Method for preparing elastic probe card, elastic probe card

Abstract

The present invention provides a method for preparing an elastic probe card and an elastic probe card. The present invention etches a substrate through a first etching pattern to obtain a probe card consisting of a base and a probe connected to the base, wherein the elastic portion of the probe is formed by connecting a plurality of reverse protrusions arranged alternately end to end, so that the probe has a good elastic deformation effect, and etches a metal layer through a second etching pattern to obtain a surface metallized probe, so that electrical isolation is achieved between the probes, and the strength of the probes is increased, so that the probes are more stable during elastic deformation. The present invention can produce an elastic probe card with a smaller spacing by using only two masks, so that the manufacturing cost is lower, the manufacturing process is simpler, and the probes can be disassembled and replaced in a targeted manner, which greatly improves the service life and flexibility of the probes, and is more conducive to batch manufacturing and cost control.

Description

Technical Field

[0001] The present invention relates to the technical field of probe preparation, and in particular to a method for preparing an elastic probe card and an elastic probe card. Background Art

[0002] The probe is used to contact and communicate with the chip when conducting electrical testing on the chip on the wafer, and feed back the test data to the test device for comparison to detect whether the electrical characteristics and logical functions of the wafer meet the requirements. Unqualified wafers are removed through testing to avoid packaging unqualified chips, resulting in avoidable defective products and waste of resources. In order to effectively control the test cost, the service life of the probe becomes an important breakthrough. When testing the chip, the probe needs to frequently contact the contact points on the chip, and in order to ensure the test effect, it is necessary to take into account that all the probes can effectively contact the contact points on the chip at the same time, and the probe is required to have good resistance to mechanical fatigue so that the probe can meet the use requirements of a longer life. In the prior art, the probe is often used as a whole and does not have the function of detachable replacement, resulting in the probe being damaged or reaching the end of its service life. It can only be replaced as a whole, and the cost cannot be reasonably and effectively controlled. Summary of the invention

[0003] In view of this, it is necessary to provide a removable and replaceable elastic probe card to increase the service life of the probe and to reasonably and effectively control the manufacturing cost of the probe.

[0004] The present invention provides a method for preparing an elastic probe card, wherein the probe card comprises a plurality of probe metal layers, and the preparation method comprises the following steps:

[0005] forming a first photoresist on a surface of the substrate;

[0006] exposing and developing the first photoresist to obtain a first etching pattern, wherein the first etching pattern corresponds to the probe card structure;

[0007] The substrate is etched according to the first etching pattern to obtain the probe card, wherein the probe card comprises a base and the probes connected to the base and arranged at a certain distance, the probes comprise an elastic part and a needle tip, the tail of the needle tip is connected to one end of the elastic part, and the elastic part is formed by connecting a plurality of reverse protrusions arranged alternately end to end;

[0008] removing the remaining first photoresist;

[0009] forming a metal layer on the surface of the probe card;

[0010] forming a second photoresist on the surface of the metal layer;

[0011] exposing and developing the second photoresist to obtain a second etching pattern, wherein the second etching pattern corresponds to the probe metal layer structure;

[0012] Etching the metal layer according to the second etching pattern to obtain the probe metal layer covering at least one side of the probe and a metal block connected to the metal layer, wherein the metal block is located on the base, and the metal blocks corresponding to adjacent probes are arranged at a certain distance to form a space for electrical insulation between adjacent probes;

[0013] The remaining second photoresist is removed to obtain the probe card with surface metallization.

[0014] Furthermore, the substrate is an SOI wafer, the surface is a surface corresponding to the top silicon layer of the SOI wafer, and after removing the remaining second photoresist to obtain the probe card with surface metallization, the preparation method further includes:

[0015] The buried oxide layer of the SOI wafer is removed to obtain the probe card with surface metallization.

[0016] Furthermore, the step etches the substrate according to the first etching pattern to obtain the probe card, wherein the probe card includes a base and the probe connected to the base and arranged at a certain distance, the probe includes an elastic part and a needle tip, the tail of the needle tip is connected to one end of the elastic part, the elastic part is formed by a plurality of reverse protrusions arranged alternately and connected end to end, and a deep reactive ion etching process is used to remove unnecessary top silicon layer.

[0017] Furthermore, the etching depth of the deep reactive ion etching process is not less than the thickness of the top silicon layer, so that the top silicon layer is etched in an area according to the first etching pattern through the buried oxide layer.

[0018] Furthermore, before forming the first photoresist on a surface of the substrate, the preparation method further includes:

[0019] The substrate is cleaned according to the RCA standard process.

[0020] Furthermore, the step etches the metal layer according to the second etching pattern to obtain the probe metal layer covering at least one side of the probe and a metal block connected to the metal layer, wherein the metal block is located on the base, and the metal blocks corresponding to adjacent probes are arranged at a certain distance to form a space for electrical insulation between adjacent probes, and a plasma etching process is used to remove unnecessary metal layers.

[0021] The present invention also provides an elastic probe card, which is made by any of the elastic probe card preparation methods described above, and the probe card includes a base and a probe, one end of the probe is connected to one side of the base, the probe includes an elastic part and a needle tip, the tail of the needle tip is connected to the end of the elastic part away from the base, wherein the elastic part is formed by connecting a plurality of reverse protrusions arranged alternately end to end.

[0022] Furthermore, the elastic part includes a first arm and a second arm, and the first arm and the second arm are respectively formed by a plurality of reverse protrusions arranged alternately and connected end to end, wherein the protrusions are V-shaped.

[0023] Furthermore, a plurality of the probes are connected to the base at a certain distance, at least one side of the probe is covered with a probe metal layer, the probe metal layer of one probe extends toward the base to form a metal block, and the metal blocks corresponding to adjacent probes are arranged at a certain distance to form a space for electrical insulation between adjacent probes.

[0024] Furthermore, the probe metal layer is one of gold, silver, nickel, chromium, rhodium, palladium, or an alloy formed by at least two of them.

[0025] Compared with the prior art, the present invention has the following beneficial effects: the present invention exposes and develops the first photoresist to obtain a first etching pattern for subsequently etching the substrate to form a probe, and etches the substrate according to the first etching pattern to obtain a probe card consisting of a base and the probe connected to the base, wherein the elastic portion of the probe is formed by connecting a plurality of reverse protrusions arranged alternately end to end, so that the probe has a better elastic deformation effect, avoiding the probe from being in too rigid contact with the contact point on the chip during testing, resulting in probe bending damage and / or severe needle marks on the contact point, affecting the service life of the probe and damaging the chip, and etching the metal layer through the second etching pattern to obtain the surface metallized probe, so that the probes are electrically isolated from each other, and the strength of the probe is increased, so that the probe is more stable during elastic deformation. The present invention can produce an elastic probe card with a smaller spacing by using only two masks, so that the manufacturing cost is lower, the manufacturing process is simpler, and the probe can be disassembled and replaced in a targeted manner, which greatly improves the service life and flexibility of the probe, and is more conducive to batch manufacturing and cost control. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a flowchart of a specific implementation method of the elastic probe card preparation method.

[0027] Figure 2Another flowchart of a specific implementation method of the elastic probe card preparation method of the present invention.

[0028] Figure 3 and Figure 4 It is a structural schematic diagram of the elastic probe card manufacturing process of the present invention, wherein A1 is a top view, A2 is a side view corresponding to A1, B1 is a top view, B2 is a side view corresponding to B1, and so on.

[0029] Figure 5 It is a schematic structural diagram of an embodiment of the elastic probe card of the present invention.

[0030] Figure 6 FIG. 4 is a schematic structural diagram of another embodiment of the elastic probe card of the present invention. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention. It is understood that the drawings are only provided for reference and illustration, and are not used to limit the present invention. The connection relationship shown in the drawings is only for the convenience of clear description and does not limit the connection method.

[0032] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to another component, or there may be an intermediate component at the same time. Unless otherwise defined, all technical and scientific terms used in this document have the same meaning as those generally understood by technicians in the technical field of the present invention. It should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0033] It should also be noted that in the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0034] See also Figure 1-4 The present invention provides a method for preparing an elastic probe card, wherein the probe card 100 includes a plurality of probe metal layers 50, and the preparation method includes the following steps:

[0035] Forming a first photoresist 20 on a surface of a substrate 10 (S10);

[0036] exposing and developing the first photoresist 20 to obtain a first etching pattern, wherein the first etching pattern corresponds to the probe card structure (S20);

[0037] The substrate 10 is etched according to the first etching pattern to obtain the probe card 100, wherein the probe card 100 includes a base 101 and the probes 102 connected to the base 101 and arranged at a certain distance, the probes 102 include an elastic part 1021 and a needle tip 1022, the tail of the needle tip 1022 is connected to one end of the elastic part 1021, and the elastic part 1021 is formed by connecting a plurality of reverse protrusions arranged alternately end to end (S30);

[0038] removing the remaining first photoresist 20 (S40);

[0039] forming a metal layer 30 on the surface of the probe card 100 (S50);

[0040] forming a second photoresist 40 on the surface of the metal layer 30 (S60);

[0041] exposing and developing the second photoresist 40 to obtain a second etching pattern, wherein the second etching pattern corresponds to the structure of the probe metal layer 50 (S70);

[0042] Etching the metal layer 30 according to the second etching pattern to obtain the probe metal layer 50 covering at least one side of the probe 102 and a metal block 51 connected to the probe metal layer 50, wherein the metal block 51 is located on the base 101, and the metal blocks 51 corresponding to adjacent probes 102 are arranged at a certain distance to form a space for electrical insulation between adjacent probes 102 (S80);

[0043] The remaining second photoresist 40 is removed to obtain the probe card 100 with surface metallization ( S90 ).

[0044] The substrate 10 is an SOI wafer, the surface is a surface corresponding to the top silicon layer 11 of the SOI wafer, and after removing the remaining second photoresist 40 to obtain the probe card 100 with surface metallization (S90), the preparation method further includes:

[0045] The buried oxide layer 12 of the SOI wafer is removed to obtain the probe card 100 with surface metallization ( S100 ).

[0046] The buried oxide layer 12 is removed by using a buffered oxide etching solution, namely, a BOE solution, wherein the BOE solution is a 49% HF aqueous solution: a 40% NH4F aqueous solution, and the etching time is 60 minutes.

[0047] After the buried oxide layer 12 is removed by etching to obtain the probe card 100 , the probe card 100 may be cleaned by ultrasonic cleaning.

[0048] In one embodiment, the thickness of the top silicon layer 11 of the SOI wafer is 10 μm, the thickness of the buried oxide layer 12 is 2 μm, and the thickness of the substrate 13 of the SOI wafer is 500 μm.

[0049] The first photoresist 20 is a positive photoresist or a negative photoresist. The coating speed of the first photoresist 20 is 1500 rpm, the coating acceleration is 1000 rpm / s, and the coating time is 20 s.

[0050] After coating the first photoresist 20 and confirming the coating effect, the first photoresist 20 needs to be baked at a temperature of 120° C. for 160 seconds to accelerate the curing of the first photoresist 20 .

[0051] The SOI wafer after curing the first photoresist 20 is placed in a photolithography machine, and the first photoresist 20 is exposed for 5 seconds according to a first etching pattern, wherein the first etching pattern is a mask pattern corresponding to the probe card 100 .

[0052] The exposed SOI wafer is placed in a developer for development to remove unnecessary first photoresist 20 to obtain the probe card 100. The time for developing the exposed first photoresist 20 is 30 seconds.

[0053] After development, the SOI wafer is repeatedly cleaned with ultrapure water and it is confirmed whether the remaining first photoresist 20 is consistent with the first etching pattern. When the first photoresist 20 is consistent with the first etching pattern, the SOI wafer is baked at a temperature of 180 degrees Celsius for 120 seconds to solidify the remaining first photoresist 20 to facilitate subsequent processes.

[0054] The step etches the substrate 10 according to the first etching pattern to obtain the probe card 100, wherein the probe card 100 includes a base 101 and the probe 102 connected to the base 101 and arranged at a certain distance, the probe 102 includes an elastic part 1021 and a needle tip 1022, the tail of the needle tip 1022 is connected to one end of the elastic part 1021, and the elastic part 1021 is formed by connecting a plurality of reverse protrusions arranged alternately end to end (S30). A deep reactive ion etching process is used to remove unnecessary top silicon layer 11.

[0055] Furthermore, the etching depth of the deep reactive ion etching process is not less than the thickness of the top silicon layer 11, so that the etched area of ​​the top silicon layer 11 according to the first etching pattern penetrates through the buried oxide layer 12, so as to facilitate the subsequent etching of the buried oxide layer 12, separate the substrate 13 from the probe card 100, and obtain the probe card 100 with surface metallization.

[0056] In one embodiment, the thickness of the top silicon layer 11 is 10 μm, and the depth of the deep reactive ion etching is 10.08-10.2 μm, so that the top silicon layer 11 is etched through according to the first etching pattern to form the probe card 100 .

[0057] By setting the probe 102 into an elastic structure, the probe 102 has an elastic buffering effect during use, thereby improving the fatigue resistance of the probe 102 and being able to better contact the contact points on the chip, thereby avoiding bending of the probe 102 and affecting the chip test effect and the service life of the probe 102.

[0058] The second photoresist 40 is a negative photoresist or a positive photoresist. The coating speed of the second photoresist 40 is 3000 rpm, the coating acceleration is 2000 rpm / s, and the coating time is 20s.

[0059] After coating the second photoresist 40 and confirming the coating effect, the second photoresist 40 needs to be baked at a temperature of 180° C. for 120 seconds to accelerate the curing of the second photoresist 40 for subsequent processes.

[0060] The SOI wafer after curing the second photoresist 40 is put into the photolithography machine again, and the second photoresist 40 is exposed for 5 seconds according to the second etching pattern. The second etching pattern is a pattern corresponding to the probe metal layer 50.

[0061] The exposed SOI wafer is placed in a developer for development to remove unnecessary second photoresist 40 to obtain a mask pattern corresponding to the probe metal layer 50. The time for developing the exposed second photoresist 40 is 30 seconds.

[0062] After development, the SOI wafer is repeatedly cleaned with ultrapure water and it is confirmed whether the remaining second photoresist 40 is consistent with the second etching pattern. When the second photoresist 40 is consistent with the second etching pattern, the SOI wafer is baked at a temperature of 180°C for 120 seconds to solidify the remaining second photoresist 40.

[0063] Then, the metal layer 30 is etched according to the second etching pattern to obtain the probe metal layer 50 and the metal block 51 at least covering one side of the probe.

[0064] The step etches the metal layer 30 according to the second etching pattern to obtain the probe metal layer 50 covering at least one side of the probe and a metal block 51 connected to the probe metal layer 50, wherein the metal block 51 is located on the base 101, and the metal blocks 51 corresponding to adjacent probes 102 are arranged at a certain distance to form a space for electrical insulation between adjacent probes 102, and a plasma etching process is used to remove unnecessary metal layer 30.

[0065] By providing the space for electrical insulation on the base 101 , it can be ensured that when the probes 102 are tested, there will be no electrical conduction between adjacent probes 102 .

[0066] Before forming the first photoresist 20 on a surface of the substrate 10, the preparation method further includes:

[0067] The substrate 10 is cleaned according to the RCA standard process (S11), so as to clean the substrate 10 and prevent dirt from affecting the subsequent process implementation.

[0068] See also Figure 5-6 The present invention also provides an elastic probe card 100, the probe card 100 includes a base 101 and a probe 102, one end of the probe 102 is connected to one side of the base 101, the probe 102 includes an elastic part 1021 and a needle tip 1022, the tail of the needle tip 1022 is connected to the end of the elastic part 1021 away from the base 101, wherein the elastic part 1021 is formed by connecting a plurality of reverse protrusions arranged alternately end to end.

[0069] In one embodiment, the elastic portion 1021 is formed by connecting a plurality of S-shaped structures end to end, so that the probe 102 can be elastically deformed during testing, so that all the probes 102 can effectively contact the corresponding contact points on the chip, thereby improving the efficiency of the test.

[0070] In another embodiment, the elastic part 1021 includes a first arm 1023 and a second arm 1024, wherein the first arm 1023 and the second arm 1024 are respectively formed by connecting a plurality of reverse protrusions 1025 arranged alternately end to end, wherein the protrusions 1025 are V-shaped, so that the probe 102 has good mechanical and electrical properties, and has lower resistance, higher current, faster response speed, smaller parasitic effect, and better uniformity during testing.

[0071] A plurality of probes 102 are connected to the base 101 at a certain distance, and at least one side of the probe 102 is covered with a probe metal layer 50. The probe metal layer 50 of one probe 102 extends toward the base 101 to form a metal block 51. The metal blocks 51 corresponding to adjacent probes 102 are arranged at a certain distance to form a space for electrical insulation between adjacent probes 102.

[0072] The probe metal layer 50 is one of gold, silver, nickel, chromium, rhodium, palladium, or an alloy formed by at least two of them, so that the user can prepare the probe card 100 with different conductive properties according to the needs.

[0073] By using the probe card 100 as a unit, it is convenient to assemble, disassemble and replace a plurality of the probe cards 100 in a targeted manner, thereby avoiding the high cost and waste of resources caused by replacing the entire probe body.

[0074] In the specification and claims of the present application, the words "include / comprise" and the words "have / include" and their variations are used to specify the existence of stated features, values, steps or components, but do not exclude the existence or addition of one or more other features, values, steps, components or combinations thereof.

[0075] Some features of the present invention are described in different embodiments for clarity of description, however, these features may also be described in combination in a single embodiment. Conversely, some features of the present invention are described in only a single embodiment for brevity, however, these features may also be described in different embodiments alone or in any suitable combination.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an elastic probe card, the probe card comprising a plurality of probe metal layers, characterized in that: The preparation method comprises the following steps: forming a first photoresist on a surface of the substrate; exposing and developing the first photoresist to obtain a first etching pattern, wherein the first etching pattern corresponds to the probe card structure; The substrate is etched according to the first etching pattern to obtain the probe card, wherein the probe card comprises a base and the probes connected to the base and arranged at a certain distance, the probes comprise an elastic part and a needle tip, the tail of the needle tip is connected to one end of the elastic part, and the elastic part is formed by connecting a plurality of reverse protrusions arranged alternately end to end; removing the remaining first photoresist; forming a metal layer on the surface of the probe card; forming a second photoresist on the surface of the metal layer; exposing and developing the second photoresist to obtain a second etching pattern, wherein the second etching pattern corresponds to the probe metal layer structure; Etching the metal layer according to the second etching pattern to obtain the probe metal layer covering at least one side of the probe and a metal block connected to the probe metal layer, wherein the metal block is located on the base, and the metal blocks corresponding to adjacent probes are arranged at a certain distance to form a space for electrical insulation between adjacent probes; The remaining second photoresist is removed to obtain the probe card with surface metallization.

2. The method for preparing an elastic probe card according to claim 1, characterized in that: The substrate is an SOI wafer, the surface is a surface corresponding to the top silicon layer of the SOI wafer, and after removing the remaining second photoresist to obtain the probe card with surface metallization, the preparation method further includes: The buried oxide layer of the SOI wafer is removed to obtain the probe card with surface metallization.

3. The method for preparing an elastic probe card according to claim 2, characterized in that: The step etches the substrate according to the first etching pattern to obtain the probe card, wherein the probe card includes a base and the probe connected to the base and arranged at a certain distance, the probe includes an elastic part and a needle tip, the tail of the needle tip is connected to one end of the elastic part, and the elastic part is formed by connecting a plurality of reverse protrusions arranged alternately end to end. The above step adopts a deep reactive ion etching process to remove unnecessary top silicon layer.

4. The method for preparing an elastic probe card according to claim 3, characterized in that: The etching depth of the deep reactive ion etching process is not less than the thickness of the top silicon layer, so that the top silicon layer is etched in accordance with the first etching pattern and penetrates through the buried oxide layer.

5. The method for preparing an elastic probe card according to claim 1, characterized in that: Before forming a first photoresist on a surface of the substrate, the preparation method further comprises: The substrate is cleaned according to the RCA standard process.

6. The method for preparing an elastic probe card according to claim 1, characterized in that: The step etches the metal layer according to the second etching pattern to obtain the probe metal layer covering at least one side of the probe and a metal block connected to the probe metal layer, wherein the metal block is located on the base, and the metal blocks corresponding to adjacent probes are arranged at a certain distance to form a space for electrical insulation between adjacent probes, and the above step uses a plasma etching process to remove unnecessary metal layers.

7. An elastic probe card, wherein the elastic probe card is made by the elastic probe card preparation method according to any one of claims 1 to 6, characterized in that: The probe comprises a base and a probe, one end of which is connected to one side of the base, the probe comprises an elastic part and a needle tip, the tail of the needle tip is connected to an end of the elastic part away from the base, wherein the elastic part is formed by connecting a plurality of reverse protrusions arranged alternately end to end.

8. The elastic probe card according to claim 7, characterized in that: The elastic part includes a first arm and a second arm, wherein the first arm and the second arm are respectively formed by a plurality of reverse protrusions arranged alternately and connected end to end, wherein the protrusions are V-shaped.

9. The elastic probe card according to claim 7, characterized in that: A plurality of the probes are connected to the base at a certain distance, at least one side of the probe is covered with a probe metal layer, the probe metal layer of one probe extends toward the base to form a metal block, and the metal blocks corresponding to adjacent probes are arranged at a certain distance to form a space for electrical insulation between adjacent probes.

10. The elastic probe card according to claim 9, characterized in that: The probe metal layer is one of gold, silver, nickel, chromium, rhodium and palladium, or an alloy formed by at least two of them.

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