Alignment marks between exposure fields and method for forming the same, and encapsulation process

Abstract

The application provides an alignment mark between exposure fields, a forming method of the alignment mark, and a detection process. The target alignment mark is first divided into at least two part marks, and the length of each part mark is not greater than the width of the cutting track. Then, each part mark is processed to meet the mask design rule, and the processed part mark is arranged in different areas of the mask. Subsequently, at least two exposure processes are performed to transfer the at least two part marks to the cutting track of the wafer, and the at least two part marks jointly constitute the alignment mark. The unexpected effect of the application is that the design requirement is met without changing the size of the existing wafer cutting track and the layout of the existing mask, and the complete large-size alignment mark is formed through at least double exposure of the cutting track of the exposure field by using the characteristics of photolithography, so as to meet the requirement of the large-size alignment mark between exposure fields.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit technology, and in particular to an alignment mark between exposure fields, a method for forming the mark, and a packaging and testing process. Background Technology

[0002] Large alignment marks are required for dicing or bonding during packaging and testing. However, current solutions cannot achieve large alignment marks within a single mask. This means the size of the large alignment mark is larger than the dicing trace. A single mask typically covers only the area containing one chip, or at most two chips. Therefore, when the size of the large alignment mark is larger than the dicing trace in all four directions, a single mask cannot create a complete large alignment mark. Currently, packaging and testing uses small masks, resulting in poor identification accuracy, frequent alarms, and the need for manual intervention. Furthermore, the manual alignment method used for dicing or bonding during packaging and testing impacts efficiency. Summary of the Invention

[0003] The purpose of this invention is to provide an alignment mark between exposure fields and its formation method, as well as a packaging and testing process, to solve the problem that manual alignment during cutting or bonding in packaging and testing affects the efficiency of packaging and testing.

[0004] To solve the above-mentioned technical problems, the present invention provides a method for forming alignment marks between exposure fields, comprising:

[0005] A target alignment mark is provided, the length of which is greater than the width of the dicing track between adjacent exposure fields of the wafer;

[0006] The target alignment mark is divided into at least two part marks, and the length of each part mark is not greater than the width of the cutting path;

[0007] Each part of the mark is processed to conform to the mask design rules, and the processed part marks are placed in different areas of the mask.

[0008] Perform at least two exposure processes to transfer at least two partial marks onto the wafer dicing track, the at least two partial marks together forming alignment marks.

[0009] Optionally, the alignment mark is located between two exposure fields; the target alignment mark is divided into two parts, namely a first part and a second part, the length of the first part is greater than the length of the second part, and the length of the second part is half the difference between the length of the target alignment mark and the width of the cut.

[0010] Optionally, the steps for processing each part marker include:

[0011] The first part is placed on one side of the mask template after being reduced in size to the target size on the side closer to the second part, and the second part is placed on the opposite side of the mask template after being compensated for the target size on the side closer to the first part.

[0012] Optionally, the alignment mark is located between the four exposure fields; the target alignment mark is divided into three parts, namely a first part, a second part, and a third part, wherein the length of the first part is greater than the length of the second part, and the length of the first part is greater than the length of the third part.

[0013] Optionally, the steps for processing each part marker include:

[0014] The first part is arranged at the first corner of the mask template after being reduced inward by the target size on the side near the second part and the side near the third part, and the second part is arranged at the adjacent corner of the first corner of the mask template after being compensated for the target size on the side near the first part, and the third part is arranged at the other adjacent corner of the first corner of the mask template after being compensated for the target size on the side near the first part.

[0015] Optionally, the target alignment marks on the photomask are transferred to the dicing track of the wafer, and alignment marks including the first portion, the second portion and the third portion are formed on the dicing track between adjacent exposure fields of the wafer.

[0016] Optionally, in the first direction, the length of the second portion is half the difference between the length of the target alignment mark and the width of the cutting track; in the second direction, the length of the third portion is half the difference between the length of the target alignment mark and the width of the cutting track, wherein the first direction is perpendicular to the second direction.

[0017] Optionally, the target size is the minimum dimension from the graphic in the cut track to the boundary of the cut track in the mask design rules.

[0018] Based on the same inventive concept, the present invention also provides an alignment mark between exposure fields, which is prepared by the method for forming an alignment mark between exposure fields as described in any of the above claims.

[0019] Based on the same inventive concept, the present invention also provides a packaging and testing process, including: alignment using the alignment marks between the exposure fields described above.

[0020] In a method for forming alignment marks between exposure fields provided by this invention, the length of the target alignment mark is greater than the width of the dicing track between adjacent exposure fields of the wafer. First, the target alignment mark is divided into at least two part marks, each part mark having a length no greater than the width of the dicing track. Then, each part mark is processed to conform to the mask design rules, and the processed part marks are arranged in different areas of the mask. Next, at least two exposure processes are performed to transfer the at least two part marks to the dicing track of the wafer, whereby the at least two part marks together constitute the alignment mark. An unexpected effect of this invention is that, without changing the existing wafer dicing track size or other existing mask layouts, it meets design requirements while utilizing the characteristics of photolithography to form a complete large-size alignment mark after at least two exposures of the wafer's exposure field dicing track, thus satisfying customer demand for large-size alignment marks between exposure fields. Attached Figure Description

[0021] Figure 1 This is a flowchart of a method for forming alignment marks between exposure fields according to an embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of the target alignment mark segmentation in Embodiment 1 of the present invention.

[0023] Figure 3 This is a schematic diagram of processing the first part of the target alignment mark in Embodiment 1 of the present invention.

[0024] Figure 4 This is a schematic diagram illustrating the processing of the second part of the target alignment mark in Embodiment 1 of the present invention.

[0025] Figure 5 This is a schematic diagram showing the position of the target alignment mark in the mask template in Embodiment 1 of the present invention.

[0026] Figure 6 This is a schematic diagram showing the position of the alignment mark in the exposure field in Embodiment 1 of the present invention.

[0027] Figure 7 This is a schematic diagram of forming a complete alignment mark in Embodiment 1 of the present invention.

[0028] Figure 8 This is a schematic diagram of the target alignment mark segmentation in Embodiment 2 of the present invention.

[0029] Figure 9 This is a schematic diagram of processing the first part of the target alignment mark in Embodiment 2 of the present invention.

[0030] Figure 10This is a schematic diagram of processing the second part of the target alignment mark in Embodiment 2 of the present invention.

[0031] Figure 11 This is a schematic diagram illustrating the processing of the third part of the target alignment mark in Embodiment 2 of the present invention.

[0032] Figure 12 This is a schematic diagram showing the position of the target alignment mark in the mask template in Embodiment 2 of the present invention.

[0033] Figure 13 This is a schematic diagram showing the position of the alignment mark in the exposure field in Embodiment 2 of the present invention.

[0034] Figure 14 This is a schematic diagram of forming a complete alignment mark in Embodiment 2 of the present invention.

[0035] In the figure: 10-Mask; 10a-First side; 10b-Second side; 10c-First corner; 10d-Second corner; 10e-Third corner; 10f-Fourth corner; 11-Target alignment mark; 11a-First part; 11b-Second part; 11c-Third part; 12-Passivation layer; 13-Metal layer; 14-Chip area; 15a-First side of the second direction dicing; 15b-Second side of the second direction dicing; 16a-First side of the first direction dicing; 16b-Second side of the first direction dicing; 30-Exposure field. Detailed Implementation

[0036] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a more detailed explanation of the alignment mark between exposure fields, its formation method, and the packaging and testing process 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, used only to facilitate and clarify the illustration of the embodiments of this invention. Furthermore, the structures shown in the drawings are often part of the actual structure. In particular, different proportions may be used in different drawings to illustrate different aspects.

[0037] Figure 1 This is a flowchart illustrating a method for forming alignment marks between exposure fields according to an embodiment of the present invention. Figure 1 As shown, this embodiment provides a method for forming alignment marks between exposure fields, including:

[0038] Step S10: Provide a target alignment mark, the length of which is greater than the dicing width between adjacent exposure fields of the wafer;

[0039] Step S20: The target alignment mark is divided into at least two part marks, and the length of each part mark is not greater than the width of the cutting path;

[0040] Step S30: Process each part mark to conform to the mask design rules, and arrange the processed part marks in different areas of the mask;

[0041] Step S40: Perform at least two exposure processes to transfer at least two partial marks to the dicing track of the wafer, wherein the at least two partial marks together constitute alignment marks.

[0042] Figures 2 to 14 This is a schematic diagram showing the structural steps corresponding to the method for forming alignment marks between exposure fields according to an embodiment of the present invention. To make the above-mentioned objectives, features, and beneficial effects of the present invention more apparent and understandable, the following description is provided in conjunction with the appendix to the specification. Figures 2 to 14 Specific embodiments of the present invention will be described in detail below.

[0043] In one embodiment, the alignment mark is located between the two exposure fields. (See below for details.) Figures 2 to 7 Example 1 will be described in detail.

[0044] Figure 2 This is a schematic diagram of the target alignment mark segmentation in Embodiment 1 of the present invention. Combined with... Figure 2 Detailed explanation of step S10. For example... Figure 2 As shown, in step S10, a target alignment mark 11 is provided. The target alignment mark 11 is, for example, cross-shaped, and has the same length, C, in both the first and second directions. The first direction is, for example, the X direction, and the second direction is, for example, the Y direction. The first and second directions are perpendicular. The length C of the target alignment mark 11 is greater than the dicing width W between adjacent exposure fields of the wafer. The pattern of the target alignment mark 11 includes a metal layer 13 and a passivation layer 12. The metal layer (TopMetal, TM) is used to define a precise lithography pattern. The passivation layer (Passivation, PV) is used to enhance chip stability and meet packaging requirements. The passivation layer region is a light-transmitting region. The width of the metal layer 13 is A, and the width of the passivation layer 12 is B. The width A of the metal layer 13 is greater than the width B of the passivation layer 12. The width A of the metal layer 13 is less than or equal to the dicing width W minus twice the target size D. In this embodiment, the dicing width W is, for example, 60 μm, i.e., A ≤ 60 - 2D.

[0045] Please continue to refer to this. Figure 2 , combined Figure 2Step S20 is described in detail. In step S20, the target alignment mark 11 is divided, for example, by cutting along the second side 15b of the cutting channel in the second direction. The target alignment mark 11 is divided into at least two part marks, the length of each part mark being no greater than the width of the cutting channel. The two part marks are a first part 11a and a second part 11b. The length E of the first part 11a in the first direction is greater than the length F of the second part 11b in the first direction. The length F of the second part 11b is half the difference between the length C of the target alignment mark 11 and the width W of the cutting channel, that is, F = (CW) / 2.

[0046] Figure 3 This is a schematic diagram of processing the first part of the target alignment mark in Embodiment 1 of the present invention. Figure 4 This is a schematic diagram illustrating the processing of the second part of the target alignment mark in Embodiment 1 of the present invention. Figure 5 This is a schematic diagram showing the position of the target alignment mark in the mask template in Embodiment 1 of the present invention. (In conjunction with...) Figures 3 to 5 Detailed explanation of step S30. For example... Figures 3 to 5 As shown, in step S30, each part mark is processed to conform to the mask design rules, and the processed part marks are arranged in different areas of the mask. That is, the first part 11a and the second part 11b are processed to conform to the mask design rules, and the processed first part 11a and second part 11b are arranged in different areas of the mask 10. The steps for processing the first part 11a and the second part 11b include: as follows Figure 3 As shown, the first part 11a is recessed by a target size D on the side closest to the second part 11b and placed on one side of the mask 10, i.e., the first side 10a of the mask 10. The second part 11b is compensated for by a target size D on the side closest to the first part 11a and placed on the opposite side of the mask 10, i.e., the second side 10b of the mask 10. The target size D is the minimum dimension from the graphic in the cutting path to the boundary of the cutting path in the mask design rules.

[0047] Figure 6 This is a schematic diagram showing the position of the alignment mark in the exposure field in Embodiment 1 of the present invention. Figure 7 This is a schematic diagram illustrating the formation of a complete alignment mark in Embodiment 1 of the present invention. (In conjunction with...) Figure 6 and Figure 7 Step S40 is explained in detail. For example... Figure 6 and Figure 7As shown, in step S40, at least two exposure processes are performed to transfer at least two partial marks to the dicing channels of the wafer. These at least two partial marks together constitute an alignment mark. That is, the target alignment mark 11 on the mask 10 is transferred to the dicing channels of the wafer, forming an alignment mark including at least the first part 11a and the second part 11b on the dicing channels between adjacent exposure fields 30. In other words, after the second exposure of the dicing channels, the first part 11a and the second part 11b can be combined to form a complete cross-shaped alignment mark. In this embodiment, the length of the target alignment mark 11 is greater than the width of the wafer dicing channels (the width between adjacent chip regions 14). Without changing the existing wafer dicing channel size and other existing alignment mark layouts, by first dividing the target alignment mark 11 and then performing double exposures through the wafer dicing channel region to form a complete large-size alignment mark, the customer's need for large-size alignment marks between exposure fields is solved. Manual alignment is no longer required during packaging and testing, improving packaging and testing efficiency.

[0048] In another embodiment, alignment marks are located between the four exposure fields. (See below for details.) Figures 8 to 14 Example 2 will be described in detail. The size of the alignment mark in Example 2 is the same as that in Example 1, and will not be repeated here.

[0049] Figure 8 This is a schematic diagram of the target alignment mark segmentation in Embodiment 2 of the present invention. Combined with... Figure 8 Step S20 is explained in detail. (Combined with...) Figure 8 Step S20 is described in detail. In step S20, the target alignment mark 11 is divided, for example, by dividing it along the first side 15a and the second side 16b of the cutting channel in the second direction. The target alignment mark 11 is divided into three parts: a first part 11a, a second part 11b, and a third part 11c. The length E of the first part 11a in the first direction is greater than the length F of the second part 11b in the first direction. The length F of the second part 11b is half the difference between the length C of the target alignment mark 11 and the width W of the cutting channel, i.e., F = (CW) / 2. The length E of the first part 11a in the second direction is greater than the length F of the third part 11c in the second direction. The length F of the third part 11c is half the difference between the length C of the target alignment mark 11 and the width W of the cutting channel, i.e., F = (CW) / 2.

[0050] Figure 9 This is a schematic diagram of processing the first part of the target alignment mark in Embodiment 2 of the present invention. Figure 10 This is a schematic diagram of processing the second part of the target alignment mark in Embodiment 2 of the present invention. Figure 11This is a schematic diagram illustrating the processing of the third part of the target alignment mark in Embodiment 2 of the present invention. Figure 12 This is a schematic diagram showing the position of the target alignment mark in the mask template in Embodiment 2 of the present invention. (In conjunction with...) Figures 9 to 12 Detailed explanation of step S30. For example... Figures 9 to 12 As shown, in step S30, the first part 11a is reduced inward by a target size D on the side near the second part 11b and the side near the third part 11c, and then placed at the first corner 10c of the mask template 10. The second part 11b is compensated for by a target size D on the side near the first part 11a and then placed at the adjacent corner of the first corner of the mask template 10, i.e., the second corner 10d. The third part 11c is compensated for by a target size D on the side near the first part 11a and then placed at another adjacent corner of the first corner of the mask template 10, i.e., the fourth corner 10f. No graphic is placed at the diagonal of the first corner of the mask template 10, i.e., the third corner 10e. The target size D is the minimum dimension from the graphic in the cutting path to the boundary of the cutting path in the mask template design rules.

[0051] Figure 13 This is a schematic diagram showing the position of the alignment mark in the exposure field in Embodiment 2 of the present invention. Figure 14 This is a schematic diagram illustrating the formation of a complete alignment mark in Embodiment 2 of the present invention. (In conjunction with...) Figure 13 and Figure 14 Step S40 is explained in detail. For example... Figure 13 and Figure 14 As shown, in step S40, four exposure processes are performed (one of which has no alignment mark), and the target alignment mark 11 on the mask 10 is transferred to the dicing track of the wafer. Alignment marks including at least the first part 11a, the second part 11b and the third part 11c are formed on the dicing track between adjacent exposure fields 30 of the wafer.

[0052] It is worth emphasizing that, in other embodiments, when dividing the target alignment mark 11, it can also be divided along any one or any two adjacent sides of the first side 15a, the second side 15b, the first side 16a, and the second side 16b of the second direction cutting path. Furthermore, the target alignment mark 11 can also be divided into four parts. This embodiment does not limit this.

[0053] Figure 14 This is a schematic diagram illustrating the formation of a complete alignment mark in Embodiment 2 of the present invention. For example... Figure 14As shown, this embodiment also provides an alignment mark between exposure fields, which is prepared using the method for forming an alignment mark between exposure fields as described in any of the above embodiments. The length of the target alignment mark 11 is greater than the dicing width between adjacent exposure fields of the wafer (the width between adjacent chip regions 14). The distance G from the target alignment mark 11 to the chip region 14 is half the difference between the dicing width W and the target alignment mark width A, that is, G = (WA) / 2.

[0054] This embodiment also provides a packaging and testing process, including: alignment using the alignment marks between exposure fields described above.

[0055] In summary, in the method for forming alignment marks between exposure fields provided by this invention, the length of the target alignment mark is greater than the width of the dicing track between adjacent exposure fields of the wafer. First, the target alignment mark is divided into at least two part marks, each part mark having a length no greater than the width of the dicing track. Then, each part mark is processed to conform to the mask design rules, and the processed part marks are arranged in different areas of the mask. Next, at least two exposure processes are performed to transfer the at least two part marks to the dicing track of the wafer, whereby the at least two part marks together constitute the alignment mark. The unexpected effect of this invention is that, without changing the existing wafer dicing track size or other existing mask layouts, it meets design requirements while utilizing the characteristics of photolithography to form a complete large-size alignment mark after at least two exposures of the wafer's exposure field dicing track, thus satisfying customer demand for large-size alignment marks between exposure fields.

[0056] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to mutually. In addition, the different parts between embodiments can also be combined with each other, and this invention does not limit this.

[0057] 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 method for forming alignment marks between exposure fields, characterized in that, include: A target alignment mark is provided, the length of which is greater than the width of the dicing track between adjacent exposure fields of the wafer; The target alignment mark is divided into at least two part marks, and the length of each part mark is not greater than the width of the cutting path; Each part of the mark is processed to conform to the mask design rules, and the processed part marks are placed in different areas of the mask. Perform at least two exposure processes to transfer at least two partial marks onto the wafer dicing track, the at least two partial marks together forming alignment marks.

2. The method for forming alignment marks between exposure fields as described in claim 1, characterized in that, The alignment mark is located between two exposure fields; the target alignment mark is divided into two parts, namely a first part and a second part, the length of the first part is greater than the length of the second part, and the length of the second part is half the difference between the length of the target alignment mark and the width of the cut.

3. The method for forming alignment marks between exposure fields as described in claim 2, characterized in that, The steps for processing each part marker include: The first part is placed on one side of the mask template after being reduced in size to the target size on the side closer to the second part, and the second part is placed on the opposite side of the mask template after being compensated for the target size on the side closer to the first part.

4. The method for forming alignment marks between exposure fields as described in claim 1, characterized in that, The alignment mark is located between the four exposure fields; the target alignment mark is divided into three parts, namely a first part, a second part and a third part, the length of the first part is greater than the length of the second part, and the length of the first part is greater than the length of the third part.

5. The method for forming alignment marks between exposure fields as described in claim 4, characterized in that, The steps for processing each part marker include: The first part is arranged at the first corner of the mask template after being reduced inward by the target size on the side near the second part and the side near the third part, and the second part is arranged at the adjacent corner of the first corner of the mask template after being compensated for the target size on the side near the first part, and the third part is arranged at the other adjacent corner of the first corner of the mask template after being compensated for the target size on the side near the first part.

6. The method for forming alignment marks between exposure fields as described in claim 5, characterized in that, The target alignment mark on the photomask is transferred to the dicing track of the wafer, and an alignment mark including the first part, the second part and the third part is formed on the dicing track between adjacent exposure fields of the wafer.

7. The method for forming alignment marks between exposure fields as described in claim 4, characterized in that, In the first direction, the length of the second portion is half the difference between the length of the target alignment mark and the width of the cutting track; in the second direction, the length of the third portion is half the difference between the length of the target alignment mark and the width of the cutting track, and the first direction is perpendicular to the second direction.

8. The method for forming alignment marks between exposure fields as described in claim 3 or 5, characterized in that, The target size is the minimum dimension from the graphic in the cutting path to the boundary of the cutting path in the mask design rules.

9. An alignment mark between exposure fields, characterized in that, It is prepared by the method of forming alignment marks between exposure fields as described in any one of claims 1 to 8.

10. A packaging and testing process, characterized in that, include: Alignment is performed using the alignment marks between exposure fields as described in claim 9.

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