The present disclosure relates to probe cards.
The main function of a probe card is to directly contact with the welding pads or bumps on a device under test (such as a wafer not yet packaged, a chip or a die) with its probe, in order to achieve the purpose of testing the device under test with the configuration of a testing machine or software control, such that defective products can be screened. In general, a testing signal is generated from the testing machine, and the testing signal reaches the device under test through the probe card. Afterwards, a signal of testing result is transmitted back to the testing machine through the probe card for analysis.
Therefore, a stable electrical performance of a probe card is undoubtedly an important issue in the industry.
A technical aspect of the present disclosure is to provide a probe card, which can securely fix the space transformer and the printed circuit board, thus improving the stability of the end product.
According to an embodiment of the present disclosure, a probe card includes a space transformer, a printed circuit board and a plurality of welding elements. The space transformer is disposed with a plurality of first conductive protrusions. Each of the first conductive protrusions has a first end surface. The printed circuit board is disposed with a plurality of second conductive protrusions. Each of the second conductive protrusions has a second end surface. The welding elements are respectively and electrically connected between each of the second end surfaces and the corresponding first end surface. A first surface of the space transformer away from the printed circuit board has a first degree of flatness. A second surface of the printed circuit board away from the space transformer has a second degree of flatness. The first degree of flatness is less than the second degree of flatness.
In one or more embodiments of the present disclosure, the first surface has a first height difference defining the first degree of flatness. The second surface has a second height difference defining the second degree of flatness.
In one or more embodiments of the present disclosure, at least two of the first end surfaces have different distances from the space transformer.
In one or more embodiments of the present disclosure, at least two of the second end surfaces have different distances from the printed circuit board.
In one or more embodiments of the present disclosure, each of the first conductive protrusions includes a base portion and a protruding portion. The base portion is connected with the space transformer. The base portion has a supporting surface away from the space transformer. The protruding portion has a third end surface opposite to the first end surface. The third end surface connects with the supporting surface. An area of the supporting surface is larger than an area of the third end surface.
In one or more embodiments of the present disclosure, an area of the first end surface is same as the area of the third end surface.
In one or more embodiments of the present disclosure, an area of the first end surface is less than the area of the third end surface.
In one or more embodiments of the present disclosure, the probe card further includes a solder mask. The solder mask is located on the space transformer and at least partially covers the base portion.
In one or more embodiments of the present disclosure, the probe card further includes a dielectric layer. The dielectric layer is located on a side of the solder mask away from the space transformer, in which at least one of the protruding portions is embedded in the dielectric layer to form a concave structure.
In one or more embodiments of the present disclosure, the probe card further includes a dielectric layer. The dielectric layer is located on a side of the solder mask away from the space transformer. Each of the protruding portions further includes a first subsidiary protruding portion and a second subsidiary protruding portion. The third end surface is located on the first subsidiary protruding portion. The first subsidiary protruding portion is at least partially coated by the dielectric layer. The second subsidiary protruding portion is connected with an end of the first subsidiary protruding portion away from the third end surface. The first end surface is located on the second subsidiary protruding portion. The second subsidiary protruding portion is exposed from the dielectric layer.
In one or more embodiments of the present disclosure, the dielectric layer has a through hole to expose at least a portion of the space transformer. The probe card further includes an electronic element. The electronic element is disposed on the space transformer and located within the through hole. The space transformer has a groove. The groove is communicated with the through hole. The electronic element is disposed within the groove.
According to another embodiment of the present disclosure, a probe card includes a space transformer, a probe head and a printed circuit board. The space transformer includes a lower structure and an upper structure. The lower structure has a first surface. The upper structure is electrically connected with the lower structure. The upper structure has a second surface away from the lower structure. The first surface is away from the upper structure. The probe head is electrically connected with the first surface. The upper structure is located between the printed circuit board and the lower structure. The first surface has a first height difference. The second surface has a second height difference. The first height difference is less than the second height difference.
In one or more embodiments of the present disclosure, the upper structure is multi-layered organic (MLO) or multi-layered ceramic (MLC) and the lower structure is multi-layered organic.
In one or more embodiments of the present disclosure, the first height difference defines a first degree of flatness. The second height difference defines a second degree of flatness. The first degree of flatness is less than the second degree of flatness.
In one or more embodiments of the present disclosure, the upper structure is disposed with a plurality of first conductive protrusions. The first conductive protrusions face to the lower structure. Each of the first conductive protrusions has a first end surface away from the second surface. At least two of the first end surfaces have different distances from the second surface.
In one or more embodiments of the present disclosure, the lower structure is disposed with a plurality of second conductive protrusions. Each of the second conductive protrusions has a second end surface. The second end surface is electrically connected with the corresponding first end surface. At least two of the second end surfaces have different distances from the first surface.
In one or more embodiments of the present disclosure, the probe card further includes a plurality of welding elements. The welding elements are respectively welded and electrically connected between each of the second end surfaces and the corresponding first end surface.
In one or more embodiments of the present disclosure, each of the first conductive protrusions includes a base portion and a protruding portion. The base portion is connected with the upper structure. The base portion has a supporting surface away from the upper structure. The protruding portion has a third end surface opposite to the first end surface. The third end surface connects with the supporting surface. An area of the supporting surface is larger than an area of the third end surface.
The disclosure can be more fully understood by reading the following detailed description of the embodiments, with reference made to the accompanying drawings as follows:
Drawings will be used below to disclose embodiments of the present disclosure. For the sake of clear illustration, many practical details will be explained together in the description below. However, it is appreciated that the practical details should not be used to limit the claimed scope. In other words, in some embodiments of the present disclosure, the practical details are not essential. Moreover, for the sake of drawing simplification, some customary structures and elements in the drawings will be schematically shown in a simplified way. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Reference is made to
Furthermore, a first surface 114 of the space transformer 110 away from the printed circuit board 130 has a first degree of flatness. A second surface 131 of the printed circuit board 130 away from the space transformer 110 has a second degree of flatness. The first degree of flatness is less than the second degree of flatness. In other words, the first surface 114 of the space transformer 110 is flatter than the second surface 131 of the printed circuit board 130.
In addition, the first surface 114 of the space transformer 110 has a first height difference A. The first height difference A defines the first degree of flatness of the first surface 114. The first height difference A can be a distance between the highest point and the lowest point of the first surface 114. Thus, the smaller the first height difference A, the flatter the first surface 114 and the smaller the first degree of flatness will be. On the contrary, the second surface 131 of the printed circuit board 130 has a second height difference B. The second height difference B defines the second degree of flatness of the second surface 131. The second height difference B can be a distance between the highest point and the lowest point of the second surface 131. Thus, the smaller the second height difference B, the flatter the second surface 131 and the smaller the second degree of flatness will be. In this embodiment, the first height difference A is smaller than the second height difference B. That is, as mentioned above, the first surface 114 of the space transformer 110 is flatter than the second surface 131 of the printed circuit board 130, and the first degree of flatness of the first surface 114 is smaller than the second degree of flatness of the second surface 131.
To be specific, even if the printed circuit board 130 appears with the condition of warp, i.e., the second degree of flatness of the second surface 131 is poor, through the compensation by the different heights of the first conductive protrusions 120 and the second conductive protrusions 140 to the warp of the printed circuit board 130, the effect of the warped printed circuit board 130 to the flatness of the space transformer 110 is effectively reduced. In this way, the first surface 114 of the space transformer 110 can be flatter than the second surface 131 of the printed circuit board 130. That is, as mentioned above, the first height difference A of the first surface 114 is smaller than the second height difference B of the second surface 131, and the first degree of flatness of the first surface 114 is smaller than the second degree of flatness of the second surface 131.
On the other hand, even if the space transformer 110 and/or the printed circuit board 130 appears with the condition of warp, since the second end surfaces 141 of the second conductive protrusions 140 and the first end surfaces 121 of the first conductive protrusions 120 face to each other and are parallel with each other, the welding elements 150 can be evenly connected between the second end surfaces 141 and the first end surfaces 121. Thus, the space transformer 110 and the printed circuit board 130 can be securely fixed, improving the stability of the end product. To be more specific, for the welding elements 150 located between the second end surfaces 141 and the first end surfaces 121, the consistency of volume can be effectively controlled. In practical applications, the welding elements 150 can be solder, which joints the second conductive protrusions 140 and the first conductive protrusions 120 during the reflow process. However, this does not intend to limit the present disclosure.
In other words, the warp condition of the space transformer 110 and the printed circuit board 130 are respectively compensated by the first conductive protrusions 120 of different heights and the second conductive protrusions 140 of different heights. Therefore, the connection between the space transformer 110 and the printed circuit board 130 is not affected by the warp condition of the space transformer 110 and/or the printed circuit board 130.
In practical applications, taking the space transformer 110 as an example, the heights of the first conductive protrusions 120 should be larger than or equal to the degree of warp of the space transformer 110. In this way, the warp of the space transformer 110 can be compensated by the first conductive protrusions 120. As shown in
Similarly, for the warp of the printed circuit board 130 to be compensated by the second conductive protrusions 140, the heights of the second conductive protrusions 140 should be larger than or equal to the degree of warp of the printed circuit board 130. In practical applications, since the dimensions of the printed circuit board 130 is larger than the space transformer 110, the degree of warp of the printed circuit board 130 may be larger than the degree of warp of the space transformer 110. When the degree of warp of the printed circuit board 130 is obviously larger than the degree of warp of the space transformer 110, the user can use only the second conductive protrusions 140 of different heights, but not the first conductive protrusions 120 of different heights, to compensate the warp of the printed circuit board 130, according to the actual situation.
Reference is made to
Furthermore, according to the actual situation, the material of the protruding portion 124 can be copper, copper-silver alloy, nickel-palladium alloy and nickel-cobalt alloy etc. However, this does not intend to limit the present disclosure.
In addition, the protruding portion 124 can be in the shape of a circular column, a square column or a rectangular column etc. The height of the protruding portion 124 can be smaller than the width of the first end surface 121. For example, the height of the protruding portion 124 can be about 150 μm, while the width of the first end surface 121 can be 180 μm. However, in other embodiments, the height of the protruding portion 124 can be larger than the width of the first end surface 121.
Furthermore, as shown in
In this embodiment, as shown in
Reference is made to
Reference is made to
Furthermore, the probe card 110 further includes a circuit 128. As shown in
Reference is made to
Reference is made to
Reference is made to
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Reference is made to
In practical applications, for example, the upper structure 112 can be multi-layered organic (MLO) or multi-layered ceramic (MLC). The lower structure 113 can be multi-layered organic.
In summary, when compared with the prior art, the embodiments of the present disclosure mentioned above have at least the following advantages:
(1) Even if the printed circuit board appears with the condition of warp, i.e., the second degree of flatness of the second surface is poor, through the compensation by the different heights of the first conductive protrusions and the second conductive protrusions to the warp of the printed circuit board, the effect of the warped printed circuit board to the flatness of the space transformer is effectively reduced. In this way, the first surface of the space transformer can be flatter than the second surface of the printed circuit board.
(2) Even if the space transformer and/or the printed circuit board appears with the condition of warp, since the second end surfaces of the second conductive protrusions and the first end surfaces of the first conductive protrusions face to each other and are parallel with each other, the welding elements can be evenly connected between the second end surfaces and the first end surfaces. Thus, the space transformer and the printed circuit board can be securely fixed, improving the stability of the end product.
(3) Since the warp condition of the space transformer and the printed circuit board are respectively compensated by the first conductive protrusions of different heights and the second conductive protrusions of different heights, the connection between the space transformer and the printed circuit board is not affected by the warp condition of the space transformer and/or the printed circuit board.
(4) Through setting the heights of the first conductive protrusions and the second conductive protrusions, a space can be provided for installing the electronic element, thus increasing the electrical performance of the probe card.
Although the present disclosure has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.
It will be apparent to the person having ordinary skill in the art that various modifications and variations can be made to the structure of the present disclosure without departing from the scope or spirit of the present disclosure. In view of the foregoing, it is intended that the present disclosure cover modifications and variations of the present disclosure provided they fall within the scope of the following claims.
Number | Date | Country | Kind |
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107124356 | Jul 2018 | TW | national |
This application claims priority to U.S. Provisional Application Ser. No. 62/613,780, filed Jan. 5, 2018, and Taiwanese Application Serial Number 107124356, filed Jul. 13, 2018, which are herein incorporated by reference.
Number | Date | Country | |
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62613780 | Jan 2018 | US |