Wafer film pasting method

Abstract

The invention provides a wafer film pasting method, and the method comprises the steps: enabling a film pasting roller to dynamically adjust the film pasting pressure P of the film pasting roller at any time of film pasting to be a fixed value in a process of pasting an ultraviolet curing protection film on the front surface of a wafer from the edge of one side of the wafer in the diameter direction of the wafer through the film pasting roller; the pressure intensity of any area of the front face of the wafer is the same, the unified film pasting pressure is changed into the unified film pasting pressure intensity, it is guaranteed that the strength of contact points of the film pasting rolling shaft and the ultraviolet curing protective film is unified regardless of the edge area or the center area of the wafer, and the phenomenon that in the wafer thinning process, due to the influence of the pressure factor of the film pasting rolling shaft, the film pasting rolling shaft is damaged is avoided. And the UV film residual glue is formed in a region with a relatively large offset on the surface of the wafer, such as a cutting channel, so that the subsequent wafer appearance, the machine operation condition and the reliability verification are not influenced at all.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor manufacturing, in particular to a wafer film pasting method. BACKGROUND

[0002] At present, 12-inch wafers usually adopt TAIKO type thinning mode. In the process of traditional TAIKO type wafer thinning, in order to provide support for the wafer and reduce wafer warping, a UV film is usually used to protect the front surface of the wafer. After the UV film (ultraviolet curing protective film) is irradiated by a UV (ultraviolet) lamp, the photosensitizer coated on the front surface of the wafer will be cured, so as to be separated from the wafer. Therefore, compared with a non-UV film, the UV film is easier to tear. However, affected by the UV light conditions, film inner step difference, pressure and other factors, especially the pressure factor, it is easy to form residual glue in the areas with large surface step difference of the wafer, such as the cutting path, thereby seriously affecting the subsequent wafer appearance, machine operation condition and reliability verification. SUMMARY

[0003] The present application provides a wafer film pasting method, which can solve the problem that in the wafer thinning process, the UV film is easy to form residual glue in the areas with large surface step difference of the wafer, such as the cutting path, thereby seriously affecting the subsequent wafer appearance, machine operation condition and reliability verification.

[0004] The present application provides a wafer film pasting method, which can solve the problem that in the wafer thinning process, the UV film is easy to form residual glue in the areas with large surface step difference of the wafer, such as the cutting path, thereby seriously affecting the subsequent wafer appearance, machine operation condition and reliability verification.

[0005] The wafer to be pasted with the film is placed on a vacuum adsorption workbench;

[0006] A ultraviolet curing protective film is provided, and the release paper on the bottom surface of the ultraviolet curing protective film is removed;

[0007] The ultraviolet curing protective film is pasted on the wafer from the edge of one side of the wafer and along the diameter direction of the wafer by using a film pasting roller;

[0008] The wafer pasted with the film is placed in a ultraviolet curing machine, and the wafer is irradiated by ultraviolet rays to fix the ultraviolet curing protective film on the front surface of the wafer;

[0009] In the process of pasting the ultraviolet curing protective film on the wafer from the edge of one side of the wafer and along the diameter direction of the wafer by using the film pasting roller, the film pasting pressure P of the film pasting roller is controlled to be a fixed value, so that the pressure received by any area of the front surface of the wafer is the same.

[0010] Optionally, in the wafer film pasting method, the calculation formula of the film pasting pressure Fn of the film pasting roller is: Fn=P×Sn, wherein P is the film pasting pressure of the film pasting roller, and Sn is the contact area of the film pasting roller and the wafer at any moment.

[0011] Optionally, in the wafer film pasting method, the calculation formula of the contact area Sn of the film pasting roller with the wafer at any time is Sn=W×L, wherein W is the width of the film pasting roller in contact with the wafer at any time, and L is the length of the film pasting roller in contact with the wafer at any time.

[0012] Optionally, in the wafer film pasting method, the calculation formula of the width W of the film pasting roller in contact with the wafer at any time is: wherein P is the film pasting pressure of the film pasting roller, R is the radius of the cylinder of the film pasting roller, and E is the comprehensive elastic modulus of the ultraviolet curing protective film and the material of the film pasting roller, wherein E is a constant.

[0013] Optionally, in the wafer film pasting method, the calculation formula of the length L of the film pasting roller in contact with the wafer at any time is: wherein r is the radius of the wafer, v is the rolling speed of the film pasting roller on the front surface of the wafer, and t is the time for the film pasting roller to roll from the edge of one side of the wafer to the edge of the other side of the wafer along the diameter direction of the wafer.

[0014] Optionally, in the wafer film pasting method, the film pasting pressure P of the film pasting roller is selected from the interval [0.1 MPa, 0.3 MPa].

[0015] Optionally, in the wafer film pasting method, the rolling speed of the film pasting roller on the front surface of the wafer is 5 cm / s-20 cm / s.

[0016] Optionally, in the wafer film pasting method, during the process of ultraviolet irradiation of the wafer after film pasting in the ultraviolet curing machine, the irradiation light source is 365 nm ultraviolet light; the irradiation intensity is 500 mJ / cm 2 -2000 mJ / cm 2 ; the irradiation time is 10 s-30 s.

[0017] Optionally, in the wafer film pasting method, while the ultraviolet curing protective film is pasted on the wafer from the edge of one side of the wafer to the edge of the other side of the wafer along the diameter direction of the wafer by using the film pasting roller, the ultraviolet curing protective film is rolled and extruded by using the film pasting roller to expel the air between the ultraviolet curing protective film and the wafer, so that the bottom surface of the ultraviolet curing protective film is completely pasted with the front surface of the wafer.

[0018] The technical scheme of the present application has at least the following advantages:

[0019] In the wafer film pasting method provided by the present application, in the process of pasting the ultraviolet curing protective film on the front surface of the wafer from the edge of one side of the wafer along the diameter direction of the wafer by using the film pasting roller, the film pasting pressure P of the film pasting roller at any moment is dynamically adjusted to a fixed value, so that the pressure on any area of the front surface of the wafer is the same, the uniform film pasting pressure becomes uniform film pasting pressure, and the strength of the contact point between the film pasting roller and the ultraviolet curing protective film is uniform regardless of the edge area or the center area of the wafer, thereby avoiding the formation of UV film residue in the area with large surface discontinuity such as the cutting path during the wafer thinning process due to the influence of the film pasting roller pressure factor, and thus not causing any impact on the subsequent wafer appearance, machine operation condition and reliability verification. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the specific embodiments or prior art of the present application, the drawings needed in the description of the specific embodiments or prior art will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 is a flow chart of the wafer film pasting method of the embodiment of the present application;

[0022] Figure 2 is a schematic diagram of the contact area between the film pasting roller on the surface of the wafer and the wafer of the embodiment of the present application;

[0023] Among them, the sign explanation is as follows:

[0024] 10-wafer. DETAILED DESCRIPTION

[0025] The technical solutions in the present application will be described in detail below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0026] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0027] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication between two elements, it can be wireless connection, or it can be wired connection. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0028] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0029] The inventors found that if the same (uniform) film pressing force is used for the whole wafer, more residual glue is likely to remain in the edge area of the wafer at 3 o'clock and 9 o'clock directions. The inventors further found that adjusting the film pressing force can improve the residual glue, but too small pressure can easily cause the film to wrinkle and thus cause wafer fragments, so there is an urgent need to provide a new wafer film pasting method to solve the above problems.

[0030] The present application provides a wafer film pasting method, which refers to Figure 1 , Figure 1 The wafer film pasting method of the present application is shown in the flowchart, which comprises:

[0031] First, step S1 is performed: placing the wafer to be pasted on a vacuum adsorption workbench.

[0032] Preferably, before performing step S1, the wafer to be pasted will also be cleaned. Deionized water, a brush or ultrasonic cleaning is used to clean the wafer surface to remove particles, organic matter, metal ions and other pollutants, and then nitrogen blowing or spin drying is used to ensure that there is no water residue on the wafer surface, so that the wafer surface remains dry.

[0033] Then, step S2 is performed: providing an ultraviolet curing protective film, and tearing off the release paper on the bottom surface of the ultraviolet curing protective film.

[0034] In this embodiment, the thickness of the ultraviolet curing protective film is 50 μm-200 μm.

[0035] Next, step S3 is performed: at room temperature (20°C-25°C), the ultraviolet curing protective film is attached to the wafer by using a film-attaching roller, starting from the edge of one side of the wafer and along the diameter direction of the wafer.

[0036] In the process of attaching the ultraviolet curing protective film to the wafer by using the film-attaching roller, starting from the edge of one side of the wafer and along the diameter direction of the wafer, the film-attaching pressure P of the film-attaching roller is controlled to be a fixed value, so that the wafer front surface receives the same pressure in any area.

[0037] In other embodiments, the wafer is preheated to 40°C-60°C, and then the ultraviolet curing protective film is attached to the wafer by using a film-attaching roller, starting from the edge of one side of the wafer and along the diameter direction of the wafer. Preheating the wafer to 40°C-60°C can enhance the attachment effect of the ultraviolet curing protective film.

[0038] Preferably, the film-attaching pressure P of the film-attaching roller is selected from the interval [0.1 MPa, 0.3 MPa].

[0039] In this embodiment, the film-attaching pressure P of the film-attaching roller can be selected as 0.2 MPa.

[0040] Preferably, the film-attaching pressure P of the film-attaching roller is selected from the interval [0.1 MPa, 0.3 MPa]. Figure 2 , Figure 2 is a schematic diagram of the contact area between the film-attaching roller and the wafer on the wafer surface in the embodiment of the application. The calculation formula of the film-attaching pressure Fn of the film-attaching roller is: Fn=P×Sn, wherein P is the film-attaching pressure of the film-attaching roller, and Sn is the contact area between the film-attaching roller and the wafer 10 at any moment.

[0041] In this embodiment, the film-attaching roller and the wafer are in elastic contact, and the pressure deformation is considered. The wafer surface covered by the ultraviolet curing protective film is an elastomer, which produces a small deformation after the pressure is applied, forming a rectangular contact area.

[0042] Further, the calculation formula of the contact area Sn between the film-attaching roller and the wafer 10 at any moment is: Sn=W×L, wherein W is the width of the contact between the film-attaching roller and the wafer 10 at any moment, and L is the length of the contact between the film-attaching roller and the wafer 10 at any moment.

[0043] wherein the calculation formula of the length L of the contact between the film-attaching roller and the wafer 10 at any moment is: wherein, r is the radius of the wafer, v is the rolling speed of the film-attaching roller on the front side of the wafer 10, and t is the time for the film-attaching roller to roll from the edge of one side of the wafer to the edge of the other side of the wafer along the diameter direction of the wafer.

[0044] Further, according to Hertz Contact Theory, the calculation formula of the width W of the contact between the film-attaching roller and the wafer at any time is: wherein, P is the film-attaching pressure of the film-attaching roller; R is the radius of the cylinder of the film-attaching roller; and E is the comprehensive elastic modulus of the ultraviolet-cured protective film and the material of the film-attaching roller, wherein E is a constant, and the unit of E is Pa.

[0045] In the present embodiment, the rolling speed v of the film-attaching roller on the front side of the wafer 10 is 5 cm / s to 20 cm / s.

[0046] According to all the above formulas, the calculation formula of the film-attaching pressure Fn of the film-attaching roller is: By presetting a fixed film-attaching pressure P of the film-attaching roller in advance, the film-attaching pressure Fn of the film-attaching roller at any time t can be calculated by the formula: The film-attaching pressure Fn of the film-attaching roller at any time t in the film-attaching process is dynamically adjusted by using the film-attaching equipment, so that the film-attaching pressure Fn of the film-attaching roller is dynamically adjusted, thereby making the pressure (the film-attaching pressure P of the film-attaching roller) received by any area on the front side of the wafer the same.

[0047] It is worth noting that, while the ultraviolet-cured protective film is attached to the wafer from the edge of one side of the wafer to the edge of the other side of the wafer along the diameter direction of the wafer by using the film-attaching roller, the film-attaching roller rolls and presses the ultraviolet-cured protective film to expel the air between the ultraviolet-cured protective film and the wafer, so that the bottom surface of the ultraviolet-cured protective film is completely attached to the front side of the wafer.

[0048] Finally, step S4 is performed: the wafer after film-attaching is placed into an ultraviolet curing machine to irradiate the wafer with ultraviolet light, so as to fix the ultraviolet-cured protective film on the front side of the wafer.

[0049] Preferably, during the process of placing the wafer after film-attaching into the ultraviolet curing machine to irradiate the wafer with ultraviolet light, the irradiation light source is ultraviolet light of 365 nm; the irradiation intensity is 500 mJ / cm 2 ~ 2000 mJ / cm 2 ; and the irradiation time length is 10 s to 30 s.

[0050] In the application, in the process of pasting the ultraviolet curing protective film on the front surface of the wafer from the edge of one side of the wafer and along the diameter direction of the wafer by using the film roller, the film pressure P of the film roller at any moment is dynamically adjusted to a fixed value, so that the wafer front surface in any area receives the same pressure, the uniform film pressure becomes uniform film pressure, and the strength of the contact point between the film roller and the ultraviolet curing protective film is uniform whether it is the edge area of the wafer or the center area of the wafer, avoiding the situation that the UV film residue is formed in the area with large surface gap such as the cutting path during the wafer thinning process due to the influence of the film roller pressure factor, so as to not cause any impact on the subsequent wafer appearance, machine operation and reliability verification.

[0051] Obviously, the above embodiments are only examples for clearly illustrating, but not limitation to the embodiments. Other different forms of changes or variations can be made on the basis of the above description for those skilled in the art. Here, all the embodiments are not required to be exhausted, and the obvious changes or variations derived therefrom are still within the protection scope of the application.

Claims

1. A wafer lamination method, characterized in that: include: Place the wafer to be filmed on a vacuum adsorption workbench; Providing a UV curable protective film and removing the release paper on the bottom surface of the UV curable protective film; Using a film-laminating roller, the ultraviolet curing protective film is laminated onto the wafer starting from the edge of one side of the wafer and along the diameter direction of the wafer; placing the wafer after film application into an ultraviolet curing machine and irradiating the wafer with ultraviolet light to fix the ultraviolet curing protective film on the front surface of the wafer; In the process of using a film-sticking roller to stick the ultraviolet curing protective film on the wafer starting from the edge of one side of the wafer and along the diameter direction of the wafer, the film-sticking pressure P of the film-sticking roller is controlled to a fixed value so that the pressure on any area on the front side of the wafer is the same.

2. The wafer lamination method according to claim 1, wherein: The calculation formula of the film laminating pressure Fn of the film laminating roller is: Fn=P×Sn, wherein P is the film laminating pressure of the film laminating roller, and Sn is the contact area between the film laminating roller and the wafer at any time.

3. The wafer lamination method according to claim 2, wherein: The calculation formula for the contact area Sn between the film-laminating roller and the wafer at any time is: Sn=W×L, where W is the width of the contact between the film-laminating roller and the wafer at any time, and L is the length of the contact between the film-laminating roller and the wafer at any time.

4. The wafer lamination method according to claim 3, characterized in that: The calculation formula for the contact width W between the laminating roller and the wafer at any time is: Among them, P is the film-laminating pressure of the film-laminating roller, R is the cylindrical radius of the film-laminating roller, and E is the comprehensive elastic modulus of the ultraviolet curing protective film and the material of the film-laminating roller, wherein E is a constant.

5. The wafer lamination method according to claim 3, wherein: The calculation formula for the contact length L between the film laminating roller and the wafer at any time is: Among them, r is the radius of the wafer, v is the rolling speed of the film roller on the front of the wafer, and t is the time it takes for the film roller to roll from the edge of one side of the wafer and along the diameter direction of the wafer to the edge of the other side of the wafer.

6. The wafer attaching method according to claim 1, wherein: The film-sticking pressure P of the film-sticking roller is selected in the range of [0.1 MPa, 0.3 MPa].

7. The wafer attaching method according to claim 1, wherein: The rolling speed of the film-sticking roller on the front side of the wafer is 5 cm / s to 20 cm / s.

8. The wafer attaching method according to claim 1, wherein: The wafer after film lamination is placed in a UV curing machine and irradiated with UV light. The irradiation light source is 365nm UV light with an irradiation intensity of 500mJ / cm 2 ~2000mJ / cm 2 ; The irradiation time is 10s to 30s.

9. The wafer attaching method according to claim 1, wherein: While using a film-sticking roller to stick the UV curing protective film on the wafer starting from the edge of one side of the wafer and along the diameter direction of the wafer, the film-sticking roller is used to roll and squeeze the UV curing protective film to expel the air between the UV curing protective film and the wafer so that the bottom surface of the UV curing protective film is completely stuck to the front surface of the wafer.

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