Patent Publication Number: US-2016223590-A1

Title: Probe head and upper guider plate

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention The present invention relates generally to a probe head and an upper guider plate, and more particularly to a probe head and an upper guider plate, which are adapted for being used in a vertical probe card. 
     2. Description of the Related Art 
     Semiconductor integrated circuit chips are usually tested in electrical properties by means of a probe card. The vertical probe card usually includes a printed circuit board, a space transformer and a probe head, wherein the probe head is adapted for electrically connecting a circuit board with a device under test (hereinafter referred to as “DUT”), so that the DUT can be tested in the electrical properties. Specifically speaking, the probe head at least includes an upper guider plate, a lower guider plate, and a plurality of probes. Each of the upper guider plate and the lower guider plate of the probe head usually has a plurality of through holes. In the assembling process of the probe head, each of the probes has to be inserted through associated through holes of the upper and lower guider plates, so that the upper and lower guider plates are aligned and coupled with each other. The aforesaid assembling process should be carefully carried out to prevent the probes from damage. 
     However, if the to-be-tested contacts of the DUT have small pitches therebetween, the corresponding probes of the probe head should also have small pitches therebetween, so as to conform to the requirement of fine pitch. In such condition, it is relatively more difficult to align and couple the upper and lower guider plates with each other. For example, under the requirement of conforming to fine pitch, the probes are very thin and the through holes of the upper guider plate are very small; in addition, under the condition that the upper guider plate is opaque, the positions of the tails of the probes can not be observed directly and precisely because the through holes of the upper guider plate are too small to be passed through by light. Therefore, the relative positions between the tails of the probes and the through holes of the opaque upper guider plate can only be observed roughly, but not precisely. As a result, the probes are liable to be damaged in the assembling process of the probe head, and the efficiency of assembling the probe head is lowered. Therefore, how to solve the aforesaid problems is an important task for the related field. 
     SUMMARY OF THE INVENTION 
     It is an objective of the present invention to provide a probe head which is adapted for a vertical probe card for testing the DUT with the contacts conforming to fine pitch. Besides, the probe head is easily assembled, so the probes thereof are less possibly damaged. 
     It is another objective of the present invention to provide an upper guider plate which is adapted for a probe head of a vertical probe card, and facilitates the assembly of the probe head which is adapted for testing the DUT with the contacts conforming to fine pitch, so that the probes of the probe head are less possibly damaged. 
     To attain the above objectives, the present invention provides a probe head which is adapted for a vertical probe card, and includes an upper guider plate, a lower guider plate, and a plurality of probes. The upper guider plate has a plurality of upper through holes. The lower guider plate is located by one side of the upper guider plate and has a plurality of lower through holes. Each of the probes is positioned through one of the upper through holes of the upper guider plate and one of the lower through holes of the lower guider plate. The upper guider plate has a light transmittance of at least 75%, and is made of a material having a Moh&#39;s hardness of at least 5. 
     To attain the above objectives, the present invention provides an upper guider plate which is adapted for a probe head of a vertical probe card, has a plurality of upper through holes and a light transmittance of at least 75%, and is made of a material having a Moh&#39;s hardness of at least 5. 
     As a result, in the probe head of the present invention, the upper guider plate with the light transmittance of at least 75% enables the precise positions of the tails of the probes to be observed directly, so the tails of the probes can be easily inserted through the upper through holes of the upper guider plate. Besides, even though the probe head conforms to the requirement of fine pitch, the probes thereof are still less possibly damaged in the installation process and the efficiency of assembling the probe head can be improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
         FIG. 1  is a schematic perspective view showing the structure of a probe head according to an embodiment of the present invention; 
         FIG. 2A  is a schematic perspective view of a lower guider plate and a positioning member as shown in  FIG. 1 ; 
         FIG. 2B  is a top view of the lower guider plate and the positioning member as shown in  FIG. 1 ; 
         FIG. 2C  is a schematic perspective view of a probe as shown in  FIG. 1 ; 
         FIG. 3  is similar to  FIG. 2B , but further showing that the probes shown in  FIG. 2C  are inserted in positioning through holes of the positioning member; 
         FIG. 4A  is a schematic view showing that the probes shown in  FIG. 2C  are about to be inserted through a conventional upper guider plate; 
         FIG. 4B  is a schematic view showing that the probes shown in  FIG. 2C  are about to be inserted through the upper guider plate shown in  FIG. 1 ; and 
         FIG. 5  is a lateral sectional view of a probe head according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a schematic perspective view showing the structure of a probe head according to an embodiment of the present invention. Referring to  FIG. 1 , the probe head  100  in this embodiment is adapted for being used in a vertical probe card. Specifically speaking, the probe head  100  as shown in  FIG. 1  includes an upper guider plate  110 , a lower guider plate  120 , at least one positioning member  130 , and a plurality of probes  140 . It should be noticed here that the probe head of the present invention applied to a vertical probe card is adapted for testing the DUT with the contacts conforming to fine pitch, which means the pitches between the contacts are smaller than 400 micrometers (μm). 
     In detail, the upper guider plate  110  in this embodiment has a light transmittance of at least 75%, and is made of a material having a Moh&#39;s hardness of at least 5. Specifically speaking, the upper guider plate  110  in this embodiment may, but not limited to, be made of a glass substrate or a sapphire substrate. Besides, the thickness of the upper guider plate  110  in this embodiment is at most 800 micrometers and preferably ranges from 200 micrometers to 800 micrometers. Because the probes  140  conforming to the requirement of fine pitch are very thin, the thinner the upper guider plate  110  is, the lower risk of damaging the probes  140  is taken when the very thin probes  140  are inserted through the very small upper through holes  111  of the upper guider plate  110 . 
     Furthermore, because the upper guider plate  110  is made of the material having the Moh&#39;s hardness of at least 5, the surface of the upper guider plate  110  is uneasily damaged by the probes  140 , so that the upper guider plate  110  can maintain the light transmittance to a certain extent. Besides, the upper guider plate  110  may be made of the glass substrate or the sapphire substrate, thereby uneasily bent and quite flat. Therefore, the upper guider plate  110  is less possible to have the problem of deformation which causes difficulty in installation of the probes. In other words, if the upper guider plate is made of acrylic, it is not hard enough, thereby probably not flat enough. Besides, the acrylic upper guider plate usually has the thickness of at least 1000 micrometers; therefore, the hardness and the thickness of the acrylic upper guider plate are both unable to satisfy the present testing condition, thereby unsuitable to serve as the upper guider plate of the present invention. 
     As shown in  FIG. 1 , in this embodiment the upper guider plate  110  has a plurality of upper through holes  111 , and the lower guider plate  120  has a plurality of lower through holes  121 . Besides, in this embodiment a pitch of less than 400 micrometers is provided between two adjacent upper through holes  111 . Preferably, the aforesaid pitch may range from 40 micrometers to 400 micrometers. Of course the aforesaid pitch provided between two adjacent upper through holes  111  may, but not limited to, range from 40 micrometers to 200 micrometers, so that the probe head  100  applied to the vertical probe card can conform to the requirement of fine pitch. It should be noticed that the two adjacent upper through holes  111  mentioned here refers to any two adjacent upper through holes, which means the upper guider plate may have only one pair of upper through holes  111  adjacent to each other and answering to the aforesaid limitation in the pitch therebetween. 
     As shown in  FIG. 1 , in this embodiment the lower guider plate  120  is located by one side of the upper guider plate  110 , i.e. located beneath the upper guider plate  110 , and the positioning member  130  is disposed between the upper guider plate  110  and the lower guider plate  120 . Specifically speaking, the positioning member  130  in this embodiment assists each of the probes  140  in being positioned through one of the upper through holes  111  of the upper guider plate  110  and one of the lower through holes  121  of the lower guider plate  120 . Detailed description will be given hereunder by reference to  FIGS. 2A-4B . 
       FIG. 2A  is a schematic perspective view of the lower guider plate and the positioning member as shown in  FIG. 1 .  FIG. 2B  is a top view of the lower guider plate and the positioning member as shown in  FIG. 1 .  FIG. 2C  is a schematic perspective view of the probe as shown in  FIG. 1 . Referring to  FIG. 2A and 2B , the positioning member  130  in this embodiment has a light transmittance of at least 75%, and is made of a material having a Moh&#39;s hardness of at least 5. Specifically speaking, the positioning member  130  may, but not limited to, be made of a glass substrate or a sapphire substrate. On the other hand, as shown in  FIG. 2C , the probes  140  in this embodiment may be made of metal and configured with elasticity. The probes  140  are the so-called formed probes, which are made of wires by mechanical pressing process. The probes  140  in this embodiment are cobra probes, which belong to a kind of formed probe. Each of the probes  140  is provided in order with a pinpoint  141 , a body  143  and a tail  145 , wherein the tail  145  has substantially circular cross sections and the body  143  has substantially elliptic or rectangular cross sections. The body  143  of the probe  140  has an elastic portion  1431  serving as a buckling structure, so the probe  140  will be buckled by an external force and generate an elastic force resulted from deformation. In other embodiments, the probes may be the so-called MEMS (Microelectromechanical Systems) probes, which are made by the MEMS manufacturing process, and may be MEMS straight probes, MEMS cobra probes or MEMS pogo probes. In other embodiments, the probes may be pogo probes made of wires by mechanical pressing process. In other embodiments, the probes may be vertical straight probes made of enameled wires. The type of the probes is not a limitation in the present invention. 
       FIG. 3  is similar to  FIG. 2B , but further showing that probes shown in  FIG. 2C  are inserted in positioning through holes of the positioning member. Referring to  FIGS. 2A, 2B and 3 , the positioning member  130  has a plurality of positioning through holes  131  for assisting positioning of the probes  140 . Specifically speaking, the aforesaid probe head  100  in this embodiment may be assembled by the following process. At first, the positioning member  130  is disposed on the lower guider plate  120 , and the pinpoints  141  of the probes  140  are inserted into the positioning through holes  131  and the lower through holes  121 . Then, the positioning member  130  is pulled up to the direction opposite to the lower guider plate  130  to pass by the bodies  143  of the probes  140  and let the tails  145  of the probes  140  be positioned through the positioning through holes  131 . It should be noted that the aforesaid process of installing the probes is not the limitation in the present invention. In this embodiment, because the positioning member  130  has the light transmittance of at least 75%, the relative positions between the pinpoints  141  of the probes  140  and the lower through holes  121  of the lower guider plate  120  can be clearly observed while the pinpoints  141  of the probes  140  are inserted through the positioning through holes  131  of the positioning member  130  and about to be inserted through the lower through holes  121  of the lower guider plate  120 , so that the probes  140  can be adjusted in the positions thereof, thereby installed more quickly. Besides, the positioning member  130  may be made of a glass substrate or a sapphire substrate having the Moh&#39;s hardness of at least 5, thereby uneasily bent and quite flat. Therefore, the positioning member  130  is less possible to have the problem of deformation which may cause separation of the probe  140  from the positioning member  130 . That means the probes  140  are less possibly separated from the positioning member  130  in the aforesaid process that the positioning member  130  is pulled up toward the direction opposite to the lower guider plate  120  to pass by the bodies  143  of the probes  140  and let the tails  145  of the probes  140  be positioned through the positioning through holes  131 . In other words, if the positioning member is made of a translucent or flexible material such as a film, it may have the problems of light reflection or insufficient flatness, thereby unable to satisfy the present testing condition and unsuitable to serve as the positioning member of the present invention. 
     As a result, the pinpoints  141  of the probes  140  are easily inserted through the positioning through holes  131  of the positioning member  130  and the lower through holes  121  of the lower guider plate  120 , and the positioning through holes  131  can limit the positions of the probes  140 . It should be noticed that this embodiment takes the probe head having one positioning member  130  as an instance, but the amount of the positioning member  130  is not limited. In other embodiments, the probe head may have a plurality of positioning members piled on one another; in such condition, the positioning through holes of the positioning members are not limited to be shaped to conform with the body of the probe. For example, if the probe head has two positioning members, namely first and second positioning members, each first positioning through hole of the first positioning member may be configured to accommodate at least two probes, and each second positioning through hole of the second positioning member may be configured to accommodate only one probe. In the assembling process of such probe head, the probes can be roughly positioned at first by the first positioning member in a way that each first positioning through holes is passed through by two probes; after that, the probes can be further positioned by the second positioning member in a way that the two probes in the same first positioning through hole are separated or staggered by two second positioning through holes, each of which can be passed through by only one probe. Therefore, using a plurality of positioning members can also make the probes  140  easily installed, limit the positions of the probes  140 , and achieve the aforesaid effects and advantages that will not be repeatedly mentioned hereunder. It should be noticed that the aforesaid upper through holes  111  and lower through holes  121  may, but not limited to, be substantially shaped as circles or rectangles; the positioning through holes  131  may, but not limited to, be substantially shaped as ellipses, rectangles or non-circles. 
     The process of inserting the tails  145  of the probes  140  into the upper through holes  111  of the upper guider plate  110  will be further illustrated in the following contents by reference to  FIGS. 4A-4B . 
       FIG. 4A  is a schematic view showing that the probes shown in  FIG. 2C  are about to be inserted through a conventional upper guider plate.  FIG. 4B  is a schematic view showing that the probes shown in  FIG. 2C  are about to be inserted through the upper guider plate shown in  FIG. 1 . In each of the embodiments shown in  FIGS. 4A and 4B , the positioning through holes  131  are arranged correspondingly in position to the upper through holes  11 ,  111  of the upper guider plates  10 ,  110 . However, in the embodiment shown in  FIG. 4A , the conventional upper guider plate  10  is made of an opaque material. Therefore, under the condition of fine pitch, the positions of the tails  145  of the probes  140  can not be observed directly and precisely, but can only be observed through the upper through holes  11  of the upper guider plate  10  for rough determination. In such condition, if the tails  145  of the probes  140  are located out of the area of the upper through holes  11  of the upper guider plate  10 , as shown in  FIG. 4A , it is difficult to determine the positions of the tails  145  of the probes  140 . At this time, if the upper guider plate  10  is directly capped onto the probes  140  to try to let the tails  145  of the probes  140  be inserted through the upper through holes  11 , the probes  140  are liable to be damaged. 
     In contrast, the upper guider plate  110  in this embodiment as shown in  FIG. 4B  has the light transmittance of at least 75%. Therefore, while the tails  145  of the probes  140  are inserted through the upper through holes  111  of the upper guider plate  110 , the precise positions of the tails  145  of the probes  140  can be observed directly. Even though the tails  145  of the probes  140  are located out of the area of the upper through holes  111  of the upper guider plate  110 , the positions of the tails  145  of the probes  140  can be easily observed, such that all the tails  145  of the probes  140  can be easily adjusted to correspond in position to the upper through holes  111  before the upper guider plate  110  is capped onto the probes  140  to let the tails  145  of the probes  140  be inserted through the upper through holes  111  of the upper guider plate  110 . In this way, the probes  140  are less possibly damaged in the assembling process of the probe head or after the upper guider plate  110  is installed and the probe head is completely assembled, and the efficiency of assembling the probe head  100  is also improved. 
       FIG. 5  is a lateral sectional view of a probe head according to another embodiment of the present invention. Referring to  FIG. 5 , the probe head  500  is similar to the probe head  100  as shown in  FIG. 1 , but has the difference as described hereinafter. The probe head  500  further includes a fastening member  550  which is shaped as a ring in this embodiment and disposed between the lower guider plate  120  and the positioning member  130 . In this way, in the process that the probes  140  are inserted through the upper through holes  111  of the upper guider plate  110 , the positioning through holes  131  of the positioning member  130  and the lower through holes  121  of the lower guider plate  120 , the fastening member  550  can support and fasten the positioning member  130  in good position, so that the probes are conveniently installed. It should be mentioned that the upper guider plate  110  and the positioning member  130  are arranged in contact with each other in  FIG. 5 , but the upper guider plate  110  and the positioning member  130  of the present invention are not limited to be arranged in contact with each other. 
     Besides, the positioning member  130  and the upper guider plate  110  in this embodiment also have the light transmittance of at least 75%, and are made of the material having the Moh&#39;s hardness of at least 5. Therefore, the precise positions of the tails  145  of the probes  140  can be observed directly, so that the tails  145  of the probes  140  are easily inserted through the positioning through holes  131  of the positioning member  130  and the upper through holes  111  of the upper guider plate  110 , the probes  140  are less possibly damaged, and the efficiency of assembling the probe head  500  is improved. Therefore, the effects and advantages of the probe head  500  are similar to that of the probe head  100 , which will not be repeatedly mentioned hereunder. 
     In conclusion, the probe head provided in the embodiments of the present invention has the positioning member and the upper guider plate, which have the light transmittance of at least 75% and are made of the material having the Moh&#39;s hardness of at least 5. Therefore, in the assembling process of the probe head under the condition of conforming to the requirement of fine pitch, the lower through holes of the lower guider plate can be observed directly, thereby facilitating the installation of the probes. When the upper guider plate is aligned with the probes, the precise positions of the tails of the probes under the upper guider plate can be observed directly, so that the tails of the probes are easily inserted through the upper through holes of the upper guider plate. In this way, the probes are less possibly damaged in the installation process, and the efficiency of assembling the probe head can be improved. It should be mentioned that the lower guider plate in the present invention may, but not limited to, be made of a material having a light transmittance of at least 75% and a Mohs hardness of at least 5. 
     The invention has been described in the aforesaid embodiments, but the aforesaid embodiments are not intended to limit the scope of the invention. The invention may be able to be varied or modified by one skilled in the art, and such variations and modifications may not to be regarded as a departure from the spirit and scope of the invention. So the scope the invention intended to protect should be determined according to the following claims.