Laminated vertical probe and preparation method thereof

Abstract

The invention discloses a laminated vertical probe and a preparation method thereof. The method comprises the steps that 1, a bearing disc is provided, a plurality of metal sheets are placed on the bearing disc, the metal sheets are sequentially arranged in the horizontal direction to form a lamination set, and the lamination set is clamped and fixed from the two sides of the thickness direction of the lamination set through a fixing mechanism; 2, processing the two ends of the lamination group in the length direction; 3, the surface of the bearing disc is coated with photoresist, photoetching development is carried out on the photoresist, the lamination set and the needle head area and the needle tail area of the probe are exposed out of the surface of the bearing disc, and the needle head area and the needle tail area are oppositely located at the two ends of the lamination set; 4, respectively electroplating a probe head and a probe tail in the probe head area and the probe tail area, and respectively connecting the probe head and the probe tail with the lamination group to form a probe; and 5, removing the residual photoresist, and releasing the probe from the fixing mechanism and the bearing disc. According to the scheme, the inertia moment can be limited under the condition that the cross section area S of the probe is increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of probe card, in particular to a laminated vertical probe and a preparation method thereof. BACKGROUND

[0002] Probe card is an interface instrument for testing chip, and one of the core components of probe card is probe head (PH). A common PH structure of vertical probe card is shown in Figure 1 , which is made by machining needle planting holes on the upper guide plate 1 and the lower guide plate 2, and then inserting tens of thousands of probes 3 into the holes. The upper guide plate and the lower guide plate are separated by a distance, so that the probes bend in this space (for simplicity of the drawing, Figure 1 only a few probes and their upper and lower guide plates are drawn).

[0003] The PH of the vertical probe card usually has two forms of needle insertion state and working state, and can be quickly switched between the two states through the positioning pin. Figure 2 , which is shown in the needle insertion state. At this time, the needle planting holes of the upper guide plate 1 and the lower guide plate 3 are aligned, which facilitates the assembly of linear probes into the holes. Figure 3 , which is shown in the working state. The upper and lower guide plates are offset by a certain distance, so that the probes become curved, and the probes have elastic buffer function, avoiding damage to the wafer or the probes during testing.

[0004] In the design of the probe, the ideal situation is that the probe has appropriate elastic force and better current resistance. Too small elastic force may cause poor contact, and too large elastic force may damage the wafer or the probe. When the number of probes is large, too large elastic force will also cause the deformation of the probe card structure and affect the wafer test. The common method to improve the current resistance of the probe is to increase the cross-sectional area of the probe, but the change of the cross-sectional area of the probe directly affects its elastic force. Specifically, taking the probe cross section represented by the Figure 4 shadow area as an example, assuming that the bending direction is around the axis (the same analysis conclusion can be obtained by bending around the y axis), the cross-sectional moment of inertia is known from the bending moment formula. The larger the cross-sectional moment of inertia, the greater the ability of the probe to resist bending, and the greater the elastic force generated by the probe to achieve the same degree of bending. The cross-sectional area of the probe, according to the above formula, the larger the cross-sectional area, the larger the current resistance of the probe, but the problem that follows is that the elastic force generated by the probe is larger. Therefore, how to limit the moment of inertia of the probe while increasing its cross-sectional area S is a problem that technicians in the field continue to work on. SUMMARY

[0005] In order to overcome the defects in the prior art, the embodiment of the present application provides a laminated vertical probe and a preparation method thereof, which are used to solve the above problems.

[0006] The embodiment of the present application discloses a preparation method of a laminated vertical probe, comprising the following steps:

[0007] Step 1: providing a bearing disc, placing a plurality of metal sheets on the bearing disc, sequentially arranging the plurality of metal sheets in a horizontal direction to form a laminated group, and clamping and fixing the laminated group from both sides of the thickness direction of the laminated group by using a fixing mechanism;

[0008] Step 2: processing both ends of the laminated group in the length direction;

[0009] Step 3: coating photoresist on the surface of the bearing disc, performing photoetching and development on the photoresist, and exposing the laminated group, a needle head area and a needle tail area of the probe on the surface of the bearing disc, wherein the needle head area and the needle tail area are located at both ends of the laminated group oppositely;

[0010] Step 4: electroplating a needle head and a needle tail in the needle head area and the needle tail area respectively, and connecting the needle head and the needle tail with the laminated group to form a probe;

[0011] Step 5: removing residual photoresist, and releasing the probe from the fixing mechanism and the bearing disc.

[0012] Specifically, the thickness of the metal sheet is between 2 μm and 10 μm.

[0013] Specifically, the material of the metal sheet is silver alloy or copper alloy.

[0014] Specifically, the fixing mechanism comprises a first positioning block and a second positioning block which are detachably connected to the bearing disc.

[0015] Specifically, if the bearing disc is made of non-conductive material, a metal is deposited on the surface of the bearing disc as a seed layer for the electroplating process before the photoresist is coated on the surface of the bearing disc.

[0016] Specifically, in step 3, the photoresist is coated on the surface of the bearing disc in the following manner: the photoresist is coated on the area of the surface of the bearing disc except the fixing mechanism and the laminated group, and the photoresist is subjected to photoetching and development, so that the needle head area and the needle tail area of the probe are exposed on the surface of the bearing disc; or the photoresist is coated on all areas of the surface of the bearing disc, and the photoresist is subjected to photoetching and development, so that the laminated group, the needle head area and the needle tail area of the probe are exposed on the surface of the bearing disc.

[0017] Specifically, in step 5, it specifically comprises:

[0018] Step 51: removing residual photoresist;

[0019] Step 52: grinding the probe;

[0020] Step 53: separating the probe from the carrier plate by using chemical solution, removing the excess part of the metal sheet on both sides of each probe, and obtaining the probe.

[0021] Specifically, in step 2, further comprising: grinding the side of the lamination stack away from the carrier plate, so that the width of the lamination stack reaches a preset value.

[0022] Specifically, one lamination stack is used to prepare a plurality of probes.

[0023] The embodiment of the application further discloses a lamination stack vertical probe prepared by the method.

[0024] The application has at least the following beneficial effects:

[0025] Compared with a conventional probe whose bending section is an integral piece of metal, the lamination stack vertical probe has the following advantages: in the case that the two probes have the same cross-sectional area (so as to have the same flow cross section), when the probe is cut back from the working state to the insertion state, the lamination stack vertical probe needs less elastic force, so that the stability of the probe is better and the wafer is less likely to be damaged. .

[0026] In order to make the above and other objects, features and advantages of the application more apparent, the following will specifically describe a preferred embodiment, and the accompanying drawings will be described in detail as follows. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0028] Figure 1 is a structural schematic diagram of a probe head in the prior art;

[0029] Figure 2 is a schematic diagram of a probe head in the prior art in an insertion state;

[0030] Figure 3is a schematic diagram of the probe head in the working state in the prior art;

[0031] Figure 4 is a schematic diagram of the probe cross section;

[0032] Figure 5 is a flow chart of the preparation method of the laminated vertical probe in the embodiment of the present application;

[0033] Figure 6 is a contrast diagram of the laminated group before and after grinding in the embodiment of the present application;

[0034] Figure 7 is a schematic diagram of the needle insertion state of the laminated vertical probe in the embodiment of the present application;

[0035] Figure 8 is a schematic diagram of the working state of the laminated vertical probe in the embodiment of the present application.

[0036] The reference signs of the above drawings are as follows: 1, upper guide plate; 2, lower guide plate; 3, probe; 31, needle head; 32, needle tail; 33, bending section; 4, bearing disc; 5, laminated group; 61, first positioning block; 62, second positioning block; 7, photoresist; 71, needle head area; 72, needle tail area. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0038] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms “mounting”, “connection”, “fixing”, “connection” should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium, or can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0039] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature can include that the first feature and the second feature are in direct contact, or that the first feature and the second feature are not in direct contact but are in contact through another feature between them. Moreover, the first feature is "on", "under" and "above" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the first feature is higher in horizontal height than the second feature. The first feature is "under", "below" and "below" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the first feature is lower in horizontal height than the second feature.

[0040] In the description of the present embodiment, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the scope of protection of the present application.

[0041] In addition, the terms "first", "second" and the like are only used to distinguish in description and have no special meaning.

[0042] In combination Figures 5 to 8 As shown, the preparation method of the laminated vertical probe of the present embodiment includes the following steps:

[0043] Step 1: Provide a carrier disc 4, place a plurality of metal sheets on the carrier disc 4, and arrange the plurality of metal sheets in a horizontal direction to form a laminated group 5. In other words, a laminated group 5 is arranged on the carrier disc 4, and the laminated group 5 includes a plurality of metal sheets arranged in a horizontal direction. The laminated group 5 is clamped and fixed from both sides of its thickness direction by using a fixing mechanism. The adjacent two metal sheets are only pasted together, not glued. The metal sheet can be a silver alloy sheet or a copper alloy sheet with a thickness of 2-10 μm.

[0044] Step 2: Process the two ends of the laminated group 5 in the length direction thereof. Specifically, in this step, a laser processing device can be used to cut the two ends of the laminated group 5 to obtain the required length, and the length of each metal sheet in the laminated group 5 is equal.

[0045] Step 3: A photoresist 7 is coated on the surface of the carrier plate 4 with the laminated group 5, and then the photoresist 7 is developed by photolithography, so that the surface of the carrier plate 4 exposes the laminated group 5 and the needle head area 71 and the needle tail area 72 of the probe 3, wherein one needle head area 71 and one needle tail area 72 are arranged at the two ends of the laminated group 5 correspondingly. The needle head area 71 is the area exposed on the carrier plate 4 corresponding to the shape of the needle head 31 of the probe 3, and the needle tail area 72 is the area exposed on the carrier plate 4 corresponding to the shape of the needle tail 32 of the probe 3.

[0046] Step 4: The needle head 31 and the needle tail 32 of the probe 3 are respectively electroplated in the above-mentioned needle head area 71 and the needle tail area 72, and one needle head 31, one corresponding needle tail 32 and a part of the laminated group 5 connected between them together constitute one probe 3.

[0047] Step 5: The remaining photoresist 7 on the carrier plate 4 is removed, and the probe 3 is released from the fixing mechanism and the carrier plate 4, to obtain a single probe 3.

[0048] The probe 3 prepared by the method of the embodiment has a bending section 33 (located between the needle head 31 and the needle tail 32, and used for bending in the working state) composed of a plurality of metal foils which are attached but not bonded to each other. When the probe 3 is in the working state, each metal foil bends respectively, and when the probe 3 ends the work, each metal foil can only be restored to the state perpendicular to the guide plate by a small elastic force. Therefore, the problem that the probe 3 is easily deformed and damages the wafer due to too large elastic force required is avoided.

[0049] Compared with the existing probe 3 with a bending section 33 of an integral piece of metal (hereinafter referred to as a conventional probe 3), the laminated vertical probe of the embodiment has the following advantages: in the case that the two probes 3 have the same cross-sectional area (thus having the same flow-through cross section), the elastic force required by the bending section 33 of the probe 3 of the embodiment is significantly smaller when the probe 3 is cut back from the working state to the insertion state, and thus the stability of the probe 3 of the embodiment is better and the wafer is not easily damaged. That is to say, the probe 3 prepared by the method of the embodiment can limit the moment of inertia I of the probe 3 in the case of increasing the cross-sectional area S of the probe 3. .

[0050] Specifically, as shown in Figure 5 the fixing mechanism of the embodiment includes a first positioning block 61 and a second positioning block 62 which are detachably connected to the carrier plate 4, and the first positioning block 61 and the second positioning block 62 enclose a space for accommodating a plurality of metal foils, and the metal foils are placed in the space and are perpendicular to the carrier plate 4 after being placed in the space.

[0051] The carrier plate 4 can be made of conductive material or non-conductive material. When the carrier plate 4 is made of conductive material, the photoresist 7 can be coated on the surface of the carrier plate 4, and then photoetching and electroplating are performed. When the carrier plate 4 is made of non-conductive material, a layer of metal is deposited on the surface of the carrier plate 4 as a seed layer before the photoresist 7 is coated on the surface of the carrier plate 4.

[0052] Specifically, there are two ways to coat the photoresist 7 on the surface of the carrier plate 4. The first way is to coat the photoresist 7 on the surface of the carrier plate 4 except the fixing mechanism and the lamination group 5, and then photoetching and electroplating are performed to expose the needle head area 71 and the needle tail area 72 on the surface of the carrier plate 4, and the needle head area 71 and the needle tail area 72 are connected with the lamination group 5 which is not covered by the photoresist 7. The second way is to coat the photoresist 7 on the entire surface of the carrier plate 4, and then photoetching and electroplating are performed to expose the lamination group 5, the needle head area 71 and the needle tail area 72 on the carrier plate 4.

[0053] In step 5, the following steps are included. In step 51, the residual photoresist 7 on the carrier plate 4 is removed. In step 52, the upper surface of the probe 3 is ground flat by using a grinding device to ensure the uniform thickness of the probe 3, and at the same time, to ensure that the part of the lamination group 5 corresponding to the curved section 33 of the probe 3 is not covered by the electroplated metal. In step 53, the probe 3 is separated from the carrier plate 4 by using etching solution, and then the excess part of the metal sheet on both sides of each probe 3 is removed to obtain the probe 3.

[0054] Preferably, one lamination group 5 is used to prepare a plurality of probes 3. That is to say, one lamination group 5 can be prepared into a plurality of curved sections 33 of the probes 3. Of course, there are several metal sheets between the adjacent two curved sections 33 of the probes 3 which are not used to prepare the probes 3 (as shown in Figure 5

[0055] In step 2, the following step is further included. The side of the lamination group 5 away from the carrier plate 4 is ground to make the width of the lamination group 5 reach a preset value (as shown in Figure 6

[0056] The principles and implementation manners of the present application are described by using specific embodiments, and the above description of the embodiments is only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, the specific implementation manners and application ranges can be changed according to the idea of the present application, and the above description of the present application should not be understood as a limitation.​​

Claims

1. A method for preparing a stacked vertical probe, characterized in that, Includes the following steps: Step 1: Provide a support plate, place multiple metal sheets on the support plate, arrange the multiple metal sheets in sequence along the horizontal direction to form a stack, and use a fixing mechanism to clamp and fix the stack from both sides in the thickness direction. Step 2: Process both ends of the stacked sheet assembly along its length; Step 3: Coat the surface of the carrier disk with photoresist, and perform photolithography development on the photoresist to expose the stacked wafer assembly and the probe tip and tail regions on the surface of the carrier disk. The probe tip and tail regions are located at opposite ends of the stacked wafer assembly. Step 4: Electroplating a needle tip and a needle tail in the needle tip area and the needle tail area respectively, and connecting the needle tip and needle tail to the stacked plate group to form a probe; Step 5: Remove the residual photoresist and release the probe from the fixing mechanism and the carrier plate.

2. The method for preparing the stacked vertical probe according to claim 1, characterized in that, The thickness of the metal sheet is between 2 μm and 10 μm.

3. The method for preparing a stacked vertical probe according to claim 1, characterized in that, The metal sheet is made of silver alloy or copper alloy.

4. The method for preparing a stacked vertical probe according to claim 1, characterized in that, The fixing mechanism includes a first positioning block and a second positioning block that are detachably connected to the carrier plate.

5. The method for preparing a stacked vertical probe according to claim 1, characterized in that, If the carrier disk is made of a non-conductive material, metal is deposited on the surface of the carrier disk before photoresist is coated on the surface of the carrier disk as a seed layer for the electroplating process.

6. The method for preparing a stacked vertical probe according to claim 1, characterized in that, In step 3, the method of coating the photoresist on the surface of the carrier disk is as follows: the photoresist is coated on the area of ​​the carrier disk surface other than the fixing mechanism and the stacking group, and the photoresist is photolithographically developed to expose the probe tip area and probe tail area on the surface of the carrier disk. Alternatively, photoresist can be coated on all areas of the carrier disk surface, and the photoresist can be photolithographically developed to expose the stacked wafer assembly and the probe tip and tail areas on the carrier disk surface.

7. The method for preparing a stacked vertical probe according to claim 1, characterized in that, Step 5 specifically includes: Step 51: Remove residual photoresist; Step 52: Grind the probe; Step 53: Use a chemical solution to separate the probe from the carrier plate, remove the excess portion of the metal sheet on both sides of each probe, and obtain the probe.

8. The method for preparing a stacked vertical probe according to claim 1, characterized in that, Step 2 further includes: grinding the side of the stacked pieces away from the support plate so that the width of the stacked pieces reaches a preset value.

9. The method for preparing a stacked vertical probe according to claim 1, characterized in that, One of the stacks is used to prepare multiple probes.

10. A stacked vertical probe, characterized in that, Prepared using the method described in any one of claims 1 to 9.

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