Low-damage dry etching method and equipment for SD (Secure Digital) layer of display panel

Abstract

The invention discloses a low-damage dry etching method and equipment for an SD (Secure Digital) layer of a display panel, and the method comprises the steps: providing a substrate with a Ti / Al / Ti laminated structure, and forming a photoresist mask for patterning on the substrate; an upper Ti layer in the Ti / Al / Ti laminated structure is etched; under the second etching condition, mixed gas of Cl2, BCl3 and N2 is adopted for etching the middle Al layer in the Ti / Al / Ti laminated structure, the flow of Cl2 ranges from 800 SCCM to 850 SCCM, the flow of BCl3 ranges from 150 SCCM to 180 SCCM, the flow of N2 ranges from 40 SCCM to 60 SCCM, the BI power in the etching cavity ranges from 850 W to 950 W, the pressure intensity in the etching cavity ranges from 1.5 pa to 2 pa, and the bottom temperature in the etching cavity ranges from 60 DEG C to 70 DEG C; and etching the lower Ti layer in the Ti / Al / Ti laminated structure. Therefore, the etching gas is optimized to inhibit the lateral corrosion of the Al layer, and the pressure intensity and the BI power in the etching chamber are optimized and adjusted, so that the pollution of deposition of by-products to the etching chamber can be remarkably reduced, the cleanliness of the etching chamber can be improved, the pollution of the etching chamber can be reduced, and the etching damage of the Al layer can be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of display panels, and in particular to a low-damage dry etching method and equipment for an SD layer of a display panel. Background Art

[0002] With the continuous advancement of display technology, display panels are increasingly used in electronic devices such as smartphones, tablets, and televisions. Etching the SD layer (source / drain metal layer) is a critical step in display panel manufacturing. The SD layer is typically made of metal, and its structure and properties play a crucial role in the electrical performance and reliability of the display panel.

[0003] In dry etching, the SD layer typically consists of a three-layer stack structure, namely Ti / Al / Ti (titanium-aluminum-titanium). In traditional SD etching processes, etching the metal Al layer of the SD layer often results in damage such as lateral corrosion of the Al layer. Etching byproducts (AlCl3) remain in the chamber, causing chamber contamination and ultimately leading to quality issues such as etching damage to the Al layer. Summary of the Invention

[0004] The object of the present invention is to overcome at least one shortcoming of the prior art and provide a low-damage dry etching method for the SD layer of a display panel, thereby improving the etching quality.

[0005] The object of the present invention is achieved through the following technical solutions:

[0006] A low-damage dry etching method for a display panel SD layer, comprising:

[0007] Providing a substrate having a Ti / Al / Ti stacked structure, and forming a photoresist mask for patterning on the substrate;

[0008] Under the first etching condition, a chlorine-containing mixed gas is used to etch the upper Ti layer in the Ti / Al / Ti stacked structure;

[0009] Under the second etching conditions, a mixed gas of Cl2, BCl3 and N2 is used to etch the middle Al layer in the Ti / Al / Ti stacked structure, wherein the Cl2 flow rate is 800-850 SCCM, the BCl3 flow rate is 150-180 SCCM, the N2 flow rate is 40-60 SCCM, the BI power in the etching chamber is 850W-950W, the pressure in the etching chamber is 1.5-2 Pa, and the bottom temperature in the etching chamber is 60-70°C;

[0010] Under the third etching condition, a chlorine-containing mixed gas is used to etch the lower Ti layer in the Ti / Al / Ti stacked structure;

[0011] The photoresist mask is removed to complete the patterning of the SD layer.

[0012] In one embodiment, the substrate is placed in an etching chamber having an inner sidewall with a Y2O3 anti-puncture coating to perform an etching reaction.

[0013] In one embodiment, the chlorine-containing mixed gas includes Cl 2 and BCl 3 .

[0014] In one embodiment, the bottom temperature of the etching chamber is lower than the sidewall temperature of the etching chamber and the upper temperature of the etching chamber.

[0015] In one embodiment, the sidewall temperature in the etching chamber is 83-87°C.

[0016] In one embodiment, the upper temperature in the etching chamber is 83-87°C.

[0017] In one embodiment, in the step of removing the photoresist mask and completing the patterning of the SD layer, O2 plasma is used to remove the photoresist mask.

[0018] In one embodiment, under the second etching condition, the SO power in the etching chamber is 4400-4600W.

[0019] A low-damage dry etching device for a display panel SD layer, comprising

[0020] An etching chamber, wherein a Y2O3 anti-puncture coating is provided on the inner side wall of the etching chamber;

[0021] A gas supply system, the gas supply system is used to deliver etching gas to the etching chamber;

[0022] Power supply system, the power supply system is used to provide SO power and BI power to the etching chamber;

[0023] Temperature control system: The temperature control system is used to control the temperature in the etching chamber.

[0024] In one embodiment, the thickness of the Y2O3 anti-puncture coating is 200-300 μm.

[0025] Compared with the prior art, the present invention has at least the following advantages:

[0026] 1. The low-damage dry etching method for the SD layer of the display panel of the present invention optimizes the etching process gas during the etching of the Al layer, adopts a mixed gas of Cl2, BCl3 and N2 for etching, and adjusts the ratio of each gas at the same time, thereby suppressing the lateral corrosion of the Al layer. At the same time, the pressure and BI power in the etching chamber are optimized and adjusted, thereby significantly reducing the deposition of by-products that contaminate the etching chamber, thereby improving the cleanliness of the etching chamber, reducing the pollution of the etching chamber, and avoiding etching damage to the Al layer.

[0027] 2. The low-damage dry etching method for the display panel SD layer of the present invention improves the upper inner wall of the etching chamber and adds a Y2O3 anti-penetration coating, thereby reducing the etching of the Al layer contaminated by byproduct particles and further reducing the risk of damage to the Al layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments.

[0029] Figure 1 Schematic diagram of the process of a low-damage dry etching method for a display panel SD layer in one embodiment of the present invention; DETAILED DESCRIPTION

[0030] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings.

[0031] See also Figure 1 As shown, a low-damage dry etching method for a display panel SD layer includes:

[0032] S100: providing a substrate having a Ti / Al / Ti stacked structure, and forming a photoresist mask for patterning on the substrate;

[0033] S200: Under the first etching condition, a chlorine-containing mixed gas is used to etch the upper Ti layer in the Ti / Al / Ti (titanium / aluminum / titanium) stacked structure; the chlorine-containing mixed gas is ionized by the SO radio frequency power in the etching chamber to generate plasma, which chemically reacts with Ti to generate volatile TiCl4; for example, the chlorine-containing mixed gas includes Cl2 and BCl3.

[0034] S300: under the second etching conditions, a mixed gas of Cl2, BCl3 and N2 is used to etch the middle Al layer in the Ti / Al / Ti stacked structure, wherein the Cl2 flow rate is 800-850 SCCM, the BCl3 flow rate is 150-180 SCCM, the N2 flow rate is 40-60 SCCM, the BI (bias) power in the etching chamber is 850 W-950 W, the pressure in the etching chamber is 1.5-2 Pa, and the bottom temperature in the etching chamber is 60-70° C.;

[0035] In the traditional etching process, the Cl2 flow rate is relatively high, while the BCl3 flow rate is relatively low, that is, the Cl2 flow rate is usually 1080SCCM, and the BCl3 flow rate is usually 120SCCM. The higher Cl2 flow rate usually aggravates the chemical corrosion of the Al layer, while the lower flow rate of BCl3 will reduce the anisotropic etching and reduce the inhibition of lateral corrosion. In other words, the lower flow rate of BCl3 will lead to aggravated lateral corrosion of the Al layer, causing damage to the Al layer and reducing the etching accuracy. Therefore, the flow rates of Cl2 and BCl3 are adjusted, reducing the Cl2 flow rate and increasing the BCl3 flow rate. After the flow rates of Cl2 and BCl3 are reduced, the effect comparison is as follows:

[0036] Comparative Example: Cl2 / BCl3=1080 / 120 SCCM, the sidewall angle of the Al layer was measured to be 62°±3°;

[0037] Example: Cl2 / BCl3=830 / 165 SCCM, the sidewall angle of the Al layer was measured to be 87°±1°;

[0038] Among them, a clear cross-sectional image of the side wall of the Al layer can be obtained through an existing scanning electron microscope (SEM), and the side wall angle of the Al layer can be calculated through the cross-sectional image to evaluate the degree of lateral corrosion. By reducing the flow rate of Cl2 and increasing the flow rate of BCl3 at the same time, anisotropic etching is enhanced, which is conducive to suppressing the lateral corrosion of the Al layer, thereby significantly reducing lateral corrosion. At the same time, as the Cl2 flow rate is reduced, the generation of the byproduct AlCl3 is also reduced, thereby reducing the amount of AlCl3 remaining on the inner wall of the etching chamber, avoiding further contamination of the etching chamber, and thus preventing the contaminated etching chamber from causing further damage to the etching of the Al layer. In this way, production quality can be improved and damage can be reduced.

[0039] In order to further improve the protection of the Al layer and reduce the damage problems such as lateral corrosion of the Al layer, N2 is added to the etching gas. The plasma dissociates N2 to generate active N atoms (N*). N* reacts with the exposed Al surface to form a dense AlN layer. The chemical inertness of AlN blocks the corrosion of Cl2 on the Al side wall, thereby achieving the protection of the Al layer. The reaction equation is: 2Al+2N *→2AlN, preferably, the flow rate of N2 is 40-60 SCCM.

[0040] The BI power in the etching chamber in the traditional process is relatively high, generally 1200W. Excessive BI power will aggravate the physical sputtering corrosion of Al, thereby aggravating the damage of the Al layer. Therefore, in order to reduce the damage of the Al layer, the BI power is reduced from 1200W to 850W-950W. Since the BI power directly affects the ion bombardment energy, reducing the BI power can reduce the high-energy Cl + Physical sputtering of the Al surface can avoid damage such as pits on the Al layer surface. The comparison is as follows:

[0041] Comparative Example: The BI power is 1200 W, and the surface roughness Ra of the Al layer is measured to be 35±3 nm. At this power, the etching rate is 510±15 (nm / min);

[0042] Example 1: The BI power was reduced to 950W, and the surface roughness Ra of Al was measured to be 20±1nm. At this power, the etching rate was 450±5 (nm / min);

[0043] Example 2: The BI power was reduced to 700 W, and the surface roughness Ra of Al was measured to be 15±0.5 nm. At this power, the etching rate was 380±5 (nm / min);

[0044] For example, the surface roughness Ra of the Al layer can be obtained by scanning and measuring with existing atomic force microscope equipment. By reducing the BI power to 850W-950W, the surface roughness Ra of the Al layer can be significantly reduced, and the etching rate in this BI power range is relatively good. This can improve the etching quality of the Al layer, reduce etching damage, and maintain a high etching rate to ensure production efficiency.

[0045] The pressure in the etching chamber in the traditional process is 3-5Pa, which is relatively high and may cause the etching reaction products to stay and not be easily discharged into the etching chamber, thereby damaging the etching of the Al layer during etching and reducing the etching quality of the Al layer. Therefore, by reducing the pressure in the etching chamber from 3Pa to 1.5-2Pa, the physical directionality of the ions can be improved, the deposition of the product (AlCl3) can be reduced, and the product can be prevented from staying on the side walls and in the cavity, causing problems such as short circuits or increased contact resistance, thereby avoiding secondary damage to the Al layer caused by the contaminated etching chamber, thereby improving the etching accuracy of the Al layer; the following comparison:

[0046] Comparative Example: The pressure in the etching chamber is 3-5 Pa, and the measured AlCl3 residual thickness is 50 ± 10 nm;

[0047] Example: The pressure in the etching chamber is 1.5-2 Pa, and the residual thickness of AlCl3 is measured to be 3.5±0.5 nm;

[0048] For example, X-ray photoelectron spectroscopy can be used to detect the thickness of AlCl3; after reducing the pressure, the ion directionality can be enhanced, thereby effectively reducing the residual thickness of AlCl3.

[0049] The bottom temperature of the etching chamber in the conventional process is usually 50°C, which is relatively low. In order to further discharge the products generated during etching from the etching chamber, the bottom temperature is increased from 50°C to above 60°C, preferably 65°C, so as to reduce the residual thickness of AlCl3. In this embodiment, the bottom temperature of the etching chamber is lower than the side wall temperature and the upper temperature of the etching chamber. In this way, a temperature gradient is formed on the inner walls of the etching chamber, and the side wall temperature is higher, thereby suppressing the deposition of side wall byproducts. Maintaining a low bottom temperature can also prevent the substrate from overheating and causing deformation of the photoresist mask, thereby ensuring etching accuracy. Specifically, the side wall temperature of the etching chamber is 83-87°C, preferably 85°C; the upper temperature of the etching chamber is 83-87°C, preferably 85°C.

[0050] S400: Under the third etching condition, a chlorine-containing mixed gas is used to etch the lower Ti layer in the Ti / Al / Ti stacked structure; the chlorine-containing mixed gas is ionized by the SO radio frequency power in the etching chamber to generate plasma, which chemically reacts with Ti to generate volatile TiCl4; wherein the etching conditions of the upper Ti layer and the lower Ti layer are the same, that is, the first etching condition is the same as the third etching condition; for example, the chlorine-containing mixed gas includes Cl2 and BCl3.

[0051] S500: removing the photoresist mask to complete the patterning of the SD layer. In this embodiment, O2 plasma is used to remove the photoresist mask.

[0052] It should also be noted that, in the present invention, by controlling the layered etching of the SD layer, it is possible to avoid premature exposure of the Al layer to the highly active Cl2 environment, thereby ensuring the etching accuracy of the Al layer;

[0053] In one embodiment, a substrate is placed in an etching chamber whose inner sidewalls are coated with a Y2O3 anti-penetration coating to undergo an etching reaction. Conventional etching chambers have Al2O3 metal plates on their upper inner sidewalls. During the etching process, the Al2O3 metal plates are easily penetrated. After penetration, the Al2O3 metal plates are less likely to absorb product, resulting in excessive particles that easily fall off, causing etching residues and potentially damaging the underlying Al layer. Therefore, by providing a Y2O3 anti-penetration coating on the inner sidewalls of the etching chamber, the probability of penetration is reduced, thereby preventing product adhesion within the etching chamber after penetration, causing them to fall off and form etching residues, thereby preventing damage to the Al layer.

[0054] Preferably, in the second etching condition, the SO (radio frequency) power in the etching chamber is 4400-4600W.

[0055] A low-damage dry etching device for a display panel SD layer, comprising:

[0056] An etching chamber, wherein a Y2O3 anti-puncture coating is provided on the inner side wall of the etching chamber;

[0057] A gas supply system, the gas supply system is used to deliver etching gas to the etching chamber;

[0058] Power supply system, the power supply system is used to provide SO (radio frequency) power and BI (bias) power to the etching chamber;

[0059] Temperature control system: The temperature control system is used to control the temperature in the etching chamber.

[0060] Preferably, the thickness of the Y2O3 anti-puncture coating is 200-300 μm.

[0061] The above embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A low-damage dry etching method for a display panel SD layer, characterized in that: include: Providing a substrate having a Ti / Al / Ti stacked structure, and forming a photoresist mask for patterning on the substrate; Under the first etching condition, a chlorine-containing mixed gas is used to etch the upper Ti layer in the Ti / Al / Ti stacked structure; Under the second etching conditions, a mixed gas of Cl2, BCl3 and N2 is used to etch the middle Al layer in the Ti / Al / Ti stacked structure, wherein the Cl2 flow rate is 800-850 SCCM, the BCl3 flow rate is 150-180 SCCM, the N2 flow rate is 40-60 SCCM, the BI power in the etching chamber is 850W-950W, the pressure in the etching chamber is 1.5-2 Pa, and the bottom temperature in the etching chamber is 60-70°C; Under the third etching condition, a chlorine-containing mixed gas is used to etch the lower Ti layer in the Ti / Al / Ti stacked structure; The photoresist mask is removed to complete the patterning of the SD layer.

2. The low-damage dry etching method for the display panel SD layer according to claim 1, characterized in that: The substrate is placed in an etching chamber with a Y2O3 anti-penetration coating on the inner sidewall to perform etching reaction.

3. The low-damage dry etching method for the display panel SD layer according to claim 1, characterized in that: The chlorine-containing mixed gas includes Cl2 and BCl3.

4. The low-damage dry etching method for the display panel SD layer according to claim 1, characterized in that: The bottom temperature in the etching chamber is lower than the side wall temperature in the etching chamber and the upper temperature in the etching chamber.

5. The low-damage dry etching method for the display panel SD layer according to claim 4, characterized in that: The sidewall temperature in the etching chamber is 83-87°C.

6. The low-damage dry etching method for the display panel SD layer according to claim 4, characterized in that: The upper temperature in the etching chamber is 83-87°C.

7. The low-damage dry etching method for the display panel SD layer according to claim 1, characterized in that: In the step of removing the photoresist mask and completing the patterning of the SD layer, O2 plasma is used to remove the photoresist mask.

8. The low-damage dry etching method for the display panel SD layer according to claim 1, characterized in that: In the second etching condition, the SO power in the etching chamber is 4400-4600w.

9. A low-damage dry etching device for the SD layer of a display panel, characterized in that: include An etching chamber, wherein a Y2O3 anti-puncture coating is provided on the inner side wall of the etching chamber; A gas supply system, the gas supply system is used to deliver etching gas to the etching chamber; Power supply system, the power supply system is used to provide SO power and BI power to the etching chamber; Temperature control system: The temperature control system is used to control the temperature in the etching chamber.

10. The low-damage dry etching device for the display panel SD layer according to claim 9, characterized in that: The thickness of the Y2O3 anti-puncture coating is 200-300μm.

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