Method for defining read-only memory coding mode by using metal wire

Abstract

The invention provides a method for defining an encoding mode of a read-only memory by using metal wires, which comprises the following steps: providing a substrate, forming a semiconductor device of the read-only memory on the substrate, the top end of the semiconductor device comprising an interlayer dielectric layer, a plurality of metal wires distributed at intervals in the interlayer dielectric layer, and a top end metal layer, the disconnection and connection conditions of the metal wires are used for determining the coding mode of the read-only memory; forming a photoresist layer on the interlayer dielectric layer, wherein the photoresist layer above the top metal layer and the metal wire close area is thicker; selecting a required coding mode and corresponding photoetching energy for different products, and opening the photoresist layer on each product by utilizing adjacent metal, the load effect of the photoresist layer on the top metal layer, the photomask defining the top metal layer and the corresponding photoetching energy; and etching the corresponding metal wires according to the coding mode of each product. According to the method, the exposed metal wire is cut off to define the coding mode type of the read-only memory, and only one additional metal wire etching step is needed in the process.

Description

Technical Field

[0001] The invention relates to the field of semiconductor technology, and in particular to a method for defining a read-only memory coding mode by using a metal wire. Background Art

[0002] In the semiconductor manufacturing process, the design positions of customers' metal fuses vary. Specific process problems may occur in special positions, causing abnormal burning of the customer's metal fuses.

[0003] In order to solve the above problems, it is necessary to propose a new method of defining a read-only memory encoding mode using metal wires. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a method for defining a read-only memory coding mode using metal wires, so as to solve the problem that the design positions of the metal wires in the prior art are various and specific process problems may occur at special positions.

[0005] To achieve the above-mentioned and other related purposes, the present invention provides a method for defining a read-only memory coding mode using a metal wire, comprising:

[0006] Step 1: providing a substrate, forming a semiconductor device of a read-only memory on the substrate, wherein the top of the semiconductor device comprises an interlayer dielectric layer, a plurality of spaced metal wires located in the interlayer dielectric layer and a top metal layer, the thickness of the interlayer dielectric layer above the top metal layer is thicker than that of the interlayer dielectric layer above the metal wires, the top metal layer is located above the metal wires and one side is close to the metal wires, and the disconnection and connection of the metal wires are used to determine the coding mode of the read-only memory;

[0007] Step 2, forming a photoresist layer on the interlayer dielectric layer, wherein the photoresist layer above the top metal layer and the area near the metal wire is thicker;

[0008] Step 3: selecting the required coding mode and corresponding photolithography energy for different products, utilizing the loading effect of the photoresist layer on the adjacent metal and the top metal layer, and utilizing the mask defining the top metal layer and the corresponding photolithography energy to open the photoresist layer on each product;

[0009] Step 4: Etch the corresponding metal wire according to the coding pattern of each product.

[0010] Preferably, the material of the interlayer dielectric layer in step 1 is oxide.

[0011] Preferably, the top metal layer exists at three sides of the metal wire used to define the coding mode of the read-only memory in step one.

[0012] Preferably, the encoding mode of the read-only memory in step one includes first to third encoding modes.

[0013] Preferably, in step three, the first to third encoding modes are defined according to the disconnection and connection conditions of the first and second metal wires.

[0014] Preferably, in step three, the first encoding mode is defined by connecting the first and second metal wires.

[0015] Preferably, in step three, a second encoding mode is defined by connecting the first metal wire and disconnecting the second metal wire.

[0016] Preferably, in step three, a third encoding mode is defined by disconnecting the first and second metal wires.

[0017] Preferably, in step three, the photoresist layer is opened using an i-line projection stepper.

[0018] Preferably, the etching method in step 4 is dry etching.

[0019] As described above, the method of defining a read-only memory coding mode using metal wires of the present invention has the following beneficial effects:

[0020] The present invention utilizes the load effect of metal wires and adjacent top metal layers. Without the need for a photomask, different photolithography energies are used to define the photoresist residues above several metal wires close to the short sides, and then the exposed metal wires are cut to define the coding mode type of the read-only memory. This process only requires an additional step of metal wire etching. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Shown is a schematic diagram of the process flow of the present invention;

[0022] Figure 2 It is a schematic diagram of forming a photoresist layer according to the present invention;

[0023] Figure 3 A schematic diagram showing the invention title of an embodiment;

[0024] Figure 4 Shown is a schematic diagram of a first encoding mode of the present invention;

[0025] Figure 5 Shown is a schematic diagram of a second encoding mode of the present invention;

[0026] Figure 6 Shown is a schematic diagram of a third encoding mode of the present invention;

[0027] Figure 7 It is a schematic diagram showing the loading effect of the metal layer at the top of the metal wire 3 edge ring of the present invention. DETAILED DESCRIPTION

[0028] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0029] See also Figure 1 The present invention provides a method for defining a read-only memory encoding mode using a metal wire, comprising:

[0030] Step 1: providing a substrate, forming a semiconductor device of a read-only memory on the substrate, wherein the top of the semiconductor device comprises an interlayer dielectric layer 101, a plurality of metal wires 102 spaced apart in the interlayer dielectric layer 101, and a top metal layer 103, wherein the thickness of the interlayer dielectric layer 101 above the top metal layer 103 is thicker than that of the interlayer dielectric layer 101 above the metal wire 102, the top metal layer 103 is located above the metal wire 102 and one side of the top metal layer 103 is close to the metal wire 102, and the disconnection and connection of the metal wire 102 are used to determine the coding mode of the read-only memory;

[0031] In some embodiments, the material of the interlayer dielectric layer 101 in step 1 is oxide.

[0032] In some embodiments, see Figure 7 In step 1, there are top metal layers 103 at three sides of the metal wire 102 used to define the coding mode of the read-only memory, and the load effect of the top metal layer 103 of the metal wire 1023 is used (for example Figure 7 The top metal layer 103 at the rectangular frame) is defined by different photolithography energies without the need for a mask to define several metal wires 102 near the short side (such as Figure 7 The photoresist remains on the metal wire 102 at the circle, and then the exposed metal wire 102 is cut to define the coding mode type of the read-only memory. This process only requires one more step of etching the metal wire 102.

[0033] In some embodiments, the coding mode of the read-only memory in step 1 includes coding modes 1 to 3. It should be noted that in other embodiments, the coding mode of the read-only memory may also be other types of coding modes, and the corresponding state of the metal wire 102 may also be adjusted.

[0034] Step 2: Form a photoresist layer 104 on the interlayer dielectric layer 101. The photoresist layer 104 above the top metal layer 103 and the metal wire 102 is thicker. Figure 2 The structure shown;

[0035] Step three, for different products, the required coding mode and corresponding lithography energy are selected, and the load effect of the photoresist layer 104 on the adjacent metal and top metal layer 103 is utilized, and the photoresist layer 104 on each product is opened by using the mask that defines the top metal layer and the corresponding lithography energy; under normal circumstances, when a customer upgrades from version V1 to version V2, it may be necessary to update the metal layer below the top metal 103, and a new mask is required here. The present invention is that the customer pre-designs the circuit on the metal layer below the top metal 103, and then defines different versions by connecting and disconnecting the metal wire 102, utilizing the deposition effect of the photoresist, so there is no need for an extra mask.

[0036] In some embodiments, in step three, the first to third encoding modes are defined by the disconnection and connection conditions of the first and second metal wires (1021, 1022).

[0037] In some embodiments, see Figure 4 In step three, the first and second metal wires (1021, 1022) are connected to define a first encoding mode.

[0038] In some embodiments, see Figure 5 In step three, the second encoding mode is defined by connecting the first metal wire 1021 and disconnecting the second metal wire 1022.

[0039] In some embodiments, see Figure 6 In step three, the first and second metal wires (1021, 1022) are disconnected to define a third encoding mode.

[0040] In some embodiments, in step three, an i-line projection stepper is used to open the photoresist layer 104 .

[0041] For example, see Figure 3 , the thickness of the metal wire 102 is 0.45um, the spacing between the metal wires 102 is 4um, the width is 0.8um, and the distance from the metal wire 102 to the window is 3.5um;

[0042] The thickness of the top metal layer 103 is 4 um, and the distance between the three-side openings of the metal wire 102 and the nearby top metal layer 103 is 6.5 um;

[0043] The thickness of the interlayer dielectric layer 101 on the top metal layer 103 is 3.25 um, and the thickness of the photoresist layer 104 is 5 um;

[0044] The lithography energies corresponding to the first to third coding modes are 550 milliseconds, 650 milliseconds, and 750 milliseconds, respectively, and the equipment is an i-line projection stepper exposure machine.

[0045] Step 4: Etch the corresponding metal wire 102 according to the coding pattern of each product.

[0046] In some embodiments, the etching method in step 4 is dry etching.

[0047] It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner. Therefore, the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0048] In summary, the present invention utilizes the load effect of the metal wire and the adjacent top metal layer, and defines the photoresist residue above the metal wires near the short side by different photolithography energies without the need for a photomask, and then cuts the exposed metal wires to define the coding mode type of the read-only memory. This process only requires one more step of metal wire etching. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.

[0049] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for defining a read-only memory encoding mode using a metal wire, characterized in that: At least: Step 1: providing a substrate, forming a semiconductor device of a read-only memory on the substrate, wherein the top of the semiconductor device comprises an interlayer dielectric layer, a plurality of spaced metal wires located in the interlayer dielectric layer and a top metal layer, the thickness of the interlayer dielectric layer above the top metal layer is thicker than that of the interlayer dielectric layer above the metal wires, the top metal layer is located above the metal wires and one side is close to the metal wires, and the disconnection and connection of the metal wires are used to determine the coding mode of the read-only memory; Step 2, forming a photoresist layer on the interlayer dielectric layer, wherein the photoresist layer above the top metal layer and the area near the metal wire is thicker; Step 3: selecting the required coding mode and corresponding photolithography energy for different products, utilizing the loading effect of the photoresist layer on the adjacent metal and the top metal layer, and utilizing the mask defining the top metal layer and the corresponding photolithography energy to open the photoresist layer on each product; Step 4: Etch the corresponding metal wire according to the coding pattern of each product.

2. The method for defining a read-only memory encoding mode using a metal wire according to claim 1, characterized in that: The material of the interlayer dielectric layer in step 1 is oxide.

3. The method for defining a read-only memory encoding mode using a metal wire according to claim 1, characterized in that: The top metal layer exists at three sides of the metal wire used to define the coding mode of the read-only memory in step one.

4. The method for defining a read-only memory encoding mode using a metal wire according to claim 1, characterized in that: The coding mode of the read-only memory in step 1 includes first to third coding modes.

5. The method for defining a read-only memory coding mode using a metal wire according to claim 4, characterized in that: In step three, the first to third encoding modes are defined according to the disconnection and connection conditions of the first and second metal wires.

6. The method for defining a read-only memory coding mode using a metal wire according to claim 5, characterized in that: In step three, a first encoding mode is defined by connecting the first and second metal wires.

7. The method for defining a read-only memory coding mode using a metal wire according to claim 5, characterized in that: In step three, a second encoding mode is defined by connecting the first metal wire and disconnecting the second metal wire.

8. The method for defining a read-only memory coding mode using a metal wire according to claim 5, characterized in that: In step three, a third encoding mode is defined by disconnecting the first and second metal wires.

9. The method for defining a read-only memory coding mode using a metal wire according to claim 1, characterized in that: In step three, the photoresist layer is opened by using an i-line projection stepper.

10. The method for defining a read-only memory coding mode using a metal wire according to claim 1, characterized in that: The etching method in step 4 is dry etching.

Images