invention provides another chip scale sensing chip package module, wherein the base and the spacer are consisted of a material comprising glass. 
     An embodiment of this invention provides another chip scale sensing chip package module, wherein the base comprises a touch plate, a color layer and a second adhesive sandwiched between the touch plate and the color layer, and the spacer is formed on the color layer. 
     An embodiment of this invention provides another chip scale sensing chip package module, wherein the base and the touch plate are consisted of a material comprising glass, and the spacer is consisted of a material comprising glass or silicon. 
     An embodiment of this invention provides another chip scale sensing chip package module, wherein the first adhesive is consisted of a low-K or medium-K dielectric material. 
     An embodiment of this invention provides another chip scale sensing chip package module, wherein the conductive structures are selected from a group of solder balls, solder bumps, and conductive pillars, and mixtures thereof 
     An embodiment of this invention provides another chip scale sensing chip package module, wherein the sensing device is selected from a group of a touch device, a biometric identification device and an environmental factors sensing device, and mixtures thereof. 
     An embodiment of this invention provides another chip scale sensing chip package module, wherein the biometric recognition device comprises a fingerprint identification device. 
     An embodiment of this invention provides another chip scale sensing chip package module, further comprising a buffer apparatus placed on the bottom of the print circuit board. 
     An embodiment of this invention provides another chip scale sensing chip package module, wherein the buffer apparatus comprises a spring or a spring button. 
     An embodiment of this invention provides another chip scale sensing chip package module, further comprising a trigger device formed within the cavity of the chip scale sensing chip package and electrically connected to the sensing chip. 
     An embodiment of this invention provides a method of manufacturing a chip scale sensing chip package module, comprising the steps of providing a plurality of chip scale sensing chips, each chip scale sensing chip comprising a first top substrate and a first bottom substrate opposite to each other, wherein the sensing chip has a sensing device and a plurality of conductive pads adjacent to the first top substrate, and a plurality of conductive structures adjacent to the first bottom surface electrically connected to the conductive pads by a re-distribution layer; providing a touch plate wafer having a color layer and a plurality of bonding areas spaced with scribing lines, and each of the bonding areas having a base and a spacer formed on the base, wherein the spacer has a cavity with a bottom wall exposing part of the surface of the base and a side wall surrounding the bottom wall; and providing an first adhesive layer to join the first top surface of each sensing chip to the bottom wall of each cavity and surround each sensing chip by each side wall of the cavities; applying a scribing process along the scribing lines to generate a plurality of chip scale sensing chip packages, wherein each the chip scale sensing package comprises a sensing chip with a first top substrate and a first bottom substrate opposite to the first top substrate, wherein the sensing chip has a sensing device and a plurality of conductive pads adjacent to the first top substrate, and a plurality of conductive structures connected to the conductive pads by a re-distribution layer adjacent to the first bottom surface; a touch plate having a color layer comprising a base and a spacer formed on the base, wherein the spacer has a cavity with a bottom wall exposing part of the surface of the base and a side wall surrounding the bottom wall; and a first adhesive layer sandwiched between the sensing chip and the touch plate to adjoin the first top surface of the sensing chip to the bottom wall of the cavity of the touch plate and surround the sensing chip by the side wall of the cavity; and providing a print circuit board and bonding one of the chip scale sensing chip packages to the print circuit board by the conductive structures. 
     An embodiment of this invention provides a method of manufacturing a chip scale sensing chip package module, wherein the area of the touch plate is greater than that of the sensing chip. 
     An embodiment of this invention provides another method of manufacturing a chip scale sensing chip package module, wherein the top-viewing profile of the cavity is rectangular and the top-viewing profile of the touch plate is circular. 
     An embodiment of this invention provides another method of manufacturing a chip scale sensing chip package module, wherein the thickness of the spacer is 10-folds of that of the base. 
     An embodiment of this invention provides another method of manufacturing a chip scale sensing chip package module, wherein the color layer is coated on the side wall and the bottom wall of the cavity. 
     An embodiment of this invention provides another method of manufacturing a chip scale sensing chip package module, wherein the base and the spacer are consisted of a material comprising glass. 
     An embodiment of this invention provides another method of manufacturing a chip scale sensing chip package module, wherein the steps of manufacturing the touch plate wafer having a color layer comprise providing a touch plate wafer with a second top surface and a second bottom surface opposite to the second top surface; coating a color layer on the second top surface of the touch plate wafer; coating a second adhesive layer on the color layer; bonding a touch plate to the second adhesive layer; thinning the second bottom surface of the touch plate wafer; and pattering the thinned second bottom surface of the touch plate wafer to form a plurality of bonding areas spaced by scribing lines, and each bonding area comprising a base and a spacer formed on the base, wherein each base has a touch plate, a color layer and a second adhesive layer sandwiched between the touch plate and the color layer, and the spacer is formed on the color layer and has a cavity exposing the color layer. 
     An embodiment of this invention provides another method of manufacturing a chip scale sensing chip package module, wherein the base and the touch plate are consisted of a material comprising glass, and the spacer is consisted of a material comprising glass or silicon. 
     An embodiment of this invention provides another method of manufacturing a chip scale sensing chip package module, wherein the first adhesive is consisted of a low-K or medium-K dielectric material. 
     An embodiment of this invention provides another method of manufacturing a chip scale sensing chip package module, wherein the conductive structures are selected from a group of solder balls, solder bumps, and conductive pillars, and mixtures thereof. 
     An embodiment of this invention provides another method of manufacturing a chip scale sensing chip package module, wherein the sensing device is selected from a group of a touch device, a biometric identification device and an environmental factors sensing device, and mixtures thereof. 
     An embodiment of this invention provides another method of manufacturing a chip scale sensing chip package module, wherein the biometric recognition device is a fingerprint identification device. 
     An embodiment of this invention provides another method of manufacturing a chip scale sensing chip package module, further comprising a step of forming a buffer apparatus on the bottom of the print circuit board. 
     An embodiment of this invention provides another method of manufacturing a chip scale sensing chip package module, wherein the buffer apparatus comprises a spring or a spring button. 
     An embodiment of this invention provides another method of manufacturing a chip scale sensing chip package module, further comprising a step of forming a trigger device within the cavity of the chip scale sensing chip package and electrically connected to the sensing chip. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings. 
         FIGS. 1A ˜ 1 E and  FIGS. 1C ′˜ 1 E′are cross-sectional views of an exemplary embodiment 1 of a method of manufacturing a chip scale sensing chip package module according to this invention. 
         FIGS. 2A ˜ 2 C and  FIG. 2B ′˜ 2 C′ are cross-sectional views of an exemplary embodiment 2 of a method of manufacturing a chip scale sensing chip package module according to this invention. 
         FIGS. 3A ˜ 3 D are cross-sectional views of a method of manufacturing the bonding areas as shown in  FIG. 2A . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The making and using of the embodiments of the present disclosure are discussed in detail below. However, it should be noted that the embodiments provide many applicable inventive concepts that can be embodied in a variety of specific methods. The specific embodiments discussed are merely illustrative of specific methods to make and use the embodiments, and do not limit the scope of the disclosure. The disclosed contents of the present disclosure include all the embodiments derived from claims of the present disclosure by those skilled in the art. In addition, the present disclosure may repeat reference numbers and/or letters in the various embodiments. This repetition is for the purpose of simplicity and clarity, and does not imply any relationship between the different embodiments and/or configurations discussed. Furthermore, when a first layer is referred to as being on or overlying a second layer, the first layer may be in direct contact with the second layer, or spaced apart from the second layer by one or more material layers. 
     Embodiment 1 
     Embodiment 1 disclosing a method of manufacturing a chip scale sensing chip package module according to this invention will be described below and accompanied with  FIGS. 1A ˜ 1 E and  FIGS. 1C ′˜ 1 E′. 
     As shown in  FIG. 1A , a touch plate wafer  300  includes a plurality of bonding areas  30  is provided. Each bonding area  30  is surrounded by a circular scribe line SC. The touch plate wafer  300  of this embodiment 1 is consisted of a transparent material with a hardness higher than 7, for example glass. 
       FIG. 1B  is a cross-sectional view of the bonding area  30  along the cross-sectional line I-I′ of  FIG. 1A . As shown in  FIG. 1B , the bonding area includes a base  310  and a spacer  320  formed on the base  310 . The spacer  320  has a cavity  330  exposing the surface of base  310 , and the cavity  330  includes a bottom wall  330   a  and a side wall  330   b  surrounding the bottom wall  330   a.  The cavity  330  of this embodiment can be finished by photolithography and etching, milling or molding. The spacer  320  has a thickness 10-folds of that of the base  310 . The spacer  320  of this embodiment has a thickness of about 500 μm, and the base  310  of this embodiment has a thickness of about 50 μm. Moreover, a color layer  350  is overlay on the spacer  30  and the bottom wall  330   a  and side wall  330   b  of the cavity  330 . 
     Next, a plurality of chip scale sensing chips  10  as shown in  FIG. 1C  or a plurality of chip scale sensing chips  10 ′ as shown in  FIG. 1C ′ is provided. Each chip scale sensing chip  10  or  10 ′ includes a substrate  100  with a first top surface  100   a  and a first bottom surface  100   b  opposite to the first top surface  100   b.  A sensing device  150  and a plurality of conductive pads  115  are formed adjacent to the first top surface  100   a,  and a dielectric layer  210 , a re-distribution layer (RDL)  220 , a passivation layer  230  and conductive structures are formed adjacent to the first bottom surface  100   b.  The conductive structures  250  is electrically connected to the conductive pads  115  via the re-distribution layer (RDL)  220 . The conductive structures  250  of the chip scale sensing chip  10  as shown in  FIG. 1C  are solder balls. The conductive structures  250  of another embodiments according to this invention can be solder bumps or conductive pillars. Besides, the conductive structures  250  of the chip scale sensing chip  10 ′ as shown in  FIG. 1C ′ are consisted of solder balls and conductive pillars, wherein the conductive pillars are gap-filled in the through holes (not shown), penetrating the passivation layer  230  and the molding layer  245  formed on the passivation layer  230 , exposing part of the re-distribution layer (RDL)  220 , and each solder ball is formed on the molder layer  246  to connect to each conductive pillar. The molding layer  246  of this embodiment is consisted of epoxy and has a thickness of about 100 μm. 
     Next, referring to  FIG. 1D  and  FIG. 1D ′, a first adhesive  400  is coated on the first top surface  100   a  or the bottom wall  330   a  of the cavity  300  of the chip scale sensing chip  10  as shown in  FIG. 1D  or the chip scale sensing chip  10  as shown in  FIG. 1D ′, and the chip scale sensing chip  10  or  10 ′ is bonding to the color layer  350  formed on the bottom wall  330   a  of the cavity  330   a  locating in each bonding area  30 . Moreover, other electronic devices for triggering sensing chips like trigger devices (not shown) can also be bond onto the color layer  350  formed on the bottom wall  330   a  of the cavity  330   a  locating in each bonding area  30  and electrically connected the sensing chips  10  or  10 ′. 
     Next, scribing the touch plate wafer  300  along the scribing lines SC to generate a plurality of individual chip scale sensing chips A or A′. Each chip scale sensing chips A or A′ includes a sensing chip  100  with a top-view profile of rectangular, and each sensing chip  100  has a sensing device  150  surrounded by a plurality of conductive pads  115  and a touch pad  300 ′ with a top-view profile of circular including a base  310  and a spacer  320  formed on the base  310 , wherein the area of the touch pad  300 ′ is greater than that of the sensing chip  300 . 
     Finally, a print circuit board  450  with a plurality of conductive bonding pads  445  formed thereon as shown in  FIG. 1E and 1E ′ is provided. The chip scale sensing chip package A or A′ manufactured by above processes is electrically bonded to the print circuit board  450  via the join of the conductive structures  250  and the conductive bonding pads to generate a chip scale sensing chip package module  1000  or  1000 ′. Besides, a buffer apparatus  460  like a spring or a spring button can be placed on the bottom of the print circuit board  450  to provide a buffering force which can avoid the defect of the conjunction of the chip scale sensing chip package A or A′ and the print circuit board  450  caused by the pressing force of the user. 
     Embodiment 2 
     Embodiment 2 disclosing a method of manufacturing a chip scale sensing chip package module according to this invention will be described below accompanying with  FIGS. 2A ˜ 2 C and  FIGS. 2B ′˜ 2 C′. 
       FIG. 2A  is a cross-sectional view of the bonding area  50  formed on the touch plate wafer. As shown in  FIG. 2A , the bonding area  50  includes a base  510  and a spacer  540  surrounding the base  510 . The spacer  545  has a cavity  550  exposing the surface of base  510 , and the cavity  550  includes a bottom wall  330   a  and a side wall  330   b  surrounding the bottom wall  330   a.  The base  510  includes a touch pad  540 , a color layer  520  and a second adhesive  530  sandwiched therebetween. The spacer layer  545  is formed on the color layer  520 . 
     Next, referring to  FIG. 2B  and  FIG. 2B ′, the chip scale sensing chip  10  as shown in  FIG. 1C  or the chip scale sensing chip  10 ′ as shown in  FIG. 1C ′ is bond to the exposed color layer  520  formed on the bottom of the cavity  550  of the bonding area  50  by sandwiched a first adhesive  400  therebetween. A plurality of individual chip scale sensing chip packages B or B′ as shown in  FIG. 2B  or  FIG. 2B ′ can be generated by scribing the touch plate wafer along the scribing lines SC outside of the bonding areas  50 . 
     Next, referring to  FIG. 2C  and  FIG. 2C ′, a print circuit board  450  as shown in  FIG. 1E  is provided, and the chip scale sensing chip package B or B′ generated according to above-mentioned process is bonded to the conductive bonding pads  445  of the print circuit board  450  by the conductive structures of B or B′ to form a chip scale sensing chip package module  2000  or  2000 ′. 
     Moreover, other electronic devices like a triggering device (not shown) which triggers the sensing chip  10  or  10 ′ to start can also be formed on the color later  350  formed on the bottom of the cavity  550  of each bonding area  50  and electrically connected to the sensing chips  10  or  10 ′. 
     The steps of manufacturing the above-mentioned bonding areas  50  will be described in  FIG. 3A ˜ FIG. 3D . As shown in  FIG. 3A , a touch plate wafer  500  selected from a material comprising silicon or glass is provided. Next, referring to  FIG. 3B , a color layer  520 , a second adhesive  530 , and a touch plate  540  are formed on the second top surface (not shown) of the touch plate wafer  500  in series. The touch plate wafer  500  of this embodiment can be selected from a material comprising transparent glass or silicon wafer, and the touch plate  540  can be selected from a transparent material with a hardness higher than  7  such as glass, sapphire or silicon nitride. 
     Next, the second bottom surface (not shown) of the touch plate wafer  500  is thinning by etching, milling, gridding or polishing to generate a thinner touch plate wafer  500 ′ as shown in  FIG. 3C . 
     Next, referring to  FIG. 3D , the thinned second bottom surface (not shown) of the touch plate wafer  500 ′ is patterned by etching or milling to form a plurality of bonding areas  50  spaced by each other. Each bonding area  50  comprises a base  510  and a spacer  545  formed on the base  510 , and each base  510  comprises a touch pad  540 , a color layer  520  and a second adhesive  530  sandwiched therebetween. The spacer  545  is formed on the color layer  520 , and the spacer  545  has a cavity  550  exposing the color layer  520 . 
     While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.