Preparation method of probe in semiconductor probe card

Abstract

The invention provides a method for preparing a probe in a semiconductor probe card, which comprises the following steps of: forming a second photoresist layer on the top surface of an intermediate product, and exposing, developing and coating to form a first metal support arm; forming a third photoresist layer on the top surfaces of the first metal support arm and the second photoresist layer, and exposing, developing and coating to form a first metal support column; removing all the photoresist layers; forming a fourth photoresist layer on the uncovered top surfaces of the silicon substrate, the first metal layer and the first metal support arm, and exposing, developing and coating to form a second metal support column; forming a fifth photoresist layer on the top surfaces of the first metal pillar, the second metal pillar and the fourth photoresist layer and between the first metal pillar and the second metal pillar, and exposing, developing and coating to form a second metal support arm; and removing all the photoresist layers. According to the preparation method of the probe in the semiconductor probe card, the probe can be effectively prevented from being broken, and the service life of the probe is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductors, and in particular relates to a method for preparing a probe in a semiconductor probe card. Background Art

[0002] A probe card is a key component used in semiconductor front-end wafer testing, which realizes the electrical connection between the wafer chip and the tester. It consists of multiple probes and tests the electrical performance of the wafer chip by contacting it.

[0003] The MEMS probe card is a new type of probe card manufactured using micro-electromechanical systems (MEMS) technology. MEMS probes use micromachining technology to integrate more than 100,000 probes on a probe card to meet the testing needs of electronic devices. The MEMS probe tip has a fine shape and the tip diameter can be as small as a few microns. Within a tiny contact area, the MEMS probe can provide stable and reliable contact force and electrical contact, greatly improving test accuracy.

[0004] The current MEMS probe manufacturing process is as follows: first, a silicon substrate is coated multiple times to form a first metal layer. After obtaining a pattern through adhesive coating, photolithography, and development, the first metal layer and silicon substrate are etched to obtain the groove morphology. The groove is then coated and filled with a second metal to form a probe. The second metal layer located in the silicon substrate is the probe tip, and the second metal layer located next to the first metal layer is the probe body. During packaging, the probe body is bonded to the ceramic substrate. However, during the use of the probe card, the probe will bend. After being subjected to bending stress multiple times, the bonding point of the probe will be subjected to greater stress, making it more likely to cause metal fatigue and cause the probe to break. Summary of the Invention

[0005] The present invention provides a method for preparing a probe in a semiconductor probe card, which can effectively prevent the probe from breaking and increase the service life of the probe.

[0006] To solve the above technical problems, the present invention provides a method for preparing a probe in a semiconductor probe card, comprising the following steps: Step 10: applying photoresist on the top surface of the intermediate product to form a second photoresist layer; the intermediate product includes a silicon substrate, a first metal layer covering a portion of the top surface of the silicon substrate, a probe tip located in the silicon substrate, and a probe body located at the top of the probe tip, wherein the area between the probe body and the first metal layer and other areas on the top surface of the silicon substrate are covered with the first photoresist layer; Step 20, performing exposure and development at a preset position of the second photoresist layer to form a first arm growth position; the first arm growth position is located above the first metal layer and the probe tip; Step 30, forming a first metal arm at the first arm growth position by electroplating; Step 40, applying photoresist on the top surfaces of the first metal arm and the second photoresist layer to form a third photoresist layer; Step 50, performing exposure and development at predetermined positions of the third photoresist layer to form a plurality of first pillar growth positions arranged at intervals; Step 60, forming a plurality of first metal pillars at the first pillar growth position by electroplating; Step 70, removing the first photoresist layer, the second photoresist layer and the third photoresist layer; Step 80, applying photoresist on the uncovered top surfaces of the silicon substrate, the first metal layer, and the first metal arm to form a fourth photoresist layer; Step 90 , performing exposure and development at a preset position of the fourth photoresist layer to form a second pillar growth position located between two adjacent first metal pillars; Step 100, forming a second metal pillar at a second pillar growth position by electroplating; Step 110, coating photoresist on the top surfaces of the first metal pillar, the second metal pillar and the fourth photoresist layer to form a fifth photoresist layer; Step 120 , performing exposure and development on a preset position of the fifth photoresist layer to form a second arm growth position; Step 130 , forming a second metal arm at the second arm growth position by electroplating; Step 140 , removing the fourth photoresist layer and the fifth photoresist layer.

[0007] As a further improvement of the present invention, the thickness of the second photoresist layer is 40-80 μm.

[0008] As a further improvement of the present invention, the first metal arm and the first metal layer are made of different materials, and the first metal arm and the second metal arm are made of the same material.

[0009] As a further improvement of the present invention, the first metal pillar and the first metal layer are made of different materials, and the second metal pillar and the first metal layer are made of the same material.

[0010] As a further improvement of the present invention, the number of the first metal pillars is 2, and the two first metal pillars are symmetrically arranged at both ends above the first metal support arm.

[0011] As a further improvement of the present invention, the projections of the second metal support arm and the first metal support arm on the horizontal plane coincide with each other.

[0012] As a further improvement of the present invention, in step 30, the surface of the first arm growth position is pretreated before electroplating; in step 60, the surface of the first pillar growth position is pretreated before electroplating; in step 100, the surface of the second pillar growth position is pretreated before electroplating; in step 130, the surface of the second arm growth position is pretreated before electroplating.

[0013] As a further improvement of the present invention, in step 100, a gap is formed between the second metal pillar and the first metal pillar.

[0014] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: The present invention provides a method for preparing a probe in a semiconductor probe card. After the probe is formed, a first metal arm, a plurality of first metal pillars and a second metal arm are sequentially formed on the probe. The first metal arm, the plurality of first metal pillars and the second metal arm form a structure, which acts as a stress barrier layer. One end of the structure connected to the probe is a supporting end, and the other end is a bonding end, which disperses the stress on the probe during use of the probe card and prevents the probe from breaking, so that the probe can withstand greater stress, cope with more complex test environments, improve the service life of the probe card, and increase the number of tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The figure is a flow chart of a method for preparing probes in a semiconductor probe card according to an embodiment of the present invention.

[0016] The figure includes: silicon substrate 1, first metal layer 2, probe tip 31, probe body 32, first photoresist layer 4, second photoresist layer 5, first arm growth position 51, first metal arm 6, third photoresist layer 7, first pillar growth position 71, first metal pillar 8, fourth photoresist layer 9, second metal pillar 10, fifth photoresist layer 11, second arm growth position 111, and second metal arm 12. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is described in detail below with reference to the accompanying drawings.

[0018] The embodiment of the present invention provides a method for preparing a probe in a semiconductor probe card, such as Figure 1 As shown, the following steps are included: Step 10: Apply photoresist on the top surface of the intermediate product to form a second photoresist layer 5.

[0019] Among them, the intermediate product includes a silicon substrate 1, a first metal layer 2 covering a partial area of ​​the top surface of the silicon substrate 1, a probe tip 31 located in the silicon substrate 1 and a probe body 32 located at the top of the probe tip 31, and the area between the probe body 32 and the first metal layer 2 and other areas of the top surface of the silicon substrate are covered with a first photoresist layer 4.

[0020] The first photoresist layer 4 between the probe needle body 32 and the first metal layer 2 is formed in the previous process. A gap is set between the probe needle body 32 and the first metal layer 2 to facilitate the removal of the first metal layer 2 after the bonding process between the silicon substrate 1 and the first metal layer 2 is completed, ensuring that there is enough space around the probe for testing.

[0021] Specifically, the photoresist is applied by spin coating and then baked to form a second photoresist layer 5 with a thickness of 40 to 80 μm.

[0022] In step 20 , exposure and development are performed on a preset position of the second photoresist layer 5 to form a first arm growth position 51 . The first arm growth position 51 is located above the first metal layer 2 and the probe tip 31 .

[0023] In step 30, the surface of the first arm growth site 51 is rinsed with deionized water to remove the surface photoresist, and then spin-dried. A first metal arm 6 is formed on the first arm growth site 51 by electroplating. Preferably, the horizontal projection of the first metal arm 6 completely covers the horizontal projection of the probe, but does not necessarily cover the horizontal projection of the first metal layer 2.

[0024] Since the first metal layer 2 needs to be removed after the subsequent bonding process, the first metal arm 6 is made of a material different from that of the first metal layer 2 , so that the first metal arm 6 will not be damaged when the first metal layer 2 is removed.

[0025] In step 40 , photoresist is coated on the top surfaces of the first metal support arm 6 and the second photoresist layer 5 to form a third photoresist layer 7 .

[0026] Step 50 , performing exposure and development at preset positions of the third photoresist layer 7 to form a plurality of first pillar growth positions 71 arranged at intervals.

[0027] Preferably, the number of the first pillar growth positions 71 is 2, and the two first pillar growth positions 71 are symmetrically arranged at both ends above the first metal support arm 6 .

[0028] In step 60, the surface of the first pillar growth site 71 is rinsed with deionized water to remove the photoresist on the surface, and then the surface is spin-dried. A plurality of first metal pillars 8 are formed on the first pillar growth site 71 by electroplating.

[0029] Preferably, the number of the formed first metal pillars 8 is 2, and the two first metal pillars 8 are symmetrically arranged at both ends above the first metal support arm 6.

[0030] Preferably, since the first metal layer 2 needs to be removed after the subsequent bonding process, the first metal pillar 8 is made of a material different from that of the first metal layer 2 , so that the first metal pillar 8 will not be damaged when the first metal layer 2 is removed.

[0031] Step 70 , removing the first photoresist layer 4 , the second photoresist layer 5 and the third photoresist layer 7 .

[0032] Subsequently, it is necessary to form a second pillar growth position 91 between adjacent first metal pillars 8. The third photoresist layer 7 is filled between adjacent first metal pillars 8. The third photoresist layer 7 has participated in the exposure and development reaction, so the third photoresist layer 7 needs to be removed. When removing the third photoresist layer 7, the first photoresist layer 4 and the second photoresist layer 5 are also removed.

[0033] Step 80 : Apply photoresist on the uncovered top surfaces of the silicon substrate 1 , the first metal layer 2 and the first metal support arm 6 to form a fourth photoresist layer 9 .

[0034] Step 90 , performing exposure and development at a preset position of the fourth photoresist layer 9 to form a second pillar growth position 91 located between two adjacent first metal pillars 8 .

[0035] In step 100, the surface of the second pillar growth site 91 is rinsed with deionized water to remove the photoresist on the surface, and then the surface is spin-dried. The second metal pillar 10 is formed on the second pillar growth site 91 by electroplating.

[0036] In order to facilitate the formation of the structure above the first metal pillar 8, a second metal pillar 10 is set between adjacent first metal pillars 8. The second metal pillar 10 needs to be removed after the subsequent bonding process is completed. The second metal pillar 10 uses the same material as the first metal layer 2, which facilitates the subsequent simultaneous removal of the second metal pillar 10 and the first metal layer 2.

[0037] Preferably, there is a gap between the second pillar growth position 91 and the first metal pillar 8, that is, photoresist is retained between the second pillar growth position 91 and the first metal pillar 8. After the electroplating is completed, the second metal pillar 10 is not in contact with the first metal pillars 8 on both sides, which facilitates the subsequent removal of the second metal pillar 10.

[0038] In step 110 , photoresist is applied on the top surfaces of the first metal pillar 8 , the second metal pillar 10 and the fourth photoresist layer 9 to form a fifth photoresist layer 11 .

[0039] Step 120 , performing exposure and development at a preset position of the fifth photoresist layer 11 to form a second arm growth position 111 .

[0040] In step 130 , the surface of the second arm growth site 111 is rinsed with deionized water to remove the photoresist on the surface, and then the surface is spin-dried. The second metal arm 12 is formed on the second arm growth site 111 by electroplating.

[0041] Preferably, the second metal arm 12 is made of the same material as the first metal arm 6 and different from the first metal layer 2 , so that the second metal arm 12 will not be damaged when the first metal layer 2 is removed.

[0042] Preferably, the projections of the second metal support arm 12 and the first metal support arm 6 on the horizontal plane coincide with each other.

[0043] Step 140 : removing the fourth photoresist layer 9 and the fifth photoresist layer 11 .

[0044] The preparation method of the embodiment of the present invention forms a first metal arm, a plurality of first metal pillars and a second metal arm in sequence on the probe after the probe is formed. The first metal arm, the plurality of first metal pillars and the second metal arm constitute a structure, which acts as a stress barrier layer. One end of the structure connected to the probe is a supporting end, and the other end is a bonding end, which disperses the stress on the probe during use of the probe card and prevents the probe from breaking, so that the probe can withstand greater stress, cope with more complex test environments, improve the service life of the probe card, and increase the number of tests.

[0045] The structure consisting of the first metal arm, several first metal pillars, and second metal arms increases the probe card's moment of inertia. A greater moment of inertia reduces bending deflection and stress. Gaps are left between the several first metal pillars to better distribute stress during testing without excessively increasing the probe card's weight.

[0046] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with this technical field within the technical scope disclosed in the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing a probe in a semiconductor probe card, characterized in that: The following steps are involved: Step 10, applying photoresist on the top surface of the intermediate product to form a second photoresist layer (5); the intermediate product comprises a silicon substrate (1), a first metal layer (2) covering a portion of the top surface of the silicon substrate (1), a probe tip (31) embedded in the silicon substrate (1), and a probe body (32) located at the top of the probe tip (31), and the area between the probe body (32) and the first metal layer (2) and other areas on the top surface of the silicon substrate are covered with the first photoresist layer (4); Step 20, performing exposure and development at a preset position of the second photoresist layer (5) to form a first arm growth position (51); the first arm growth position (51) is located above the first metal layer (2) and the probe needle tip (31); Step 30, forming a first metal support arm (6) at the first support arm growth position (51) by using an electroplating method; Step 40, applying photoresist on the top surface of the first metal arm (6) and the second photoresist layer (5) to form a third photoresist layer (7); Step 50, performing exposure and development at preset positions of the third photoresist layer (7) to form a plurality of first pillar growth positions (71) arranged at intervals; Step 60, forming a plurality of first metal pillars (8) at the first pillar growth position (71) by electroplating; Step 70, removing the first photoresist layer (4), the second photoresist layer (5) and the third photoresist layer (7); Step 80, applying photoresist on the uncovered top surfaces of the silicon substrate (1), the first metal layer (2) and the first metal arm (6) to form a fourth photoresist layer (9); Step 90, performing exposure and development at a preset position of the fourth photoresist layer (9) to form a second pillar growth position (91) located between two adjacent first metal pillars (8); Step 100, forming a second metal pillar (10) at a second pillar growth position (91) by electroplating; Step 110, applying photoresist on the top surfaces of the first metal pillar (8), the second metal pillar (10) and the fourth photoresist layer (9) to form a fifth photoresist layer (11); Step 120, performing exposure and development at a preset position of the fifth photoresist layer (11) to form a second arm growth position (111); Step 130, forming a second metal arm (12) at the second arm growth position (111) by electroplating; Step 140: removing the fourth photoresist layer (9) and the fifth photoresist layer (11).

2. The method for preparing a probe in a semiconductor probe card according to claim 1, wherein: The thickness of the second photoresist layer (5) is 40-80 μm.

3. The method for preparing a probe in a semiconductor probe card according to claim 1, wherein: The first metal support arm (6) and the first metal layer (2) are made of different materials, and the first metal support arm (6) and the second metal support arm (12) are made of the same material.

4. The method for preparing a probe in a semiconductor probe card according to claim 1, wherein: The first metal support (8) is made of a different material from the first metal layer (2), and the second metal support (10) is made of the same material as the first metal layer (2).

5. The method for preparing a probe in a semiconductor probe card according to claim 1, wherein: The number of the first metal pillars (8) is 2, and the two first metal pillars (8) are symmetrically arranged at both ends above the first metal support arm (6).

6. The method for preparing a probe in a semiconductor probe card according to claim 1, wherein: The projections of the second metal support arm (12) and the first metal support arm (6) on the horizontal plane coincide with each other.

7. The method for preparing a probe in a semiconductor probe card according to claim 1, wherein: In step 30, the surface of the first arm growth position (51) is pretreated before electroplating; in step 60, the surface of the first pillar growth position (71) is pretreated before electroplating; in step 100, the surface of the second pillar growth position (91) is pretreated before electroplating; in step 130, the surface of the second arm growth position (111) is pretreated before electroplating.

8. The method for preparing a probe in a semiconductor probe card according to claim 1, wherein: In step 100, a gap is formed between the formed second metal pillar (10) and the first metal pillar (8).

Images