Photoetching overlay mark
By combining photolithography overlay marking structures, the problems of alignment accuracy and marking space occupation of multiple photolithography layers were solved, realizing the measurement of overlay accuracy of multiple photolithography layers and the optimization of cutting paths, thus improving the efficiency and accuracy of photolithography process.
Patent Information
- Application Number
- CN202610213760.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-13
- Publication Date
- 2026-05-01
AI Technical Summary
Existing technologies cannot simultaneously meet the alignment accuracy requirements between multiple photolithography layers, and the photolithography overlay marks occupy a large amount of dicing space, making it difficult to optimize device performance and dicing width.
A photolithographic overlay marking structure is formed by combining the current layer marking pattern and multiple previous layer marking patterns. Multiple overlay accuracy measurements are achieved through the first and second sets of quasi-combined pattern structures, and marking patterns are set in the cutting path to save space.
It enables the measurement of overlay accuracy between multiple photolithography layers, saves space for label placement, optimizes the cutting track area, and improves photolithography overlay accuracy and label placement efficiency.
Smart Images
Figure CN121956445A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor integrated circuit manufacturing, and in particular to a photolithographic overlay marking. Background Technology
[0002] With the continuous updates of semiconductor technology nodes, the integration of chips is getting higher and higher, and the critical linewidth of devices is getting smaller and smaller. The alignment between photolithography layers in the photolithography process has a crucial impact on device performance.
[0003] In the photolithography process, the alignment accuracy between different photolithographic layers must meet certain requirements to ensure device performance. Furthermore, some photolithographic layers need to simultaneously meet the alignment accuracy requirements of multiple preceding layers; and the dicing width affects the number of effective chips on each wafer, necessitating optimization and simplification of the dicing width.
[0004] In existing process technologies, it is often impossible to meet the alignment accuracy requirements of multiple front layers at the same time. Alignment can only be performed on the most critical front layer, prioritizing the alignment accuracy between the current photolithography layer and the most critical front layer. Furthermore, the overlay marks used for each photolithography layer must be placed independently, which occupies a lot of cutting track space. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to provide a photolithographic overlay mark that can simultaneously measure multiple overlay accuracies and save space for mark placement.
[0006] To solve the above-mentioned technical problems, the photolithographic overlay marking provided by the present invention includes: a current layer marking pattern and a previous layer marking pattern.
[0007] The front layer identification pattern is composed of multiple front layer partial identification patterns of different front layer photolithography layers, with each front layer partial identification pattern corresponding to one front layer photolithography layer.
[0008] The center points of the current layer's identifier graphic and the previous layer's identifier graphic in each layer are consistent.
[0009] The current layer identification graphic and the previous layer partial identification graphic of each layer respectively form a first set of quasi-combined graphic structures, which are used to realize the overlay accuracy measurement between the current layer photolithography layer and each of the previous layer photolithography layers.
[0010] A further improvement is that at least two adjacent front layer partial identification patterns form a second set of quasi-combined pattern structures to achieve overlay accuracy measurement between corresponding adjacent two front layer photolithography layers.
[0011] A further improvement is that the front layer identification pattern is composed of the front layer partial identification patterns of the two front layer photolithography layers.
[0012] A further improvement is that both the current layer identifier graphic and each of the previous layer identifier graphics are set in the cutting channel.
[0013] A further improvement is that each of the aforementioned front-layer logo graphics is composed of a first bar combination structure consisting of multiple parallel bar cycles.
[0014] A further improvement is that each of the aforementioned front layer identifiers has four of the first strip combination structures, and the four first strip combination structures have 90° rotational symmetry around the center point.
[0015] A further improvement is that, in the front layer identification graphics of two adjacent layers, each of the first strip combination structures of the adjacent layers corresponds to one another and is staggered from each other, and the stripes of the two corresponding first strip combination structures of the adjacent layers are aligned.
[0016] A further improvement is that the current layer identification graphic is composed of multiple second bar combination structures arranged in parallel bar cycles; the number of second bar combination structures is equal to the total number of each of the first bar combination structures of all the previous layer identification graphics, and one second bar combination structure corresponds to one first bar combination structure.
[0017] A further improvement is that each of the second strip combination structures and the corresponding first strip combination structure has two configuration structures.
[0018] The first configuration structure is as follows: each strip of the second strip combination structure is set on the corresponding strip of the first strip combination structure.
[0019] The second configuration structure is as follows: each strip of the second strip combination structure is set in the interval area between the corresponding strips of the first strip combination structure.
[0020] A further improvement is that the first setting structure and the second setting structure are arranged alternately between the current layer identifier graphic and the corresponding previous layer identifier graphic.
[0021] In the two adjacent front layer identification graphics, the corresponding and staggered first strip combination structure of the adjacent layer and the second strip combination structure at the top are respectively the first setting structure and the second setting structure.
[0022] Unlike existing technologies where photolithographic overlay markings consist of a combination of a current layer marking pattern and a previous layer marking pattern, the photolithographic overlay markings of this invention employ a structure composed of a current layer marking pattern and multiple previous layer marking patterns related to the previous photolithographic layers. This allows for multiple overlay accuracies between the current photolithographic layer and the multiple previous photolithographic layers, thereby enabling the measurement of multiple overlay accuracies. Furthermore, the marking patterns of the multiple photolithographic layers in this invention form a unified composite structure. Compared to existing structures where each layer of marking pattern is placed independently, this invention saves marking placement space and ultimately reduces the area of the cutting path. Attached Figure Description
[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Figure 1 This is a schematic diagram of the two front-layer marking patterns in the photolithographic overlay marking of the present invention; Figure 2 This is a schematic diagram of photolithographic overlay marking according to an embodiment of the present invention. Detailed Implementation
[0024] like Figure 2 The diagram shown is a schematic diagram of photolithographic overlay marking according to an embodiment of the present invention; please refer to the front layer marking pattern in the embodiment of the present invention. Figure 1 As shown, the photolithographic overlay marking in this embodiment of the invention includes: a current layer marking pattern and a previous layer marking pattern.
[0025] The front layer identification pattern is composed of multiple front layer partial identification patterns of different front layer photolithography layers, with each front layer partial identification pattern corresponding to one front layer photolithography layer.
[0026] The center points of the current layer's identifier graphic and the previous layer's identifier graphic in each layer are consistent.
[0027] The current layer identification graphic and the previous layer partial identification graphic of each layer respectively form a first set of quasi-combined graphic structures, which are used to realize the overlay accuracy measurement between the current layer photolithography layer and each of the previous layer photolithography layers.
[0028] In this embodiment of the invention, at least two adjacent front layer partial identification patterns form a second set of quasi-combined pattern structures to achieve overlay accuracy measurement between corresponding adjacent two front layer photolithography layers.
[0029] In this embodiment of the invention, the front layer identification pattern is composed of two front layer partial identification patterns of the front layer photolithography layer. In other embodiments, the front layer identification pattern may also be composed of three or more front layer partial identification patterns of the front layer photolithography layer.
[0030] The current layer identifier graphic and each of the previous layer identifier graphics are set in the cutting channel.
[0031] like Figure 1 As shown, each of the aforementioned front-layer logo graphics is composed of a first bar combination structure consisting of multiple parallel bar cycles. Figure 1 The image shows two front-layer identification patterns corresponding to the front-layer photolithography layers. One of the front-layer identification patterns is represented by a bar marked 101a, and the first bar combination structure is represented by a dashed frame 102a. The other front-layer identification pattern is represented by a bar marked 101b, and the first bar combination structure is represented by a dashed frame 102b.
[0032] Depend on Figure 1 As shown in Figure 1, each of the aforementioned front-layer identifiers has four of the first strip combination structures, and the four first strip combination structures have 90° rotational symmetry around the center point. In other embodiments, the number and arrangement of each of the first strip combination structures of each of the aforementioned front-layer identifiers can also be changed as needed.
[0033] In the front layer identification graphics of two adjacent layers, each of the first strip combination structures in the adjacent layers corresponds one-to-one and is staggered from each other, and the stripes of the corresponding two first strip combination structures in the adjacent layers are aligned. Figure 1 As shown, Figure 1 Each of the four quadrant regions shown has a corresponding dashed box 102a corresponding to the first strip combination structure and a dashed box 102b corresponding to the first strip combination structure.
[0034] Depend on Figure 1 As shown, the overlay accuracy between the two adjacent front layer marking patterns can be measured directly.
[0035] like Figure 2 As shown, the layer identifier graphic is composed of a second strip combination structure consisting of multiple parallel stripes arranged in a periodic pattern; Figure 2 In the above, each bar of the layer identifier graphic is individually represented by the symbol 101c.
[0036] The number of the second bar combination structures is equal to the total number of each of the first bar combination structures in all the preceding layer identifier graphics, with one second bar combination structure corresponding to one first bar combination structure. Figure 2 As shown, each of the front layer identifier graphics has 4 of the first bar combination structures, so there are a total of 8 first bar combination structures. Therefore, the number of second bar combination structures is also 8.
[0037] In this embodiment of the invention, each of the second strip combination structures and the corresponding first strip combination structure has two configuration structures.
[0038] The first configuration structure is as follows: each strip of the second strip combination structure is set on the corresponding strip of the first strip combination structure. Figure 2 In the diagram, the dashed boxes 102c2 and 102c3 have the first type of configuration structure.
[0039] The second configuration structure is as follows: each strip of the second strip combination structure is set in the interval area between the corresponding strips of the first strip combination structure. Figure 2 In the middle, the dashed boxes 102c1 and 102c4 have the second type of configuration structure.
[0040] Between the current layer identifier graphic and the corresponding previous layer identifier graphic, the first setting structure and the second setting structure are arranged alternately.
[0041] In the two adjacent front layer identification graphics, the corresponding and staggered first strip combination structure of the adjacent layer and the second strip combination structure at the top are respectively the first setting structure and the second setting structure.
[0042] Depend on Figure 2 As shown, the current layer identifier pattern can be used to measure the overlay accuracy with the two preceding layer identifier patterns, resulting in two overlay accuracies. Adding the overlay accuracy between the two preceding photolithographic layers, this embodiment of the invention achieves three overlay accuracies. In other embodiments, increasing the number of preceding photolithographic layers further increases the number of measurable overlay accuracies.
[0043] Unlike the existing technology where the photolithographic overlay marking is a combination of the current layer marking pattern and a previous layer marking pattern, the photolithographic overlay marking in this embodiment of the invention adopts a structure composed of the current layer marking pattern and the previous layer marking patterns related to multiple previous photolithographic layers. This can form multiple overlay accuracies between the current photolithographic layer and the multiple previous photolithographic layers, thereby realizing the measurement of multiple overlay accuracies.
[0044] Furthermore, in this embodiment of the invention, the marking patterns of the multi-layer photolithography are a unified composite structure. Compared to existing structures where each layer of marking patterns is placed independently, this embodiment of the invention saves space for marking placement and ultimately reduces the area of the cutting path. For example, if each photolithography layer uses... Figure 1 When measuring the overlay accuracy of the photolithography overlay marks shown, a separate area needs to be set between every two photolithography layers. When the same number of overlay accuracies are obtained, the area occupied by the photolithography overlay marks will inevitably increase.
[0045] This invention provides a photolithographic overlay marker for simultaneously aligning two preceding photolithographic layers. Using a single marker, three sets of overlay accuracy data (B→A, C→A, and C→B) can be obtained, improving overlay accuracy while optimizing marker placement space. Here, C represents the current photolithographic layer, B represents a preceding photolithographic layer, and A represents the preceding photolithographic layer before B. Figure 1 The aforementioned front-layer marking pattern can obtain overlay accuracy data from B to A; Figure 2 In this process, two sets of overlay accuracy data, C→A and C→B, can be obtained.
[0046] In practical applications, the first part of the front layer marking pattern in the photolithographic overlay marking can be formed on the wafer through exposure and etching of photolithographic layer A, such as... Figure 1 The front layer part is identified by the bar corresponding to mark 101a.
[0047] Then, through exposure and etching of photolithography layer B, the second part of the front layer marking pattern in the photolithographic overlay marking is formed on the wafer, such as... Figure 1 The first part of the graphic is identified by the bars corresponding to mark 101b. The theoretical design center point of the second part of the graphic is consistent with that of the first part of the graphic. At this time, it is formed by combining photolithographic layers A and B. Figure 1 The aforementioned front layer marking pattern can be directly used to measure the overlay accuracy of photolithography layer B on photolithography layer A, i.e., the overlay accuracy data of B→A.
[0048] Based on the formation of the previous layer marking pattern and the completion of the overlay accuracy measurement, the current layer marking pattern of the photolithographic overlay marking is formed by the exposure of the photolithographic layer C. The center point of the current layer marking pattern formed by the photolithographic layer C and the previous layer marking pattern formed by the photolithographic layers A / B must be consistent. The photolithographic overlay marking can be used for the overlay accuracy measurement of photolithographic layers C→A and C→B, realizing the monitoring of the overlay accuracy of one photolithographic layer aligning with two photolithographic layers at the same time.
[0049] Therefore, in this embodiment of the invention, a photolithographic overlay mark formed by combining photolithographic layers A / B / C can obtain three sets of overlay accuracy data for photolithographic layers B→A, C→A, and C→B, thereby improving the overlay accuracy while optimizing the placement space and area of the mark.
[0050] The present invention has been described in detail above through specific embodiments, but these are not intended to limit the invention. Many modifications and improvements can be made by those skilled in the art without departing from the principles of the invention, and these should also be considered within the scope of protection of the present invention.
Claims
1. A photolithographic overlay marking, characterized in that, include: Current layer identifier graphics and previous layer identifier graphics; The front layer identification pattern is composed of multiple front layer partial identification patterns of different front layer photolithography layers, with one front layer partial identification pattern corresponding to one front layer photolithography layer; The center points of the current layer's identification graphic and the previous layer's partial identification graphic of each layer are consistent; The current layer identification graphic and the previous layer partial identification graphic of each layer respectively form a first set of quasi-combined graphic structures, which are used to realize the overlay accuracy measurement between the current layer photolithography layer and each of the previous layer photolithography layers.
2. The photolithographic overlay marking as described in claim 1, characterized in that: At least two adjacent front layer partial identification patterns form a second set of quasi-combined pattern structures to achieve overlay accuracy measurement between corresponding adjacent two front layer photolithography layers.
3. The photolithographic overlay marking as described in claim 1, characterized in that: The front layer identification pattern is composed of the front layer partial identification patterns of the two front layer photolithography layers.
4. The photolithographic overlay marking as described in claim 1, characterized in that: The current layer identifier graphic and each of the previous layer identifier graphics are set in the cutting channel.
5. The photolithographic overlay marking as described in claim 3, characterized in that: Each of the aforementioned front-layer logo graphics consists of a first bar combination structure composed of multiple parallel bar cycles.
6. The photolithographic overlay marking as described in claim 5, characterized in that: Each of the aforementioned front layer identifiers has four of the first strip combination structures, and the four first strip combination structures have 90° rotational symmetry around the center point.
7. The photolithographic overlay marking as described in claim 6, characterized in that: In the front layer identification graphics of two adjacent layers, each of the first strip combination structures of the adjacent layers corresponds to one another and is staggered from each other, and the stripes of the two corresponding first strip combination structures of the adjacent layers are aligned.
8. The photolithographic overlay marking as described in claim 7, characterized in that: The current layer identifier graphic consists of multiple second bar combination structures arranged in parallel bar cycles; the number of second bar combination structures is equal to the total number of each of the first bar combination structures of all the previous layer identifier graphics, and one second bar combination structure corresponds to one first bar combination structure.
9. The photolithographic overlay marking as described in claim 8, characterized in that: Each of the second strip combination structures and the corresponding first strip combination structure has two configuration structures; The first configuration structure is as follows: each strip of the second strip combination structure is set on the corresponding strip of the first strip combination structure; The second configuration structure is as follows: each strip of the second strip combination structure is set in the interval area between the corresponding strips of the first strip combination structure.
10. The photolithographic overlay marking as described in claim 9, characterized in that: Between the current layer identifier graphic and the corresponding previous layer identifier graphic, the first setting structure and the second setting structure are arranged alternately; In the two adjacent front layer identification graphics, the corresponding and staggered first strip combination structure of the adjacent layer and the second strip combination structure at the top are respectively the first setting structure and the second setting structure.