Wafer sand blasting layout structure
By designing the wafer sandblasting layout structure, the width of both ends of the pattern is smaller than the middle width, and the design is coaxial, the problem of sandblasting on the back of the wafer is easily penetrated, and the uniformity of sandblasting depth and process tolerance are improved.
Patent Information
- Application Number
- CN202411820674.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-11
- Publication Date
- 2025-04-25
AI Technical Summary
In the prior art, sandblasting on the back of the wafer is prone to penetrate, resulting in damage to the crystal surface on the front of the wafer and scrapping of the chip.
A wafer sandblasting layout structure is designed, with the width of both ends of the pattern smaller than the middle width, and the two ends of the pattern coaxial to the middle to reduce the impact area and energy of the high-speed sand material and improve the uniformity of the sandblasting depth.
By reducing the width of both ends of the pattern, the possibility of penetration during back sandblasting is reduced, the tolerance for sandblasting process fluctuations is improved, and effective penetration during front sandblasting is ensured.
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Figure CN119873727A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of micro-electromechanical device layout design, and in particular to a wafer sandblasting layout structure. Background Art
[0002] In the manufacturing process of MEMS devices, such as Figure 1-Figure 3 As shown in the figure, it is often necessary to make a specific pattern 1' on the wafer surface. Using fine sandblasting technology to form deep grooves on the silicon substrate is a relatively mature solution. The sand material is ejected through the nozzle at a very high speed using high-pressure airflow to impact and polish the surface of the silicon substrate. When manufacturing chips, the general process is to draw a wafer sandblasting layout structure (such as Figure 1 The back side of the working wafer is sandblasted to form a back side pattern 1', and then the front side of the working wafer is sandblasted.
[0003] like Figure 2 As shown, in some MEMS products, such as inkjet head products, there will be a layout design as shown in the figure, and the pattern 1' formed by the sandblasting slots is in the form of a narrow and long rectangle. Under ideal conditions, when the working wafer is sandblasted on one side, no penetration should occur. However, in actual production, after the back side is sandblasted and the front side is inspected, bright spots representing the penetration part can be seen, most of which are distributed at the two ends of the existing rectangular pattern 1' (such as Figure 3 As shown). This is because in the middle of the rectangular pattern 1', only the high-speed sand material at the two side clamps will be concentrated, and the concentrated high-speed sand material is less, so the impact force on the wafer is smaller, that is, the energy impacting the wafer is less, and the corresponding sandblasting groove is shallower; while at the two ends of the rectangular pattern, the high-speed sand material on the two side edges and the short bottom edge will be concentrated, and the concentrated high-speed sand material is more, so the impact force on the wafer is greater, that is, the energy impacting the wafer is more, and the corresponding depth is deeper, so it is easier to penetrate. That is, in this process, there are two factors that affect the sandblasting depth, that is, the larger the width of the sandblasting groove, the greater the sandblasting depth; the more boundaries of the sandblasting groove, the more sand gathered, and the greater the sandblasting depth. The two ends of the sandblasting groove have more boundaries, so the depth is large, that is, it is easy to penetrate, which is actually the uneven sandblasting depth.
[0004] The penetration during back blasting will cause the crystal surface of the front side of the wafer to be damaged, damage the circuit pattern on the front side of the wafer, and cause the chip to be scrapped; after the front side of the wafer is sandblasted, the corresponding position should be continuously penetrated on the central axis of the short side in the sandblasting tank. That is, penetration cannot occur during back blasting, and penetration must be completed during front blasting. The penetration position is located in the middle of the sandblasting tank and is a long strip-shaped gap. Summary of the invention
[0005] The technical problem to be solved by the present invention is to overcome the defect of easy penetration of the back side of the wafer in the prior art sandblasting, and to provide a wafer sandblasting layout structure.
[0006] The present invention solves the above technical problems through the following technical solutions:
[0007] A wafer sandblasting layout structure, the wafer sandblasting layout structure having a pattern, the width of the middle portion of the pattern being a first width;
[0008] The widths of the two ends of the pattern along the length direction are second widths, and the second widths are smaller than the first widths;
[0009] In the width direction of the pattern, both ends of the pattern are centered, and the symmetry axes of the two ends of the pattern along the length direction coincide with the symmetry axis of the pattern along the length direction.
[0010] In the technical solution, by providing the wafer sandblasting layout structure, by making the width of the two ends of the pattern (the second width) smaller than the width of the middle part of the pattern (the first width), when the high-speed sand material impacts the narrower three-sided enclosed area at the two ends of the pattern, the area impacted by the sand material at the two ends can be made smaller, so as to reduce the impact energy. That is, in the prior art, when the sandblasting groove is formed by sandblasting, the depth of the sandblasting groove is different in the middle part of the pattern and the two ends of the pattern, the depth in the middle part is shallower and the depth at the two ends is deeper; therefore, the width of the two ends of the pattern is reduced, and the depth of the sandblasting groove at the two ends is similar to that in the middle part, thereby improving the uniformity of the sandblasting depth. Since the enclosed area surrounded by the two sides and the short bottom side is destroyed, the possibility of penetration in the enclosed area during back blasting is reduced; at the same time, the impact area of the sand material on the wafer is also reduced with the two ends of the narrowed pattern, reducing the amount of high-speed sand material impacting the silicon wafer, so the impact force on the wafer is reduced, the energy impacting the wafer is less, and the depth of the groove formed by sandblasting is correspondingly reduced, which further solves the problem of penetration after back blasting. The two work together to reduce the possibility of back blasting penetrating the wafer and causing cracking, and improve the tolerance to fluctuations in the sandblasting process. In addition, by making the two ends of the pattern coaxial with the middle of the pattern, the deepest position of the groove formed by back blasting can be located on the central axis of the front and back patterns, thereby ensuring that it is easier to penetrate when sandblasting the front side.
[0011] Preferably, both sides of the middle portion of the pattern are parallel; and / or,
[0012] The two side edges at both ends of the pattern are parallel and perpendicular to the bottom edges at both ends of the pattern.
[0013] In the present technical solution, by setting the two side edges of the middle of the pattern to be parallel, or the two side edges of the two ends of the pattern to be parallel and perpendicular to the bottom edges of the two ends of the pattern, the flow of abrasive material can be better guided, and the problems of abrasive material flow and uneven depth of sandblasting caused by width fluctuation can be reduced.
[0014] Preferably, each side edge of the middle portion of the pattern and each side edge at both ends of the pattern are connected by four connecting edges respectively, and the angle between the connecting edges and the connected side edge of the middle portion of the pattern is greater than or equal to 90°.
[0015] In the technical solution, through the above arrangement, it is possible to avoid the inward sharp angles at the connection points between the middle and the two ends of the pattern, so as to further reduce the possibility of penetration when impacted by sand.
[0016] Preferably, the angle between the connecting edge and the sides of the two ends of the connected pattern is in the range of 40° to 50°.
[0017] In the present technical solution, through the above arrangement, the width fluctuation can be further made uniform, so as to further reduce the possibility of penetration when impacted by sand material.
[0018] Preferably, the connecting edge is in a straight line shape.
[0019] In this technical solution, through the above settings, the wafer sandblasting layout structure can be easily processed and the cost is reasonable.
[0020] Preferably, the second width is greater than or equal to 20 μm.
[0021] In this technical solution, through the above arrangement, both ends of the pattern can be easily processed.
[0022] Preferably, the second width is less than or equal to 40 μm.
[0023] In the technical solution, through the above arrangement, the possibility of the sand material directly impacting the side walls at both ends of the pattern can be reduced, so as to further reduce the possibility of penetration when impacted by the sand material.
[0024] Preferably, the ratio of the second width to the first width is greater than or equal to 0.25.
[0025] In the technical solution, through the above arrangement, the amount of sand material guided at both ends of the pattern can be made more reasonable, thereby achieving the effect of reasonably reducing the impact energy.
[0026] Preferably, the ratio of the lengths of both ends of the pattern to the second width is greater than or equal to 0.25.
[0027] In the technical solution, through the above arrangement, the depth of the sand material guided into the two ends of the pattern can be made more reasonable, thereby achieving the effect of reasonably reducing the impact energy.
[0028] Preferably, a ratio of the lengths of both ends of the pattern to the second width is less than or equal to 5.
[0029] In this technical solution, through the above settings, it is possible to avoid wasting too much wafer area and interfering with other parts of the sandblasting layout.
[0030] The positive and progressive effects of the present invention are:
[0031] By providing the wafer sandblasting layout structure, the second width of the two ends of the pattern is set to be smaller than the first width of the middle part of the pattern, so that when the high-speed sand material impacts the narrower three-sided enclosed area on both sides of the middle part of the pattern by sandblasting, the sand material can be guided to flow into the two ends of the narrowed pattern. That is, in the prior art, when the sandblasting groove is formed by sandblasting, the depth of the sandblasting groove is different in the middle part of the pattern and the two ends of the pattern, the depth in the middle part is shallower and the depth at the two ends is deeper; therefore, the width of the two ends of the pattern is reduced, and the depth of the sandblasting groove at the two ends is similar to that of the middle part, so that the sandblasting depth in the middle part and at the two ends of the sandblasting groove is close, thereby improving the uniformity of the sandblasting depth. Since the enclosed area surrounded by the two sides and the short bottom side is destroyed, the possibility of penetration in the enclosed area during back blasting is reduced; at the same time, the impact area of the sand material on the wafer is also reduced with the two ends of the narrowed pattern, reducing the amount of high-speed sand material impacting the silicon wafer, so the impact force on the wafer is reduced, the energy impacting the wafer is less, and the depth of the groove formed by sandblasting is correspondingly reduced, which further solves the problem of penetration after back blasting. The two work together to reduce the possibility of back blasting penetrating the wafer and causing cracks, and improve the tolerance to fluctuations in the sandblasting process. In addition, by making the two ends of the pattern coaxial with the middle of the pattern, the deepest position of the groove formed by back blasting can be located on the central axis of the front and back patterns, thereby ensuring that it is easier to penetrate when sandblasting the front side. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Figure 1 The invention is a wafer sandblasting layout structure of the prior art.
[0033] Figure 2 for Figure 1 A partial enlarged view of .
[0034] Figure 3 for Figure 2 A1 partial enlarged view.
[0035] Figure 4 This is a wafer sandblasting layout structure according to an embodiment of the present invention.
[0036] Figure 5 for Figure 4 A partial enlarged view of B.
[0037] Figure 6 for Figure 5 A partial enlarged view of B1.
[0038] Description of reference numerals:
[0039] exist Figure 1-Figure 3 middle
[0040] Pattern 1'
[0041] exist Figure 4-Figure 6 middle
[0042] Pattern 1
[0043] Central 11
[0044] 12 at both ends
[0045] Edge 13 DETAILED DESCRIPTION
[0046] A preferred embodiment is given below, and the present invention is described more clearly and completely in conjunction with the accompanying drawings.
[0047] like Figure 4-Figure 6 As shown, this embodiment provides a wafer sandblasting pattern structure, which has a pattern 1, wherein the width of the middle portion 11 of the pattern 1 is a first width D1, and the width of the two ends 12 of the pattern 1 along the length direction is a second width D2, where D2<D1.
[0048] In the width direction of the pattern 1 , the two ends 12 of the pattern 1 are centered, and the symmetry axes of the two ends 12 of the pattern 1 along the length direction coincide with the symmetry axis of the pattern 1 along the length direction.
[0049] In this way, the second width D2 of the two ends 12 of the pattern 1 is set to be smaller than the first width D1 of the middle part 11 of the pattern 1, and the two ends 12 of the pattern 1 are coaxial with the middle part 11 of the pattern 1, so that when the high-speed sand material impacts the narrower three-sided enclosed area of the two ends 12 of the pattern 1 by sandblasting, the area impacted by the sand material at the two ends 12 is smaller. That is, in the prior art, when the sandblasting groove is formed by sandblasting, the depth of the sandblasting groove is different in the middle part 11 of the pattern 1 and the two ends 12 of the pattern 1, the depth of the middle part 11 is shallower, and the depth of the two ends 12 is deeper; therefore, D2 is set to be less than D1, so that the depth of the sandblasting groove at the two ends 12 is similar to that of the middle part 11, thereby improving the uniformity of the sandblasting depth.
[0050] Because the enclosed area of the two sides and the short bottom side is destroyed, it becomes Figure 6 The polygonal structure in the back side is formed (of course, in other embodiments, the shape formed after destroying the enclosed area will also change with the difference of the basic layout design), so the possibility of penetration of the enclosed area during back side sandblasting is reduced.
[0051] At the same time, the impact area of the sand on the wafer is also reduced as the two ends 12 of the narrowed pattern 1, reducing the amount of high-speed sand impacting the silicon wafer. Therefore, the impact force on the wafer is reduced, and the energy impacting the wafer is less, which correspondingly reduces the depth of the groove formed by sandblasting, and further solves the problem of penetration after sandblasting on the back side.
[0052] The two work together to reduce the possibility of back-side sandblasting penetrating the wafer and causing cracks, and increase tolerance to fluctuations in the sandblasting process.
[0053] Furthermore, by making the two ends 12 of the pattern 1 coaxial with the middle 11 of the pattern 1, the deepest position of the groove formed by the back sandblasting can be located on the central axis of the front and back patterns 1, thereby ensuring that the front sandblasting can penetrate better and more completely.
[0054] In this embodiment, the two side edges of the middle portion 11 of the pattern 1 are parallel, and the two side edges of the two ends 12 of the pattern 1 are parallel and perpendicular to the bottom edges of the two ends 12 of the pattern 1, which can better guide the flow of abrasive materials and reduce the problems of abrasive material flow and uneven depth of sandblasting caused by width fluctuations.
[0055] In this embodiment, each side edge of the middle portion 11 of the pattern 1 and each side edge of the two ends 12 of the pattern 1 are connected by four connecting edges 13, and the angle α between the connecting edges 13 and the connected side edges of the middle portion 11 of the pattern 1 is 145°. In this way, it is possible to avoid the formation of an inward acute angle at the connection between the middle portion 11 and the two ends 12 of the pattern 1, so as to further reduce the possibility of being penetrated by the impact of sand. Of course, in other embodiments, the angle between the connecting edge and the side edge of the middle portion of the connected pattern can also be other values greater than 90°.
[0056] In this embodiment, the angle β between the connecting edge 13 and the sides of the two ends 12 of the connected pattern 1 is 45°. In this way, the width fluctuation can be further made uniform, so as to further reduce the possibility of penetration when impacted by sand.
[0057] In this embodiment, the connecting edge 13 is in a straight line shape, so that the wafer sandblasting pattern structure can be easily processed and the cost is reasonable.
[0058] In this embodiment, D2=30μm. In this way, both ends 12 of the pattern 1 can be easily processed (when it is greater than or equal to 20μm), and the possibility of sand directly impacting the side walls of the two ends 12 of the pattern 1 can be reduced (when it is less than or equal to 40μm), so as to further reduce the possibility of penetration when impacted by sand. Of course, in other embodiments, the second width can also take other values within the above range.
[0059] In this embodiment, D1=90 μm, D2 / D1=0.33. In this way, the amount of sand guided by the two ends 12 of the pattern 1 can be more reasonable, thereby achieving a reasonable effect of reducing the impact energy. Of course, in other embodiments, the first width can also take other values, so that the ratio of the second width to the first width is greater than or equal to 0.25.
[0060] In this embodiment, the length L of the two ends 12 of the pattern 1 is 100 μm, and L / D2 is 3.3. In this way, the depth of the sand material guided into the two ends 12 of the pattern 1 can be made more reasonable, thereby achieving a reasonable effect of reducing the impact energy (when L / D2 is greater than or equal to 0.25), and it can also avoid wasting too much wafer area and interfering with other parts of the sandblasting layout (when L / D2 is less than or equal to 5). Of course, in other embodiments, the length of the two ends of the pattern can also take other values within the above range.
[0061] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that this is only for illustration and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.
Claims
1. A wafer sandblasting layout structure, the wafer sandblasting layout structure having a pattern, the width of the middle portion of the pattern being a first width, characterized in that: The widths of the two ends of the pattern along the length direction are second widths, and the second widths are smaller than the first widths; In the width direction of the pattern, both ends of the pattern are centered, and the symmetry axes of the two ends of the pattern along the length direction coincide with the symmetry axis of the pattern along the length direction.
2. The wafer sandblasting layout structure according to claim 1, characterized in that: The two sides of the middle part of the pattern are parallel; and / or, The two side edges at both ends of the pattern are parallel and perpendicular to the bottom edges at both ends of the pattern.
3. The wafer sandblasting layout structure according to claim 1, characterized in that: Each side edge of the middle portion of the pattern and each side edge at both ends of the pattern are connected by four connecting edges respectively, and the angle between the connecting edges and the connected side edge of the middle portion of the pattern is greater than or equal to 90°.
4. The wafer sandblasting layout structure as claimed in claim 3, characterized in that: The included angle between the connecting edge and the sides of the two ends of the connected pattern is in the range of 40° to 50°.
5. The wafer sandblasting layout structure as claimed in claim 3, characterized in that: The connecting edge is in a straight line shape.
6. The wafer sandblasting layout structure according to claim 1, characterized in that: The second width is greater than or equal to 20 μm.
7. The wafer sandblasting layout structure according to claim 1, characterized in that: The second width is less than or equal to 40 μm.
8. The wafer sandblasting layout structure according to claim 1, characterized in that: A ratio of the second width to the first width is greater than or equal to 0.
25.
9. The wafer sandblasting layout structure according to claim 1, characterized in that: A ratio of the lengths of both ends of the pattern to the second width is greater than or equal to 0.
25.
10. The wafer sandblasting layout structure according to claim 1, characterized in that: A ratio of the lengths of both ends of the pattern to the second width is less than or equal to 5.