Etching solution capable of forming molybdenum trailing

Abstract

The invention provides an etching solution capable of forming molybdenum trailing with high uniformity for a Mo / Al / Mo / MoOx laminated metal film layer. The etching solution contains phosphoric acid, nitric acid, acetic acid, an additive and ultrapure water. The invention provides a scheme for solving the problem that the molybdenum etching rate is higher than the aluminum etching rate in the transverse etching of laminated metal structures such as molybdenum-aluminum, molybdenum-aluminum-molybdenum and the like, the etching precision is improved, and the product yield is improved.

Description

Technical Field

[0001] The invention belongs to the cross field of metal wet etching and semiconductor display technology, and in particular relates to an etching solution capable of forming a molybdenum tail. Background Art

[0002] Due to its low cost and good electrical conductivity, aluminum and its alloys have become important materials in semiconductor display manufacturing. Multilayer metals such as molybdenum-aluminum, molybdenum-aluminum-molybdenum and its alloys are often used as metal film layers in TFT-LCD manufacturing. The metal film layer used for circuit layout needs to be etched to form a specific pattern.

[0003] During etching Mo / Al / Mo / MoO x During lamination, if the amount of side etching of molybdenum is less than that of aluminum, it means that molybdenum tailing is generated, and if the amount of side etching of molybdenum is greater than that of aluminum, it means that molybdenum indentation is generated. Different display manufacturing technologies have different requirements for molybdenum indentation or molybdenum tailing. In order to improve the stability of the process and the product yield, some display manufacturing technologies require avoiding the formation of molybdenum indentation. The present invention aims to provide a molybdenum-aluminum-molybdenum etching solution that can improve molybdenum indentation and is compatible with multiple aluminum and alloy multilayer metals. Summary of the invention

[0004] In order to improve the Mo / Al / Mo / MoO x The product performance and product yield of the laminated metal film layer, the present application provides an etching solution that can form a molybdenum tail, and the molybdenum tail is controlled to 0~0.25um. The technical solution includes the following contents: An etching solution capable of forming a molybdenum tail, the etching solution comprising: 60-75% phosphoric acid, 1-5% nitric acid, 10-20% acetic acid, 0.3%-8% additives and the remainder water.

[0005] The additives include additive A and additive B; the additive A is one or more of R-(-)-sec-octanol, n-heptyl alcohol, 2-isopropyl-1,7-heptanediol, 1,2-hexanediol or Tween 40.

[0006] The additive B includes at least one of hydrogen phosphate, dihydrogen phosphate, citrate, nitrate, acetate, persulfate, diethylene glycol or phenyl urea.

[0007] The salt is selected from one or more of sodium salt, potassium salt or ammonium salt.

[0008] The dosage of the additive A is 0.005-0.05%; the dosage of the additive B is 0.3-7.95%.

[0009] An etching solution capable of forming a molybdenum tail is used for etching a metal stack containing molybdenum, aluminum and molybdenum oxide, avoiding the indentation of molybdenum and achieving the adjustment of the molybdenum tail between 0-0.25um.

[0010] The beneficial effects of the present invention are as follows: according to the requirements of different process routes, the CD Bias, Taper, Mo Tip and Mo Tail of the etching morphology are adjusted to avoid the generation of molybdenum indentation, and the molybdenum tail (including Mo Tip and Mo Tail) can be adjusted within the range of 0-0.25um, the Taper can be adjusted within the range of 45-80°, and the critical dimension deviation (CDBias) can be adjusted within the range of 0.05-0.5um. The critical dimension deviation (CD Bias), the tilt angle (Taper), the dimension deviation of the top layer molybdenum relative to aluminum (Mo Tip) and the dimension deviation of the bottom layer molybdenum relative to aluminum (Mo Tail) are more uniform, and the morphology size after etching is more uniform, which is conducive to improving the etching yield. DETAILED DESCRIPTION

[0011] The embodiments of the present invention will be described in detail below in conjunction with the examples. The following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. The experimental conditions not clearly marked in the examples are assumed to be selected according to conventional methods and conditions in the art or the product manual.

[0012] The substrate used in the embodiment is consistent with that in the comparative example, the metal film layer is MoOx / Mo / Al / Mo, and the thickness of each film layer is 500 / 150 / 3000 / 550 (unit: angstrom) respectively.

[0013] Preparation of etching solution: Phosphoric acid, nitric acid, acetic acid, additives and the remainder of ultrapure water are mixed according to the components in Table 1.

[0014] Table 1 Etching solution formula of embodiment and comparative example (unit: %)

[0015] The etching solution of the above embodiment and comparative example was used to etch MoO x / Mo / Al / Mo metal film layer is etched, and then a scanning electron microscope is used to detect the half-edge critical dimension deviation (CD Bias) of aluminum relative to the photoresist, the tilt angle (Taper), the size deviation of the top molybdenum relative to aluminum (Mo Tip), and the size deviation of the bottom molybdenum relative to aluminum (Mo Tail).

[0016] Table 2 Etching data of examples and comparative examples

[0017] In the table, "-" means that aluminum exceeds molybdenum after etching. From the data in the table, it can be seen that when additives A and additives B are used in combination, the occurrence of molybdenum indentation can be completely avoided, and the adjustment of molybdenum tailing (including Mo Tip and Mo Tail) in the range of 0~0.25um, the adjustment of Taper in the range of 45-80°, and the adjustment of critical dimension deviation (CD Bias) in the range of 0.05-0.5um can be achieved at the same time. Finally, the half-edge critical dimension deviation (CD Bias) of aluminum relative to photoresist, the tilt angle (Taper), the size deviation of the top molybdenum relative to aluminum (Mo Tip), and the size deviation of the bottom molybdenum relative to aluminum (Mo Tail) are more stable, which is conducive to the uniform size of the metal stack after etching and improves the yield.

Claims

1. An etching solution capable of forming a molybdenum tail, characterized in that: The etching solution comprises: 60-75% phosphoric acid, 1-5% nitric acid, 10-20% acetic acid, 0.3%-8% additives and the remainder water.

2. The etching solution capable of forming a molybdenum tail according to claim 1, characterized in that: The additives include additive A and additive B; the additive A is one or more of R-(-)-sec-octanol, n-heptyl alcohol, 2-isopropyl-1,7-heptanediol, 1,2-hexanediol or Tween 40.

3. The etching solution capable of forming a molybdenum tail according to claim 2, characterized in that: The additive B includes at least one of hydrogen phosphate, dihydrogen phosphate, citrate, nitrate, acetate, persulfate, diethylene glycol or phenyl urea.

4. The etching solution capable of forming a molybdenum tail according to claim 3, characterized in that: The salt is selected from one or more of sodium salt, potassium salt or ammonium salt.

5. The etching solution capable of forming a molybdenum tail according to claim 4, characterized in that: The dosage of the additive A is 0.005-0.05%; the dosage of the additive B is 0.3-7.95%.

6. Use of the etching solution according to any one of claims 1 to 5, characterized in that: Used for etching metal stacks containing molybdenum, aluminum and molybdenum oxide to avoid molybdenum indentation and achieve adjustment of molybdenum tailing between 0-0.25um.

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