Low-cost mask, preparation method thereof and photoetching method applying mask

Abstract

The invention relates to a low-cost mask plate and a preparation method and a photoetching method thereof, the low-cost mask plate comprises a substrate and a thermal transfer ribbon attached to the substrate, the thermal transfer ribbon is provided with a light-transmitting area and a non-light-transmitting area which are designed in advance, and the light-transmitting area and the non-light-transmitting area jointly form a pattern of a chip. A thermal transfer ribbon printer is used for printing a chip pattern on a thermal transfer ribbon, after the thermal transfer ribbon is printed, an area where a coating falls is transparent and can penetrate ultraviolet light of a photoetching machine, an area where the coating is reserved on the thermal transfer ribbon is black and can shield the ultraviolet light of the photoetching machine, and the thermal transfer ribbon is attached to a substrate to form a mask plate. The chip pattern on the thermal transfer ribbon is transferred to the wafer; compared with an electron beam or laser etching technology processing mask, the thermal transfer ribbon printing processing mask is low in cost and short in processing period; according to the mask, thermal transfer ribbon printing, cutting, attaching and the like are adopted, chip pattern printing is convenient and fast, and batch production can be achieved through the cutting and attaching processes; and for the mask of the low-precision chip, the preparation method can be used for quickly preparing the mask of the low-precision chip.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductors, in particular to a low-cost mask plate and a preparation method thereof, and a photolithography method using the mask plate. Background Art

[0002] The photomask is one of the key components in the semiconductor manufacturing process, and is mainly used to transfer chip patterns in the photolithography process. Photolithography is the core step in semiconductor manufacturing. Specifically, the chip pattern on the mask is projected onto a wafer coated with photoresist to form a fine structure at the micron or even nanometer level. The mask is usually made of a high-purity quartz or glass substrate, coated with a layer of chromium or other metal film on the surface, and the designed chip pattern is accurately transferred to the mask through electron beam or laser etching technology. Although the electron beam or laser etching platemaking technology has high precision, the equipment is expensive, the production requirements are high, the process is complex, the production cycle is long, and the production cost is high; and in actual production, the chip design often needs to be changed, which will also increase the production cost of the photomask and extend the production cycle accordingly.

[0003] Since the line width of low-end optical communication chips is more than 200um, the precision requirements for the mask will be reduced. In order to meet the manufacturing needs of low-end optical communication chips, it is necessary to develop a low-cost mask and lithography method for low-end chips. Summary of the invention

[0004] The first technical problem to be solved by the present invention is to provide a low-cost mask plate applied to low-end chips in view of the above-mentioned prior art.

[0005] The second technical problem to be solved by the present invention is to provide a method for preparing the above-mentioned mask plate in view of the above-mentioned prior art.

[0006] The third technical problem to be solved by the present invention is to provide a photolithography method using the above mask.

[0007] The technical solution adopted by the present invention to solve the first technical problem mentioned above is: a low-cost mask plate, including a substrate and a carbon tape attached to the surface of the substrate, the carbon tape has pre-designed transparent areas and non-transparent areas, and the transparent areas and non-transparent areas together constitute a chip pattern.

[0008] Preferably, the chip pattern is printed by a ribbon printer. The ribbon is placed in the ribbon printer, and the ribbon printer prints on the ribbon according to the pre-designed chip pattern. Since the line width of low-end chips is more than 200um, the ribbon printer can print the chip pattern; and compared with electron beam or laser etching technology, the preparation cost of the ribbon printer can be greatly reduced.

[0009] In order to facilitate the design of the chip pattern, the chip pattern is designed by CAD software. The chip pattern designed by CAD software is printed by a carbon ribbon printer, and the chip pattern is presented on the label printed by the carbon ribbon printer. The area where the coating falls off on the printed carbon ribbon is the light-transmitting area, and the area where the coating is retained on the printed carbon ribbon is the non-light-transmitting area. The light-transmitting area and the non-light-transmitting area together constitute the chip pattern.

[0010] Preferably, the carbon ribbon is one of a mixed-base carbon ribbon, a resin-base carbon ribbon or a wash-mark carbon ribbon. Considering that the carbon ribbon has steps such as cutting, attaching and ultraviolet light irradiation in the subsequent process, a friction-resistant, high-temperature-resistant and chemical-resistant carbon ribbon is selected.

[0011] Preferably, the carbon ribbon is a resin-based carbon ribbon.

[0012] Preferably, the substrate is a glass plate.

[0013] The technical solution adopted by the present invention to solve the second technical problem is: a method for preparing the above-mentioned mask, comprising the following steps:

[0014] Step S1: Draw the required chip pattern on the drawing software according to the chip design requirements;

[0015] Step S2: Printing the chip pattern drawn on the drawing software on the carbon ribbon by the carbon ribbon printer, and then taking out the printed carbon ribbon from the printer;

[0016] Step S3: cutting the printed ribbon into a target shape;

[0017] Step S4: sticking the carbon tape cut into the target shape onto one surface of the substrate to form the low-cost mask.

[0018] The technical solution adopted by the present invention to solve the third technical problem is: a photolithography method using the above low-cost mask, comprising the following steps:

[0019] Step a1: loading the low-cost mask into a photolithography machine;

[0020] Step a2: coating a photoresist layer on the wafer, and placing the wafer coated with the photoresist layer into a photolithography machine for exposure, so that ultraviolet light passes through the light-transmitting area on the carbon tape and irradiates the photoresist layer;

[0021] Step a3: Develop the exposed wafer to obtain the required chip pattern on the wafer. The technical solution adopted by the present invention to solve the third technical problem is: a photolithography method using the low-cost mask obtained by the above preparation method, characterized in that it includes the following steps:

[0022] Step b1: loading the low-cost mask into a photolithography machine;

[0023] Step b2: coating a photoresist layer on the wafer, and placing the wafer coated with the photoresist layer into a photolithography machine for exposure, so that ultraviolet light passes through the light-transmitting area on the carbon tape and irradiates the photoresist layer;

[0024] Step b3: Develop the exposed wafer to obtain the required chip pattern on the wafer.

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] First, in the low-cost mask of the invention, a carbon ribbon printer is used to print the chip pattern, and the chip pattern appears on the printed carbon ribbon. The area where the coating falls off after the carbon ribbon is printed is transparent (i.e., a light-transmitting area), which can transmit the ultraviolet light of the photolithography machine, while the area on the carbon ribbon where the coating is retained is black (i.e., a non-light-transmitting area), which can block the ultraviolet light of the photolithography machine. The carbon ribbon is attached to the substrate to form a mask, thereby transferring the chip pattern on the carbon ribbon to the wafer; compared with the mask processed by electron beam or laser etching technology, the mask processed by carbon ribbon printing in the invention is low-cost and has a short processing cycle;

[0027] In addition, the mask plate of the invention is made by steps such as carbon ribbon printing, cutting, and attaching. Printing chip patterns is convenient and quick, and the cutting and attaching processes can also be mechanized for mass production. For the mask plates of low-precision chips, the preparation method of the present application can complete the production quickly and efficiently. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the structure of the carbon ribbon before printing in an embodiment of the present invention;

[0029] Figure 2 Schematic diagram of the structure of the printed carbon ribbon in an embodiment of the present invention;

[0030] Figure 3 A schematic diagram of the structure of a low-cost mask in an embodiment of the present invention;

[0031] Figure 4 It is a schematic diagram of the structure of the wafer during exposure in an embodiment of the present invention;

[0032] Figure 5 It is a schematic diagram of the structure of the wafer after development in an embodiment of the present invention;

[0033] Figure 6 The figure is a flow chart of preparing a low-cost mask in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below with reference to the accompanying drawings.

[0035] like Figures 1 to 3 The figure shows a preferred embodiment of the low-cost mask of the present invention, which includes a substrate 100 and a carbon tape 1 attached to the surface of the substrate 100, the carbon tape 1 has pre-designed light-transmitting areas 12 and non-light-transmitting areas 11, and the light-transmitting areas 12 and non-light-transmitting areas 11 together constitute a chip pattern.

[0036] Specifically, Figure 1 , 2 As shown, the carbon ribbon 1 is completely black and cannot be transparent before printing; after the carbon ribbon 1 is printed by the carbon ribbon printer, the carbon ribbon printer prints the chip pattern pre-designed in the CAD software on the printed material, at this time, the area where the coating on the carbon ribbon 1 falls off is the transparent area 12, and the area where the coating on the carbon ribbon 1 is retained is the non-transparent area 11. The printed carbon ribbon 1 is taken out of the carbon ribbon printer, and the carbon ribbon is cut and attached to the substrate 100 to form a mask. In this embodiment, the substrate 100 is a glass plate.

[0037] The carbon ribbon 1 can be one of a mixed-base carbon ribbon, a resin-base carbon ribbon or a wash-mark carbon ribbon as required. Considering that the carbon ribbon 1 has steps such as cutting, attaching and ultraviolet light irradiation in the subsequent process, a friction-resistant, high-temperature-resistant and chemical-resistant carbon ribbon is selected. For example, the carbon ribbon 1 is preferably a resin-base carbon ribbon.

[0038] The mask produced in this application is suitable for low-end chips with a line width of more than 200um, and a carbon ribbon printer can print the pattern; and compared with electron beam or laser etching technology, the preparation cost of printing with a carbon ribbon printer can be greatly reduced.

[0039] Reference Figure 6 As shown, the present application also includes a method for preparing the above-mentioned mask, comprising the following steps:

[0040] Step S1: Draw the required chip pattern on the drawing software according to the chip design requirements;

[0041] Step S2: Printing the chip pattern drawn on the drawing software in step S1 on the carbon ribbon 1 by a carbon ribbon printer, and then taking out the printed carbon ribbon 1 from the printer;

[0042] Step S3: cutting the printed carbon ribbon 1 into a target shape;

[0043] Step S4: stick the carbon ribbon 1 cut in step S3 (ie, the carbon ribbon cut into the target shape) onto one surface of the substrate 100 to form the above-mentioned low-cost mask.

[0044] like Figure 4 , 5As shown, this embodiment also provides a photolithography method using the above low-cost mask. Specifically, the photolithography method using the above low-cost mask includes the following steps:

[0045] Step a1: Load the low-cost mask into the photolithography machine;

[0046] Step a2: coating the wafer 4 with a photoresist layer 2, and loading the wafer 4 coated with the photoresist layer into a photolithography machine for exposure, so that the ultraviolet light 5 in the photolithography machine can irradiate the photoresist layer 2 through the light-transmitting area 12 on the carbon ribbon 1;

[0047] Step a3: Develop the exposed wafer 4 , dissolve the photoresist in the area on the photoresist layer 2 irradiated by the ultraviolet light 5 , and retain the photoresist in the area not irradiated by the ultraviolet light 5 , thereby obtaining the required chip pattern on the wafer 4 .

[0048] In the low-cost mask lithography method of this embodiment, a carbon ribbon printer is used to print the designed chip pattern on the carbon ribbon. The area where the coating falls off after the carbon ribbon is printed is transparent, and the transparent area can pass through the ultraviolet light 5 of the photolithography machine, while the area on the carbon ribbon where the coating is retained is black (i.e., a non-transparent area), and the non-transparent area can block the ultraviolet light 5 of the photolithography machine. The carbon ribbon is attached to the substrate to form a mask, thereby transferring the chip pattern on the carbon ribbon to the wafer 4; the carbon ribbon printing and processing mask is low-cost and has a short processing cycle compared to the mask processed by electron beam or laser etching technology. Since the mask of the present application is made by steps such as carbon ribbon printing, cutting, and attaching, it is convenient and quick to print the chip pattern, and the cutting and attaching processes can also be mechanized for mass production; for the mask of low-precision chips, the preparation method of the present application can be quickly and effectively produced.

Claims

1. Low-cost mask, characterized by: The invention comprises a substrate (100) and a carbon ribbon (1) attached to the surface of the substrate (100), wherein the carbon ribbon (1) has a pre-designed light-transmitting area (12) and a non-light-transmitting area (11), and the light-transmitting area (12) and the non-light-transmitting area (11) together constitute a chip pattern.

2. The low-cost mask according to claim 1, characterized in that: The chip pattern is printed by a carbon ribbon printer.

3. The low-cost mask according to claim 2, characterized in that: The chip pattern is designed by CAD software.

4. The low-cost mask according to any one of claims 1 to 3, characterized in that: The carbon ribbon (1) is one of a mixed-base carbon ribbon, a resin-base carbon ribbon or a wash-mark carbon ribbon.

5. The low-cost mask according to claim 4, characterized in that: The carbon ribbon (1) is a resin-based carbon ribbon.

6. The low-cost mask according to any one of claims 1 to 3, characterized in that: The substrate (100) is a glass plate.

7. A method for preparing a low-cost mask according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step S1: Draw the required chip pattern on the drawing software according to the chip design requirements; Step S2: Printing the chip pattern drawn on the drawing software on the carbon ribbon (1) by using a carbon ribbon printer, and then taking out the printed carbon ribbon (1) from the printer; Step S3: cutting the printed carbon ribbon (1) into a target shape; Step S4: sticking the carbon tape (1) cut into a target shape onto a surface of one side of the substrate (100) to form the low-cost mask.

8. A photolithography method using the low-cost mask according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step a1: loading the low-cost mask into a photolithography machine; Step a2: coating a photoresist layer (2) on a wafer (4), and placing the wafer (4) coated with the photoresist layer into a photolithography machine for exposure, so that ultraviolet light (5) passes through the light-transmitting area (12) on the carbon tape (1) and irradiates the photoresist layer (2); Step a3: Developing the exposed wafer (4) to obtain a desired circuit pattern on the wafer (4).

9. A photolithography method using a low-cost mask obtained by the preparation method according to claim 7, characterized in that: The following steps are involved: Step b1: loading the low-cost mask into a photolithography machine; Step b2: coating a photoresist layer (2) on a wafer (4), and placing the wafer (4) coated with the photoresist layer into a photolithography machine for exposure, so that the ultraviolet light (5) passes through the light-transmitting area (12) on the carbon tape (1) and irradiates the photoresist layer (2); Step b3: Developing the exposed wafer (4) to obtain a desired chip pattern on the wafer (4).

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