The present invention relates generally to probe cards and more particularly, to a membrane probe card, a method of making the membrane probe card, and a method of making a tested semiconductor chip by using the membrane probe card.
It is known that a conventional membrane probe card is composed of a membrane circuit board and a plurality of probes protruding from a surface of the membrane circuit board. Compared to the probe card composed of a printed circuit board and a probe head, the probe lengths of the membrane probe card, i.e., the heights of the probes protruding over the surface of the membrane circuit board (hereinafter referred to as “probe heights”), are relatively short, and the signal transmission paths of the membrane probe card are relatively short too. Therefore, membrane probe cards are particularly suitable for high-frequency testing.
The known method for manufacturing probes of membrane probe cards involves first forming multiple recesses on an insulating substrate by wet etching. The shapes of the recesses correspond to the shapes of the desired probes. Then, the probes are formed in the recesses by electroplating. After the probes are bonded to the membrane circuit board, the insulating substrate is removed. However, due to process limitations, there is a certain center-to-center distance (pitch) between these probes, which makes the probes difficult to meet the testing requirements of fine pitch.
Another known method for manufacturing probes of membrane probe cards is similar to the aforementioned one, but replaces the insulating substrate with a silicon substrate. When wet etching is performed on the silicon substrate, square-based pyramidal recesses corresponding to the silicon crystal lattice directions are formed. Therefore, the probes produced by this method are square-based pyramids with specific inclined angles on their sides. The higher the probe height is required, the wider the width at the widest portion (i.e., the portion connected to the membrane circuit board) will be. Therefore, if this type of membrane probe card is to meet the testing requirements of fine pitch, the probes will be very thin, which may lead to insufficient structural strength and easy breakage. Additionally, the probes may be too short to meet the required probe height for testing.
Furthermore, to manufacture probes having specific width variations in a stepwise manner by the above-mentioned method, it is required to make different width segments by using photolithography step by step. As such, these processing steps are complicated and time-consuming, and the probe made by segmented laminations may have a weak structural strength, which is liable to break at the conjunction interfaces. Moreover, in the aforementioned method, because the probes are formed by electroplating in the recesses, during the electroplating process there may be problems with low exchange rate of the electroplating solution, leading to pinholes formed by bubbles of the electroplating solution on the surface and in the inside of the probes. This also leads to poor structural strength of the probes and may render them unusable due to the pinholes on the contact end faces of the probes.
The present invention has been accomplished in view of the above-noted circumstances. It is an objective of the present invention to provide a membrane probe card, which may have a fine probe pitch, a good structural strength, and a required probe height for testing.
To attain the above-mentioned objective, the present invention provides a membrane probe card comprising a membrane device including a membrane wiring structure and a plurality of probes. The membrane wiring structure comprises at least one trace and a probe protruding surface. The probes are disposed on the membrane wiring structure and protrude from the probe protruding surface. Each probe defines a height axis, a length axis, and a width axis, which are perpendicular to each other. Each probe comprises a base and a probe tip. The base is electrically and mechanically connected with the trace of the membrane wiring structure and protrudes from the probe protruding surface along the height axis by a first height. The base comprises a first side edge, a second side edge opposite to the first side edge, a tip placement section extending from the first side edge towards the second side edge along the length axis, and an extension section extending from the tip placement section along the length axis to the second side edge. The tip placement section defines a width in the width axis. The probe tip is made by laser processing and electroplating. The probe tip protrudes from the base along the height axis by a second height and is electrically connected with the trace of the membrane wiring structure by the base. The probe tip is located at the tip placement section of the base and includes a fixed end portion that is connected with the base and defines a width along the width axis in a way that the width of the tip placement section is greater than the width of the fixed end portion of the probe tip. Each probe defines along the length axis a first distance from a center of the probe tip to the first side edge of the base and a second distance from the center of the probe tip to the second side edge of the base in a way that the first distance is less than the second distance.
With the above-described technical features, i.e., the probe of the membrane probe card of the present invention comprises the base protruding from the membrane wiring structure and the probe tip protruding from the base, the probe height is the sum of the first height of the base and the second height of the probe tip. This allows achieving the required probe height for testing while maintaining fine pitch of the probes, without having the problem of poor structural strength due to excessively elongated probe tips. Moreover, during testing, when the probe tip makes contact with the device under test, it experiences reaction force which is then transmitted to the base. Since the base width is greater than the probe tip width, it effectively disperses the reaction force, thereby reducing the risk of probe breakage due to applied force during testing.
However, high structural strength of the probes may lead to poor elasticity, possibly causing a problem that the probes may be difficult in scraping through the oxide layers on the surfaces of the conductive contact pads of the device under test, resulting in unstable testing results. In the membrane probe card of the present invention, the probe tip is positioned closer to the first side edge of the base and farther from the second side edge, meaning the position of the probe tip on the base is biased towards one side. This technical feature enhances the elasticity of the probes, thereby preventing the problem of the probe tip struggling to scrape through the oxide layer on the device under test, consequently improving testing stability.
Preferably, the extension section of the base of each of the probes may comprise a tapered section having a width gradually reduced from the tip placement section towards the second side edge.
Due to the high structural strength of the probes, it is possible for the reactive force during testing to be too large to damage the trace connected to the base of the probe. Therefore, the extension section of the probe base is configured as having a tapered section, which reduces the reactive force transmitted from the probe tip, thereby preventing damage to the trace of the membrane wiring structure during testing.
More preferably, the extension section of the base of each probe may have two rounded corners at the second side edge.
In the probe of the present invention, since the second side edge of the base is farther from the probe tip, the reactive force during testing will be concentrated on the portion of the trace of the membrane wiring structure located at the second side edge, which may possibly lead to the breakage of this portion of the trace. In the membrane probe card of the present invention, the tapered section mentioned above has reduced the reactive force transmitted to the extension section, and the rounded corners at the second side edge further evenly distribute the reactive force transmitted to the second side edge, thereby avoiding breakage of the trace located at the second side edge.
Preferably, a connection portion between the base and the probe tip of each probe is concavely arc-shaped or shaped as a so-called filleted shape.
If a sharp angle exists at the connection portion between the base and the probe tip of the probe, stress concentration issues may arise during testing, potentially leading to probe breakage. Therefore, the connection portion between the base and the probe tip of the probe is made concave and rounded, avoiding stress concentration at the connection portion. Given the design of the structural strength of the probe, the cross-sectional area of the probe tip is smaller than that of the probe base. If the probe base and the probe tip are manufactured by using photolithography processes, where the probe base is patterned before the probe tip, it is difficult to control the connection portion between the base and the probe tip, resulting in a sharp angle. This can make products manufactured by using photolithography prone to damage. By employing the aforementioned concave and rounded structure and the subsequent manufacturing processes that will be illustrated hereunder, the connection portion between the base and the probe tip of the probe is made concave and rounded, further improving the stress concentration issue.
Preferably, the membrane wiring structure may comprise a surface dielectric layer including the probe protruding surface, and the base of each probe may include an inner embedded portion embedded in the surface dielectric layer, and an outer exposed portion protruding outside the surface dielectric layer. The cross-sectional areas of the inner embedded portion in the length axis and the width axis are greater than the cross-sectional areas of the outer exposed portion in the length axis and the width axis, respectively, and the inner embedded portions of adjacent two of the probes are separated by the surface dielectric layer.
As a result, the base of the probe is partially embedded in the membrane wiring structure. This feature allows for a more stable connection between the probe and the membrane wiring structure. Additionally, the inner embedded portions of the adjacent probes are separated by the surface dielectric layer of the membrane wiring structure, maintaining the pitch between the adjacent probes, and preventing offset or misalignment of the positions of the probe tips due to manufacturing issues. Furthermore, the feature that the base is partially embedded in the membrane wiring structure may enhance the structural strengths of the base and the membrane wiring structure, preventing the trace from breakage due to excessive stress on the connection portion between the base and the membrane wiring structure.
Preferably, the probe tip of each probe may have a contact end face farthest from the base, and the contact end face is flat.
In the present invention, the probes are manufactured by electroplating in the through holes of a metal substrate. Electroplating in the through holes allows for a high exchange rate of the plating solution, avoiding the formation of pinholes due to bubbles of the plating solution on the interior and surface of the probes. This ensures that the probes have a solid and homogeneous characteristic, leading to excellent structural strength and a flat surface without pinholes. Particularly, the contact end face of the probe tip is flat, which is advantageous for the stability of testing.
Preferably, the trace connected with the base of each probe extends from the second side edge of the base. The first side edge of the base and the trace respectively define a width in the width axis in a way that the width of the first side edge is greater than the width of the trace. Further, the second side edge of the base of each probe defines a width in the width axis in a way that the width of the second side edge is smaller than the width of the first side edge and greater than the width of the trace. Moreover, the width of the fixed end portion of the probe tip is greater than the width of the trace.
Since the probe tip of the probe is positioned closer to the first side edge of the base, the width of the first side edge is made larger than the width of the trace. This feature effectively disperses stress transmitted to the membrane wiring structure, thereby preventing stress concentration on the trace, and avoiding breakage of the trace during testing. As mentioned above, the high structural strength of the probe may result in excessive reactive force during testing, potentially damaging the traces connected to the base of the probe. Therefore, the width of the second side edge of the base of the probe is made smaller than that of the first side edge, reducing the reactive force. Additionally, the width of the second side edge is greater than that of the trace, further dispersing stress transmitted to the membrane wiring structure and preventing stress concentration on the trace, thus avoiding breakage of the trace during testing. The width of the fixed end portion of the probe tip is greater than that of the trace, allowing for the gradual dispersion of reactive forces before reaching the base of the probe. Combined with the stress-dispersing action of the base mentioned above, this effectively disperses stress transmitted to the membrane wiring structure, further preventing stress concentration on the trace, and thus more effectively avoiding trace breakage.
Preferably, each probe may comprise an outer layer exposed outside and at least one inner layer shielded by the outer layer. The outer layer and the at least one inner layer are made of different metals, and extend from the probe tip to the base.
As such, the outer layer of the probe may be made of a metal having a great hardness, such as rhodium (Rh), to enhance the wear resistance of the probe. The inner layer of the probe may be made of different metals depending on the requirements, and the probe may be configured as having a single inner layer or multiple inner layers. For example, the innermost layer may be made of a metal having a high conductivity, such as copper (Cu), while the inner layers between the innermost layer and the outer layer may be made of a metal with good oxidation resistance, such as nickel (Ni). Both the outer and inner layers extend from the probe tip to the base, indicating that each of the outer layer and the inner layer is simultaneously formed with the parts at the base and the probe tip during manufacturing. This feature ensures that there are no segmented interfaces between the probe tip and the base, making the connection portion between the probe tip and the base less prone to breakage under stress.
Preferably, each probe may have a space located inside the inner layer.
More specifically, the innermost layer of the probe may be hollow and unfilled, creating a space therein. This helps reduce the stress transmitted to the membrane wiring structure by the probe tip, thus avoiding breakage of the trace due to excessive force. Additionally, with the aforementioned space inside the probe, the trace of the membrane wiring structure may partially extend into the space within the base, and even further into the space within the probe tip. The portions of the trace inside the probe and outside the probe may be integrally formed without segmented stacked interfaces, thereby not only enhancing the structural strength of the trace itself but also protecting the trace from stress by the probe base so as to minimize the affection of the stress to the trace.
Preferably, the base of each probe may comprise a plurality of base layers, and the cross-sectional areas of the base layers in the length axis and the width axis are different. Further, a connection portion between two of the base layers is concavely arc-shaped.
Compared to the pattern having only a single base layer, the multiple base layers may gradually reduce the cross-sectional areas thereof from the membrane wiring structure towards the probe tip layer by layer, further increasing the probe height while maintaining the structural strength of the probe tip. If the connection portions of the base layers form sharp corners, stress concentration issues may occur during testing, leading to probe breakage. Therefore, forming the connection portions of the base layers into concave round arcs can prevent stress concentration at the connection portions.
Preferably, the probe tips of the probes are formed separately in a plurality of through holes of a metal substrate, and the through holes of the metal substrate are formed by laser processing.
In other words, a laser processing is first used to form through holes (through holes) in the metal substrate in a shape corresponding to the desired shape of the probe tip, and then the probe tips are further formed in the through holes of the metal substrate. Consequently, the through holes formed by the laser processing are not limited by shape or inclination angles and can achieve a high aspect ratio, thus meeting the requirements for probe height, width, pitch, and shape necessary for testing, while allowing the probe of the membrane probe card to achieve the required probe height and good structural strength while maintaining the fine pitch requirement. Additionally, the good structural strength of the metal substrate prevents the metal substrate from being affected by environmental factors such as temperature and humidity during manufacturing. Furthermore, the probe tips may be formed by electroplating in the through holes of the metal substrate. This allows for a high exchange rate of the electroplating solution flowing in and out of the through holes, avoiding the formation of pinholes due to bubbles in the electroplating solution on the surface and in the interior of the probe, thus making the probes solid and homogeneous, thereby providing good structural strength. It also ensures that the probe surface is smooth without pinholes, especially the contact end face of the probe tip is flat, which is beneficial for the stability of testing. More preferably, a pitch between adjacent two probe tips is less than 50 μm, and the heights of the probe tips are greater than 50 μm. In the present invention, using the laser processing on the metal substrate to form through holes may ensure that the pitches of the probes of the membrane probe card conform to the specified standards, and at the same time, the heights of the probe tips may also reach the specified standards. In the present invention, the metal substrate is used to be immersed in the electroplating solution for forming the probe tips. Because the metal substrate does not have water absorption characteristics, the dimensional changes of the metal substrate due to water absorption may not occur, thereby avoiding affection of the stability of the substrate size.
Preferably, the membrane probe card may further comprise a circuit board and a probe seat mounted to the circuit board. An elastic structure is provided inside the probe seat, and the membrane wiring structure is mounted to the probe seat and electrically connected with the circuit board.
As a result, the circuit board may be electrically connected with a testing machine, thereby facilitating the electrical connection between the membrane wiring structure and the probes of the membrane device and the testing machine. Additionally, the elastic structure may provide a buffering effect when the probes contact the device under test (DUT).
Anther objective of the present invention is to provide a method of making a membrane probe card having a fine probe pitch, a good structural strength, and a required probe height for testing. To attain the above-mentioned objective, the method for making the membrane probe card comprises the steps of:
By the above-mentioned features, the through holes made by the laser processing are free from shape or tilt angle restrictions, and can achieve high aspect ratios. Therefore, it can meet the requirements of probe height, width, pitch, and shape (e.g., truncated cone or square-based pyramid) needed for testing. This allows the probes of the membrane probe card to achieve the required probe height and good structural strength while achieving fine pitch requirement. Moreover, in step a), a metal substrate is used, which has good structural strength and can avoid being affected by environmental factors such as temperature and humidity during the manufacturing process. In step b), the through holes penetrate through the upper and lower surfaces of the metal substrate, and in step c), the conductive bodies are formed by electroplating within the through holes of the metal substrate. As a result, the electroplating solution can enter and exit the through holes with a high exchange rate, thereby avoiding the formation of pinholes caused by bubbles of the electroplating solution in the interior and on the external surface of the completed probe. This enables the probes to have solid and homogeneous characteristics, thereby ensuring good structural strength and a smooth surface without pinholes. Especially, the contact end face of the probe tip is flat, which is conducive to the stability of testing. Additionally, since the metal substrate and the conductive bodies may be made of different materials, in step e), when removing the metal substrate, it prevents the conductive bodies from being partially or entirely removed, thus avoiding deformation of the probe shape or structural damage that renders the probe unusable.
Preferably, after the step b) and before the step c), the through holes are subjected to micro-etching processing.
The micro-etching processing may make the hole walls of the through holes smoother, and after the micro-etching processing is performed, a step of electroplating metal (such as copper) on the hole walls may be further performed to make the hole walls more smoother. The smooth hole walls of the through holes may make the surfaces of the manufactured probes smooth, which are beneficial for the stability of the test. In addition, if the through hole has a stepwise structure, sharp corners may also be rounded by the micro-etching processing, making the probe part formed at the rounded corner concave and arc-shaped, or so-called filleted shape, thereby avoiding stress concentration at the part of the probe and preventing probe breakage.
Preferably, after step a), at least one metal layer is formed on the upper surface of the metal substrate by photolithography and electroplating in a way that the at least one metal layer is provided with a plurality of penetrating grooves, through which the upper surface of the metal substrate is exposed outside. The step b) is performed by using the laser processing to form the through holes in the metal substrate through the penetrating grooves, where each of the penetrating grooves is in communication with one of the through holes in a one-to-one manner, and a cross-sectional area of each of the penetrating grooves is greater than a cross-sectional area of associated one of the through holes. In the step c), each of the conductive bodies is formed in one of the through holes and associated one of the penetrating grooves, such that each of the conductive bodies includes a probe tip portion located inside the through hole and a base portion located inside the penetrating groove. In the step e), the metal substrate and the at least one metal layer are removed.
Accordingly, each probe formed by the respective conductive body will have a probe tip and a base formed respectively by the probe tip portion and the base portion, similar to the probes of the membrane probe card provided by the present invention as described above. Such probes including bases and probe tips can simultaneously achieve fine pitch, high structural strength, and the required probe height for testing. Further, the base width is greater than the probe tip width, effectively dispersing the reactive force from the device under test, thereby reducing the breakage risk of the probe and the trace of the membrane wiring structure. Furthermore, the base and probe tip of the probe are simultaneously formed in step c), so there is no segmented stacking interface between the base and the probe tip of the probe, making the connection portion between the probe tip and the base less susceptible to breakage due to force. In addition, the subsequent micro-etching processing after step b) can also round the connection portion between the through hole and the penetrating groove, making the connection portion between the probe tip and the base of the completed probe concave and arc-shaped, thereby avoiding stress concentration at the connection portion and preventing probe breakage. Moreover, the at least one metal layer may be a plurality of metal layers, and by stacking multiple metal layers, a stepped penetrating groove may be formed, so that the formed probe base contains a plurality of base layers with different cross-sectional areas. In this configuration, the subsequent micro-etching processing after step b) can also round the sharp corners of the stepped penetrating groove, making the connection portion between adjacent base layers of the completed probe concave and arc-shaped, thereby avoiding stress concentration at the connection portion and preventing probe breakage. Furthermore, the feature that a part of the base is embedded in the membrane wiring structure can further strengthen the base and the membrane wiring structure, avoiding the trace from breakage due to excessive stress on the connection portion between the base and the membrane wiring structure.
Preferably, the step b) further includes a substep of forming a patterned dielectric layer on the at least one metal layer in a way that the patterned dielectric layer has a plurality of openings in communication with the penetrating grooves in a one-to-one manner, and a cross-sectional area of each of the openings is greater than the cross-sectional area of associated one of the penetrating grooves. In the step c), each of the conductive bodies is formed in one of the through holes and associated one of the penetrating grooves and one of the openings.
In this way, the patterned dielectric layer can serve as the surface dielectric layer of the membrane wiring structure, and the base of the probe will have a portion (i.e., the portion formed by the conductive body within the opening of the patterned dielectric layer) embedded in the surface dielectric layer of the membrane wiring structure. This can make the connection between the probe and the membrane wiring structure more secure, and the inner embedded portions of the bases of adjacent probes are separated by the surface dielectric layer of the membrane wiring structure, thereby maintaining the pitch between the adjacent probes, and avoiding offset or misalignment of the positions of the probe tips due to manufacturing issues. Additionally, the inner embedded portion of the base of the probe is formed simultaneously with other parts of the base and the probe tip in step c), so there are no segmented stacking interfaces in the base of the probe, making the probe less susceptible to breakage due to forces. Furthermore, the subsequent micro-etching processing after step b) can also round the connection portion between the penetrating groove and the opening, creating a concave rounded shape, or so-called filleted shape, at the probe portion formed at the rounded corner, thereby avoiding stress concentration at the corner, and preventing probe breakage.
More preferably, the metal substrate and the at least one metal layer are made of a same material.
Since the step e) involves removing the metal substrate and the at least one metal layer, and the metal substrate and the at least one metal layer are made of the same material, it is easier to remove the metal substrate and the at least one metal layer simultaneously.
Preferably, the metal substrate is made of beryllium-copper alloy, silver-copper alloy, or nickel-iron alloy.
Beryllium-copper alloy, silver-copper alloy, and nickel-iron alloy have excellent structural strength and are easy to process with laser and electroplating, making them preferable materials for the metal substrate. However, the material of the metal substrate is not limited to these.
Preferably, in the step b), a plurality of recesses are formed on the upper surface of the metal substrate, and then the through holes are formed by the laser processing in a way that each of the recesses is in communication with one of the through holes in a one-to-one manner and a cross-sectional area of each of the recesses is greater than a cross-sectional area of associated one of the through holes. In the step c), each of the conductive bodies is formed in one of the through holes and associated one of the recesses in a way that each of the conductive bodies includes a probe tip portion located inside the through hole and a base portion located inside the recess.
Accordingly, each probe formed by the respective conductive body will have a probe tip and a base formed respectively by the probe tip portion and the base portion, similar to the probes of the membrane probe card provided by the present invention as described above. Such probes containing bases and probe tips can simultaneously achieve fine pitch, high structural strength, and the required probe height for testing. Further, the base width is greater than the probe tip width, effectively dispersing the reactive force from the device under test, thereby reducing the breakage risk of the probe and the trace of the membrane wiring structure. Moreover, the base and probe tip of the probe are simultaneously formed in step c), so there is no segmented stacking interface between the base and the probe tip of the probe, making the connection portion between the probe tip and the base less prone to breakage due to force. Additionally, the subsequent micro-etching processing after step (b) can also round the connection portion between the through hole and the recess, making the connection portion between the probe tip and the base of the completed probes concave and arc-shaped, or so-called filleted shape, thereby avoiding stress concentration at the connection portion between the probe tip and base and preventing probe breakage.
More preferably, the recesses are formed by micro-etching processing or laser processing.
In this way, the micro-etching processing can form appropriately sized recesses, allowing the manufactured probes to still meet the requirements of fine pitch. The laser processing can easily control the shape and size of the recesses, and after the recesses are completed, the laser processing can continue to form the through holes, resulting in good processing efficiency. In addition, the recesses formed by the laser processing may be made having a stepped profile, allowing the formed probe bases to include multiple base layers with different cross-sectional areas. In this case, the micro-etching processing after step b) can also round off the sharp corners of the stepped recesses, making the connection portions of adjacent base layers of the manufactured probes concave and rounded, or so-call filleted shape. This helps to avoid stress concentration at the connection portions of the base layers, thereby preventing probe breakage.
Preferably, the step b) further includes a substep of forming a patterned dielectric layer on the upper surface of the metal substrate in a way that the patterned dielectric layer has a plurality of openings in communication with the recesses in a one-to-one manner, and a cross-sectional area of each of the openings is greater than a cross-sectional area of associated one of the recesses; and in the step c), each of the conductive bodies is formed in one of the through holes and associated one of the recesses and one of the openings.
In this way, the patterned dielectric layer can serve as the surface dielectric layer of the membrane wiring structure, and the base of the probe will have a portion (i.e., the portion formed by the conductive body within the opening of the patterned dielectric layer) embedded in the surface dielectric layer of the membrane wiring structure. This can make the connection between the probe and the membrane wiring structure more secure, and the inner embedded portions of the bases of adjacent probes are separated by the surface dielectric layer of the membrane wiring structure, thereby maintaining the pitch between the adjacent probes, and avoiding offset or misalignment of the positions of the probe tips due to manufacturing issues. Additionally, the inner embedded portion of the base of the probe is formed simultaneously with other parts of the base and the probe tip in step c), so there are no segmented stacking interfaces in the base of the probe, making the probe less susceptible to breakage due to forces. Furthermore, the subsequent micro-etching processing after step b) can also round the connection portion between the recess and the opening, creating a concave rounded shape, or so-called filleted shape, at the probe portion formed at the rounded corner, thereby avoiding stress concentration at the corner, and preventing probe breakage.
Preferably, the step b) may further include a substep of forming a patterned dielectric layer on the upper surface of the metal substrate in a way that the patterned dielectric layer has a plurality of openings in communication with the through holes in a one-to-one manner, and a cross-sectional area of each of the openings is greater than a cross-sectional area of associated one of the through holes. In the step c), each of the conductive bodies is formed in one of the through holes and associated one of the openings.
Even without the aforementioned metal layer and penetrating grooves thereof, or without first forming recesses on the upper surface of the metal substrate, a patterned dielectric layer may still be formed on the upper surface of the metal substrate to serve as the surface dielectric layer of the membrane wiring structure, and make the base of the probe have a portion (i.e., the portion formed by the conductive body within the opening of the patterned dielectric layer) embedded in the surface dielectric layer of the membrane wiring structure. This can make the connection between the probe and the membrane wiring structure more secure, and the inner embedded portions of the bases of adjacent probes are separated by the surface dielectric layer of the membrane wiring structure, thereby maintaining the pitch between the adjacent probes, and avoiding offset or misalignment of the positions of the probe tips due to manufacturing issues. Additionally, the base of the probe is formed simultaneously with the probe tip in step c), so there are no segmented stacking interfaces between the base and the probe tip, making the connection portion between the probe tip and the base less susceptible to breakage due to forces. Furthermore, the subsequent micro-etching processing after step b) can also round the connection portion between the through hole and the opening, creating a concave rounded shape, or so-called filleted shape, at the connection portion between the base and the probe tip of the completed probe, thereby avoiding stress concentration at the aforesaid connection portion and preventing probe breakage.
Preferably, in the step b), an upper dielectric layer and a lower dielectric layer may be provided on the upper surface and the lower surface of the metal substrate, respectively, and then the through holes are formed in the metal substrate by the laser processing in a way that the through holes penetrate through the upper dielectric layer and the lower dielectric layer. In the step c), the portion of each of the through holes located in the upper dielectric layer is enlarged to form a slot, and the conductive body is also formed in the slot.
Accordingly, each probe formed by the respective conductive body will have a probe tip formed in the through hole and a base formed in the slot, similar to the probes of the membrane probe card provided by the present invention as described above. Such probes containing bases and probe tips can simultaneously achieve fine pitch, high structural strength, and the required probe height for testing. Further, the base width is greater than the probe tip width, effectively dispersing the reactive force from the device under test, thereby reducing the breakage risk of the probe and the trace of the membrane wiring structure. Moreover, in the step b) the upper and lower dielectric layers are respectively provided on the upper and lower surfaces of the metal substrate, which can prevent the metal substrate from bending or warpage during manufacturing process. Furthermore, the subsequent micro-etching processing after step b) can also round the connection portion between the through hole and the slot, creating a concave rounded shape, or so-called filleted shape, at the connection portion between the base and the probe tip of the completed probe, thereby avoiding stress concentration at the aforesaid connection portion and preventing probe breakage. After the probe is formed, the upper dielectric layer may serve as the surface dielectric layer of the membrane wiring structure, and the base of the probe has a portion embedded in the surface dielectric layer of the membrane wiring structure. This can make the connection between the probe and the membrane wiring structure more secure, and the bases of adjacent probes are separated by the surface dielectric layer of the membrane wiring structure, thereby maintaining the pitch between the adjacent probes, and avoiding offset or misalignment of the positions of the probe tips due to manufacturing issues. Additionally, the feature that the base is embedded in the membrane wiring structure may enhance the structural strengths of the base and the membrane wiring structure, thereby preventing the trace from breakage due to excessive stress on the connection portion between the base the and the membrane wiring structure.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the scope of the invention will become apparent to those skilled in the art from this detailed description.
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:
First, it is to be mentioned that same or similar reference numerals used in the following embodiments and the appendix drawings designate same or similar elements or the structural features thereof throughout the specification for the purpose of concise illustration of the present invention. It should be noticed that for the convenience of illustration, the components and the structure shown in the figures are not drawn according to the real scale and amount, and the features mentioned in each embodiment can be applied in the other embodiments if the application is possible in practice. Besides, when it is mentioned that an element is disposed on another element, it means that the former element is directly disposed on the latter element, or the former element is indirectly disposed on the latter element through one or more other elements between aforesaid former and latter elements. When it is mentioned that an element is directly disposed on another element, it means that no other element is disposed between aforesaid former and latter elements.
Referring to
a) As shown in
This step a) selects a metal substrate to serve as a support member for production. The metal substrate has a good structural strength, which can avoid being affected by the environment in subsequent processes, such as temperature, humidity, etc. Preferably, the material of the metal substrate 11 is beryllium-copper alloy, silver-copper alloy, or nickel-iron alloy, which have good structural strength and are easy to be processed by the following laser processing and electroplating steps. However, the metal substrate 11 may be other conductive metals, such as aluminum, stainless steel, etc.
b) As shown in
It should be mentioned here that each through hole 12 is used to manufacture a probe 30 (as shown in
In this embodiment, the through hole 12 gradually tapers from the upper surface 111 to the lower surface 112 for producing a probe tip having a conical shape. However, the shape of the through holes 12 in the present invention is not limited. For example, the through holes 12 can be of equal width from the upper surface 111 to the lower surface 112.
c) As shown in
In this embodiment, in step c), the conductive bodies 13 are formed by electroplating using only a single material (such as palladium-cobalt alloy). However, in the manufacturing method of the present invention, step c) can also be performed by electroplating with multiple materials separately to form the conductive bodies 13 in layers, which will be detailedly illustrated hereinafter.
Preferably, after the aforementioned step b), the through holes 12 can be processed by micro-etching processing before proceeding to step c). Specifically, after laser processing, the walls of the through holes 12 can be cleaned and micro etched to make them smoother. Even further, after the micro-etching processing, metal (such as copper) can be electroplated onto the rough surfaces of the through hole walls to fill in the rough areas, making the walls smoother. The smooth walls of the through holes 12 result in smoother surfaces of the manufactured probes 30, which is advantageous for acquiring testing stability. Additionally, if the through hole 12 has a stepped profile, sharp corners can be rounded by the micro-etching processing, such that the parts of the probe formed at the rounded corners will have a concave and arc shape. This prevents stress concentration on the parts, thereby preventing the probe from breakage.
d) As shown in
The structure of the membrane wiring structure 20 and the manufacturing method thereof in the present invention are similar to those of the conventional membrane circuit boards, and therefore, detailed descriptions will not be necessarily given here. In brief, the membrane wiring structure 20 is a structure containing laminated thin film layers produced by photolithography by using dielectric and metal materials. The metal materials form multiple traces 22 separated by the dielectric materials.
e) Remove the metal substrate 11 so that each conductive body 13 forms a probe 30 protruding from the membrane wiring structure 20, as shown in
The aforementioned manufacturing method is to produce the device as shown in
As shown in
In step b), there are no restrictions on the shape or inclination angle of the holes 12 formed by laser processing. The inner wall inclination angle of the required conical or square-based pyramidal holes 12 can be formed by controlling the angle of the laser. For example, when a larger probe height H is required and a deeper hole 12 needs to be drilled, the laser can be controlled to have a smaller inclination angle relative to the height axis to achieve a high depth-to-width ratio characteristic. Therefore, the probes 30 in the present invention can meet the required probe height H, probe width W1, pitch P, and shape (e.g., truncated cone or square-baes pyramid), allowing the probes 30 of the membrane probe card to achieve the required probe height H and good structural strength while achieving fine pitch requirement. Additionally, in step b), the through holes 12 penetrate through the upper and lower surfaces 111, 112 of the metal substrate 11, and in step c), conductive bodies 13 are formed by electroplating in the through holes 12 of the metal substrate 11. In this way, the electroplating solution can enter and exit the through holes 12 with a high exchange rate, avoiding pinholes formed by bubbles of electroplating solution in the interior or on the surface of the completed probes 30. Thus, the probes 30 have solid and homogeneous characteristics, resulting in good structural strength, and smooth surfaces of the probes 30 without pinholes. Especially, the contact end face 31 of the probe tip (the entire probe 30 is belonged to the probe tip in this embodiment) is flat, which is conducive to testing stability.
The manufacturing methods and membrane devices 10 provided by other embodiments of the present invention, which will be detailedly illustrated hereunder, have the technical features and effects same as those of the manufacturing method and membrane device 10 of the first preferred embodiment described above, and therefore they will not be redundantly described hereinafter.
Referring to
As shown in
Then, as shown in
It should be noted that the probes 30 to be formed in this embodiment are as shown in
The shapes of the base 32 and the probe tip 33 of the probe 30 are defined respectively by the aforementioned recesses 113 and through holes 12. Therefore, the depth of the recesses 113 formed by micro-etching in
As shown in
As shown in
Finally, in step e), after removing the metal substrate 11, the membrane device 10 of the membrane probe card as shown in
By the technical feature of forming the recesses 113 first in step b) and then using laser processing to form the through holes 12 within the recesses 113, the probes 30 formed by the conductive bodies 13 will have probe tips 33 and bases 32 formed respectively by the tip portions 133 and base portions 134. In this embodiment, micro-etching can form recesses 113 of appropriate size, so that the manufactured probes 30 can still meet the requirement of fine pitch. Moreover, since the base 32 and probe tip 33 of each probe 30 are formed simultaneously in step c), there is no segmented stacking interface between the base 32 and the probe tip 33. This prevents the connection portion between the probe tip 33 and the base 32 from easily breakage under stress. In the case where the probe 30 in this embodiment is made of a single material, the base 32 and the probe tip 33 are integrally formed, resulting in good structural strength. The manufacturing methods and membrane devices 10 provided by other embodiments of the present invention and detailedly described hereunder may have the technical features and effects resulted by simultaneously forming the bases 32 and the probe tips 33, and will not be repeatedly illustrated in detail below.
Referring to
As shown in
In this way, the base 32 of the probe 30 is partially embedded in the surface dielectric layer 26 of the membrane wiring structure 20, which allows the connection between the probe 30 and the membrane wiring structure 20 to be more secure. Additionally, the inner embedded portions 327 of adjacent probes 30 are separated by the surface dielectric layer 26, maintaining the pitch P between adjacent probes 30 and avoiding the positions of the probe tips 33 of the probes 30 from offset or misalignment due to manufacturing issues in the manufacturing process. Moreover, the feature of partially embedding the base 32 of the probe 30 in the membrane wiring structure 20 can further enhance the structural strengths of the base 32 and the membrane wiring structure 20, thereby preventing the traces 22 from breakage due to excessive stress exerting on the connection portion between the base 32 and the membrane wiring structure 20.
The structural features and effects of the membrane device 10 of the membrane probe card in this embodiment are further explained below. In other embodiments of the present invention, as long as the probe 30 includes a base 32 and a probe tip 33, these structural features can be applied, enabling the membrane device 10 of each embodiment of the membrane probe card to achieve corresponding effects.
Referring to
As such, the probe 30 of the membrane probe card of the present invention includes a base 32 protruding from the membrane wiring structure 20 and a probe tip 33 protruding from the base 32. Therefore, the probe height is the sum of the first height H1 of the base 32 and the second height H2 of the probe tip 33. In this way, while achieving the fine pitch requirement, the probes 30 can still have a required probe height for testing, without the problem of poor structural strength caused by exceeding thin and height feature of the probe tips 33. Moreover, during testing, the contact end face 31 of the probe tip 33 of the probe 30 contacts the DUT (Device Under Test), and the probe tip 33 receives a reaction force, which is then transmitted to the base 32. The width of the base 32 is larger than the width of the tip 33, effectively dispersing the reaction force, making the probe 30 less prone to breakage due to force during testing.
However, the high structural strength of the probe 30 may also lead to poor elasticity, possibly causing a problem that it is difficult for the probe tip 33 to scratch through the oxide layer on the surface of the conductive contact pad of the DUT, resulting in unstable testing result. In the membrane device 10 of the membrane probe card of the present invention, the probe tip 33 of the probe 30 is closer to the first side edge 321 of the base 32 than to the second side edge 322, meaning the position of the probe tip 33 on the base 32 is biased towards one side of the base 32. This feature enhances the elasticity of the probe 30, thereby avoiding the problem of the probe tip 33 being unable to scratch through the oxide layer on the DUT, thus improving testing stability.
Due to the high structural strength of the probe 30, the reaction force during testing may be too great, causing damage to the trace 22 connected to the base 32 of the probe 30. Therefore, in this embodiment, the extension section 324 of the base 32 of each probe 30 includes a tapered section 325, which gradually narrows from the tip placement section 323 towards the second side edge 322. This feature reduces the reaction force transmitted from the probe tip 33 to the tapered section 325, preventing the trace 22 of the membrane wiring structure 20 from damage during testing.
The second side edge 322 of the base 32 of the probe 30 is further away from the probe tip 33, such that the reaction force during testing may be concentrated on the portion of the trace 22 of the membrane wiring structure 20 located at the second side edge 322, which may cause this portion of the trace 22 to break. In this embodiment, the extension section 324 of the base 32 of each probe 30 has two rounded corners 326 located at the second side edge 322. In this way, the aforementioned tapered section 325 has reduced the reaction force transmitted to the extension section 324, and the rounded corners 326 located at the second side edge 322 further evenly distribute the reaction force transmitted to the second side edge 322, thereby preventing breakage of the trace 22 located at the second side edge 322.
In
More preferably, the second side edge 322 of the base 32 of each probe 30 can define a width W5 in the width axis, where the width W5 of the second side edge 322 is smaller than the width W2 of the first side edge 321 and larger than the width W4 of the trace 22. As previously described, the high structural strength of the probe 30 may result in too much reactive force during testing, damaging the trace 22 connected to the base 32 of the probe 30. Therefore, the feature of making the width W5 of the second side edge 322 of the base 32 smaller than the width W2 of the first side edge 321 can reduce the reactive force. Additionally, the feature that the width W5 of the second side edge 322 is larger than the width W4 of the trace 22 can still disperse stress transmitted to the membrane wiring structure 20, avoiding stress concentration on the trace 22 and effectively preventing the trace 22 from breakage during testing.
More preferably, the width W3 of the fixed end portion 331 of the probe tip 33 is greater than the width W4 of the trace 22. This feature allows the reactive force received by the probe tip 33 to be moderately dispersed before being transmitted to the base 32 and then further dispersed to the membrane wiring structure 20 more effectively through the effect of stress dispersion by the base 32 mentioned earlier, thus effectively avoiding stress concentration on the trace 22 and more effectively preventing the trace 22 from breakage.
As mentioned earlier, the probe tip in the present invention can (but not limited to) be conical, such as the truncated conical probe tip 33 shown in
Referring to
As shown in
As shown in
As shown in
Referring to
Specifically, the manufacturing method of the membrane probe card in this embodiment is similar to that provided in the third preferred embodiment. However, in step c) of electroplating to form the conductive body 13 as shown in
The outer layer 34 and the inner layers 35, 35a, 35b all extend from the probe tip 33 to the base 32. This feature indicates that each of the outer layer 34 and the inner layers 35, 35a, 35b is formed simultaneously with its portions located at the probe tip 33 and the base 32, so that there are no segmented stacking interfaces between the probe tip 33 and the base 32, making the connection portion between the probe tip 33 and the base 32 less prone to breakage due to stress. Furthermore, although the probe 30 has a layered structure internally, the layers are inner and outer layers rather than upper and lower layers. The portions of the probe tip 33 and the base 32 in each layer are integrally formed, so that the connection portion between the probe tip 33 and the base 32 is less prone to breakage due to stress.
As shown in
The structural features of the aforementioned probe 30, including the space 36 and/or the inner layer 35, 35a, 35b, and the outer layer 34, can be applied in various embodiments of the present invention, enabling the probes 30 of each embodiment to have the aforementioned effects.
Referring to
As shown in
As mentioned in the first preferred embodiment, after step b), micro-etching processing can be performed, during which micro-etching can be carried out on the through holes 12 to make the surface of the manufactured probe 30 smooth and conducive to stable testing, and the micro-etching can also process the connection portions of the through holes 12 and the recesses 113 into round corners 114a (as shown in
Additionally, the micro-etching can also round the sharp corners of the stepped recesses 113 into round corners 114b (as shown in
As shown in
From the foregoing, it can be seen that this embodiment also has the technical feature of first forming the recesses 113 by laser processing and then laser processing the through holes 12 in the recesses 113, and the corresponding effects thereof. Moreover, in the laser processing step of this embodiment, a patterned dielectric layer 16 is formed, which, when the membrane device 10 of the membrane probe card is completed, becomes the surface dielectric layer 26 of the membrane wiring structure 20. The base layer 37b of the base 32 of the probe 30 (i.e., the portion of the conductive body 13 formed within the opening 161 of the patterned dielectric layer 16) is embedded in the surface dielectric layer 26 of the membrane wiring structure 20, i.e., the base 32 has an inner embedded portion (i.e., the base layer 37b) embedded in the surface dielectric layer 26, and an outer exposed portion (i.e., the two base layers 37a) exposed outside the surface dielectric layer 26. This ensures a more stable connection between the probe 30 and the membrane wiring structure 20, and the inner embedded portions (i.e., the base layers 37b) of the bases 32 of adjacent probes 30 are separated by the surface dielectric layer 26 of the membrane wiring structure 20, thus maintaining the pitch between adjacent probes 30 and avoiding offset or misalignment of the position of the probe tip 33 due to manufacturing issues. Furthermore, the inner embedded portion (i.e., the base layer 37b) and the outer exposed portion (i.e., the two base layers 37a) of the base 32 of the probe 30 are formed simultaneously in step c), so the base 32 of the probe 30 does not have segmented stacking interfaces, such that the base 32 is less prone to breakage under stress.
In the membrane device 10 of the membrane probe card in this embodiment, the base 32 of each probe 30 includes multiple base layers 37a, 37b, with different cross-sectional areas along the length and width axes. Compared to the case with only a single base layer, multiple base layers can gradually reduce the cross-sectional area in the direction from the membrane wiring structure 20 towards the probe tip 33, thereby further increasing the probe height while maintaining the structural strength of the probe tip 33. This technical feature described above can also be applied in the sixth preferred embodiment described below.
Referring to
As shown in
It is worth mentioning that in this embodiment, only one metal layer 17 is formed. However, it is also possible to laminate more metal layers on the metal layer 17 by using photolithography and electroplating multiple times, so that multiple metal layers collectively form a stepped penetrating groove.
As shown in
As shown in
As shown in
Finally, step e) involves removing the metal substrate 11 and the metal layer 17 to form the membrane device 10 of the membrane probe card as shown in
In this embodiment, by providing the metal layer 17 as shown in
It is worth mentioning that the patterned dielectric layer 16 mentioned above can also be applied in cases where the metal layer 17 and its penetrating grooves 171, as shown in
Referring to
As shown in
As shown in
As shown in
As a result, the probe 30 formed by each conductive body 13 will have a probe tip 33 and a base 32 formed respectively in the through hole 12 and the slot 142, which can achieve the same effects as the probe 30 with the base 32 and the probe tip 33 as described above. Additionally, as described in the first preferred embodiment, after step b), micro-etching processing can be performed. At this time, micro-etching can not only be performed on the through holes 12 to make the surface of the manufactured probes 30 smooth and stable for testing, but also the connection portion between the through hole 12 and the slot 142 can be processed into round corner, so that the connection portion between the probe tip 33 and the base 32 of the manufactured probe 30 is concave and rounded, or so-called fillet shaped, thereby avoiding stress concentration at that portion of the probes 30 and preventing the probes 30 from breaking. Furthermore, upon completion of manufacturing, the upper dielectric layer 14 can serve as the surface dielectric layer 26 of the membrane wiring structure 20, and the base 32 of the probe 30 will be embedded in the surface dielectric layer 26, achieving the same effects as described above of embedding base 32 in the surface dielectric layer 26.
The membrane probe card of the present invention can be used for all probe tip sizes and pitches. Under specified requirements on fine pitch and probe tip height of the probes, using the methods provided in embodiments of the present invention can achieve optimal results. For example, the probe tips may be made having fine pitch less than 50 μm and the probe tip height of more than 50 μm. Under the fine pitch requirement, using laser processing on the metal substrate to form through holes can ensure that the probe tip pitch of the membrane probe card conforms to the specified standard value when the probes are formed on the membrane wiring structure, and at the same time, the probe tip height can also reach the specified standard value. After laser processing the metal substrate to form through holes, the method of the present invention further uses electroplating solution to form probe tips in the through holes by electroplating. In this step, the metal substrate will be immersed in the electroplating solution; however, because the metal substrate does not have water absorption characteristics, the dimension of the metal substrate will not change due to water absorption, thereby not affecting the stability of the size of the metal substrate. Specifically speaking, if laser processing is used on non-metallic substrates, such as substrates of photoresist, organic materials, etc., the substrate will absorb liquid, causing dimensional changes. When electroplating is performed to form probe tips, if the substrate will absorb liquid, the stability of the substrate size will be greatly affected, easily causing offset or misalignment of the position of the through hole of the substrate, and finally, the position where the probe tip is placed on the membrane wiring structure may not meet the accuracy requirement. As such, laser drilling and electroplating processes must be performed by using metal substrates.
In another aspect, the present invention provides a method of making a tested semiconductor chip by using a membrane probe card 100 shown in
At last, it should be mentioned again that the constituent elements disclosed in the above embodiments of the present invention are only taken as examples for illustration, not intended to limit the scope of the present invention. The substitution or variation of other equivalent elements should be included within the scope of the following claims of the present invention.
Number | Date | Country | Kind |
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113105817 | Feb 2024 | TW | national |
Number | Date | Country | |
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63462942 | Apr 2023 | US |