Method for removing residues of chemical plating polyimide layer

Abstract

The invention provides a method for removing residues of a chemical plating polyimide layer, which comprises the following steps of: forming a polyimide layer on a substrate, forming a photoresist layer on the polyimide layer, and patterning the photoresist layer by photoetching to expose part of the polyimide layer; chemical etching is adopted to remove exposed polyimide, and floating polyimide residues exist in the etching process; removing the residual photoresist layer; and introducing a mixed gas of O2 and N2 into the reaction chamber, and carrying out thermal oxidation treatment on the substrate, so that the polyimide residues are removed. According to the method, polyimide residues are effectively removed, and the subsequent packaging problem of the chip is solved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, in particular to a method for removing residues of a chemically plated polyimide layer. Background Art

[0002] Polyimide (PI) has excellent heat resistance and thermal oxidation resistance, and maintains excellent dielectric, insulating, and radiation-resistant properties over a wide temperature range. It is widely used in electronics, aerospace, and automotive industries. As a top protective layer in chips, polyimide provides moisture isolation, insulation, and chip protection.

[0003] After spin coating, polyimide is removed through development, stripping, and chemical plating. The polyimide chemical plating process uses organic solvents or acidic solutions. During the polyimide dissolution process, polyimide may float out, resulting in polyimide residues that affect subsequent chip packaging.

[0004] In order to solve the above problems, it is necessary to propose a new method for removing the residual electroless polyimide layer. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a method for removing the residues of the electroless polyimide layer, which is used to solve the problem that in the prior art, the polyimide electroless plating process uses organic solvents or acidic solutions, and the polyimide dissolution process may cause polyimide to float out, resulting in polyimide residues and affecting the subsequent packaging of the chip.

[0006] To achieve the above-mentioned and other related purposes, the present invention provides a method for removing residual electroless polyimide layer, comprising:

[0007] Step 1: forming a polyimide layer on a substrate, forming a photoresist layer on the polyimide layer, and patterning the photoresist layer by photolithography so that a portion of the polyimide layer is exposed;

[0008] Step 2: chemical etching is used to remove the exposed polyimide. During the etching process, there are polyimide residues that float outward;

[0009] Step 3: removing the remaining photoresist layer;

[0010] Step 4: introducing a mixed gas of O 2 and N 2 into the reaction chamber to perform a thermal oxidation treatment on the substrate to remove the polyimide residue.

[0011] Preferably, the surface of the substrate in step 1 comprises a metal layer.

[0012] Preferably, the material of the metal layer in step 1 is aluminum.

[0013] Preferably, the chemical etching in step 2 uses an organic solvent or an acidic solution.

[0014] Preferably, in step three, the photoresist layer is removed by an ashing process and a wet cleaning method.

[0015] Preferably, the volume ratio of O2 to N2 in step 4 is 10:1 to 200:1.

[0016] Preferably, the temperature range of the thermal oxidation treatment in step 4 is 100-500°C.

[0017] As described above, the method for removing the residual electroless polyimide layer of the present invention has the following beneficial effects:

[0018] The present invention effectively removes polyimide residues and solves the problem of subsequent chip packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the method for removing residual electroless polyimide layer according to the present invention. DETAILED DESCRIPTION

[0020] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0021] See also Figure 1 The present invention provides a method for removing residual electroless polyimide layer, comprising:

[0022] Step 1: forming a polyimide layer on a substrate, forming a photoresist layer on the polyimide layer, and patterning the photoresist layer by photolithography so that a portion of the polyimide layer is exposed;

[0023] In some embodiments, the surface of the substrate in step 1 comprises a metal layer.

[0024] In some embodiments, the material of the metal layer in step 1 is aluminum.

[0025] Step 2: chemical etching is used to remove the exposed polyimide. During the etching process, there are polyimide residues that float outward;

[0026] In some embodiments, the chemical etching in step 2 uses an organic solvent or an acidic solution.

[0027] Step 3: removing the remaining photoresist layer;

[0028] In some embodiments, the ashing process and wet cleaning method in step three remove the photoresist layer.

[0029] Step 4: A mixed gas of O2 and N2 is introduced into the reaction chamber to perform thermal oxidation treatment on the substrate to remove the polyimide residue. The selective removal of the polyimide residue is achieved through a non-contact thermal oxidation reaction. The non-contact feature avoids the effects of physical ion bombardment or solution penetration on the metal layer.

[0030] In some embodiments, the volume ratio of O2 to N2 in step four is 10:1 to 200:1, for example 50:1, 100:1, and 150:1. O2 reacts with polyimide (hydrocarbon) at high temperature to generate volatile products such as CO2 / H2O. N2 is used as a carrier gas to suppress excessive aggregation of oxygen free radicals and reduce oxidation of the reaction system through a dilution effect, thereby enabling the oxidation rate of the metal aluminum layer to be lower than its damage threshold.

[0031] In some embodiments, the temperature range of the thermal oxidation treatment in step 4 is 100-500°C, for example, 100°C, 200°C, 300°C, 400°C, or 500°C.

[0032] It should be noted that the illustrations provided in this embodiment are only used to schematically illustrate the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0033] In summary, the present invention effectively removes polyimide residues and solves the problem of subsequent chip packaging. Therefore, the present invention effectively overcomes various shortcomings of the prior art and has high industrial application value.

[0034] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A method for removing residual electroless polyimide layer, characterized in that: At least: Step 1: forming a polyimide layer on a substrate, forming a photoresist layer on the polyimide layer, and patterning the photoresist layer by photolithography so that a portion of the polyimide layer is exposed; Step 2: chemical etching is used to remove the exposed polyimide. During the etching process, there are polyimide residues that float outward; Step 3, removing the remaining photoresist layer; Step 4: introducing a mixed gas of O 2 and N 2 into the reaction chamber to perform a thermal oxidation treatment on the substrate to remove the polyimide residue.

2. The method for removing residual electroless polyimide layer according to claim 1, wherein: The surface of the substrate in step 1 comprises a metal layer.

3. The method for removing residual electroless polyimide layer according to claim 2, wherein: The material of the metal layer in step 1 is aluminum.

4. The method for removing residual electroless polyimide layer according to claim 1, wherein: The chemical etching in step 2 uses an organic solvent or an acidic solution.

5. The method for removing residual electroless polyimide layer according to claim 1, wherein: In step three, the photoresist layer is removed by an ashing process and a wet cleaning method.

6. The method for removing residual electroless polyimide layer according to claim 1, wherein: The volume ratio of O2 to N2 in step 4 is 10:1 to 200:

1.

7. The method for removing residual electroless polyimide layer according to claim 1, wherein: The temperature range of the thermal oxidation treatment in step 4 is 100-500°C.

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