Copper-nickel-gold bump production process based on display driving chip

Abstract

The invention discloses a copper-nickel-gold bump production process based on a display driving chip. The copper-nickel-gold bump production process comprises the following steps: S1, carrying out pre-cleaning treatment on a wafer; s2, opening the passivation layer to expose the bonding pad, and etching the wafer to form a counter bore; s3, the counter bores are filled with metal; s4, performing a yellow light process on the wafer, and forming a front rewiring layer on the wafer; s5, thinning the wafer to expose the counter bore to form a through hole; s6, performing UBM on the surface of the wafer, and forming a bump metallization layer on the rewiring layer; s7, electroplating the outer surface of the wafer to form an electroplated layer; s8, removing the bump metallization layer, which is not shielded by the electroplated layer, on the surface of the wafer; and S9, backflow and shaping of the bump. According to the production process of the wafer bump, the problem of adhesive tape residue can be effectively solved, the residual adhesive tape can be effectively removed, meanwhile, the problem of metal residue at the edge of the wafer can be effectively solved, and the problems of short circuit, packaging reliability reduction or follow-up process pollution can be avoided.

Description

Technical Field

[0001] This invention relates to the field of wafer bumping technology, specifically a copper-nickel-gold bumping manufacturing process based on display driver chips. Background Technology

[0002] Display driver chips are integrated circuits, which are electronic components that integrate a large number of tiny electronic components such as transistors, resistors, and capacitors onto a small semiconductor material. Wafers are the basic material for chip manufacturing, and wafer bumping technology can provide significant performance, size, and overall cost advantages in semiconductor packaging.

[0003] In current wafer bumping processes, especially electroplating, if the tape (such as UV tape or heat release tape) used after grinding (such as backside thinning) remains on the wafer surface during the wafer bumping electroplating process, it may cause contamination of subsequent processes or bump failure.

[0004] Therefore, in order to correct the above-mentioned defects, we propose a copper-nickel-gold bump manufacturing process based on display driver chips. Summary of the Invention

[0005] The technical problem solved by this invention is to propose a copper-nickel-gold bump manufacturing process based on a display driver chip.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a copper-nickel-gold bump manufacturing process based on a display driver chip, comprising the following steps:

[0007] S1, pre-cleaning of wafers;

[0008] S2, passivation layer opening, exposes pads, and etches countersunk holes on the wafer;

[0009] S3. Fill the countersunk hole with metal;

[0010] S4. Perform photolithography on the wafer to form a front redistribution layer on the wafer;

[0011] S5. Thin the wafer to expose the countersunk holes and form through holes;

[0012] S6. Perform UBM on the surface of the wafer to form a bump metallization layer on the redistribution layer;

[0013] S7. Electroplating is performed on the outer surface of the wafer to form an electroplating layer;

[0014] S8. Remove the bump metallization layer on the wafer surface that is not covered by the electroplating layer;

[0015] S9. Bump reflow and shaping;

[0016] S10. Use a step-by-step cleaning method: soak in acetone 2 for a period of time, then rinse with IPA, and finally rinse with deionized water.

[0017] Furthermore, in step S1, the wafer pre-cleaning process employs either RCA cleaning or plasma cleaning.

[0018] Furthermore, in step S2, the wafer etching is performed using either wet etching or dry etching.

[0019] Furthermore, when using wet etching, the wafer rotation speed is increased, and the rotation speed is maintained at 200-500 rpm.

[0020] Furthermore, when using wet etching, a spray etching device can be used for etching.

[0021] Furthermore, when dry etching is used, anisotropic etching gas is used in conjunction with edge-focused ion beam correction.

[0022] Furthermore, in step S7, a cathode shielding ring is installed in the electroplating tank during electroplating.

[0023] Furthermore, in step S5, the area of ​​residual adhesive tape at the edge is ablated using a laser.

[0024] Furthermore, in step S9, during reflow soldering, preheating is required first, with a preheating temperature of 150-180℃, and the reflow soldering temperature is controlled at 250-280℃.

[0025] Compared with the prior art, the beneficial effects of the present invention are: the wafer bump production process of the present invention can effectively solve the problem of tape residue, effectively remove residual tape, and at the same time, effectively solve the problem of metal residue at the wafer edge, avoiding short circuits, reduced packaging reliability, or contamination in subsequent processes. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the process flow of the present invention. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] This invention provides a technical solution:

[0029] Please see Figure 1A copper-nickel-gold bump manufacturing process based on a display driver chip includes the following steps:

[0030] S1, pre-cleaning of wafers;

[0031] S2, passivation layer opening, exposes pads, and etches countersunk holes on the wafer;

[0032] S3. Fill the countersunk hole with metal;

[0033] S4. Perform photolithography on the wafer to form a front redistribution layer on the wafer;

[0034] S5. Thin the wafer to expose the countersunk holes and form through holes;

[0035] S6. Perform UBM on the surface of the wafer to form a bump metallization layer on the redistribution layer;

[0036] S7. Electroplating is performed on the outer surface of the wafer to form an electroplating layer;

[0037] S8. Remove the bump metallization layer on the wafer surface that is not covered by the electroplating layer;

[0038] S9. Bump reflow and shaping;

[0039] S10. Use a step-by-step cleaning method: soak in acetone for a period of time, then rinse with IPA, and finally rinse with deionized water.

[0040] In step S1, the wafer pre-cleaning process uses either RCA cleaning or plasma cleaning. During cleaning, the temperature (70-80℃) and time (5-10 minutes) are as follows:

[0041] RCA cleaning:

[0042] SC1 (NH4OH / H2O2 / H2O) removes organic matter and particles.

[0043] SC2 (HCl / H2O2 / H2O) removes metal ions.

[0044] Plasma cleaning: O2 or Ar plasma (power 100-300W) activates the surface.

[0045] In step S2, the wafer etching is performed using either wet etching or dry etching:

[0046] When using wet etching, increase the wafer rotation speed, keeping the rotation speed between 200-500 rpm, to improve the fluidity of the etching solution at the edges.

[0047] When using wet etching, spray etching equipment, such as a single-wafer cleaning machine, can be used instead of immersion etching.

[0048] When dry etching is used, anisotropic etching gases (such as Cl2 / BCl3 for Cu) are used in conjunction with edge-focused ion beam correction.

[0049] In step S7, during electroplating, a cathode shielding ring is placed in the electroplating tank to reduce the edge electric field strength.

[0050] In step S5, the residual adhesive tape area at the edge is ablated using a laser with a wavelength of 532nm / 1064nm to avoid overall rework.

[0051] In step S9, during reflow soldering, the temperature profile is: preheating (150-180℃) → reflow (250-280℃) → cooling (slope <3℃ / s);

[0052] Laser shaping: For bumps, local laser melting improves coplanarity (accuracy ±1μm).

[0053] Finally, a step-by-step cleaning method is used: soaking in acetone for a period of time, followed by IPA rinsing, and finally rinsing with deionized water.

[0054] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A copper-nickel-gold bump manufacturing process based on a display driver chip, characterized in that: Includes the following steps: S1, pre-cleaning of wafers; S2, passivation layer opening, exposes pads, and etches countersunk holes on the wafer; S3. Fill the countersunk hole with metal; S4. Perform photolithography on the wafer to form a front redistribution layer on the wafer; S5. Thin the wafer to expose the countersunk holes and form through holes; S6. Perform UBM on the surface of the wafer to form a bump metallization layer on the redistribution layer; S7. Electroplating is performed on the outer surface of the wafer to form an electroplating layer; S8. Remove the bump metallization layer on the wafer surface that is not covered by the electroplating layer; S9. Bump reflow and shaping; S10. Use a step-by-step cleaning method: soak in acetone for a period of time, then rinse with IPA, and finally rinse with deionized water.

2. The copper-nickel-gold bump manufacturing process based on a display driver chip according to claim 1, characterized in that: In step S1, the wafer pre-cleaning process uses either RCA cleaning or plasma cleaning.

3. The copper-nickel-gold bump manufacturing process based on a display driver chip according to claim 1, characterized in that: In step S2, the wafer etching is performed using either wet etching or dry etching.

4. The copper-nickel-gold bump manufacturing process based on a display driver chip according to claim 3, characterized in that: When using wet etching, increase the wafer rotation speed and keep the rotation speed between 200-500 rpm.

5. The copper-nickel-gold bump manufacturing process based on a display driver chip according to claim 4, characterized in that: When using wet etching, a spray etching device can be used for etching.

6. The copper-nickel-gold bump manufacturing process based on a display driver chip according to claim 3, characterized in that: When dry etching is used, anisotropic etching gas is used in conjunction with edge-focused ion beam correction.

7. The copper-nickel-gold bump manufacturing process based on a display driver chip according to claim 1, characterized in that: In step S7, a cathode shielding ring is installed in the electroplating tank during electroplating.

8. The copper-nickel-gold bump manufacturing process based on a display driver chip according to claim 1, characterized in that: In step S5, the area with residual adhesive tape at the edge is ablated using a laser.

9. The copper-nickel-gold bump manufacturing process based on a display driver chip according to claim 1, characterized in that: In step S9, preheating is required before reflow soldering. The preheating temperature is 150-180℃, and the reflow soldering temperature is controlled at 250-280℃.

Images