Photolithography interleaving masks and photolithography interleaving system

Abstract

This invention discloses a photolithography overlay mask and a photolithography overlay system. The photolithography overlay mask includes: DUV plate overlay marks, I-line overlay marks, and contact overlay marks, located in the non-graphic area of ​​the mask, corresponding to DUV lithography machines, I-line stepper lithography machines, and contact lithography machines, respectively; the sizes of the DUV plate overlay marks, I-line overlay marks, and contact overlay marks are respectively 4 times, 5 times, and 1 times the designed size of the overlay marks; one or more sets of overlay offset marks and multiple sets of CD resolution marks are located in the non-graphic area of ​​the mask. This invention enables overlay of photolithography machines from different manufacturers and of different types, achieving excellent photolithography results.

Description

Technical Field

[0001] This utility model belongs to the field of semiconductor integrated circuit manufacturing technology, and more specifically, relates to a photolithography overlay mask and a photolithography overlay system. Background Technology

[0002] Currently, the mainstream lithography machine manufacturers include Nikon and Canon from Japan, ASML from the Netherlands, and SUSS from Germany. Due to the secrecy surrounding the technology of different models from these manufacturers, it is difficult to use lithography machines from different manufacturers together for the same integrated circuit product. In other words, there are certain technical defects in the interoperability of different models from different manufacturers, specifically as follows: First, the projection scaling ratios of each lithography machine are different: deep ultraviolet lithography (DUV) machines have a projection scaling ratio of 4:1, I-line stepper lithography machines have a projection scaling ratio of 5:1, and contact lithography machines have a projection scaling ratio of 1:1. Second, the principles by which different manufacturers' lithography machines detect and identify alignment marks are different, resulting in significant differences in the shape and number of overlay marks.

[0003] Furthermore, many devices (such as complementary metal-oxide-semiconductor devices, microelectromechanical systems sensors, analog devices, and radio frequency devices) involve processes like ion implantation and etching, requiring high-thickness photoresist. However, current DUV photoresists, in order to maintain nanometer-level critical dimensions (CD), generally have thicknesses at the nanometer level. This means that for process steps with lower overlay precision requirements, different types of lithography machines (such as I-line stepper lithography and contact lithography machines) can be used in combination to expose thicker photoresists. While some research and methods exist for overlaying different types of lithography machines from the same manufacturer, there are still uncertainties regarding overlaying between lithography machines from different manufacturers. Utility Model Content

[0004] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide a photolithography interlocking mask and a photolithography interlocking system, so as to at least solve the above-mentioned technical problems.

[0005] Based on the above objectives, the first aspect of this utility model provides a photolithographic overlay mask, comprising: DUV overlay marks, I-line overlay marks, and contact overlay marks, located in the non-graphic area of ​​the mask, corresponding to a DUV lithography machine, an I-line stepper lithography machine, and a contact lithography machine, respectively; the dimensions of the DUV overlay marks, the I-line overlay marks, and the contact overlay marks are respectively 4 times, 5 times, and 1 times the design size of the overlay marks; one or more sets of overlay offset marks and multiple sets of CD resolution marks are located in the non-graphic area of ​​the mask.

[0006] Preferably, the DUV overlay mark, the I-line overlay mark, and the contact overlay mark are located in the first layer of the photomask and are formed by exposure using the lithography machine with the highest exposure accuracy among the DUV lithography machine, the I-line stepper lithography machine, and the contact lithography machine.

[0007] Preferably, the photolithographic overlay mask includes multiple photolithographic masks, and each photolithographic mask has one or more photolithographic layers.

[0008] Preferably, for a photomask having multiple photolithographic layers, the non-graphic area of ​​the photomask also has a chrome-plated area, and the chrome-plated area is set between adjacent photolithographic layers.

[0009] Preferably, the width of the chrome-plated area is 1mm to 2mm.

[0010] Preferably, the dimensions of the DUV overprint mark, the I-line overprint mark, and the contact overprint mark are all smaller than the cutting width of the target product; and / or, among the DUV overprint mark, the I-line overprint mark, and the contact overprint mark, the overprint marks do not overlap or interfere with each other, and the interval between different overprint marks is not less than the minimum forbidden area required to process the target product.

[0011] Preferably, the photolithography overlay mask further includes: DUV plate alignment marks and I-line plate alignment marks, located in the non-graphic area of ​​the mask, corresponding to the DUV lithography machine and the I-line stepper lithography machine, respectively.

[0012] The second aspect of this utility model provides a photolithography interleaving system, comprising: a DUV lithography machine, an I-line stepper lithography machine, a contact lithography machine, and a photolithography interleaving mask as described above; the DUV lithography machine, the I-line stepper lithography machine, and the contact lithography machine are used to perform interleaving photolithography according to the markings on the photolithography interleaving mask.

[0013] Preferably, the DUV lithography machine, the I-line stepper lithography machine, and the contact lithography machine have the same exposure range.

[0014] Preferably, the deviation between the physical center point and the target center point of the exposure pattern of the DUV lithography machine, the I-line stepper lithography machine, and the contact lithography machine on the lithographic overlay mask does not exceed a set value.

[0015] Compared with the prior art, the advantages of this utility model include:

[0016] (1) A photolithography overlay mask is provided, wherein DUV overlay marks, I-line overlay marks and contact overlay marks are provided on the photolithography overlay mask. The sizes of these three overlay marks are respectively 4 times, 5 times and 1 times the design size of the overlay marks. The photolithography overlay mask can realize mutual overlay between different photolithography machine manufacturers and different types of photolithography machines.

[0017] (2) The DUV overlay mark, I-line overlay mark and contact overlay mark are set in the first layer of the mask and formed by the lithography machine with the highest exposure accuracy. Compared with the method of blind exposure in the first layer without overlay marks and relying on the machine's own adjustment accuracy to perform the first layer exposure, this utility model is more suitable for a variety of lithography machine manufacturers and machines and has stronger adaptability. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a photolithographic overlay mask provided in an embodiment of the present invention.

[0019] Figure 2 This diagram illustrates the alignment relationships between DUV lithography machines, I-line stepper lithography machines, and contact lithography machines.

[0020] Figure 3 This is a schematic diagram of a DUV1 version pure overlay marking mask.

[0021] Figure 4 This is a schematic diagram of the mask for line I1.

[0022] Figure 5 This is a schematic diagram of the photomask for line I-2.

[0023] Figure 6 This is a schematic diagram of a DUV2 quad mask.

[0024] Figure 7 This is a schematic diagram of the I-line 3 mask.

[0025] Figure 8 This is a schematic diagram of the 4-mask for line I.

[0026] Figure 9 A diagram illustrating the markings for CD resolution.

[0027] Figure 10 This is a schematic diagram of interlocking offset markers.

[0028] Figure 11 A physical image of the photolithographic overlay mask provided for an embodiment of this utility model. Detailed Implementation

[0029] In view of the shortcomings of the prior art, the inventor of this utility model has, through long-term research and extensive practice, proposed the technical solution of this utility model. The following will further explain and illustrate the technical solution, its implementation process, and its principles.

[0030] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0031] Furthermore, it should be understood in the description of this utility model that the terms "upper", "lower", "inner", "outer", "horizontal", "vertical", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0032] In the description of this specification, the references to terms such as "an embodiment," "a particular embodiment," or "the embodiment" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0033] This invention provides a photolithography overlay mask. The photolithography overlay mask includes: DUV plate overlay marks, I-line overlay marks, and contact overlay marks, located in the non-graphic area of ​​the mask, corresponding to a DUV lithography machine, an I-line stepper lithography machine, and a contact lithography machine, respectively; the sizes of the DUV plate overlay marks, I-line overlay marks, and contact overlay marks are respectively 4 times, 5 times, and 1 times the designed size of the overlay marks; one or more sets of overlay offset marks and multiple sets of CD resolution marks are located in the non-graphic area of ​​the mask. The structure of the photolithography overlay mask is as follows: Figure 1 As shown.

[0034] In this invention, the overlay marks are appropriately adjusted on the photomask of the lithography machine used for the exposure layer, based on the size of the overlay marks on the wafer and the scaling ratio requirements of the lithography machine type used for the corresponding exposure layer. This allows for mutual overlay of photolithography overlay masks between lithography machines from different manufacturers and of different types. Overlay offset marks and CD resolution marks are placed, for example, in the dicing area of ​​the photomask, for monitoring overlay offset and CD resolution, respectively.

[0035] In a preferred embodiment, the DUV overlay marks, I-line overlay marks, and contact overlay marks are located in the first layer of the photomask and are formed by exposure using the lithography machine with the highest exposure precision among the DUV lithography machine, I-line stepper lithography machine, and contact lithography machine. By photolithographically patterning different types of overlay marks onto the substrate and placing the overlay marks from different lithography machines in the first layer, it is ensured that subsequent lithography machines all have identifiable marks.

[0036] For example, overlay marks from different lithography machines (Canon DUV ES4, Nikon I9) are placed on the first layer. The first layer is exposed by the Canon DUV ES4, which has the highest exposure precision, thus photolithographically patterning different types of overlay marks onto the substrate. The photolithographic overlay mask contains Canon DUV ES4 overlay marks with a scaling ratio of 4:1 placed on the dicing track and Nikon I9 overlay marks with a scaling ratio of 5:1 placed on the dicing track. The overlay marks do not overlap.

[0037] In a preferred embodiment, the photolithographic overlay mask includes multiple photolithographic masks, each of which has one or more photolithographic layers.

[0038] In a preferred embodiment, for a photomask having multiple photolithographic layers, a chrome-plated area is further provided in the non-graphic area of ​​the photomask, and a chrome-plated area is provided between adjacent photolithographic layers. Preferably, the width of the chrome-plated area is 1mm to 2mm. For example, the width of the chrome-plated area is 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, or 2mm. The sum of the areas of the multiple photolithographic layers and the chrome-plated area must not exceed the maximum exposure area of ​​the corresponding photolithography machine.

[0039] by Figure 6 Taking the DUV2 four-part photomask as an example, the DUV lithography mask is divided into four regions, each containing one layer of exposure pattern. A cross-shaped chrome-plated area is used to separate the regions, thus preventing light leakage from the lithography machine's baffle. Placing different lithography layers on a single photomask saves on mask costs. Other I-line stepper lithography machines can also use photomasks divided into four exposure areas according to actual product requirements, with cross-shaped chrome-plated areas for isolation.

[0040] In a preferred embodiment, the dimensions of the DUV overprint marks, I-line overprint marks, and contact overprint marks are all smaller than the cutting width of the target product. Among the DUV overprint marks, I-line overprint marks, and contact overprint marks, each overprint mark does not overlap or interfere with the others, and the spacing between different overprint marks is not less than the minimum forbidden zone required for processing the target product.

[0041] In a preferred embodiment, the photolithography overlay mask further includes: DUV plate alignment marks and I-line plate alignment marks, located in the non-graphic area of ​​the mask, corresponding to the DUV lithography machine and the I-line stepper lithography machine, respectively.

[0042] This invention also provides a photolithography interleaving system, including: a DUV lithography machine, an I-line stepper lithography machine, a contact lithography machine, and a photolithography interleaving mask as described in the above embodiments. The DUV lithography machine, the I-line stepper lithography machine, and the contact lithography machine are used to perform interleaving photolithography based on the markings on the photolithography interleaving mask.

[0043] In a preferred embodiment, the DUV lithography machine, the I-line stepper lithography machine, and the contact lithography machine have the same exposure range. For example, the maximum exposure range of the lithography machine with the smallest maximum exposure range among all the lithography machines.

[0044] In a preferred embodiment, the deviation between the physical center point and the target center point of the exposure pattern on the photolithographic overlay mask of the DUV lithography machine, I-line stepper lithography machine, and contact lithography machine does not exceed a set value. The set value is, for example, 50 μm.

[0045] By adjusting the physical center point of the exposure patterns on the substrate of the lithography machines that need to be interleaved, it is ensured that the deviation from the center point is within a certain range. Otherwise, the lithography machines cannot automatically recognize the interleaving marks during interleaving. For example, using the exposure center of the lithography machine with the highest exposure and stepping accuracy as a benchmark, the physical centers of other lower-precision lithography machines are adjusted so that the physical centers of the two lithography machines are within a certain deviation. When DUV and I-line lithography machines are interleaved, the calculated deviation compensation is incorporated into the exposure program to ensure that the DUV and I-line lithography machines can automatically identify and find their respective interleaving marks during interleaving.

[0046] The technical solution of this utility model will be further described in detail below with reference to several preferred embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0047] The following is combined Figures 1-11 The specific examples shown illustrate the principle and process of processing products using the photolithography interlocking mask and photolithography interlocking system of this utility model.

[0048] Photolithography overlay masks include DUV1 version pure overlay marking masks (such as...) Figure 3 As shown), I-line 1 mask (as shown) Figure 4As shown), I-line 2 mask (as shown) Figure 5 (as shown), DUV2 quad mask (as shown) Figure 6 As shown), I-line 3 mask (as shown) Figure 7 (as shown) and I-line 4 mask (as shown) Figure 8 The five parts (as shown) are combined to form a photolithographic overlay mask. Figure 1 As shown, the actual image of the photolithographically interlocked photomasks is as follows: Figure 11 As shown.

[0049] See Figure 2 The exposure sequence is as follows: DUV1 pure overlay mark mask (hereinafter referred to as DUV1 mask) → I-line 1 mask (hereinafter referred to as I-line 1) → I-line 2 mask (hereinafter referred to as I-line 2) → DUV2 quarter mask (hereinafter referred to as DUV2 mask) quadrant 1 → DUV2 quarter mask 2 quadrant → DUV2 quarter mask 3 quadrant → DUV2 quarter mask 4 quadrant → I-line 3 mask (hereinafter referred to as I-line 3) → I-line 4 mask (hereinafter referred to as I-line 4). The overlay alignment relationship is shown in Table 1.

[0050] Table 1

[0051]

[0052]

[0053] The overprinting alignment is as follows: I-line 1 is aligned with the pure overprinting mark of DUV1; I-line 2 is aligned with the pure overprinting mark of DUV1; the first quadrant of DUV2 is aligned with the pure overprinting mark of DUV1, and the overprinting mark of DUV1 is designed in the first quadrant of DUV2; the second quadrant of DUV2 is aligned with the first quadrant of DUV2; the third quadrant of DUV2 is aligned with the first quadrant of DUV2; the fourth quadrant of DUV2 is aligned with the first quadrant of DUV2, and the overprinting mark of I-line and the contact overprinting mark are designed in the fourth quadrant of DUV2; I-line 3 is aligned with the fourth quadrant of DUV2 - overprinting alignment based on the overprinting mark of I-line and the contact overprinting mark; I-line 4 is aligned with the fourth quadrant of DUV2 - overprinting alignment based on the overprinting mark of I-line; I-line 3 is aligned with I-line 4 - overprinting alignment based on the contact overprinting mark.

[0054] Except for the DUV1 pure overlay marking mask, all other masks have two sets of diagonally symmetrically distributed interleaved offset marks and CD resolution marks. See the documentation for specific locations. Figures 4-8 The morphologies of the interleaved offset markers and the CD resolution markers are as follows: Figure 9 and Figure 10 As shown. The CD resolution marker design standard in this example is set based on the smallest CD on the exposure pattern of this layer. Other products can also be designed with different CD sizes, which can be placed in any free area of ​​the pattern area as needed. The more markers there are, the more accurate the calculation will be.

[0055] The individual pattern area (shot) in this product design layout is 12*16mm in size on the wafer, with a dicing width of 150μm. Depending on the size of a single shot, the corresponding magnification of the mask used in different types of lithography machines is 4 / 5 times. For example, the effective exposure area on the Nikon I9 mask is 60*80mm. Figure 4 , Figure 5 , Figure 7 , Figure 8 As shown. The effective exposure area on the Canon DUVES4 mask is 48*64mm, as... Figure 3 As shown. Figure 6 This is a four-part DUV format, with each quadrant representing a single exposure layer. The effective exposure area of ​​each quadrant is 48*64mm, and the width of the cross-shaped chrome plating area is 4mm (which needs to be reduced by a factor of 4 on the wafer). Figure 6 The effective exposure area of ​​the DUV2 mask is 100*132mm, which is smaller than the maximum exposure area of ​​104*132mm on the Canon DUV ES4 mask (the maximum exposure area on the wafer is 26*33mm, which is magnified 4 times to 104*132mm on the mask). This ensures that different types of lithography machines from different manufacturers can be combined for exposure with the same exposure size. This example only uses the Canon DUV ES4, Nikon 19 stepper lithography machine, and SUSS MA8 contact lithography machine as examples. For other types of lithography machines from other manufacturers, the same size should be adjusted appropriately due to the different maximum exposure areas.

[0056] Finally, the example product is exposed sequentially: DUV1 pure overlay marks → I-line 1 → I-line 2 → DUV2 quadrant 1 → DUV2 quadrant 2 → DUV2 quadrant 3 → DUV2 quadrant 4 → I-line 3 → I-line 4. After exposure, the quantity and positional relationship of all I-line overlay marks, DUV overlay marks, contact overlay marks, CD resolution, and overlay offset marks are displayed. Figure 1 In this context, these markers must not overlap or interfere with each other.

[0057] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this utility model. The schematic diagrams only show the number, shape and size of the components related to this utility model. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0058] It should be understood that the above embodiments are merely illustrative of the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be included within the scope of protection of this utility model.

Claims

1. A photoresist interlevel mask characterized by, include: The DUV overlay marks, I-line overlay marks, and contact overlay marks are located in the non-graphic area of ​​the mask and correspond to the DUV lithography machine, the I-line stepper lithography machine, and the contact lithography machine, respectively. The dimensions of the DUV overprint mark, the I-line overprint mark, and the contact overprint mark are respectively 4 times, 5 times, and 1 times the design size of the overprint mark; One or more interlocking offset markers and multiple sets of CD resolution markers are located in the non-graphic area of ​​the mask.

2. The photo-lithographically interlinked mask of claim 1, wherein, The DUV overlay mark, the I-line overlay mark, and the contact overlay mark are located on the first layer of the photomask and are formed by exposure using the lithography machine with the highest exposure accuracy among the DUV lithography machine, the I-line stepper lithography machine, and the contact lithography machine.

3. The photo-lithographically interlinked mask of claim 1, wherein, The photolithography overlay mask includes multiple photolithography masks, and each photolithography mask has one or more photolithography layers.

4. The photo-lithographically interlinked mask of claim 3, wherein, For a photomask having multiple photolithography layers, the non-graphic area of ​​the photomask also has a chrome-plated area, and the chrome-plated area is set between adjacent photolithography layers.

5. The photolithographic interlinked mask of claim 4, wherein, The width of the chrome-plated area is 1mm to 2mm.

6. The photolithographic interleaved photomask according to claim 1, characterized in that, The dimensions of the DUV overlay mark, the I-line overlay mark, and the contact overlay mark are all smaller than the width of the cutting path of the target product; And / or, among the DUV overprint marks, the I-line overprint marks, and the contact overprint marks, the overprint marks do not overlap or interfere with each other, and the interval between different overprint marks is not less than the minimum prohibited area required for processing the target product.

7. The photolithographic interlinked mask of claim 1, wherein, The photolithography overlay mask also includes: DUV plate alignment marks and I-line plate alignment marks, located in the non-graphic area of ​​the mask, corresponding to the DUV lithography machine and the I-line stepper lithography machine, respectively.

8. A photolithography interlocking system, characterized by, include: DUV lithography machine, I-line stepper lithography machine, contact lithography machine, and lithographic interlocking photomask as described in any one of claims 1-7; The DUV lithography machine, the I-line stepper lithography machine, and the contact lithography machine are used to perform interleaved lithography based on the markings on the interleaved lithography mask.

9. The photolithography system of claim 8, wherein, The DUV lithography machine, the I-line stepper lithography machine, and the contact lithography machine have the same exposure range.

10. The photolithography system of claim 8, wherein, The deviation between the physical center point and the target center point of the exposure pattern on the photolithography overlay mask of the DUV lithography machine, the I-line stepper lithography machine, and the contact lithography machine does not exceed a set value.

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