A method for fabricating probe cards that reduces photoresist residue

Abstract

This invention provides a method for fabricating probe cards with reduced photoresist residue, comprising the following steps: Step 10, after etching the insulating layer corresponding to the inner circuit pattern, photoresist is applied to the silicon substrate and the insulating layer to form a photoresist layer; exposure and development are performed to form the outer circuit pattern; Step 20, the insulating layer corresponding to the outer circuit pattern is etched, with the etching thickness being less than the thickness of the insulating layer; Step 30, a probe is fabricated on the silicon substrate corresponding to the inner circuit pattern; Step 40, the remaining insulating layer corresponding to the outer circuit pattern is etched. This invention provides a method for fabricating probe cards with reduced photoresist residue, effectively reducing photoresist residue at the probe tip and improving the yield of probe tip products.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor technology, specifically relating to a method for preparing probe cards that reduces photoresist residue. Background Technology

[0002] A probe card is a key device used for electronic testing and analysis. During testing, the probe card contacts the test points of a semiconductor circuit or device to measure and analyze electrical signals. The fabrication of probe cards mainly employs MEMS processing techniques such as thin-film deposition, circuit pattern building, and etching. The traditional fabrication process involves first forming an oxide insulating layer on the surface of a silicon substrate; then, photolithography is performed on the insulating layer to build the inner layer circuit pattern, and the corresponding insulating layer is etched; subsequently, photolithography is performed to build the probe pattern, and the corresponding silicon substrate is etched to form the probe; finally, photolithography is performed on the insulating layer at the probe edge to build the outer layer circuit pattern, and the corresponding insulating layer is etched.

[0003] However, after the probe tip is formed, during the process of constructing the outer circuit pattern using photolithography, the silicon wafer is placed in a spin coater, and the liquid photoresist is evenly spread by high-speed rotation, such as... Figure 1 As shown, probe 4 is completely exposed, and photoresist 5 easily remains on its sidewalls and tip grooves, requiring subsequent ashing removal. Generally, to improve photoresist removal efficiency, the ashing process may need to be repeated multiple times, making the process complex and time-consuming. Furthermore, the probe tip of the probe card is less than 10μm, and the special shape of the tip and stepped grooves makes photoresist removal very difficult; the photoresist in the tip groove area cannot be completely removed. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing probe cards that reduces photoresist residue, effectively reducing photoresist residue at the probe tip and improving the yield of probe tip finished products.

[0005] To address the aforementioned technical problems, this invention provides a method for fabricating a probe card that reduces photoresist residue, comprising the following steps:

[0006] Step 10: After etching the insulating layer corresponding to the inner circuit pattern, photoresist is applied to the silicon substrate and the insulating layer to form a photoresist layer; exposure and development are performed to form the outer circuit pattern.

[0007] Step 20: Etch the insulating layer corresponding to the outer circuit pattern, with the etching thickness being less than the thickness of the insulating layer;

[0008] Step 30: A probe is fabricated on the silicon substrate corresponding to the inner layer circuit pattern;

[0009] Step 40: Etch the remaining insulating layer corresponding to the outer circuit pattern.

[0010] As a further improvement of the present invention, in step 20, the etching thickness is 1 / 3 to 2 / 3 of the thickness of the insulating layer.

[0011] As a further improvement of the present invention, in step 20, the etching thickness is half the thickness of the insulating layer.

[0012] As a further improvement of the present invention, in step 20, a preset etching time is obtained based on the thickness of the insulating layer and the etching rate of the etching equipment; the etching equipment is used to etch the insulating layer corresponding to the outer circuit pattern for the preset etching time and then the etching is stopped.

[0013] As a further improvement of the present invention, in step 30, before the probe is fabricated on the silicon board corresponding to the inner layer circuit pattern, the photoresist layer is removed first.

[0014] As a further improvement of the present invention, the removal of the photoresist layer specifically includes: first, treating the surface of the product obtained in step 20 with an ashing process, then immersing the product in an acetone solution, then immersing the product in a mixed solution of sulfuric acid and hydrogen peroxide, and finally drying.

[0015] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0016] This invention provides a method for fabricating probe cards with reduced photoresist residue. After etching the insulating layer corresponding to the inner layer circuit pattern, the outer layer circuit pattern is first constructed using photolithography. Then, the insulating layer corresponding to the outer layer circuit pattern is etched, but only a portion of its thickness is etched, leaving a certain thickness. The probe is then fabricated on the silicon substrate corresponding to the inner layer circuit pattern. Finally, the remaining insulating layer corresponding to the outer layer circuit pattern is etched. This method avoids constructing the outer layer circuit pattern using photolithography while the probe is exposed, effectively reducing photoresist residue at the probe tip by more than 85% and improving the yield of the probe tip product. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure formed after the probe tip is formed in the traditional fabrication process and the outer circuit pattern is formed in the photolithography process.

[0018] Figure 2 This is a flowchart of a probe card fabrication method for reducing photoresist residue provided in an embodiment of the present invention.

[0019] The diagram shows: silicon substrate 1, insulating layer 2, outer circuit pattern 21, photoresist layer 3, probe 4, and photoresist 5. Detailed Implementation

[0020] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0021] This invention provides a method for fabricating probe cards that reduces photoresist residue, such as... Figure 2 As shown, it includes the following steps:

[0022] Step 10: After etching the insulating layer corresponding to the inner circuit pattern, photoresist is applied to the silicon substrate 1 and the insulating layer 2 to form a photoresist layer 3. Exposure and development are then performed to form the outer circuit pattern 21.

[0023] Step 20: Etch the insulating layer 2 corresponding to the outer circuit pattern, with the etching thickness being less than the thickness of the insulating layer 2.

[0024] Preferably, the etching thickness is 1 / 3 to 2 / 3 of the insulating layer thickness. More preferably, the etching thickness is half the insulating layer thickness.

[0025] Specifically, a dry etching process is used. The preset etching time is determined based on the thickness of the insulating layer 2 and the etching rate of the etching equipment. The etching equipment is used to etch the insulating layer 2 corresponding to the outer circuit pattern for the preset etching time, and then the etching is stopped. For example, if the thickness of the insulating layer is 5000 Å, the thickness etched in this step is 2500 Å, and the etching rate of the equipment used is 5000 Å / min, then the preset etching time is 30 seconds.

[0026] Step 30: Probe 4 is fabricated on the silicon substrate corresponding to the inner layer circuit pattern.

[0027] Step 40: Etch the remaining insulating layer 2 corresponding to the outer circuit pattern.

[0028] Preferably, in step 30, before the probe tip 4 is fabricated on the silicon substrate corresponding to the inner circuit pattern, the photoresist layer 3 is removed.

[0029] To remove photoresist layer 3, the surface of the product obtained in step 20 is first treated with an ashing process. Oxygen plasma oxidizes organic matter and other contaminants on the product surface, decomposing them into volatile gases such as CO and CO2, which are then extracted. The product is then immersed in an acetone solution, followed by immersion in a mixed solution of sulfuric acid and hydrogen peroxide to remove photoresist layer 3. Finally, it is dried.

[0030] In this preferred embodiment, the photoresist layer 3 used to construct the outer circuit pattern is removed before the probe tip is prepared, so that the photoresist layer can be recoated during the subsequent probe preparation.

[0031] The probe card fabrication method of this invention does not fabricate probe tips on the silicon substrate corresponding to the inner circuit pattern after etching the insulating layer corresponding to the inner circuit pattern. Instead, it first constructs the outer circuit pattern using photolithography, then etches the insulating layer corresponding to the outer circuit pattern, but only etches a portion of the thickness, leaving a certain thickness of insulating layer at the outer circuit pattern location. The probe is then fabricated on the silicon substrate corresponding to the inner circuit pattern, and finally, the remaining insulating layer corresponding to the outer circuit pattern is etched. This method avoids constructing the outer circuit pattern using photolithography while the probe is exposed, effectively reducing photoresist residue at the probe tip by more than 85%, and improving the yield of the probe tip product.

[0032] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for fabricating a probe card that reduces photoresist residue, characterized in that, Includes the following steps: Step 10: After etching the insulating layer corresponding to the inner circuit pattern, photoresist is applied to the silicon substrate (1) and the insulating layer (2) to form a photoresist layer (3); exposure and development are performed to form the outer circuit pattern (21). Step 20: Etch the insulating layer (2) corresponding to the outer circuit pattern, with the etching thickness being less than the thickness of the insulating layer (2); Step 30: A probe (4) is fabricated on the silicon substrate corresponding to the inner layer circuit pattern. Step 40: Etch the remaining insulating layer (2) corresponding to the outer circuit pattern.

2. The method for fabricating a probe card with reduced photoresist residue according to claim 1, characterized in that, In step 20, the etching thickness is 1 / 3 to 2 / 3 of the thickness of the insulating layer.

3. The method for fabricating a probe card with reduced photoresist residue according to claim 2, characterized in that, In step 20, the etching thickness is half the thickness of the insulating layer.

4. The method for fabricating a probe card with reduced photoresist residue according to claim 1, characterized in that, In step 20, a preset etching time is obtained based on the thickness of the insulating layer and the etching rate of the etching equipment; the etching equipment is used to etch the insulating layer (2) corresponding to the outer circuit pattern for the preset etching time and then the etching is stopped.

5. The method for fabricating a probe card with reduced photoresist residue according to claim 1, characterized in that, In step 30, before the probe (4) is prepared on the silicon board corresponding to the inner circuit pattern, the photoresist layer (3) is removed.

6. The method for fabricating a probe card with reduced photoresist residue according to claim 5, characterized in that, The removal of the photoresist layer (3) specifically includes: first, treating the surface of the product obtained in step 20 with an ashing process, then immersing the product in an acetone solution, then immersing the product in a mixed solution of sulfuric acid and hydrogen peroxide, and finally drying.

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