Vertical probe head having a probe guide with integrated circuit components therein - Patents.com

Abstract

A probe head configured to verify the operation of a device under test integrated on a semiconductor wafer comprises at least one guide with a plurality of guide holes configured to accommodate a plurality of contact probes, the guide being advantageously made of a material suitable for manufacturing integrated circuits and having a plurality of circuit components integrated therein, the guide being an electronically active element of the probe head.

Description

[Technical field]

[0001] The present invention relates to a vertical probe head for testing electronic devices integrated on a semiconductor substrate, and the following disclosure makes reference to the technical field of this application for the purposes of simplifying the discussion thereof only. [Background technology]

[0002] As is well known, a probe head is an electronic device configured to electrically connect a number of contact pads of microstructures, such as devices integrated on a semiconductor wafer, with corresponding channels of a test device performing functional testing, particularly electrical testing, or testing in general, of them.

[0003] Tests performed on integrated devices are particularly useful for detecting and isolating defective circuits as early as the manufacturing stage. Typically, probe heads are therefore used for electrical testing of multiple devices integrated on a wafer prior to their cutting and assembly in a containment package.

[0004] Generally, the probe head comprises a number of contact elements or contact probes held by at least one guide and by at least a pair of guides (or supports) that are generally plate-like and parallel to one another, with specific guide holes and spaced apart from one another to create a free zone or air gap for the movement and possible deformation of the contact probes slidably accommodated in the guide holes. The pair of guides comprises an upper guide and a lower guide, both with their guide holes in which the contact probes slide axially, the probes usually being made of a special alloy with good electrical and mechanical properties.

[0005] Proper connection between the contact probes and the contact pads of the device under test is ensured by the pressure of the probe head against the device itself, the contact probes undergoing bending in the air gaps between the guides and sliding in the respective guide holes during pressure contact. This type of probe head is usually called a "vertical probe head".

[0006] In essence, the vertical probe head has an air gap within which bending of the contact probes occurs, said bending being accelerated by a suitable configuration of the probes themselves or of their guides, as shown diagrammatically in FIG. 1.

[0007] In particular, in Figure 1 a vertical probe head is shown diagrammatically and generally indicated by 1. The probe head 1 comprises a number of contact probes 2 housed in at least one upper guide 3, usually indicated as the "upper die", and a lower guide 4, usually indicated as the "lower die", said guides having a plate shape, parallel to each other and separated by an air zone 7. The upper (3) and lower (4) guides comprise their respective guide holes 3A and 4A in which the contact probes 2 slide.

[0008] Each contact probe 2 has an end zone or area terminating in a contact tip 2A intended to abut a respective contact pad 6A of a plurality of contact pads of a device under test integrated on a semiconductor wafer 6, thus making mechanical and electrical contact between such device under test and a testing apparatus (not shown) of which such probe head 1 is a terminal element.

[0009] 1, all contact probes 2 further have a further end zone or area terminating in a so-called contact head 2B pointing towards a respective contact pad 5A of the plurality of contact pads of the space transformer 5. A proper electrical connection between the plurality of contact probes 2 and the space transformer 5 is ensured by the pressing abutment of the plurality of contact heads 2B of the plurality of contact probes 2 onto the plurality of contact pads 5A of the space transformer 5, as well as the contact between the plurality of contact tips 2A of the plurality of contact probes 2 and the plurality of contact pads 6A of the device under test.

[0010] Typically, the routing paths within the space transformer and the circuit layout of the PCB that interfaces the probe head with the test equipment are quite complex, and therefore it is desirable to reduce such complexity.

[0011] Furthermore, to increase the performance of the probe head, it is desirable for the probe head itself to be able to perform multiple operations on the signals carried by its multiple contact probes, preferably in close proximity to the device under test. Summary of the Invention [Problem to be solved by the invention]

[0012] The technical problem of the present invention is to overcome the limitations and drawbacks that still affect multiple probe heads according to the prior art, and in particular to provide a probe head having structural and functional features that make it possible to carry out processing, even complex processing, on the signals carried by the multiple contact probes. [Means for solving the problem]

[0013] The solution idea underlying the present invention is to utilize the technology of integrated circuits on semiconductor substrates in the manufacture of a guide for a probe head, said guide acting on the one hand as a housing element for a number of contact probes and on the other hand comprising an active circuit for processing the signals carried by said number of contact probes and thus acting as an electronically active element of the probe head comprising it, i.e. the guide for the probe head, preferably the lower guide, is on the one hand an integrated circuit and on the other hand a circuit board with a number of guide holes for accommodating a number of contact probes.

[0014] Based on the idea of ​​such a solution, the above technical problem is solved by a probe head configured to verify the operation of a device under test, which probe head comprises at least one guide with a plurality of guide holes configured to accommodate a plurality of contact probes, which guide is made of a material suitable for manufacturing integrated circuits and which guide comprises circuit components integrated therein, which guide is an electrically active element of the probe head.

[0015] In particular, the invention comprises the following further and optional features taken individually or, where appropriate, in combination:

[0016] According to one aspect of the invention, the material forming the guide may be selected from silicon and glass-like materials, preferably silicon.

[0017] According to one aspect of the invention, at least one guide hole of the guide may comprise a metallization. In particular, such metallization may cover at least a portion of an inner surface of the guide hole. Even further, in particular, the guide may comprise a pad electrically connected to the metallization.

[0018] According to another aspect of the invention, the guide may include at least one conductive track extending from at least one of the plurality of guide holes and / or connecting the plurality of circuit components of the guide.

[0019] According to another aspect of the invention, at least such guide includes a plurality of holes of at least one group of a plurality of guide holes and has at least one conductive portion electrically connected to each other and configured to contact a corresponding group of the plurality of contact probes, such that the plurality of contact probes of such corresponding group shorted to each other by the conductive portion may be configured to carry the same type of signal.

[0020] In particular, the guide may comprise at least one common pad connected to at least one conductive portion.

[0021] According to one aspect of the invention, at least one conductive portion is disposed on at least one surface of the guide, and a number of guide holes that should not be short-circuited can be electrically insulated from the at least one conductive portion by non-conductive zones within the guide.

[0022] Additionally, the at least one conductive portion may have the form of multiple conductive layers, and successive conductive layers may be separated by non-conductive layers.

[0023] According to another aspect of the invention, the guide is a lower guide of the probe head, which further comprises at least one upper guide parallel to the lower guide and separated therefrom by an air zone or gap, which lower guide may be adjacent to the device under test.

[0024] According to another aspect of the invention, the plurality of circuit components integrated within the guide may include at least one active component.

[0025] More particularly, the guide may include active circuitry configured to perform complex processing on signals carried by the multiple contact probes.

[0026] In accordance with another aspect of the invention, the integrated circuit components may be included in circuits formed by integrated circuit technology on a semiconductor substrate.

[0027] The present invention relates to providing at least one guide with a plurality of guide holes configured to accommodate a plurality of contact probes; and Integrating a plurality of circuit components within the guides so as to make such guides an electronically active element of the probe head. Equipped with The invention also relates to a method of manufacturing a probe head configured to verify operation of a device under test, in which the guide is made of a material suitable for housing a plurality of integrated circuits.

[0028] According to one aspect of the invention, the method may further comprise the step of forming the at least one conductive portion and / or the at least one conductive track by integrated circuit techniques. Effect of the Invention

[0029] The features and advantages of the probe head and of the method according to the invention will become apparent from the following description of embodiments thereof, given by way of non-limiting example, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0030] [Figure 1] 1 shows a schematic diagram of a probe head according to the prior art; [Diagram 2] 2 illustrates diagrammatically a probe head according to an embodiment of the present invention; [Diagram 3] 2 shows a schematic top view of a guide of a probe head according to the invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] With reference to these figures, and in particular to the example of FIG. 2, there is shown generally and generally designated 20 a probe head for testing electronic devices integrated on a semiconductor wafer, in accordance with the present invention.

[0032] It should be noted that the figures represent schematic views and are not drawn to scale, but instead are drawn to highlight important features of the invention. Moreover, in the figures, different elements are shown diagrammatically, and their shapes vary depending on the desired field of application. It should also be noted that in the figures, the same reference numbers represent elements that are identical in shape or function. Finally, certain features described with respect to an embodiment shown in a figure may also be applied to other embodiments shown in other figures.

[0033] The probe head 20 comprises at least one guide 40, a lower guide in the example of FIG. 2, said guide 40 comprising a number of guide holes 40h adapted to receive a corresponding number of contact probes.

[0034] Within the probe head 20 are contact probes configured to carry input / output operational signals to / from the device under test, as well as contact probes configured to carry power signals (herein referred to as "power probes") and ground (herein referred to as "ground probes") as known in the art, all of which are indicated herein by the reference numeral 21. Although Figure 2 shows only four contact probes 21, it will be apparent that the probe head 20 may comprise any number of contact probes, and the figure is provided merely as an illustrative, non-limiting example of the invention.

[0035] In particular, the contact probe 21 comprises a body 21p extending along a longitudinal axis HH between a first end 21a and a second end 21b. The first end 21a is configured to contact a contact pad 22 of a device under test integrated on a semiconductor wafer 23, while the second end 21b is generally configured to contact a contact pad 24 of a space transformer 25 associated with the probe head 20.

[0036] In the embodiment shown in Figure 2, the probe head 20 comprises, in addition to the guide 40 (which is a lower guide), an upper guide 50, which are spaced apart by an air zone or gap G. Obviously, the number of guides may vary depending on the needs and / or circumstances, and the above figures are given only as a non-limiting example.

[0037] Advantageously, according to the invention, at least one of the guides of the probe head 20 (lower guide 40 in the example of FIG. 2) is made of a material suitable for manufacturing integrated circuits such as semiconductor substrates, preferably silicon, for example silicon, germanium or even glassy and organic materials.

[0038] In this manner, by utilizing semiconductor integrated circuit technology to manufacture the guide 40, as will be described in more detail below, a number of integrated circuit components 60, including the active ones, are housed within the guide 40. The guide 40 is thus both the electrically active element of the probe head 20 and the mechanical support for its contact probes 21.

[0039] That is, the guide 40 is a circuit board having at least one integrated circuit, which further comprises a plurality of guide holes 40h for accommodating a plurality of contact probes 21, such that the guide 40 is capable of, and is configured to, perform processing on signals carried by such a plurality of contact probes 21 by a plurality of circuit components 60 integrated therein.

[0040] Advantageously, the guide 40 accommodates a number of active circuit components 60a, such as, for example, a number of transistors. The use of a semiconductor substrate as the starting material allows the active circuit components 60a to be easily integrated in the guide 40, for example by suitable doping techniques for creating active zones for such active components 60a (for example, a number of transistor gates). In this way, the guide 40 can accommodate active circuits, even complex ones.

[0041] That is, the circuit components 60 integrated in the guide 40 are included in a circuit, which may be quite complex, formed by the technology of circuits integrated on semiconductor substrates, and which is capable of performing processing (also complex) on signals carried by the multiple contact probes 21.

[0042] By way of example, the circuitry of the guide 40 may include signal processing circuits, logic gates, multiplexers, filtering elements, amplifiers, and the like. In particular, such circuitry may perform signal pre-processing and thus facilitate the operation of test equipment connected to the probe head 20.

[0043] The guide 40 may also comprise a number of passive circuit components 60b. By way of example, it is often desirable to perform filtering on the signals carried by the contact probes 21 to improve the frequency characteristics of the probe head 20, and thus the guide 40 may comprise suitable filtering capacitors. Similarly, in addition to or as an alternative to filtering capacitors, the guide 40 may further comprise resistors, inductors, relays, or combinations thereof, which circuit elements may act to improve the overall characteristics of the probe head 20.

[0044] Obviously, the guide 40 is not limited to the circuit components listed above, but may comprise any suitable components.

[0045] It should be noted that although the invention is disclosed here with respect to its preferred embodiment in which the guide with integrated active circuits is the lower guide 40, the same inventive concept can be applied to the upper guide 50 of the probe head 20 or to any other guide. However, it should be noted that the circuit integration in the lower guide 40 is preferred, since the integrated circuit components 60 are thus closer to the device under test and thus contribute to improving the characteristics of the probe head 20, especially in the case of filtering the signals carried by the contact probes 21.

[0046] Referring again to Fig. 2, at least one guide hole 40h of the guide 40 comprises a metallization covering at least a portion 40w of its inner surface. More preferably, the inner surface of the guide hole is entirely covered by the metallization, said portion 40w thus corresponding to the entire inner surface of the hole. In this way, for example, the presence of at least one metallized guide hole allows the signal carried by the contact probe 21 accommodated in such particular guide hole to be extracted already in the guide 40. Furthermore, the metallization of the at least one guide hole allows the contact probe 21 to be electrically connected with a plurality of circuits integrated in the guide 40.

[0047] During the formation of the integrated circuit in the guide 40, at least one conductive portion 26 including a group 40' of guide holes 40h may also be formed, i.e., the conductive portion 26 covers an area of ​​the guide 40 including the group 40' of guide holes 40h formed in such area. In particular, the guide holes of the group 40' are electrically connected to each other by the conductive portion 26 and accommodate a corresponding group of contact probes 21 contacted by such conductive portion 26. The contact probes of such corresponding group are configured to carry the same type of signal, e.g., they may be ground probes, power probes, or probes configured to carry input / output operational signals to / from the device under test.

[0048] The conductive portion 26 thus forms a common conductive plane for the contact probes 21 housed in the guide holes of the group 40', which are electrically connected to each other by means of said common conductive plane with which they are all in contact. That is to say, in the probe head 20, the contact probes 21 housed in the group 40' of guide holes 40h are short-circuited to each other, and in the case of ground or power probes, this leads to a resulting elimination of interference to the operating signals carried by the other probes and to an overall improvement of the frequency characteristics of the probe head 20.

[0049] 2, the conductive portion 26 is disposed on at least one surface of the guide 40, in particular on a surface Fa, which is the upper surface of the guide 40 according to the local reference system of the figure. Obviously, the conductive portion 26 may be formed on a surface Fb, which is the surface opposite to the surface Fa and which is the lower surface of the guide 40 according to the local reference system of the figure, as well as on both surfaces Fa and Fb.

[0050] Alternatively, in one embodiment not shown in the figures, conductive portion 26 has the form of multiple conductive layers, some of which may be embedded within guide 40, with successive conductive layers separated by non-conductive layers.

[0051] In any case, the guide holes that should not be shorted are electrically isolated from the conductive portion 26 by a non-conductive zone in the guide 40. If the contact probes that should not be shorted are too close to the probes that should be shorted (e.g., they are offset from one another), the conductive portion 26 will be locally interrupted by the non-conductive zone so as not to electrically connect the contact probes that should not be shorted.

[0052] FIG. 3 shows a schematic top view of the guide 40, in particular its face Fa, and shows generally that the circuit formed on the guide 40 extends from a number of guide holes 40h (possibly with metallization as shown above) and / or connects different circuit components 60 to each other, and a number of conductive tracks 27, which are embedded on and within the guide face 40.

[0053] Referring now specifically to FIG. 3, in one embodiment of the present invention, the guide 40 comprises at least one common pad 28 connected to the conductive portions 26, for example by a suitable conductive track of the plurality of conductive tracks 27.

[0054] Furthermore, as already mentioned above and now shown in more detail in FIG. 3, the guide 40 also comprises a metallization which metallizes the single guide hole, such metallization being designated here by the reference numeral 29.

[0055] In one embodiment of the present invention, the guide 40 further comprises a pad 30 electrically connected to a single metallized guide hole, such pad 30 being usable, for example, for monitoring a signal carried by a single contact probe.

[0056] Thus, the guide 40 comprises at least one conductive portion 26 including a plurality of guide holes 40h and / or at least one metallization 29 including a single guide hole 40h configured to accommodate a single contact probe 21. As already mentioned, both the conductive portion 26 and the metallization 29 preferably cover portions 40w of the inner surfaces of the plurality of guide holes 40h.

[0057] The possibility of metallizing a single guide hole is also particularly advantageous when there is a need to short-circuit two or more contact pads of a device under test: in this case, a number of guide holes accommodating a number of signal contact probes 21 are metallized and electrically connected to one another by conductive tracks 27 (or possibly also by conductive portions 26), so that the paths of the signals which do not pass through all the contact elements to and from the test device but stop in the guide 40 are significantly shortened forming a loop-back configuration, which has as a result advantages in terms of the frequency characteristics of the probe head 20.

[0058] As mentioned above, the invention provides for the use of semiconducting materials (suitable for circuit integration) that allow for the integration, by known methods, of circuits configured to process the signals carried by the contact probes in the manufacture of the guide 40. By way of example, as shown in Figure 3, a contact probe may contact the source terminal of an n-Mos transistor integrated in the guide 40, and another contact probe may contact its drain terminal.

[0059] The present invention also relates to a method of manufacturing a probe head 20, which includes a preliminary step of providing at least one guide 40 (preferably, but not limited to, a lower guide) with a plurality of guide holes 40h configured to accommodate a plurality of contact probes 21.

[0060] Preferably, the method of the present invention includes integrating a plurality of circuit components 60 within the guide 40 to become electronically active elements of the probe head 20 .

[0061] In particular, the guide 40 is made of a material suitable for housing an integrated circuit, for example a semiconductor substrate, preferably silicon, such as, for example, silicon, germanium or also glassy materials, organic materials and other suitable materials.

[0062] The use of integrated circuit techniques for forming the guide 40 furthermore allows the conductive tracks 27 and the conductive portions 26 to be formed simultaneously. In this way it is already possible to form the metallization during the production of the guide 40.

[0063] In summary, the invention provides a probe head in which the technology of integrated circuits on semiconductor substrates is used for manufacturing at least one of its guides, so that said guide acts on the one hand as a housing element for the contact probes and on the other hand comprises active circuits for processing the signals carried by such contact probes.

[0064] Advantageously, according to the invention, the accommodation of even complex active circuits in the guide of the probe head is greatly simplified, since well-known and efficient techniques are used for integrating such circuits, in particular the guide is made of a semiconducting material suitable for integrating active circuit components and for forming integrated circuits.

[0065] In this way it is possible to easily and efficiently manufacture a guide for a probe head which, on the one hand, acts as a support and housing element for the contact probe, and, on the other hand, acts as an electronically active element within such a probe head and also performs complex processing on the signals carried by the contact probe.

[0066] Obviously, those skilled in the art may make numerous modifications and variations to the above-described probe head and method to meet non-specific and specific requirements, all of which fall within the scope of protection of the present invention as defined by the following claims.

Claims

1. A probe head (20) configured to verify operation of a device under test, the probe head (20) comprising at least one guide (40, 50) with a plurality of guide holes (40h, 50h) configured to receive a plurality of contact probes (21); The probe head (20) includes a guide (40, 50) made of silicon and including a plurality of circuit components (60, 60a, 60b) integrated therein; the guide (40, 50) comprises at least one active circuit configured to perform processing on signals carried by the plurality of contact probes, the active circuit being obtained by integrated circuit technology on a semiconductor substrate, the active circuit including a transistor; a contact probe contacts the source terminal of the transistor and another contact probe contacts the drain terminal of the transistor, or the semiconductor substrate of the guide (40, 50) is doped to create an active zone of the transistor. A probe head (20).

2. The probe head (20) of claim 1, wherein at least one guide hole (40h) of the guide (40) is provided with a metallization (29).

3. The probe head (20) of claim 2, wherein the metallization (29) covers at least a portion (40w) of an inner surface of the guide hole (40h).

4. The probe head (20) of claim 2, wherein the guide (40, 50) comprises a pad (30) electrically connected to the metallization (29).

5. The probe head (20) of claim 1, wherein the guide (40, 50) comprises at least one conductive track (27) extending from at least one of the plurality of guide holes (40h, 50h).

6. The probe head (20) of claim 1, wherein the guide (40, 50) comprises at least one conductive track (27) connecting the plurality of circuit components (60, 60a, 60b) of the guide (40).

7. 2. The probe head (20) of claim 1, wherein the guide (40, 50) includes a plurality of holes of at least one group (40') of the plurality of guide holes (40h, 50h) and is provided with at least one conductive portion (26) configured to electrically connect with each other and to contact a corresponding group of the plurality of contact probes (21), the plurality of contact probes of the corresponding group being configured to carry the same type of signal.

8. The probe head (20) of claim 7, wherein the guide (40, 50) comprises at least one common pad (28) connected to the at least one conductive portion (26).

9. 8. The probe head (20) of claim 7, wherein the at least one conductive portion (26) is disposed on at least one face (Fa, Fb, Fc, Fd) of the guide (40, 50), and a number of guide holes that should not be short-circuited are electrically insulated from the at least one conductive portion (26) by non-conductive zones in the guide (40, 50).

10. 9. The probe head (20) of claim 8, wherein the at least one conductive portion (26) is in the form of a plurality of conductive layers, successive conductive layers being separated by non-conductive layers.

11. 2. The probe head (20) of claim 1, wherein the guide (40) is a lower guide of the probe head (20), the probe head also including at least one upper guide (50) parallel to the lower guide (40) and separated from the lower guide by an air zone (G), the lower guide (40) being closer to the device under test under test.

12. 1. A method of manufacturing a probe head (20) configured to verify operation of a device under test, comprising the steps of: providing at least one guide (40, 50) with a plurality of guide holes (40h, 50h) configured to receive a plurality of contact probes (21); and integrating a plurality of circuit components (60) into said guide (40, 50); Equipped with the guide (40) is made of silicon, and the step of integrating the plurality of circuit components (60) in the guide (40, 50) comprises integrating at least one active circuit configured to perform processing on signals carried by the plurality of contact probes, the active circuit being obtained by integrated circuit technology on a semiconductor substrate, the active circuit comprising a transistor, a contact probe contacts a source terminal of the transistor and another contact probe contacts a drain terminal of the transistor, or the method includes doping the semiconductor substrate of the guide (40, 50) to create an active zone of the transistor. method.

13. The method of claim 12, further comprising forming at least one conductive portion (26) on said guide (40) by integrated circuit techniques.

14. 13. The method of claim 12, further comprising forming at least one conductive portion (26) on at least one surface of said guide (40) by integrated circuit techniques.

15. 13. The method of claim 12, further comprising the step of forming at least one conductive track (27) on said guide (40) by integrated circuit techniques.

16. 13. The method according to claim 12, further comprising the step of forming on said guide (40) at least one conductive portion (26) and at least one conductive track (27), both by integrated circuit techniques.

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