Liquid infrared microscope objective and wafer bonding visual system

Abstract

The invention provides a liquid infrared microscope objective and a wafer bonding visual system, and relates to the technical field of semiconductor processing, the liquid infrared microscope objective sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens from an emergent side to an object side; wherein the first lens is a liquid lens, the second lens and the third lens are glued to form a group of doublet lens, the fourth lens and the fifth lens are glued to form a group of doublet lens, and the sixth lens and the seventh lens are glued to form a group of doublet lens. The liquid infrared microscope objective is used in high-precision wafer bonding equipment, zooming is achieved through the liquid infrared microscope objective, marks of an upper wafer and a lower wafer can be observed respectively without moving the objective in the bonding process, and the aims of reducing errors in the alignment process and improving the alignment speed are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor processing, and in particular to a liquid infrared microscope objective lens and a wafer bonding vision system. Background Art

[0002] The alignment accuracy in wafer bonding equipment is the most critical factor to ensure the quality of wafer bonding, and the visual system plays a decisive role. The latest high-precision bonding equipment has applied near-infrared optical systems. The near-infrared band can penetrate the semiconductor wafer to directly observe the marking points. For example, during the bonding process, the infrared system is first used to observe the marking points on the lower surface of the upper wafer, and then the piezoelectric ceramic driver is used to move the optical system downward as a whole, and then the marking points on the upper surface of the lower wafer are observed, and the positions of the marking points of the upper and lower wafers are recorded. Then, the position of the lower wafer is adjusted through the high-precision displacement platform to move the lower wafer marking point to the position of the upper wafer marking point. In this process, since the infrared system can observe the position of the marking point, the bonding accuracy is greatly improved.

[0003] However, this method requires the infrared system to be moved to image the marking points on the upper and lower wafers respectively. During the bonding process, only one marking point can be observed in real time. Since there must be a slight error in the perpendicularity between the optical axis of the infrared optical system and the horizontal direction of the wafer, the movement process will cause the infrared system to observe the position of the marking point on the lower surface and the absolute position of the recorded marking point on the upper surface. These errors cannot be ignored for the alignment accuracy of only tens of nanometers in wafer bonding. Summary of the invention

[0004] In view of this, an embodiment of the present application provides a liquid infrared microscope objective lens and a wafer bonding vision system, which are used in high-precision wafer bonding equipment. Zoom is achieved through a liquid infrared microscope objective lens. During the bonding process, the marks of the upper and lower wafers can be observed separately without moving the objective lens, so as to achieve the purpose of reducing errors in the alignment process while improving the alignment speed.

[0005] The embodiment of the present application provides the following technical solution: a liquid infrared microscope objective lens, the liquid infrared microscope objective lens comprises, from the exit side to the object side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens; wherein the first lens is a liquid lens, and the second lens and the third lens are glued to form a doublet lens, the fourth lens and the fifth lens are glued to form a doublet lens, and the sixth lens and the seventh lens are glued to form a doublet lens;

[0006] And the following relationship is satisfied: 3.0≤f*NA≤4.0;

[0007] 0.25≤WD / TTL≤0.30;

[0008] WD ≥ 15 mm;

[0009] 100μm≤△WD max ≤200μm;

[0010] H1≤4mm;

[0011] Wherein, f is the focal length of the liquid infrared microscope objective lens, NA is the numerical aperture of the liquid infrared microscope objective lens, WD is the working distance of the liquid infrared microscope objective lens, TTL is the total length of the liquid infrared microscope objective lens from the first lens to the focusing position, △WD max is the change in working distance of the liquid infrared microscope objective lens, and H1 is the radius of the effective aperture of the first lens.

[0012] According to an embodiment of the present application, the focal length f of the liquid infrared microscope objective lens is 10 mm, the numerical aperture NA is 0.35, the field of view is 0.4 mm, and the operating wavelength is 1150-1250 nm.

[0013] According to an embodiment of the present application, the focal length of the first lens is f1, and the focal length of a doublet lens glued together by the second lens and the third lens is f 23 The fourth lens and the fifth lens are glued together to form a doublet lens with a focal length of f 45 The sixth lens and the seventh lens are glued together to form a doublet lens with a focal length of f 67 , the focal length of the eighth lens is f8, the focal length of the liquid infrared microscope objective lens is f, and the following relationship is satisfied:

[0014] -4.5≤f1 / f≤-3.5;

[0015] 17.0≤f 23 / f≤23.0;

[0016] 3.0≤f 45 / f≤4.0;

[0017] 25.5≤f 67 / f≤34.5;

[0018] 2.0≤f8 / f≤3.0.

[0019] According to an embodiment of the present application, the first surface curvature radius of the first lens is r1, the first surface curvature radius of the second lens is r3, the curvature radius of the bonding surface formed by the second surface of the second lens and the first surface of the third lens is r4, the curvature radius of the second surface of the third lens is r5, the curvature radius of the first surface of the fourth lens is r6, the curvature radius of the bonding surface formed by the second surface of the fourth lens and the first surface of the fifth lens is r7, the curvature radius of the second surface of the fifth lens is r8, the curvature radius of the first surface of the sixth lens is r9, and the curvature radius of the bonding surface formed by the second surface of the sixth lens and the first surface of the seventh lens is r10. 10 , the radius of curvature of the second surface of the seventh lens is r 11 , the radius of curvature of the first surface of the eighth lens is r 12 , the radius of curvature of the second surface of the eighth lens is r 13 , and satisfy the following relationship:

[0020] 14.0≤r1≤18.0;

[0021] 16.0≤(r3+r4) / (r3-r4)≤22.0;

[0022] -5.5≤(r4+r5) / (r4-r5)≤-4.0;

[0023] 2.0≤(r6+r7) / (r6-r7)≤3.0;

[0024] -2.0≤(r7+r8) / (r7-r8)≤-1.5;

[0025] -3.5≤(r9+r 10 ) / (r9-r 10 )≤-2.5;

[0026] 5.5≤(r 10 +r 11 ) / (r 10 -r 11 )≤7.5;

[0027] -4.0≤(r 12 +r 13 ) / (r 12 -r 13 )≤-3.0.

[0028] According to an embodiment of the present application, the thickness of the first lens is d1, the thickness of the second lens is d2, the thickness of the third lens is d3, the thickness of the fourth lens is d4, the thickness of the fifth lens is d5, the thickness of the sixth lens is d6, the thickness of the seventh lens is d7, the thickness of the eighth lens is d8, and the total length of the liquid infrared microscope objective from the first lens to the focusing position is TTL, and satisfies the following relationship:

[0029] 0.05≤d1 / TTL≤0.07;

[0030] 0.06≤d2 / TTL≤0.09;

[0031] 0.03≤d3 / TTL≤0.04;

[0032] 0.03≤d4 / TTL≤0.04;

[0033] 0.08≤d5 / TTL≤0.10;

[0034] 0.03≤d6 / TTL≤0.04;

[0035] 0.08≤d7 / TTL≤0.10;

[0036] 0.06≤d8 / TTL≤0.09.

[0037] According to an embodiment of the present application, the interval between the first lens and the doublet lens formed by bonding the second lens and the third lens is t1, the interval between the doublet lens formed by bonding the second lens and the third lens and the doublet lens formed by bonding the fourth lens and the fifth lens is t2, the interval between the doublet lens formed by bonding the fourth lens and the fifth lens and the doublet lens formed by bonding the sixth lens and the seventh lens is t3, the interval between the doublet lens formed by bonding the sixth lens and the seventh lens and the eighth lens is t4, and the total length of the liquid infrared microscope objective from the first lens to the focusing position is TTL, and satisfies the following relationship:

[0038] 0.08≤t1 / TTL≤0.10;

[0039] 0.04≤t2 / TTL≤0.06;

[0040] 0.03≤t3 / TTL≤0.04;

[0041] 0.01≤t4 / TTL≤0.02.

[0042] According to an embodiment of the present application, the refractive index of the first lens is n1, the refractive index of the second lens is n2, the refractive index of the third lens is n3, the refractive index of the fourth lens is n4, the refractive index of the fifth lens is n5, the refractive index of the sixth lens is n6, the refractive index of the seventh lens is n7, and the refractive index of the eighth lens is n8, and the following relationship is satisfied:

[0043] 1.25≤n1≤1.50;

[0044] 1.80≤n2≤2.20;

[0045] 1.40≤n3≤1.70;

[0046] 1.75≤n4≤2.15;

[0047] 1.40≤n5≤1.75;

[0048] 1.50≤n6≤1.80;

[0049] 1.55≤n7≤1.90;

[0050] 1.55≤n8≤1.90.

[0051] According to an embodiment of the present application, the first lens is a plano-concave lens, the second lens is a meniscus positive lens, the third lens is a meniscus negative lens, the fourth lens is a meniscus negative lens, the fifth lens is a biconvex positive lens, the sixth lens is a biconcave negative lens, the seventh lens is a biconvex positive lens, and the eighth lens is a biconvex positive lens.

[0052] According to an embodiment of the present application, the material of the first lens is OL1129 liquid lens, and the zoom of the liquid infrared microscope objective lens is achieved by changing the concave radius of the first lens.

[0053] The present application also provides a wafer bonding vision system, comprising:

[0054] The liquid infrared microscope objective lens as described above is used to receive near-infrared light;

[0055] An imaging device and a target wafer, wherein the imaging device is arranged on the exit side of the liquid infrared microscope objective lens, and the target wafer is arranged on the object side of the liquid infrared microscope objective lens;

[0056] The target wafer comprises an upper wafer and a lower wafer, the upper wafer and the lower wafer are placed face to face, an upper wafer alignment mark is set on the lower surface of the upper wafer, and a lower wafer alignment mark is set on the upper surface of the lower wafer; the near-infrared light is focused on the upper wafer alignment mark after passing through the liquid infrared microscope objective lens, and the focus point forms a reflected image and is imaged for the first time in the imaging device, and the position of the upper wafer alignment mark is recorded by the imaging device;

[0057] By changing the radius of the first lens of the liquid infrared microscope objective lens, the near infrared light is focused on the alignment mark of the lower wafer after passing through the liquid infrared microscope objective lens, and the focus point forms a reflected image and then forms a second image in the imaging device, and the position of the alignment mark of the lower wafer is recorded by the imaging device;

[0058] The wafer positions are adjusted according to the positions of the upper wafer alignment marks and the lower wafer alignment marks, so as to align and bond the upper wafer and the lower wafer.

[0059] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above-mentioned technical solutions adopted in the embodiments of this specification include at least the following: the liquid infrared microscope objective lens and wafer bonding vision system of the embodiments of the present invention can achieve zooming of the liquid infrared microscope objective lens by changing the radius of the first lens of the liquid infrared microscope objective lens, and can observe the marking points of the two wafers to be bonded without moving the objective lens during the bonding process, which not only reduces the movement error during the bonding process but also improves the bonding efficiency. At the same time, the liquid infrared microscope objective lens can achieve continuous zooming, which is suitable for different bonding requirements and can be widely used in high-precision bonding equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0061] Figure 1 Schematic diagram of the structure of a liquid infrared microscope objective lens in an embodiment of the present invention;

[0062] Figure 2 This is a point diagram of the liquid infrared microscope objective lens at a focal length of 1 in an embodiment of the present invention;

[0063] Figure 3 It is a point diagram of the liquid infrared microscope objective lens in the embodiment of the present invention when the focal length is 2;

[0064] Figure 4This is a point diagram of the liquid infrared microscope objective lens at a focal length of 3 in an embodiment of the present invention;

[0065] Figure 5 This is the MTF diagram of the liquid infrared microscope objective lens at a focal length of 1 in an embodiment of the present invention;

[0066] Figure 6 This is the MTF diagram of the liquid infrared microscope objective lens at a focal length of 2 in an embodiment of the present invention;

[0067] Figure 7 This is the MTF diagram of the liquid infrared microscope objective lens at a focal length of 3 in an embodiment of the present invention;

[0068] Figure 8 This is a distortion diagram of the liquid infrared microscope objective lens at a focal length of 1 in an embodiment of the present invention;

[0069] Fig. 9 This is a distortion diagram of the liquid infrared microscope objective lens in an embodiment of the present invention at a focal length of 2;

[0070] Fig.10 This is a distortion diagram of the liquid infrared microscope objective lens at a focal length of 3 in an embodiment of the present invention. DETAILED DESCRIPTION

[0071] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0072] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0073] like Figure 1As shown, an embodiment of the present invention provides a liquid infrared microscope objective lens, which includes, from the exit side to the object side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8; wherein the first lens L1 is a liquid lens, and the second lens L2 and the third lens L3 are glued to form a doublet lens, the fourth lens L4 and the fifth lens L5 are glued to form a doublet lens, and the sixth lens L6 and the seventh lens L7 are glued to form a doublet lens;

[0074] And the following relationship is satisfied: 3.0≤f*NA≤4.0;

[0075] 0.25≤WD / TTL≤0.30;

[0076] WD ≥ 15 mm;

[0077] 100μm≤△WD max ≤200μm;

[0078] H1≤4mm;

[0079] Wherein, f is the focal length of the liquid infrared microscope objective lens, NA is the numerical aperture of the liquid infrared microscope objective lens, WD is the working distance of the liquid infrared microscope objective lens, TTL is the total length of the liquid infrared microscope objective lens from the first lens to the focusing position, △WD max is the change in working distance of the liquid infrared microscope objective lens, and H1 is the radius of the effective aperture of the first lens.

[0080] In the traditional wafer bonding process, an infrared system is first used to observe the marking points on the lower surface of the upper wafer, and then a piezoelectric ceramic driver is used to move the optical system downward as a whole, thereby observing the marking points on the upper surface of the lower wafer, recording the positions of the marking points of the upper and lower wafers, and then adjusting the position of the lower wafer through a high-precision displacement platform to move the lower wafer marking points to the position of the upper wafer marking points. In the process of moving the optical system, a certain error will occur between the position of the marking points on the lower surface observed by the infrared system and the absolute position of the upper surface marking points recorded. Based on this, the embodiment of the present invention overcomes the above-mentioned defects and designs a liquid infrared microscope objective lens, which can observe the markings of the upper and lower wafers separately without moving the objective lens during the bonding process, greatly improving the bonding speed and success rate.

[0081] The liquid infrared microscope objective lens of the embodiment of the present invention designs the objective lens structure, adopts a liquid lens, and combines the near-infrared microscope objective lens designed with a traditional optical lens. The liquid lens can change the radius through voltage control, thereby changing the focal length of the objective lens (corresponding to the working distance). The change of the focal length of the objective lens is achieved through the liquid lens. During the bonding process, it is no longer necessary to move the objective lens to observe the marks of the upper and lower wafers respectively, reducing the error in the alignment process while improving the alignment speed and accuracy. In addition, the liquid near-infrared microscope objective lens of this embodiment can achieve continuous zooming, is suitable for different bonding requirements, and can be widely used in high-precision bonding equipment.

[0082] In some specific implementations of the present application, the first lens of the liquid infrared microscope objective lens is a liquid lens, and the material of the first lens is OL1129 liquid lens. When the liquid infrared microscope objective lens is zoomed, the concave radius of the first lens is changed to achieve a small zoom of the liquid infrared microscope objective lens. OL1129 liquid lens, the liquid lens uses the principle of electrowetting on dielectric (EWOD) to change the zoom optical lens by changing the curvature of the liquid. It can change the shape of the droplet by applying an external voltage, thereby changing its focal length.

[0083] In the specific implementation, the first lens of the liquid infrared microscope objective lens is a liquid lens, and the remaining lenses are optical glass. Since the spacing distance between two wafers to be bonded in the current wafer bonding process is 30 to 200 μm, and most of them are within 100 μm, the working distance change △WD of the liquid infrared microscope objective lens is max It must be at least 100μm, and does not need to exceed 200μm. The radius H1 of the effective aperture of the first lens needs to be controlled within 4mm. H1 is the radius of the effective aperture of the first liquid lens. The aperture of the liquid lens cannot be made very large at present. The maximum diameter can only be controlled at 10mm, and the half-height is controlled to 5mm. A certain fixed space is left for the machine. Therefore, the radius of the effective aperture needs to be controlled within 4mm. According to the lens structure, the liquid lens is placed in the first piece to ensure the minimum liquid aperture. At this aperture, the maximum numerical aperture NA of the liquid infrared microscope objective can only reach 0.35.

[0084] In some specific implementations of the present application, the first lens is a plano-concave lens, the second lens is a meniscus positive lens, the third lens is a meniscus negative lens, wherein the second lens and the third lens are glued into a group of doublet lenses, the fourth lens is a meniscus negative lens, the fifth lens is a biconvex positive lens, wherein the fourth lens and the fifth lens are glued into a group of doublet lenses, the sixth lens is a biconcave negative lens, the seventh lens is a biconvex positive lens, wherein the sixth lens and the seventh lens are glued into a group of doublet lenses, and the eighth lens is a biconvex positive lens.

[0085] In some specific implementations of the present application, the focal length of the liquid infrared microscope objective lens is f=10 mm, the numerical aperture NA is 0.35, the field of view is 0.4 mm, and the operating wavelength is 1150-1250 nm.

[0086] In specific implementation, the lens parameters of the liquid infrared microscope objective lens designed in this embodiment are as follows:

[0087] (1) Focal length: f = 10 mm (the liquid infrared microscope objective lens in the embodiment of the present invention is a 20X objective lens);

[0088] (2) Wavelength: 1150-1250nm, using a near-infrared light box with a central wavelength of 1200nm. The light box has a wavelength range of 1150-1250nm and has a very high wafer transmittance in this wavelength range;

[0089] (3) Field of view: 2y = 0.4 mm;

[0090] (4) Numerical aperture: NA = 0.35;

[0091] (5) Distortion: ≤0.04%;

[0092] (6) Working distance: WD ≥ 15 mm;

[0093] (7) Working distance change: 100μm≤△WD max ≤200μm.

[0094] In some specific implementations of the present application, the focal length of the first lens is f1, and the focal length of a doublet lens formed by gluing the second lens and the third lens is f 23 The fourth lens and the fifth lens are glued together to form a doublet lens with a focal length of f 45 The sixth lens and the seventh lens are glued together to form a doublet lens with a focal length of f 67 , the focal length of the eighth lens is f8, the focal length of the liquid infrared microscope objective lens is f, and the following relationship is satisfied:

[0095] -4.5≤f1 / f≤-3.5;

[0096] 17.0≤f 23 / f≤23.0;

[0097] 3.0≤f 45 / f≤4.0;

[0098] 25.5≤f 67 / f≤34.5;

[0099] 2.0≤f8 / f≤3.0.

[0100] In some specific implementations of the present application, the first surface curvature radius of the first lens is r1, the first surface curvature radius of the second lens is r3, the curvature radius of the bonding surface formed by the second surface of the second lens and the first surface of the third lens is r4, the curvature radius of the second surface of the third lens is r5, the curvature radius of the first surface of the fourth lens is r6, the curvature radius of the bonding surface formed by the second surface of the fourth lens and the first surface of the fifth lens is r7, the curvature radius of the second surface of the fifth lens is r8, the curvature radius of the first surface of the sixth lens is r9, and the curvature radius of the bonding surface formed by the second surface of the sixth lens and the first surface of the seventh lens is r10. 10 , the radius of curvature of the second surface of the seventh lens is r 11 , the radius of curvature of the first surface of the eighth lens is r 12 , the radius of curvature of the second surface of the eighth lens is r 13 , and satisfy the following relationship:

[0101] 14.0≤r1≤18.0;

[0102] 16.0≤(r3+r4) / (r3-r4)≤22.0;

[0103] -5.5≤(r4+r5) / (r4-r5)≤-4.0;

[0104] 2.0≤(r6+r7) / (r6-r7)≤3.0;

[0105] -2.0≤(r7+r8) / (r7-r8)≤-1.5;

[0106] -3.5≤(r9+r 10 ) / (r9-r 10 )≤-2.5;

[0107] 5.5≤(r 10 +r 11 ) / (r 10 -r 11 )≤7.5;

[0108] -4.0≤(r 12 +r 13 ) / (r 12 -r 13 )≤-3.0.

[0109] In a specific implementation, the range of the curvature radius r is as follows: the range of the curvature radius of the first surface of the first lens is 14.0≤r1≤18.0, the range of the curvature radius r2 of the second surface of the first lens is unlimited and can be an infinite value, 9.0≤r3≤11.0, 8.5≤r4≤10.0, 12.0≤r5≤15.0, 18.0≤r6≤22.5, 7.0≤r7≤9.0, 23.5≤r8≤29.0, 8.5≤r9≤10.5, 16.5≤r 10 ≤20.5, 13.0≤r 11 ≤15.5, 23.5≤r 12 ≤28.5,41.5≤r 13 ≤50.5.

[0110] The rear working distances corresponding to different first surface curvature radii r1 of the first lens are shown in Table 1 below.

[0111] Table 1 Rear working distance corresponding to different first surface curvature radius r1

[0112]

[0113]

[0114] In some specific implementations of the present application, the thickness of the first lens is d1, the thickness of the second lens is d2, the thickness of the third lens is d3, the thickness of the fourth lens is d4, the thickness of the fifth lens is d5, the thickness of the sixth lens is d6, the thickness of the seventh lens is d7, the thickness of the eighth lens is d8, and the total length of the liquid infrared microscope objective from the first lens to the focusing position is TTL, and satisfies the following relationship:

[0115] 0.05≤d1 / TTL≤0.07;

[0116] 0.06≤d2 / TTL≤0.09;

[0117] 0.03≤d3 / TTL≤0.04;

[0118] 0.03≤d4 / TTL≤0.04;

[0119] 0.08≤d5 / TTL≤0.10;

[0120] 0.03≤d6 / TTL≤0.04;

[0121] 0.08≤d7 / TTL≤0.10;

[0122] 0.06≤d8 / TTL≤0.09.

[0123] In specific implementation, the thickness d ranges from 2.7≤d1≤3.3, 3.6≤d2≤4.4, 1.8≤d3≤2.2, 1.8≤d4≤2.2, 4.5≤d5≤5.5, 1.8≤d6≤2.2, 4.5≤d7≤5.5, 3.6≤d8≤4.4. The total length TTL of the liquid infrared microscope from the first lens to the focusing position ranges from 52 to 53 mm.

[0124] In some specific implementations of the present application, the interval between the first lens and the doublet lens formed by the second lens and the third lens is t1, the interval between the doublet lens formed by the second lens and the third lens and the doublet lens formed by the fourth lens and the fifth lens is t2, the interval between the doublet lens formed by the fourth lens and the fifth lens and the doublet lens formed by the sixth lens and the seventh lens is t3, the interval between the doublet lens formed by the sixth lens and the seventh lens and the eighth lens is t4, the total length of the liquid infrared microscope objective from the first lens to the focusing position is TTL, and satisfies the following relationship:

[0125] 0.08≤t1 / TTL≤0.10;

[0126] 0.04≤t2 / TTL≤0.06;

[0127] 0.03≤t3 / TTL≤0.04;

[0128] 0.01≤t4 / TTL≤0.02.

[0129] In some specific implementations of the present application, the refractive index of the first lens is n1, the refractive index of the second lens is n2, the refractive index of the third lens is n3, the refractive index of the fourth lens is n4, the refractive index of the fifth lens is n5, the refractive index of the sixth lens is n6, the refractive index of the seventh lens is n7, and the refractive index of the eighth lens is n8, and the following relationship is satisfied:

[0130] 1.25≤n1≤1.50;

[0131] 1.80≤n2≤2.20;

[0132] 1.40≤n3≤1.70;

[0133] 1.75≤n4≤2.15;

[0134] 1.40≤n5≤1.75;

[0135] 1.50≤n6≤1.80;

[0136] 1.55≤n7≤1.90;

[0137] 1.55≤n8≤1.90.

[0138] Table 2 shows the design data of the 20X liquid infrared microscope objective lens according to an embodiment of the present invention.

[0139] Table 2 Design data of liquid infrared microscope objective

[0140]

[0141]

[0142] like Figure 2-Figure 10 shown. Figure 2 This is a point diagram of the liquid infrared microscope objective lens at a focal length of 1 in an embodiment of the present invention; Figure 3 It is a point diagram of the liquid infrared microscope objective lens in the embodiment of the present invention when the focal length is 2; Figure 4 This is a point diagram of the liquid infrared microscope objective lens at a focal length of 3 in an embodiment of the present invention; Figure 5 This is an MTF curve diagram of the liquid infrared microscope objective lens at a focal length of 1 in an embodiment of the present invention; Figure 6 This is an MTF curve diagram of the liquid infrared microscope objective lens at a focal length of 2 in an embodiment of the present invention; Figure 7 This is an MTF curve diagram of the liquid infrared microscope objective lens at a focal length of 3 in an embodiment of the present invention; Figure 8 This is a distortion diagram of the liquid infrared microscope objective lens at a focal length of 1 in an embodiment of the present invention; Fig. 9 This is a distortion diagram of the liquid infrared microscope objective lens in an embodiment of the present invention at a focal length of 2; Fig.10 3 is a distortion diagram of the liquid infrared microscope objective lens at a focal length of 3 in an embodiment of the present invention; wherein the focal length 1, focal length 2, and focal length 3 are 10 mm, 9.97 mm, and 9.93 mm, respectively.

[0143] from Figure 2-Figure 4 It can be seen that the liquid near-infrared microscope objective lens can image the spot diagrams at the three focusing positions within the Airy disk by changing the radius of curvature of the first surface of the liquid lens. Figure 5-Figure 7 It can be seen that the MTF curves of the liquid near-infrared microscope objective at the three focusing positions are close to the diffraction limit by changing the radius of curvature of the first surface of the liquid lens. Figure 8-Figure 10 It can be seen that the distortion value of the imaging point at the three focusing positions of the liquid near-infrared microscope objective lens is less than 0.04% by changing the radius of curvature of the first surface of the liquid lens. The above shows that the imaging quality of the liquid near-infrared microscope objective lens is close to the theoretical limit and the image is not deformed within the different focusing ranges of 100 μm by changing the radius of the liquid lens.

[0144] The present application also provides a wafer bonding vision system, comprising:

[0145] The liquid infrared microscope objective lens as described above is used to receive near-infrared light;

[0146] An imaging device and a target wafer, wherein the imaging device is arranged on the exit side of the liquid infrared microscope objective lens, and the target wafer is arranged on the object side of the liquid infrared microscope objective lens;

[0147] The target wafer comprises an upper wafer and a lower wafer, the upper wafer and the lower wafer are placed face to face, an upper wafer alignment mark is set on the lower surface of the upper wafer, and a lower wafer alignment mark is set on the upper surface of the lower wafer; the near-infrared light is focused on the upper wafer alignment mark after passing through the liquid infrared microscope objective lens, and the focus point forms a reflected image and is imaged for the first time in the imaging device, and the position of the upper wafer alignment mark is recorded by the imaging device;

[0148] By changing the radius of the first lens of the liquid infrared microscope objective lens, the near infrared light is focused on the alignment mark of the lower wafer after passing through the liquid infrared microscope objective lens, and the focus point forms a reflected image and then forms a second image in the imaging device, and the position of the alignment mark of the lower wafer is recorded by the imaging device;

[0149] According to the position of the upper wafer alignment mark and the position of the lower wafer alignment mark, upper and lower wafer compensation values ​​are calculated, the position of the lower wafer is adjusted according to the upper and lower wafer compensation values, and the upper wafer and the lower wafer are aligned and bonded.

[0150] The wafer bonding visual system of this embodiment adopts the above-mentioned liquid infrared microscope objective lens, which focuses on the upper wafer alignment mark for the first time and returns to the system. The upper wafer alignment mark is imaged for the first time in the imaging device, and the position coordinates of the upper wafer alignment mark are recorded; then, by controlling the voltage, the radius of the first liquid lens is changed, and then the focal length of the liquid infrared microscope objective lens is changed, so that the liquid infrared microscope objective lens focuses on the lower wafer alignment mark for the second time, and the lower wafer alignment mark is imaged for the second time in the imaging device, and the position coordinates of the lower wafer alignment mark are recorded. According to the position coordinates of the upper wafer alignment mark and the position coordinates of the lower wafer alignment mark, the upper and lower wafer compensation values ​​are calculated, and the lower wafer is adjusted to the predetermined position of the upper wafer according to the compensation value, so as to achieve accurate alignment of the upper and lower wafers, and finally wafer bonding is performed. In this embodiment, it is no longer necessary to move the objective lens in the bonding process to observe the marks of the upper and lower wafers respectively, which reduces the error in the alignment process and improves the speed and accuracy of alignment.

[0151] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A liquid infrared microscope objective lens, characterized in that: The liquid infrared microscope objective lens includes, from the exit side to the object side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens in sequence; wherein the first lens is a liquid lens, and the second lens and the third lens are glued together to form a double glued lens, the fourth lens and the fifth lens are glued together to form a double glued lens, and the sixth lens and the seventh lens are glued together to form a double glued lens; And the following relationship is satisfied: 3.0≤f*NA≤4.0; 0.25≤WD / TTL≤0.30; WD ≥ 15 mm; 100μm≤△WD max ≤200μm; H1≤4mm; Wherein, f is the focal length of the liquid infrared microscope objective lens, NA is the numerical aperture of the liquid infrared microscope objective lens, WD is the working distance of the liquid infrared microscope objective lens, TTL is the total length of the liquid infrared microscope objective lens from the first lens to the focusing position, △WD max is the change in working distance of the liquid infrared microscope objective lens, and H1 is the radius of the effective aperture of the first lens.

2. The liquid infrared microscope objective lens according to claim 1, characterized in that: The focal length f of the liquid infrared microscope objective lens is 10 mm, the numerical aperture NA is 0.35, the field of view is 0.4 mm, and the working wavelength is 1150-1250 nm.

3. The liquid infrared microscope objective lens according to claim 1, characterized in that: The focal length of the first lens is f1, and the focal length of a doublet lens formed by the second lens and the third lens is f 23 The fourth lens and the fifth lens are glued together to form a doublet lens with a focal length of f 45 The sixth lens and the seventh lens are glued together to form a doublet lens with a focal length of f 67 , the focal length of the eighth lens is f8, the focal length of the liquid infrared microscope objective lens is f, and the following relationship is satisfied: -4.5≤f1 / f≤-3.5; 17.0≤f 23 / f≤23.0; 3.0≤f 45 / f≤4.0; 25.5≤f 67 / f≤34.5; 2.0≤f8 / f≤3.

0.

4. The liquid infrared microscope objective lens according to claim 1, characterized in that: The first surface curvature radius of the first lens is r1, the first surface curvature radius of the second lens is r3, the curvature radius of the bonding surface formed by the second surface of the second lens and the first surface of the third lens is r4, the curvature radius of the second surface of the third lens is r5, the curvature radius of the first surface of the fourth lens is r6, the curvature radius of the bonding surface formed by the second surface of the fourth lens and the first surface of the fifth lens is r7, the curvature radius of the second surface of the fifth lens is r8, the curvature radius of the first surface of the sixth lens is r9, and the curvature radius of the bonding surface formed by the second surface of the sixth lens and the first surface of the seventh lens is r 10 , the radius of curvature of the second surface of the seventh lens is r 11 , the radius of curvature of the first surface of the eighth lens is r 12 , the radius of curvature of the second surface of the eighth lens is r 13 , and satisfy the following relationship: 14.0≤r1≤18.0； 16.0≤(r3+r4) / (r3-r4)≤22.0； -5.5≤(r4+r5) / (r4-r5)≤-4.0； 2.0≤(r6+r7) / (r6-r7)≤3.0； -2.0≤(r7+r8) / (r7-r8)≤-1.5； -3.5≤(r9+r 10 ) / (r9-r 10 )≤-2.5； 5.5≤(r 10 +r 11 ) / (r 10 -r 11 )≤7.5； -4.0≤(r 12 +r 13 ) / (r 12 -r 13 )≤-3.0。 5. The liquid infrared microscope objective lens according to claim 1, characterized in that: The thickness of the first lens is d1, the thickness of the second lens is d2, the thickness of the third lens is d3, the thickness of the fourth lens is d4, the thickness of the fifth lens is d5, the thickness of the sixth lens is d6, the thickness of the seventh lens is d7, the thickness of the eighth lens is d8, and the total length of the liquid infrared microscope objective from the first lens to the focusing position is TTL, and satisfies the following relationship: 0.05≤d1 / TTL≤0.07; 0.06≤d2 / TTL≤0.09; 0.03≤d3 / TTL≤0.04; 0.03≤d4 / TTL≤0.04; 0.08≤d5 / TTL≤0.10; 0.03≤d6 / TTL≤0.04; 0.08≤d7 / TTL≤0.10; 0.06≤d8 / TTL≤0.

09.

6. The liquid infrared microscope objective lens according to claim 1, characterized in that: The interval between the first lens and the doublet lens formed by the second lens and the third lens is t1, the interval between the doublet lens formed by the second lens and the third lens and the doublet lens formed by the fourth lens and the fifth lens is t2, the interval between the doublet lens formed by the fourth lens and the fifth lens and the doublet lens formed by the sixth lens and the seventh lens is t3, the interval between the doublet lens formed by the sixth lens and the seventh lens and the eighth lens is t4, and the total length of the liquid infrared microscope objective from the first lens to the focusing position is TTL, and satisfies the following relationship: 0.08≤t1 / TTL≤0.10; 0.04≤t2 / TTL≤0.06; 0.03≤t3 / TTL≤0.04; 0.01≤t4 / TTL≤0.

02.

7. The liquid infrared microscope objective lens according to claim 1, characterized in that: The refractive index of the first lens is n1, the refractive index of the second lens is n2, the refractive index of the third lens is n3, the refractive index of the fourth lens is n4, the refractive index of the fifth lens is n5, the refractive index of the sixth lens is n6, the refractive index of the seventh lens is n7, and the refractive index of the eighth lens is n8, and the following relationship is satisfied: 1.25≤n1≤1.50； 1.80≤n2≤2.20； 1.40≤n3≤1.70； 1.75≤n4≤2.15； 1.40≤n5≤1.75； 1.50≤n6≤1.80； 1.55≤n7≤1.90； 1.55≤n8≤1.90。 8. The liquid infrared microscope objective lens according to claim 1, characterized in that: The first lens is a plano-concave lens, the second lens is a meniscus positive lens, the third lens is a meniscus negative lens, the fourth lens is a meniscus negative lens, the fifth lens is a biconvex positive lens, the sixth lens is a biconcave negative lens, the seventh lens is a biconvex positive lens, and the eighth lens is a biconvex positive lens.

9. The liquid infrared microscope objective lens according to claim 8, characterized in that: The material of the first lens is OL1129 liquid lens, and the zoom of the liquid infrared microscope objective lens is achieved by changing the concave radius of the first lens.

10. A wafer bonding vision system, characterized in that: include: The liquid infrared microscope objective lens as claimed in any one of claims 1 to 9, used for receiving near-infrared light; An imaging device and a target wafer, wherein the imaging device is arranged on the exit side of the liquid infrared microscope objective lens, and the target wafer is arranged on the object side of the liquid infrared microscope objective lens; The target wafer comprises an upper wafer and a lower wafer, the upper wafer and the lower wafer are placed face to face, an upper wafer alignment mark is set on the lower surface of the upper wafer, and a lower wafer alignment mark is set on the upper surface of the lower wafer; The near-infrared light is focused on the upper wafer alignment mark after passing through the liquid infrared microscope objective lens, and the focus point forms a reflection image, which is imaged for the first time in the imaging device, and the position of the upper wafer alignment mark is recorded by the imaging device; By changing the radius of the first lens of the liquid infrared microscope objective lens, the near infrared light is focused on the alignment mark of the lower wafer after passing through the liquid infrared microscope objective lens, and the focus point forms a reflected image and then forms a second image in the imaging device, and the position of the alignment mark of the lower wafer is recorded by the imaging device; The wafer positions are adjusted according to the positions of the upper wafer alignment marks and the lower wafer alignment marks, so as to align and bond the upper wafer and the lower wafer.

Images