Advanced semiconductor packaging thick glue stripping liquid and glue removing method

Abstract

The invention relates to a semiconductor advanced packaging thick glue stripping liquid and a glue removing method. An efficient film stripping liquid system is constructed through an organic solvent, organic alkali, a decrosslinking agent, a swelling agent and a metal corrosion inhibitor. And for advanced packaging of a semiconductor, 60-120 [mu] m thick glue can be rapidly stripped without generating residues, and corrosion to metals such as Cu, Al, Ti and the like deposited by PVD and electroplating is not generated. A rotary spraying spin mode is adopted, and technologies such as spraying flow, rotating speed, pressure, film stripping liquid and cleaning liquid parameters are adjusted, so that thick glue with different aperture ratios and different design structures on a 12-inch wafer can be completely removed, and the problems of photoresist residue, after-tack, metal corrosion, short stripping life and the like in advanced semiconductor packaging are well solved.

Description

Technical Field

[0001] This invention relates to the intersection of wet electronic chemicals and advanced semiconductor packaging manufacturing, specifically to a thick adhesive stripping solution and adhesive removal method for advanced semiconductor packaging. Background Technology

[0002] IC chip manufacturing is inseparable from packaging processes. Advanced semiconductor packaging, through methods such as shortening electrical signal path distances, increasing electrical transmission density, and three-dimensional stacking, not only achieves the functions of external connection and isolation during normal chip packaging and testing, but also enhances chip computing or storage performance and integrates different chips. Therefore, advanced semiconductor packaging is one of the key technology routes for future semiconductor development. One process route for advanced semiconductor packaging is to use thick resist technology to prepare thick metal bumps. After completing the metal bump process, the thick photoresist in the non-bump areas needs to be thoroughly removed. The electronic chemicals used are called thick resist stripping solutions or stripping fluids. Currently, the process of removing thick resist in advanced semiconductor packaging often encounters a series of problems, such as residual thick resist after removal, re-adhesion affecting subsequent etching, slow resist removal speed affecting production cycle, corrosion of seed layer and bump metals affecting electrical signals, low PR loading leading to fewer wafers removed, increasing costs, and increasing the frequency of stripping fluid replacement.

[0003] Therefore, a stripping solution needs to be designed to solve the above problems. Summary of the Invention

[0004] To address the aforementioned issues, a semiconductor advanced packaging thick adhesive stripping solution, by mass fraction, comprises the following components: Organic solvent 60-90%, organic base 0.1-5%, decrosslinking agent 0.1-2%, swelling agent 0.5-5%, metal corrosion inhibitor 0.1-2%, and balance water.

[0005] Furthermore, the organic solvent is a strongly polar solvent, comprising one or more of dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), propylene glycol methyl ether acetate (PGMEA), propylene glycol methyl ether (PGME), γ-butyrolactone (GBL), N,N-dimethylformamide (DMF), N-methylformamide (NMF), or N,N-dimethylacetamide (DMAc), with a single metal impurity ≤30 ppb.

[0006] Furthermore, the ionization constant pKa of the organic base is between 11 and 20, and it comprises one or more of short-chain ammonium hydroxide, aliphatic amines, or heterocyclic amidines / guanidines.

[0007] Furthermore, the short-chain ammonium hydroxide comprises one or more of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), or tetrabutylammonium hydroxide (TBAH).

[0008] Furthermore, the fatty amine comprises one or both of N,N-diisopropylethylamine (DIPEA) or 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU).

[0009] Furthermore, the heterocyclic amidines / guanidines include one or more of 1,5,7-triazabicyclo[4,4,0]dec-5-ene TBD, tetramethylguanidine TMG, or 1,5-diazabicyclo[4,3,0]non-5-ene DBN.

[0010] Furthermore, the decrosslinking agent is one or both of dichloromethane (DCM) or trifluoroacetic acid (TFA).

[0011] Furthermore, the swelling agent is a water-soluble short-chain ketone, including one or more of acetone, butanone, 2-pentanone, 3-pentanone, methyl isobutyl ketone, or cyclohexanone.

[0012] Furthermore, the metal corrosion inhibitor is a nitrogen-containing heterocyclic small molecule organic compound with a pKa value ≤ 7, including one or more of imidazole, indole, or quinoline.

[0013] A method for removing thick adhesive from advanced semiconductor packaging uses the aforementioned stripping solution and employs a rotary spray mode, comprising three stages: stripping, stripping-water washing, and water washing. During the stripping stage, the temperature is controlled at 50-70℃, the rotation speed is 300-800 r / min, and the time is 3-8 min. The stripping-water washing stage is a transitional stage, with a rotation speed of 0-300 r / min and a time of 5-30 s. During the water washing stage, the temperature is at room temperature, the rotation speed is 200-500 r / min, and the time is 20-60 s. The nozzle swings and moves throughout the process.

[0014] The beneficial effects of this invention are as follows: This invention constructs a highly efficient stripping solution system using organic solvents, organic bases, decrosslinking agents, swelling agents, and metal corrosion inhibitors. For 60-120µm thick photoresist in advanced semiconductor packaging, a suitable pKa alkaline organic base reacts with the acidic groups in the photoresist. Combined with the swelling and intercalation effects of the swelling agent, this increases solvent penetration. Furthermore, the decrosslinking agent disrupts the crosslinking of the photoresist, comprehensively accelerating the dissolution of thick photoresist in the organic solvent, enabling rapid stripping without residue. The addition of the metal corrosion inhibitor forms a weakly electrophilic bond with the metal on the wafer surface, forming a soluble organic film that isolates the photoresist from oxidation and alkaline corrosion during the stripping process, thus preventing corrosion of PVD and electroplated metals such as Cu, Al, and Ti. By employing a rotating spray spin mode and adjusting the spray flow rate, rotation speed, pressure, stripping solution, and cleaning solution parameters, thick photoresist with different aperture ratios and design structures on 12-inch wafers can be completely removed. This effectively solves problems such as photoresist residue, re-adhesion, metal corrosion, and short stripping life (existing stripping solutions can only effectively remove thick photoresist from more than 100 12-inch wafers) in advanced semiconductor packaging. Detailed Implementation

[0015] The embodiments of the present invention will be described in detail below with reference to the examples. The following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention.

[0016] (1) Preparation of stripping solution: The components of each example and comparative example are shown in Table 1 by mass fraction, and the remainder is water; mix the components in Table 1 and water at room temperature, and then filter with a 0.2 μm filter to remove particulate impurities to obtain stripping solution.

[0017] (2) Stripping: Stripping is performed on 12-inch wafers with 60-120um thick adhesive. The stripping solution is pumped into the tank of a 40L rotary stripper, the temperature is set to 60℃, and the stripping begins as follows: S1. During the film peeling stage, set the equipment spin rate to 500r / min, the nozzle swing angle to ±60°, the swing distance to ±10cm from the center of the wafer, and the spraying time to 2 times EPD. S2, during the stripping-washing transition stage, set the equipment speed to 300 r / min and spray the wafer with stripping solution for 5 seconds; then, naturally reduce the speed from 300 r / min to 0 r / min, and spray deionized water for 5 seconds while reducing the speed. S3, Water washing stage: Set the equipment speed to 300r / min, time to 30s, and move the swing arm normally; blow dry after the process is complete.

[0018] The number of PR loading wafers was recorded, and the status of photoresist (PR) residue or re-adhesion on the wafer surface and metal corrosion were recorded after the stripping was completed. The results are shown in Table 1.

[0019] EPD: The exact time it takes to peel off the entire thick piece of negative adhesive.

[0020] Table 1

[0021] Comparative examples and implementation examples show that using an alkali with a pKa less than 10 (Comparative Example 9) in the rotary spray resist removal method results in minimal corrosion, but a significantly slower resist removal rate and a smaller number of resist sheets removed. Using an alkali with a pKa greater than 20 results in a higher metal corrosion rate (Comparative Example 10), and both methods are prone to causing photoresist residue and re-adhesion. By selecting suitable organic alkalis and organic solvents, and combining them with swelling agents, de-crosslinking agents, and metal corrosion inhibitors in the resist removal method, better resist removal can be achieved without re-adhesion or residue, without bubbling, and with minimal corrosion to the metal.

Claims

1. A thick adhesive stripping solution for advanced semiconductor packaging, characterized in that, By mass fraction, it consists of the following components: Organic solvent 60-90%, organic base 0.1-5%, decrosslinking agent 0.1-2%, swelling agent 0.5-5%, metal corrosion inhibitor 0.1-2%, and balance water.

2. The semiconductor advanced packaging thick adhesive stripping solution according to claim 1, characterized in that, The organic solvent is a strongly polar solvent, comprising one or more of dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), propylene glycol methyl ether acetate (PGMEA), propylene glycol methyl ether (PGME), γ-butyrolactone (GBL), N,N-dimethylformamide (DMF), N-methylformamide (NMF), or N,N-dimethylacetamide (DMAc), with a single metal impurity ≤30 ppb.

3. The semiconductor advanced packaging thick adhesive stripping solution according to claim 1, characterized in that, The ionization constant pKa of the organic base is between 11 and 20, and it contains one or more of short-chain ammonium hydroxide, fatty amines, or heterocyclic amidines / guanidines.

4. The semiconductor advanced packaging thick adhesive stripping solution according to claim 3, characterized in that, The short-chain ammonium hydroxide comprises one or more of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), or tetrabutylammonium hydroxide (TBAH).

5. The semiconductor advanced packaging thick adhesive stripping solution according to claim 3, characterized in that, The fatty amine comprises one or both of N,N-diisopropylethylamine (DIPEA) or 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU).

6. The semiconductor advanced packaging thick adhesive stripping solution according to claim 3, characterized in that, The heterocyclic amidines / guanidines include one or more of 1,5,7-triazabicyclo[4,4,0]dec-5-ene TBD, tetramethylguanidine TMG, or 1,5-diazabicyclo[4,3,0]non-5-ene DBN.

7. The semiconductor advanced packaging thick adhesive stripping solution according to claim 1, characterized in that, The decrosslinking agent is one or both of dichloromethane (DCM) and trifluoroacetic acid (TFA).

8. The semiconductor advanced packaging thick adhesive stripping solution according to claim 1, characterized in that, The swelling agent is a water-soluble short-chain ketone, including one or more of acetone, butanone, 2-pentanone, 3-pentanone, methyl isobutyl ketone, or cyclohexanone.

9. The semiconductor advanced packaging thick adhesive stripping solution according to claim 1, characterized in that, The metal corrosion inhibitor is a nitrogen-containing heterocyclic small molecule organic compound with a pKa value ≤ 7, including one or more of imidazole, indole, or quinoline.

10. A method for removing thick adhesive from advanced semiconductor packaging, characterized in that, Using the stripping solution described in any one of claims 1-9, a rotary spray mode is adopted, which is divided into three stages: stripping, stripping-washing, and washing. The temperature of the stripping stage is controlled at 50-70℃, the rotation speed is 300-800 r / min, and the time is 3-8 min. The stripping-washing stage is a transition stage with a rotation speed of 0-300 r / min and a time of 5-30 s. The temperature of the washing stage is at room temperature, the rotation speed is 200-500 r / min, and the time is 20-60 s. The nozzle swings and moves throughout the entire process.

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