An interconnect mask structure for cross lithographic field metal interconnects

Abstract

The application discloses an interlayer connection mask structure of cross-photolithography field metal interconnection, and belongs to the technical field of semiconductor manufacturing. The interlayer connection mask structure is located at the edge of a single mask, and is included in the secondary exposure area on the upper side, the lower side, the left side or the right side, and is used for forming the cross-photolithography field metal interconnection line between two adjacent photolithography fields; the interlayer connection mask structure is composed of a set of masks matched with each other, and includes the nth metal M n mask, the (n+1)th metal M n+1 mask, the connection M n and the through hole Via n+1 of M n mask, and jointly forms the "metal layer exchange" connection of the cross-photolithography field metal in the secondary exposure area, wherein n is a positive integer. The application has important significance for solving the problems caused by the "metal layer exchange" strategy in the photolithography field, including the unnecessary lengthening of the metal interconnection line, the reduction of the design efficiency, the waste of the wiring resources, the application of the cross-photolithography field metal interconnection technology to the large-area chip, and the realization of the "metal layer exchange" in the secondary exposure area.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to an interlayer interconnect mask structure for cross-lithographic field metal interconnects. Background Technology

[0002] Trans-field metal interconnect technology is of great significance for manufacturing chips with an area larger than the maximum lithographic field size in a single exposure of a stepper lithography system. These ultra-large area chips can be manufactured by dividing the entire chip into multiple sub-chips, thereby ensuring that the area of ​​each sub-chip is smaller than the single exposure limit of the stepper lithography system.

[0003] Currently, when applying cross-lithography field metal interconnect technology in ultra-large area chips, via prohibition zones are usually set at the boundary of the lithography field (i.e., within the secondary exposure area). That is, no interlayer vias are set within the secondary exposure area, and all layer-to-layer connections are completed within a single lithography field. Cross-lithography field metal interconnects use only the same metal layer to achieve cross-field connections.

[0004] This "deliberate avoidance" strategy may lead to a decrease in the routing efficiency of cross-lithography field interconnect metal lines. First, this strategy cuts off the shortcut for signals to "change layers" at the boundary. Metal interconnects that could originally change layers nearby within the secondary exposure area must now be extended to cross the secondary exposure area to reach the next lithography field before they can change layers, resulting in an unnecessary increase in line length. Second, since cross-lithography field metal interconnects are forcibly constrained to the same metal layer, "blocking layers" need to be set on both sides of the lithography field boundary (secondary exposure area) to prevent the tool from automatically generating vias, increasing the complexity of the design. In severe cases, it may even require manual processing of each cross-lithography field interconnect metal line, greatly lengthening the design cycle. Third, due to the restriction that layers cannot be changed at the boundary, designers have to sacrifice valuable routing resources. A forced extension of a certain interconnect metal line may cause surrounding metal lines to detour, resulting in inefficient use of metal layers and routing space.

[0005] Therefore, while this "deliberate avoidance" strategy reduces the process risk during metal layer switching in the secondary exposure area, it comes at the cost of sacrificing electrical performance, design efficiency, and wiring resources. To overcome this bottleneck, researching interlayer interconnect mask structures for metal interconnects across lithography fields to achieve "metal layer switching" within the secondary exposure area is of great significance. Summary of the Invention

[0006] The purpose of this invention is to provide an interlayer interconnect mask structure for cross-lithographic field metal interconnects to solve the problems in the prior art.

[0007] To address the aforementioned technical problems, this invention provides an interlayer interconnect mask structure for cross-lithographic field metal interconnects. Located at the edge of a single photomask, including the upper, lower, left, or right secondary exposure area, it is used to form a cross-photomask metal interconnect between two adjacent photomask fields; The interlayer connection mask structure consists of a set of mating masks, including the nth metal layer M. n Mask, n+1th metal layer M n+1 Mask, Connection M n With M n+1 Via n The photomask together forms a "metal swapping" connection between the metal across the lithography field in the secondary exposure area, where n is a positive integer.

[0008] In one embodiment, the nth metal layer M n The mask consists of two secondary exposure area masks, one on the left and one on the right, or two secondary exposure area masks, one on the top and one on the bottom. The (n+1)th metal layer M n+1 The mask consists of two secondary exposure area masks, one on the left and one on the right, or two secondary exposure area masks, one on the top and one on the bottom. Via n The mask consists of two secondary exposure area masks, one on the left and one on the right, or two secondary exposure area masks, one on the top and one on the bottom.

[0009] In one embodiment, when using a copper interconnect process, the nth metal layer M n In a photomask, either the left or right secondary exposure area photomask, or the top and bottom secondary exposure area photomask, the light-transmitting area of ​​one of the two photomasks is used to define the metal M. n The shape is such that the other corresponding position is an opaque black plate; When using copper interconnect technology, the (n+1)th metal layer M n+1 Two secondary exposure area masks, one on the left and one on the right, or one on the top and one on the bottom, are used to define the metal M using the light-transmitting area of ​​one of them. n+1 The shape is such that the other corresponding position is an opaque black plate; Via n In the left and right secondary exposure area masks or the top and bottom secondary exposure area masks, the light-transmitting area of ​​one of them is used to define the via. n The shape is one piece, and the corresponding position is an opaque black plate.

[0010] In one embodiment, when using a copper interconnect process, the nth metal layer M n The mask has two secondary exposure areas on the left and right sides, and the mask contains a defined metal M. n A mask of shape, the through-hole Via n The mask has two secondary exposure areas on the left and right sides, and the mask has defined vias.n A shape mask, when defining metal M n Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n The shape of the light-transmitting area will be through the hole Via n The shape and the light-transmitting area are included; When using copper interconnect technology, the (n+1)th metal layer M n+1 The mask has two secondary exposure areas on the left and right sides, and the mask contains a defined metal M. n+1 A mask of shape, the through-hole Via n The mask has two secondary exposure areas on the left and right sides, and the mask has defined vias. n A shape mask, when defining metal M n+1 Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n+1 The shape of the light-transmitting area will be through the hole Via n The shape and the light-transmitting area are included; When using copper interconnect technology, the nth metal layer M n The upper and lower secondary exposure areas of the mask contain defined metal M. n A mask of shape, the through-hole Via n The upper and lower secondary exposure areas of the mask have defined vias. n A shape mask, when defining metal M n Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n The shape of the light-transmitting area will be through the hole Via n The shape and the light-transmitting area are included; When using copper interconnect technology, the (n+1)th metal layer M n+1 The upper and lower secondary exposure areas of the mask contain defined metal M. n+1 A mask of shape, the through-hole Via n The upper and lower secondary exposure areas of the mask have defined vias. n A shape mask, when defining metal M n+1 Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n+1 The shape of the light-transmitting area will be through the hole Via n The shape includes the light-transmitting area.

[0011] In one embodiment, when using an aluminum interconnect process, the nth metal layer M nIn a photomask, either the left and right secondary exposure area photomasks or the top and bottom secondary exposure area photomasks, the opaque area of ​​one of them is used to define the metal M. n The shape is such that the other corresponding position is an opaque black plate; When using aluminum interconnect technology, the (n+1)th metal layer M n+1 Two secondary exposure area masks, one on the left and one on the right, or one on the top and one on the bottom, are used to define the metal M using the opaque area of ​​one of them. n+1 The shape is such that the other corresponding position is an opaque black plate; Via n In the left and right secondary exposure area masks or the top and bottom secondary exposure area masks, the light-transmitting area of ​​one of them is used to define the via. n The shape is one piece, and the corresponding position is an opaque black plate.

[0012] In one embodiment, when using an aluminum interconnect process, the nth metal layer M n The mask has two secondary exposure areas on the left and right sides, and the mask contains a defined metal M. n A mask of shape, the through-hole Via n The mask has two secondary exposure areas on the left and right sides, and the mask has defined vias. n A shape mask, when defining metal M n Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n The shape of the opaque area will be through the hole Via n The shape and the light-transmitting area are included; When using aluminum interconnect technology, the (n+1)th metal layer M n+1 The mask has two secondary exposure areas on the left and right sides, and the mask contains a defined metal M. n+1 A mask of shape, the through-hole Via n The mask has two secondary exposure areas on the left and right sides, and the mask has defined vias. n A shape mask, when defining metal M n+1 Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n+1 The shape of the opaque area will be through the hole Via n The shape and the light-transmitting area are included; When using aluminum interconnect technology, the nth metal layer M n The upper and lower secondary exposure areas of the mask contain defined metal M. n A mask of shape, the through-hole Via n The upper and lower secondary exposure areas of the mask have defined vias.n A shape mask, when defining metal M n Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n The shape of the opaque area will be through the hole Via n The shape and the light-transmitting area are included; When using aluminum interconnect technology, the (n+1)th metal layer M n+1 The upper and lower secondary exposure areas of the mask contain defined metal M. n+1 A mask of shape, the through-hole Via n The upper and lower secondary exposure areas of the mask have defined vias. n A shape mask, when defining metal M n+1 Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n+1 The shape of the opaque area will be through the hole Via n The shape includes the light-transmitting area.

[0013] This invention provides an interlayer interconnect mask structure for cross-lithographic field metal interconnects, which allows for the connection of M through vias at any location within the secondary exposure area. n Metal connects upwards to M n+1 Metal interconnects avoid unnecessary extension of metal interconnects, improve design efficiency, and avoid wasting wiring resources. They are of great significance for the application of cross-lithography field metal interconnect technology in large-area chips and for realizing metal layer replacement in the secondary exposure area. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure distribution of a single mask on the left.

[0015] Figure 2 This is a schematic diagram of the structure distribution of a single mask on the right.

[0016] Figure 3 It is a schematic diagram showing the two photomasks connected by a secondary exposure area.

[0017] Figure 4 This is a longitudinal cross-sectional diagram of a traditional metal "layer replacement".

[0018] Figure 5 This is a longitudinal cross-sectional schematic diagram of the interlayer interconnection method for cross-lithographic field metal interconnection proposed in this invention.

[0019] Figure 6 It is the second exposure area M of the left-side mask. n The shape of a metal mask.

[0020] Figure 7 It is the second exposure area M of the right-side mask. n The shape of a metal mask.

[0021] Figure 8 It is the second exposure area M of the right-side mask. n Example of incorrect drawing of a metal mask.

[0022] Figure 9 It is the second exposure area M of the right-side mask. n Example of a standard way to draw a metal mask.

[0023] Figure 10 It is the second exposure area M of the right-side mask. n+1 The shape of a metal mask.

[0024] Figure 11 It is the second exposure area M of the left-side mask. n+1 The shape of a metal mask.

[0025] Figure 12 It is the second exposure area M of the left-side mask. n+1 Example of incorrect drawing of a metal mask.

[0026] Figure 13 It is the second exposure area M of the left-side mask. n+1 Example of a standard way to draw a metal mask.

[0027] Figure 14 Via is the through-hole in the secondary exposure area of ​​the left-side mask. n The shape of the mask.

[0028] Figure 15 Via is the through-hole in the second exposure area of ​​the right-side photomask. n The shape of the mask.

[0029] Figure 16 Via is the through-hole in the second exposure area of ​​the right-side photomask. n A standard example of how to draw a mask.

[0030] Figure 17 yes Figure 6 and Figure 14 After the mask's secondary exposure area overlaps, Figure 6 M in n Metallic translucent area includes Figure 14 Via n A schematic diagram of the light-transmitting area through the aperture.

[0031] Figure 18 yes Figure 10 and Figure 14 After the mask's secondary exposure area overlaps, Figure 10 M in n+1Metallic translucent area includes Figure 14 Via n A schematic diagram of the light-transmitting area through the aperture. Detailed Implementation

[0032] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a more detailed explanation of the interlayer interconnect mask structure for cross-lithographic field metal interconnects proposed in this invention. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of this invention.

[0033] This invention provides an interlayer interconnect mask structure for cross-photolithography field metal interconnects, suitable for positive photoresist lithography. Positive photoresist refers to photoresist areas not covered by the mask (exposed areas) that undergo a chemical reaction, with the exposed portion dissolving in the developer; the photoresist areas covered by the mask do not dissolve in the developer.

[0034] This invention applies to both copper interconnect and aluminum interconnect processes. Copper interconnects employ a damascus etching followed by electroplating for filling, while aluminum interconnects employ a process of first depositing a metal layer and then etching the pattern. The mask structure will be described below using copper interconnects as an example. For aluminum interconnects, the mask pattern needs to be adjusted accordingly to match the etching process.

[0035] Figure 1 This is a schematic diagram showing the distribution of a single mask structure on the left. (See diagram below.) Figure 1 As shown, the 00 area inside the single mask on the left is the single exposure area, and the 01 area to the right of the single exposure area is the double exposure area. There may be other areas above and below the 00 and 01 areas, or there may be no other areas, which are indicated by ellipses in the figure and will not be specifically drawn in this invention.

[0036] Figure 2 This is a schematic diagram showing the distribution of a single mask structure on the right. (Example) Figure 2 As shown, the 02 area inside the single mask on the right is the single exposure area, and the 01 area to the left of the single exposure area is the double exposure area. There may be other areas above and below the 02 and 01 areas, or there may be no other areas, which are indicated by ellipses in the figure and will not be specifically drawn in this invention.

[0037] Figure 3 This is a schematic diagram showing the left and right photomasks connected by a secondary exposure area. (See diagram below.) Figure 3 As shown, during photolithography, the secondary exposure areas of the two masks on the left and right sides completely overlap in position, realizing cross-photolithography field metal interconnection.

[0038] A schematic diagram showing the interconnection of the upper and lower photomasks through a secondary exposure area. Figure 3Similarly, simply arrange the two lithography fields vertically and overlap the secondary exposure areas of the two masks; this will not be elaborated further here. The following examples will use left and right masks.

[0039] Figure 4 This is a schematic diagram of a longitudinal cross-section of a traditional metal "layer replacement". (Example) Figure 4 As shown, no interlayer vias are provided in the secondary exposure area 01, and the M on the right edge of the single exposure area 00... n The metal traverses the entire secondary exposure zone 01 until it enters the single exposure zone 02, before passing through the via. n Connect upwards to M n+1 Metals, leading to M n There is no need to increase the length of the metal wire.

[0040] Figure 5 This is a longitudinal cross-sectional schematic diagram of the interlayer interconnection method for cross-lithographic field metal interconnects proposed in this invention. This invention does not preclude the placement of vias within the secondary exposure area, such as... Figure 5 As shown, the M on the right edge of the single exposure area 00 n The metal needs to be replaced with an upper layer to connect to M. n+1 For metals, the secondary exposure area does not affect metal layer replacement; there is no need to specifically remove the M layer. n The metal extends to the next single-exposure zone 02, and can be passed through the via in the secondary exposure zone 01 whenever needed. n Connect upwards to M n+1 Metal.

[0041] Figure 6 For the interlayer interconnect mask structure for cross-lithographic field metal interconnects proposed in this invention, it is necessary to define M on one of the left or right sides. n The shape of the metal, in this example, is defined as M within the secondary exposure area of ​​the left-hand mask. n Metallic mask structure. For example... Figure 6 As shown, because this example uses copper interconnect technology, the mask only needs to be applied to M... n The metal parts are made to be translucent, while the rest are opaque.

[0042] Figure 7 M is the second exposure area of ​​the right-side mask. n The shape of a metal mask. For example... Figure 7 As shown, M in the double exposure area on the right n The metallic mask is a single, opaque black plate. The right-side secondary exposure mask must be used in conjunction with the left-side secondary exposure mask to expose the desired M. n The shape of the metal.

[0043] Figure 8 M is the second exposure area of ​​the right-side mask.n Example of incorrect drawing of a metal mask. For example... Figure 8 As shown, at this time, the M area of ​​the double exposure zone on the right... n The metal mask is a single, transparent white plate. When the mask for the secondary exposure area on the right is used in conjunction with the mask for the secondary exposure area on the left, the secondary exposure will expose all the photoresist in the secondary exposure area. After development, the secondary exposure area will have no photoresist protection, and after etching and electroplating, a solid piece of copper metal will be formed in the secondary exposure area, causing errors.

[0044] Figure 9 M is the second exposure area of ​​the right-side mask. n A typical example of drawing a metal mask. (e.g.) Figure 9 As shown, the shape of the secondary exposure area on the right side at this time is similar to... Figure 6 The left secondary exposure area is exactly the same. At this point, the mask for the right secondary exposure area is used in conjunction with the mask for the left secondary exposure area. Theoretically, this can expose the desired M. n The shape of the metal, but actually M n The grooves etched in the metal are wider than expected, resulting in copper interconnects that are wider than expected after electroplating.

[0045] Figure 10 For the interlayer interconnect mask structure for cross-lithographic field metal interconnects proposed in this invention, it is necessary to define M on one of the left or right sides. n+1 The shape of the metal, in this example, is defined as M within the secondary exposure area of ​​the mask on the right. n+1 Metallic mask structure. For example... Figure 10 As shown, because this example uses copper interconnect technology, the mask only needs to be applied to M... n+1 The metal parts are made to be translucent, while the rest are opaque.

[0046] Figure 11 M is the secondary exposure area of ​​the left-side mask. n+1 The shape of a metal mask. For example... Figure 11 As shown, M in the left-hand double exposure area n+1 The metallic mask is a single, opaque black plate. The right-side secondary exposure mask must be used in conjunction with the left-side secondary exposure mask to expose the desired M. n+1 The shape of the metal.

[0047] Figure 12 M is the secondary exposure area of ​​the left-side mask. n+1 Example of incorrect drawing of a metal mask. For example... Figure 12 As shown, at this time, the M area of ​​the left-side secondary exposure zone... n+1The metal mask is a single, transparent white plate. When the mask for the secondary exposure area on the right is used in conjunction with the mask for the secondary exposure area on the left, the secondary exposure will expose all the photoresist in the secondary exposure area. After development, the secondary exposure area will have no photoresist protection, and after etching and electroplating, a solid piece of copper metal will be formed in the secondary exposure area, causing errors.

[0048] Figure 13 M is the secondary exposure area of ​​the left-side mask. n+1 A typical example of drawing a metal mask. (e.g.) Figure 13 As shown, the shape of the secondary exposure area on the left side at this time is similar to... Figure 10 The right-side secondary exposure area is exactly the same. At this point, the mask for the right-side secondary exposure area is used in conjunction with the mask for the left-side secondary exposure area. Theoretically, this can expose the desired M. n+1 The shape of the metal, but actually M n+1 The grooves etched in the metal are wider than expected, resulting in copper interconnects that are wider than expected after electroplating.

[0049] Figure 14 For the interlayer interconnect mask structure for cross-lithographic field metal interconnects proposed in this invention, it is necessary to define a via on one of the left or right sides. n The shape, in this example, defines a via within the secondary exposure area of ​​the left-side mask. n The mask structure. For example... Figure 14 As shown, only the via Via n The area is made to be translucent, while the rest is opaque.

[0050] Figure 15 Via is the through-hole in the secondary exposure area of ​​the right-side mask. n The shape of the mask. For example... Figure 15 As shown, the via in the right-side secondary exposure area is Via n The mask is a single, opaque black plate. The mask for the right-side secondary exposure area must be used in conjunction with the mask for the left-side secondary exposure area to achieve the desired exposure. n The shape of the through hole.

[0051] Figure 16 Via is the through-hole in the secondary exposure area of ​​the right-side mask. n A common example of how to draw a mask. For example... Figure 16 As shown, the shape of the secondary exposure area on the right side at this time is similar to... Figure 14 The left-side secondary exposure area is completely identical. At this point, the mask for the right-side secondary exposure area is used in conjunction with the mask for the left-side secondary exposure area. Theoretically, this can expose the desired through-hole. n The shape, but actually Via n The etched trenches will be larger than expected.

[0052] It should be noted that, Figure 6 M, defined by the double exposure zone n Metal, Figure 10 M, defined by the double exposure zone n+1 Metal, Figure 14 Via definition of double exposure zone n Through holes need to be used in conjunction with other devices to allow for exposure of materials such as... Figure 5 The interlayer connection of the cross-lithographic field metal interconnect is shown.

[0053] Therefore, it is required Figure 6 , Figure 10 , Figure 14 After the mask's secondary exposure area overlaps, Figure 6 M in n The metal light-transmitting area will Figure 14 Via n The light-transmitting area through the opening is included according to the design rules, such as... Figure 17 As shown.

[0054] Similarly, requirements Figure 6 , Figure 10 , Figure 14 After the mask's secondary exposure area overlaps, Figure 10 M in n+1 The metal light-transmitting area will Figure 14 Via n The light-transmitting area through the opening is included according to the design rules, such as... Figure 18 As shown.

[0055] When using aluminum interconnect technology, the nth metal layer M n In a photomask, either the left and right secondary exposure area photomasks or the top and bottom secondary exposure area photomasks, the opaque area of ​​one of them is used to define the metal M. n The shape is such that the other corresponding position is an opaque black plate; When using aluminum interconnect technology, the (n+1)th metal layer M n+1 Two secondary exposure area masks, one on the left and one on the right, or one on the top and one on the bottom, are used to define the metal M using the opaque area of ​​one of them. n+1 The shape is such that the other corresponding position is an opaque black plate; Via n In the left and right secondary exposure area masks or the top and bottom secondary exposure area masks, the light-transmitting area of ​​one of them is used to define the via. n The shape is one piece, and the corresponding position is an opaque black plate.

[0056] When using aluminum interconnect technology, the nth metal layer M n The mask has two secondary exposure areas on the left and right sides, and the mask contains a defined metal M.n A mask of shape, the through-hole Via n The mask has two secondary exposure areas on the left and right sides, and the mask has defined vias. n A shape mask, when defining metal M n Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n The shape of the opaque area will be through the hole Via n The shape and the light-transmitting area are included; When using aluminum interconnect technology, the (n+1)th metal layer M n+1 The mask has two secondary exposure areas on the left and right sides, and the mask contains a defined metal M. n+1 A mask of shape, the through-hole Via n The mask has two secondary exposure areas on the left and right sides, and the mask has defined vias. n A shape mask, when defining metal M n+1 Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n+1 The shape of the opaque area will be through the hole Via n The shape and the light-transmitting area are included; When using aluminum interconnect technology, the nth metal layer M n The upper and lower secondary exposure areas of the mask contain defined metal M. n A mask of shape, the through-hole Via n The upper and lower secondary exposure areas of the mask have defined vias. n A shape mask, when defining metal M n Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n The shape of the opaque area will be through the hole Via n The shape and the light-transmitting area are included; When using aluminum interconnect technology, the (n+1)th metal layer M n+1 The upper and lower secondary exposure areas of the mask contain defined metal M. n+1 A mask of shape, the through-hole Via n The upper and lower secondary exposure areas of the mask have defined vias. n A shape mask, when defining metal M n+1 Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n+1 The shape of the opaque area will be through the hole Via n The shape includes the light-transmitting area.

[0057] The interlayer interconnect mask structure for cross-lithographic field metal interconnects proposed in this invention allows for the connection of M through vias at any location within the secondary exposure area. n Metal connects upwards to M n+1 Using metal avoids unnecessary extensions of metal interconnects, improves design efficiency, and avoids waste of wiring resources.

[0058] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A layer interconnect mask structure for cross-lithographic field metal interconnects, characterized in that, Located at the edge of a single photomask, including the upper, lower, left, or right secondary exposure area, it is used to form a cross-photomask metal interconnect between two adjacent photomask fields; The interlayer connection mask structure consists of a set of mating masks, including the nth metal layer M. n Mask, n+1th metal layer M n+1 Mask, Connection M n With M n+1 Via n The photomask together forms a "metal swapping" connection between the metal across the lithography field in the secondary exposure area, where n is a positive integer.

2. The interlayer interconnect mask structure for cross-lithographic field metal interconnects as described in claim 1, characterized in that, The nth metal layer M n The mask consists of two secondary exposure area masks, one on the left and one on the right, or two secondary exposure area masks, one on the top and one on the bottom. The (n+1)th metal layer M n+1 The mask consists of two secondary exposure area masks, one on the left and one on the right, or two secondary exposure area masks, one on the top and one on the bottom. Via n The mask consists of two secondary exposure area masks, one on the left and one on the right, or two secondary exposure area masks, one on the top and one on the bottom.

3. The interlayer interconnect mask structure for cross-lithographic field metal interconnects as described in claim 1, characterized in that, When using copper interconnect technology, the nth metal layer M n In a photomask, either the left or right secondary exposure area photomask, or the top and bottom secondary exposure area photomask, the light-transmitting area of ​​one of the two photomasks is used to define the metal M. n The shape is such that the other corresponding position is an opaque black plate; When using copper interconnect technology, the (n+1)th metal layer M n+1 Two secondary exposure area masks, one on the left and one on the right, or one on the top and one on the bottom, are used to define the metal M using the light-transmitting area of ​​one of them. n+1 The shape is such that the other corresponding position is an opaque black plate; Via n In the left and right secondary exposure area masks or the top and bottom secondary exposure area masks, the light-transmitting area of ​​one of them is used to define the via. n The shape is one piece, and the corresponding position is an opaque black plate.

4. The interlayer interconnect mask structure for cross-lithographic field metal interconnects as described in claim 1, characterized in that, When using copper interconnect technology, the nth metal layer M n The mask has two secondary exposure areas on the left and right sides, and the mask contains a defined metal M. n A mask of shape, the through-hole Via n The mask has two secondary exposure areas on the left and right sides, and the mask has defined vias. n A shape mask, when defining metal M n Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n The shape of the light-transmitting area will be through the hole Via n The shape and the light-transmitting area are included; When using copper interconnect technology, the (n+1)th metal layer M n+1 The mask has two secondary exposure areas on the left and right sides, and the mask contains a defined metal M. n+1 A mask of shape, the through-hole Via n The mask has two secondary exposure areas on the left and right sides, and the mask has defined vias. n A shape mask, when defining metal M n+1 Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n+1 The shape of the light-transmitting area will be through the hole Via n The shape and the light-transmitting area are included; When using copper interconnect technology, the nth metal layer M n The upper and lower secondary exposure areas of the mask contain defined metal M. n A mask of shape, the through-hole Via n The upper and lower secondary exposure areas of the mask have defined vias. n A shape mask, when defining metal M n Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n The shape of the light-transmitting area will be through the hole Via n The shape and the light-transmitting area are included; When using copper interconnect technology, the (n+1)th metal layer M n+1 The upper and lower secondary exposure areas of the mask contain defined metal M. n+1 A mask of shape, the through-hole Via n The upper and lower secondary exposure areas of the mask have defined vias. n A shape mask, when defining metal M n+1 Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n+1 The shape of the light-transmitting area will be through the hole Via n The shape includes the light-transmitting area.

5. The interlayer interconnect mask structure for cross-lithographic field metal interconnects as described in claim 1, characterized in that, When using aluminum interconnect technology, the nth metal layer M n In a photomask, either the left and right secondary exposure area photomasks or the top and bottom secondary exposure area photomasks, the opaque area of ​​one of them is used to define the metal M. n The shape is such that the other corresponding position is an opaque black plate; When using aluminum interconnect technology, the (n+1)th metal layer M n+1 Two secondary exposure area masks, one on the left and one on the right, or one on the top and one on the bottom, are used to define the metal M using the opaque area of ​​one of them. n+1 The shape is such that the other corresponding position is an opaque black plate; Via n In the left and right secondary exposure area masks or the top and bottom secondary exposure area masks, the light-transmitting area of ​​one of them is used to define the via. n The shape is one piece, and the corresponding position is an opaque black plate.

6. The interlayer interconnect mask structure for cross-lithographic field metal interconnects as described in claim 1, characterized in that, When using aluminum interconnect technology, the nth metal layer M n The mask has two secondary exposure areas on the left and right sides, and the mask contains a defined metal M. n A mask of shape, the through-hole Via n The mask has two secondary exposure areas on the left and right sides, and the mask has defined vias. n A shape mask, when defining metal M n Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n The shape of the opaque area will be through the hole Via n The shape and the light-transmitting area are included; When using aluminum interconnect technology, the (n+1)th metal layer M n+1 The mask has two secondary exposure areas on the left and right sides, and the mask contains a defined metal M. n+1 A mask of shape, the through-hole Via n The mask has two secondary exposure areas on the left and right sides, and the mask has defined vias. n A shape mask, when defining metal M n+1 Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n+1 The shape of the opaque area will be through the hole Via n The shape and the light-transmitting area are included; When using aluminum interconnect technology, the nth metal layer M n The upper and lower secondary exposure areas of the mask contain defined metal M. n A mask of shape, the through-hole Via n The upper and lower secondary exposure areas of the mask have defined vias. n A shape mask, when defining metal M n Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n The shape of the opaque area will be through the hole Via n The shape and the light-transmitting area are included; When using aluminum interconnect technology, the (n+1)th metal layer M n+1 The upper and lower secondary exposure areas of the mask contain defined metal M. n+1 A mask of shape, the through-hole Via n The upper and lower secondary exposure areas of the mask have defined vias. n A shape mask, when defining metal M n+1 Shape mask and defined vias Via n When the masks of the shapes overlap, the metal M n+1 The shape of the opaque area will be through the hole Via n The shape includes the light-transmitting area.

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