Gluing method

Abstract

The gluing method comprises the following steps: providing a wafer to be glued; providing a glue material for the front surface of the wafer; rotating the wafer so as to enable the glue material to be coated on the surface of the wafer, and performing edge washing treatment on the edge position of the wafer and performing back washing treatment on the back surface of the wafer within part of or all of the duration of rotating the wafer; the wafer is continuously rotated, after the wafer is spin-dried, the wafer is subjected to in-situ standing for a first preset time length, and the first preset time length is longer than the time length of spin-drying treatment on the wafer. According to the invention, through relatively long-time in-situ standing, a relatively short-time spin-drying process can be compensated, so that the formation amount of glue threads can be better reduced, and the wafer can be better dried.

Description

TECHNICAL FIELD

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

[0002] In the semiconductor manufacturing and packaging process, there are many processes involving glue layer coating, such as coating photoresist in the photolithography process, coating polyimide material in the packaging process, and coating bonding glue in the bonding process, etc.

[0003] Taking the photolithography process as an example, it can include multiple process steps such as gluing, exposure, development, alignment measurement, line width measurement, and defect microscopy. In the gluing process step, a wafer (such as a semiconductor substrate or a silicon wafer, hereinafter referred to as a wafer) can be coated with a layer of photoresist. As a special photosensitive material, the photoresist changes in properties when exposed to light. By using a mask with a precise pattern to block part of the light, a pattern of light and dark can be formed on the wafer, and then this pattern can be transferred to the wafer through the exposure and development processes of the photoresist.

[0004] However, in the existing gluing technology, the wafer is easily contaminated by glue filaments, and in severe cases, the cavity and the back of the wafer are covered with glue filaments, resulting in the rejection of contaminated products, and even due to the flow of contaminated products to the next station, causing more widespread contamination of the machine, affecting mass production. SUMMARY

[0005] The technical problem solved by the present application is to provide a gluing method that can compensate for the short spin-drying process by relatively long in-situ standing, which helps to better reduce the amount of glue filaments formed and dry wafers.

[0006] To solve the above technical problems, the present application provides a gluing method, comprising: providing a wafer to be glued; providing a glue material to the front surface of the wafer; rotating the wafer to allow the glue material to be coated on the surface of the wafer, wherein the edge position of the wafer is subjected to edge washing treatment and the back surface of the wafer is subjected to back washing treatment during part or all of the rotation time of the wafer; continuing to rotate the wafer to perform spin-drying treatment on the wafer, and then standing the wafer in-situ for a first preset time, wherein the first preset time is greater than the time for spin-drying treatment of the wafer.

[0007] Optionally, the viscosity coefficient of the glue material is greater than or equal to 800 cp.

[0008] Optionally, the first preset time is greater than or equal to 15s; and / or the spin-drying time of the wafer is selected from [5s, 15s].

[0009] Optionally, the edge of the wafer is subjected to edge cleaning, and the back of the wafer is subjected to back cleaning, including: using a cleaning agent with a volatilization rate greater than a preset volatilization rate to clean the edge of the wafer and clean the back of the wafer.

[0010] Optionally, the edge of the wafer is subjected to edge cleaning, and the back of the wafer is subjected to back cleaning, including: using one or more of the following combinations to clean the edge of the wafer and clean the back of the wafer: propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate.

[0011] Optionally, the glue material is a photoresist material; wherein the combination of propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate is used to clean the edge of the wafer and clean the back of the wafer; the content ratio of propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate is selected from [8:2, 6:4].

[0012] Optionally, rotating the wafer to coat the glue material to the surface of the wafer includes: step A: rotating the wafer at a first rotation rate R1 to uniformly coat the glue material on the front of the wafer; step B: after rotating the wafer at the first rotation rate R1 to make the glue material on the front of the wafer reach a preset thickness, adjusting the rotation rate to rotate the wafer at a second rotation rate R2, wherein R2≥R1; step C: rotating the wafer at a third rotation rate R3 while cleaning the back of the wafer, wherein R3≥R2; wherein during part or all of the time from step A to step B, the edge of the wafer is cleaned while the back of the wafer is cleaned.

[0013] Optionally, one or more of the following is included: the first rotation rate R1 is selected from [1600 rpm, 1640 rpm]; the second rotation rate R2 is selected from [1780 rpm, 1820 rpm]; the third rotation rate R3 is selected from [1960 rpm, 2040 rpm].

[0014] Optionally, the rotation time of step A is a first rotation time T1, the rotation time of step B using the first rotation rate R1 is a second rotation time T2, the rotation time of step B using the second rotation rate R2 is a third rotation time T3, and the rotation time of step C is a fourth rotation time T4; the method includes one or more of the following: T2≥T1≥T3; T2≥T1≥T4.

[0015] Optionally, one or more of the following is included: the first rotation duration T1 is selected from [2s, 4s]; the second rotation duration T2 is selected from [15s, 30s]; the third rotation duration T3 is selected from [0.1s, 2s]; and the fourth rotation duration T4 is selected from [0.1s, 2s].

[0016] Optionally, between the step B and the step C, the method further comprises one or more of the following: a step D of rotating the wafer at the second rotation rate R2 to perform edge cleaning on the edge of the wafer while performing back cleaning on the back of the wafer, and the rotation duration is a fifth rotation duration T5; and a step E of rotating the wafer at the second rotation rate R2 to perform edge cleaning on the edge of the wafer while performing back cleaning on the back of the wafer, and the rotation duration is a sixth rotation duration T6; wherein T6≥T5.

[0017] Optionally, between the step B and the step C, the method further comprises the step D and the step E; wherein a continuous rotation is maintained between the step D and the step E, or a non-zero duration of pause rotation is provided between the step D and the step E.

[0018] Optionally, one or more of the following is included: the fifth rotation duration T5 is selected from [1s, 3s]; and the sixth rotation duration T6 is selected from [3s, 5s].

[0019] Optionally, the glue material is a photoresist material; and the preset thickness is greater than or equal to 18μm.

[0020] Optionally, the continuing rotation of the wafer to perform spin-drying processing on the wafer comprises: rotating the wafer at a fourth rotation rate R4; wherein R4≥R3.

[0021] Optionally, the fourth rotation rate R4 is selected from [2200rpm, 2800rpm].

[0022] Optionally, the method further comprises: performing baking processing on the wafer.

[0023] Optionally, the glue material is a photoresist material, a bonding glue material, or a polyimide material.

[0024] Compared with the prior art, the technical scheme of the embodiment of the present application has the following beneficial effects:

[0025] In the embodiment of the present application, after the glue material is provided to the front surface of the wafer, the edge position of the wafer can be subjected to edge cleaning and the back surface of the wafer can be subjected to back cleaning during part or all of the rotation time of the wafer. Compared with the large-dose cleaning of the cavity after the glue coating process in the prior art, the small-range and small-dose cleaning of the wafer itself can be performed in advance, and by setting a certain cleaning time for the wafer itself or even increasing the cleaning time according to specific conditions, the glue filaments adhered to the wafer and the cavity can be better broken, and the formation of glue filaments can be reduced to a greater extent. Further, during the spin-drying process, more glue filaments are likely to be formed, and the thickness of the formed glue material layer is also likely to be affected, for example, the film thickness is thinned due to long-time high-speed spin-drying, affecting the process quality. In the embodiment of the present application, by additionally adding the step of in-situ standing of the wafer, the wafer can be dried to a certain extent without relying on sufficient spin-drying time, and the first preset time of in-situ standing of the wafer is also greater than the spin-drying time of the wafer. After setting a certain cleaning time for the wafer itself or even increasing the cleaning time according to specific conditions, the relatively long in-situ standing time can compensate for the relatively short spin-drying process, which helps to better reduce the amount of glue filaments and dry the wafer.

[0026] Further, the first preset time is greater than or equal to 15s; and / or the spin-drying time of the wafer is selected from [5s, 15s]. In the embodiment of the present application, by adopting an appropriate spin-drying time, the amount of glue filaments can be effectively reduced, and the influence on the thickness of the formed glue material layer can be reduced, thereby maintaining the device quality. At the same time, by adopting an appropriate first preset time of in-situ standing of the wafer, the technical effect of compensating for the relatively short spin-drying process by the relatively long in-situ standing can be achieved, thereby further reducing the amount of glue filaments and better drying the wafer.

[0027] Further, a cleaning agent with a volatilization rate greater than a preset volatilization rate is used to clean the edge position of the wafer and the back surface of the wafer. By selecting a cleaning agent with a higher volatilization rate, the difficulty of wafer drying can be reduced, which is conducive to further improving the application effect of the technical scheme of compensating for the relatively short spin-drying process by the relatively long in-situ standing.

[0028] Further, the edge of the wafer is subjected to edge cleaning and the back of the wafer is subjected to back cleaning by using one or more of the following combinations: propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate. Since propylene glycol monomethyl ether has the characteristics of slowly reaching the harmful pollution level in the air at room temperature (such as about 20℃), and has strong solubility; propylene glycol monomethyl ether acetate has the characteristics of high volatility, low toxicity and strong solubility to polar and non-polar substances, therefore, by selecting one of the above two materials or using a combination of the two, it can not only meet the effective cleaning of the wafer by its solubility, but also meet the requirement of high evaporation rate and reduce the difficulty of wafer drying process.

[0029] Further, by performing edge cleaning and back cleaning at the same time during the uniform coating step and the film thickness adjusting step, the cleaning effect can be maximized. Further, since the uniform coating step usually takes a long time in the entire coating process, by additionally adding edge cleaning and back cleaning during the uniform coating step, the wafer can be more effectively separated from the cavity, and the formation of the glue filament can be more effectively reduced. In addition, by setting step C, the glue material flowing to the back of the wafer along the edge under the action of surface tension can be effectively cleaned in the last stage of rotating the wafer, and the cleaning effect of the glue filament can be further improved.

[0030] Further, the method includes one or more of the following: T2≥T1≥T3; T2≥T1≥T4. In the embodiments of the present application, by setting the rotation rate with an increasing trend after the key steps of coating glue (such as the uniform coating step and the film thickness adjusting step), the process efficiency can be effectively improved; and by setting one or more short rotation time periods, the influence of the newly formed glue filament on the formed film thickness can be effectively reduced, so that the process efficiency and device quality can be considered.

[0031] Further, by setting one or more of steps D and E between the step B and the step C, one or two simultaneous edge washing and back washing processes can be additionally added to further improve the cleaning effect, better cut off the wafer and cavity adhesion of the glue filament, and to a greater extent reduce the formation of glue filaments. In addition, in the case of additionally adding two simultaneous edge washing and back washing processes, the formed glue filaments can be better dissolved by setting T6≥T5, that is, using a short-long processing time.

[0032] Further, the steps D and E maintain continuous rotation, so as to further improve the process efficiency, or the steps D and E have a non-zero duration of pause rotation, so as to destroy the ductility of the glue filament by non-continuous rotation.

[0033] Further, in the process which further includes a wafer baking process step, not only is the residual glue filament extremely easy to leave marks during baking, but the cleaning liquid used for edge washing and back washing is also extremely easy to leave marks during baking, and both are difficult to remove, which can cause He leakage vacuum alarm in subsequent processes (such as etching process after photolithography process), or even unable to continue working, so in the above application scenarios, it is particularly necessary to use the technical solution of the embodiment of the present application to better reduce the amount of glue filament formation and to perform a pre-drying process on the wafer. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a flowchart of a glue coating method in an embodiment of the present application;

[0035] Figure 2 is a schematic diagram of a glue coating chamber in an embodiment of the present application;

[0036] Figures 3 to 8 is a process scene diagram corresponding to each step of a glue coating method in an embodiment of the present application. DETAILED DESCRIPTION

[0037] As described above, in semiconductor manufacturing and packaging processes, there are many places involving glue layer coating processes, such as coating photoresist in photolithography process, coating polyimide material in packaging process, and coating bonding glue in bonding process. However, in the existing glue coating technology, the wafer is easily contaminated by glue filaments, and in severe cases, the cavity and the back of the wafer are full of glue filaments, resulting in the rejection of contaminated products, and even due to the contaminated products flowing to the next station, causing greater pollution to the machine, affecting mass production.

[0038] It is found that the glue disc in the glue coating cavity of the machine table is particularly easy to get dirty. Not only will it be covered with glue filaments, but the back of the wafer will also be contaminated with glue filaments. This is because during the glue throwing process, the glue often does not break off, but one end is attached to the edge of the wafer and the other end is attached to the inner wall of the cavity. When the wafer rotates at high speed, one end of the glue will break off and the glue filament will float in the cavity. As more and more glue is thrown out, the number of floating glue filaments will increase, resulting in the cavity and the back of the wafer being covered with glue filaments.

[0039] This problem is particularly important in the photolithography process, which can include coating, exposure, development, alignment measurement, line width measurement, defect microscopy, and other process steps. In the coating process step, a wafer (such as a semiconductor substrate or a silicon wafer, hereinafter referred to as a wafer) can be coated with a layer of photoresist. Photoresist is a special photosensitive material that changes its properties when exposed to light. By using a mask with a precise pattern to block part of the light, a light and dark pattern can be formed on the wafer, and then this pattern can be transferred to the wafer through the exposure and development processes of the photoresist.

[0040] Since photolithography is a key process step in semiconductor device and integrated circuit manufacturing, it can accurately transfer the designed circuit pattern to the semiconductor wafer. This process is crucial for manufacturing high-integration chips, as it determines how many transistors and other electronic components can be integrated on the chip. The glue filaments produced during the photoresist coating stage have a greater impact on device quality.

[0041] In an existing improved process, the cavity (including equipment inside the chamber and the inner wall of the chamber) can be cleaned by device engineers in time after each batch of wafers is completed.

[0042] It should be noted that the method of cleaning after each batch of wafers is completed significantly increases the product operation time, reduces the machine table capacity, and consumes labor. In addition, in order to clean the cavity, the requirements for the cleaning agent are often higher, such as using acetone for cleaning, and the dosage is often larger, resulting in higher process costs.

[0043] In the embodiment of the present application, after the glue material is provided to the front surface of the wafer, the edge position of the wafer can be subjected to edge cleaning treatment and the back surface of the wafer can be subjected to back cleaning treatment during part or all of the rotation time of the wafer. Compared with the large-dose cleaning of the cavity after the glue coating process in the prior art, the wafer itself can be subjected to small-range and small-dose cleaning in advance. By setting a certain cleaning time for the wafer itself, or even increasing the cleaning time according to the specific situation, the glue filaments adhered to the wafer and the cavity can be better cut off. Further, during the spin-drying process, more glue filaments are likely to be formed, and the thickness of the formed glue material layer is also likely to be affected, for example, the film thickness is thinned due to long-time high-speed spin-drying, affecting the process quality. In the embodiment of the present application, by additionally adding the step of in-situ standing of the wafer, the wafer can be dried without relying on sufficient spin-drying time. The first preset time of in-situ standing of the wafer is also greater than the spin-drying time of the wafer. After setting a certain cleaning time for the wafer itself, or even increasing the cleaning time according to the specific situation, the relatively long in-situ standing time can compensate for the short spin-drying process, which helps to better reduce the amount of glue filaments formed and dry the wafer.

[0044] In order to make the above-mentioned purposes, features and benefits of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0045] Reference Figure 1 , Figure 1 is a flowchart of a glue coating method in the embodiment of the present application. The glue coating method can include steps S11 to S14, and can also include step S15:

[0046] Step S11: providing a wafer to be coated with glue;

[0047] Step S12: providing a glue material to the front surface of the wafer;

[0048] Step S13: rotating the wafer to allow the glue material to be coated on the surface of the wafer, wherein the edge position of the wafer is subjected to edge cleaning treatment and the back surface of the wafer is subjected to back cleaning treatment during part or all of the rotation time of the wafer;

[0049] Step S14: continuing to rotate the wafer to perform spin-drying treatment on the wafer, and then in-situ standing the wafer for a first preset time, wherein the first preset time is greater than the spin-drying time of the wafer;

[0050] Step S15: performing baking treatment on the wafer.

[0051] The above method will be described below. Figures 2 to 8 The above method will be described below.

[0052] Figure 2 is a schematic diagram of a principle of a glue coating chamber in an embodiment of the present application, Figures 3 to 8 is a schematic diagram of a process scene corresponding to each step in a glue coating method in an embodiment of the present application.

[0053] With reference to Figure 2 and Figure 3 , a wafer to be coated with glue can be provided, and glue material is provided to the front surface of the wafer.

[0054] Among them, the wafer to be coated with glue can be a wafer that has completed the corresponding process step.

[0055] Taking coating photoresist as an example, the wafer can be a wafer after pretreatment, which is to be coated with glue in the photoetching process. The photoresist can also be called photoresist (PR), which can be used to represent an etch-resistant thin film material whose solubility changes under ultraviolet light, electron beam, ion beam, X-ray, etc. irradiation or radiation.

[0056] Taking coating bonding glue as an example, the wafer can be a device wafer, and the process step of a suitable device such as a logic device or a pixel device has been completed.

[0057] Among them, the step of providing glue material to the front surface of the wafer can be completed in a glue coating chamber.

[0058] In Figure 2 the glue coating chamber shown, there can be a wafer pedestal capable of rotating the wafer, and a cavity surrounding the wafer pedestal.

[0059] It can be understood that in the process of rotating the wafer, the objects (such as solid glue filaments or liquid cleaning agents) on the wafer can fall onto the wafer pedestal or be thrown onto the inner wall of the cavity under the action of centripetal force.

[0060] With reference to Figure 3 , glue material is provided to the front surface of the wafer.

[0061] Among them, Figure 3 the step shown can also be called glue dropping treatment.

[0062] In some embodiments, a sufficient amount of glue material can be delivered to the center of the wafer under the condition that the wafer is rotated at a certain rotational speed.

[0063] In one specific embodiment, the wafer can be rotated under the process condition that the rotational speed is [1400rpm, 1600rpm] (for example, 1500rpm), and the rotational speed duration is [2s, 4s] (for example, 3s).

[0064] It should be noted that in the embodiments of the present application, the rotation of the wafer in the glue dropping step can not be limited, and in some other embodiments, a sufficient amount of glue material can also be delivered to the center of the wafer when the wafer is stationary (i.e., the wafer is in a non-rotating state).

[0065] Further, the viscosity coefficient of the glue material can be greater than or equal to 800 cp.

[0066] Specifically, for glue materials with a larger viscosity coefficient, it is more prone to generate glue filaments when being spun off the wafer, especially this problem is more likely to occur.

[0067] In specific implementation, by setting the viscosity coefficient to be greater than or equal to 800 cp, glue materials with a larger viscosity coefficient can be processed to be used in more critical application scenarios, while special processing of glue materials with a smaller viscosity coefficient can be reduced to make it more consistent with the conventional process.

[0068] Referring to Figure 4 The wafer is rotated at a first rotation rate R1 to uniformly coat the glue material on the front surface of the wafer.

[0069] wherein, Figure 4 The illustrated step can also be referred to as a uniform coating process.

[0070] In some embodiments, Figure 4 The first rotation rate R1 used in the illustrated glue coating step can be greater than or equal to Figure 3 The rotation rate of the wafer in the illustrated glue dropping step can thus improve the process efficiency.

[0071] In some embodiments, in the uniform coating step, the back washing process can be performed on the back surface of the wafer while the edge washing process is performed on the edge position of the wafer.

[0072] The edge washing process can include: from the front surface of the wafer, using a cleaning nozzle to deliver cleaning agent from above the edge position of the wafer, to perform edge washing on the edge area of the front surface of the wafer to remove glue material pushed to the edge area of the front surface of the wafer by centrifugal force due to rotation.

[0073] The back washing process can include: from the back surface of the wafer, using a cleaning nozzle to deliver cleaning agent from below the middle area between the center position and the edge position of the wafer to the back surface of the wafer to perform back washing on the back surface of the wafer to remove glue material flowing along the edge to the back surface of the wafer due to surface tension.

[0074] Specifically, because in the process of spin coating of the glue material, the excess glue material is pushed to the edge of the wafer by centrifugal force, most of it is spun off the wafer, and part of it remains at the edge of the wafer. At the edge of the wafer, the relative speed of the airflow is very large, causing the remaining glue to solidify quickly and form a raised edge. Under the action of surface tension, a small amount of glue even flows along the edge to the back of the wafer, causing contamination to the back of the wafer.

[0075] It should be noted that, since the glue uniformization step often takes a long time in the entire glue coating process, by additionally adding the simultaneous edge washing treatment and back washing treatment during the glue uniformization stage, the glue filaments adhering the wafer to the cavity can be cut off to a greater extent, and the formation of glue filaments can be reduced to a greater extent.

[0076] In addition, by simultaneously performing the edge washing treatment on the edge position of the wafer and the back washing treatment on the back of the wafer, the cleaning effect can be maximized during the glue uniformization step by simultaneously performing the edge washing treatment and the back washing treatment.

[0077] In a specific embodiment, the first rotation rate R1 can be selected from [1600 rpm, 1640 rpm], for example [1610 rpm, 1630 rpm], such as 1620 rpm.

[0078] In specific implementations, a cleaning agent with a volatilization rate greater than the preset volatilization rate can be used to perform the edge washing treatment on the edge position of the wafer and the back washing treatment on the back of the wafer.

[0079] In the embodiments of the present application, a cleaning agent with a volatilization rate greater than the preset volatilization rate is used to perform the edge washing treatment on the edge position of the wafer and the back washing treatment on the back of the wafer. By using the above scheme, a cleaning agent with a higher volatilization rate can be selected to reduce the difficulty of wafer drying treatment, which is conducive to further improving the application effect of the technical scheme of compensating for the relatively short spin-drying process with a relatively long in-situ standing time.

[0080] In some embodiments, one or more of the following combinations can be used to perform the edge washing treatment on the edge position of the wafer and the back washing treatment on the back of the wafer: propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate.

[0081] wherein the chemical formula of propylene glycol monomethyl ether (PGME) is C4H 10 O2, also known as propylene glycol methyl ether, is a colorless and transparent liquid with a special odor. Its molecular formula is C4H 10 O2, and its molecular weight is 90.12. At 20℃, the vapor of this substance slowly reaches the harmful pollution level in the air, and has extremely strong solubility.

[0082] The chemical formula of propylene glycol monomethyl ether acetate (PGMEA) is C6H 12 O3, is a colorless hygroscopic liquid, with special odor, is a non-polluting solvent. It has multiple functional groups, mainly used as solvents for inks, paints, inks, textile dyes, textile oil, and can also be used as cleaning agent in the production of liquid crystal display. This solvent has low toxicity and strong solubility to polar and non-polar substances.

[0083] In the embodiment of the present application, one or more of the following combinations are used to perform edge cleaning on the edge position of the wafer and back cleaning on the back surface of the wafer: propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate. Because propylene glycol monomethyl ether has the characteristics of slowly reaching the harmful pollution level in the air at room temperature (such as about 20℃), and has strong solubility; propylene glycol monomethyl ether acetate has the characteristics of high volatility, low toxicity and strong solubility to polar and non-polar substances, therefore, by selecting one of the above two materials or using a combination of the two, it can not only meet the effective cleaning of the wafer by its solubility, but also meet the requirement of high evaporation rate and low difficulty of wafer drying treatment.

[0084] In a specific embodiment, the glue material can be photoresist material; wherein the combination of propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate is used to perform edge cleaning on the edge position of the wafer and back cleaning on the back surface of the wafer; the content ratio of propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate is selected from [8:2, 6:4].

[0085] Specifically, the content ratio of propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate can be selected from [8:2, 6:4], for example 7:3.

[0086] In the embodiment of the present application, the cleaning agent mainly contains 70% propylene glycol monomethyl ether (PGME) and 30% propylene glycol monomethyl ether acetate (PGMEA), which can effectively dissolve the photoresist, especially suitable for cleaning the photoresist formed glue silk.

[0087] Referring to Figure 5 , the wafer is rotated at the first rotation rate R1, so that the glue material on the front surface of the wafer reaches a predetermined thickness, and then the rotation rate is adjusted to rotate the wafer at the second rotation rate R2.

[0088] Wherein, R2≥R1.

[0089] Wherein, Figure 5 The step shown can also be called adjusting the film thickness.

[0090] In the embodiment of the present application, in the key step of adjusting the film thickness, after the glue material on the front surface of the wafer reaches the preset thickness required by the process, the rotation rate with an increasing trend is set to spin off the excess glue material.

[0091] In a specific embodiment, the second rotation rate R2 can be selected from [1780 rpm, 1820 rpm], for example [1790 rpm, 1810 rpm], such as 1800 rpm.

[0092] It can be understood that the use of an increasing rotation rate can provide greater centripetal force, reducing the problem of excess glue material remaining on the wafer, however, it can cause more glue filaments to form.

[0093] Further, the glue material is a photoresist material; wherein the preset thickness can be greater than or equal to 18 μm.

[0094] Specifically, due to the importance of the photoetching process, in the photoresist coating process, for the case of a larger preset thickness, a longer uniform coating step and / or film thickness adjusting step is often required, and in this application scenario, the technical solution of the embodiment of the present application is particularly needed to better reduce the amount of glue filaments formed and to perform a pre-drying process on the wafer.

[0095] Referring to Figure 6 , the wafer is rotated, and the back surface of the wafer is back washed while the edge position of the wafer is edge washed.

[0096] Specifically, between the step B shown in Figure 5 and the step C shown in Figure 7 , the method can further include step D and / or step E.

[0097] Step D can include: rotating the wafer at the second rotation rate R2, back washing the back surface of the wafer while edge washing the edge position of the wafer, and the rotation time is a fifth rotation time T5.

[0098] Step E can include: rotating the wafer at the second rotation rate R2, back washing the back surface of the wafer while edge washing the edge position of the wafer, and the rotation time is a sixth rotation time T6.

[0099] In the embodiment of the present application, by setting one or more of steps D and E between the step B and the step C, one or two simultaneous edge washing and back washing processes can be additionally added, further improving the cleaning effect, better cutting off the glue filaments adhered to the wafer and the cavity, and reducing the formation of glue filaments to a greater extent.

[0100] Further, T6≥T5.

[0101] Specifically, in the case of additionally increasing two simultaneous edge washing and back washing processes, the formed adhesive filaments can be better dissolved by setting T6≥T5, that is, adopting the processing time length of long first and short later.

[0102] In some embodiments, the fifth rotation time T5 is selected from [1s, 3s], and / or the sixth rotation time T6 is selected from [3s, 5s].

[0103] In a specific embodiment, the fifth rotation time T5 can be selected from [1s, 3s], for example [1.5s, 2.5s], such as 2s.

[0104] In a specific embodiment, the sixth rotation time T6 can be selected from [3s, 5s], for example [3.5s, 4.5s], such as 4s.

[0105] Further, between the step B and the step C, the method further comprises a step D and a step E; wherein, the step D and the step E maintain continuous rotation, or the step D and the step E have a non-zero time length of pause rotation between them.

[0106] In the embodiments of the present application, the step D and the step E maintain continuous rotation, so as to further improve the process efficiency, or the step D and the step E have a non-zero time length of pause rotation between them, so as to destroy the ductility of the adhesive filaments by discontinuous rotation.

[0107] Referring to Figure 7 , the wafer is rotated at a third rotation rate R3, and a back washing process is performed on the back surface of the wafer.

[0108] wherein, Figure 7 The step shown can also be referred to as back washing.

[0109] In a specific implementation, by stopping the edge washing process and continuing the back washing process, the adhesive material flowing to the back surface of the wafer along the edge under the action of surface tension can be effectively cleaned.

[0110] wherein, R3≥R2.

[0111] In a specific embodiment, the third rotation rate R3 can be selected from [1960rpm, 2040rpm], for example [1980rpm, 2020rpm], such as 2000rpm.

[0112] In the embodiments of the present application, by adjusting the rotation speed to the second rotation speed R2 after the wafer is rotated at the first rotation speed R1 to the preset thickness of the glue material on the front surface of the wafer, the cleaning effect can be maximized during the glue uniformizing step and the film thickness adjusting step by simultaneously performing the edge washing and back washing. Further, since the glue uniformizing step usually takes a long time in the entire glue coating process, by additionally adding the simultaneously performed edge washing and back washing during the glue uniformizing stage, the wafer adhesion to the cavity can be broken to a greater extent, and the formation of glue filaments can be reduced to a greater extent. In addition, by setting step C, the glue material flowing along the edge to the back surface of the wafer under the action of surface tension can be effectively cleaned by stopping the edge washing and continuing the back washing during the last stage of rotating the wafer, further improving the cleaning effect of the glue filaments.

[0113] It should be noted that, in the embodiments shown Figures 3 to 7 In a specific implementation of the embodiments shown, the rotation time used in each step (such as steps A, B, C, and D / E) can be adjusted as appropriate. Figure 4 The step A shown is Figure 5 The step B shown is Figure 6 The step D / E shown is Figure 7 The step C shown is

[0114] Specifically, the rotation time of the step A is a first rotation time T1, the rotation time of the first rotation speed R1 in the step B is a second rotation time T2, the rotation time of the second rotation speed R2 in the step B is a third rotation time T3, and the rotation time of the step C is a fourth rotation time T4; the method can include one or more of the following: T2≥T1≥T3; T2≥T1≥T4.

[0115] In the embodiments of the present application, by setting a rotation speed with an increasing trend after the key steps of glue coating (such as the glue uniformizing step and the film thickness adjusting step), the process efficiency can be effectively improved; and by setting one or more rotation time periods that are relatively short, the influence of newly formed glue filaments on the formed film thickness can be effectively reduced, so that the process efficiency and device quality are considered.

[0116] In some embodiments, one or more of the following can be included: the first rotation time T1 is selected from [2s, 4s]; the second rotation time T2 is selected from [15s, 30s]; the third rotation time T3 is selected from [0.1s, 2s]; and the fourth rotation time T4 is selected from [0.1s, 2s].

[0117] In one embodiment, the first rotation duration T1 can be selected from [2s, 4s], for example [2.5s, 3.5s], such as 3s.

[0118] In one embodiment, the second rotation duration T2 can be selected from [15s, 30s], for example [20s, 27s], such as 25s.

[0119] In one embodiment, the third rotation duration T3 can be selected from [0.1s, 2s], for example [0.5s, 1.5s], such as 1s.

[0120] In one embodiment, the fourth rotation duration T4 can be selected from [0.1s, 2s], for example [0.5s, 1.5s], such as 1s.

[0121] It can be understood that, in specific implementation, the rotation rate and rotation duration can also be selected according to the specific process platform and device, and the rotation rate and rotation duration shown in each step are only for illustration. Figures 3 to 7 The rotation rate and rotation duration shown in each step are only for illustration.

[0122] Referring to Figure 8 After the wafer continues to rotate for the spin-drying treatment, the wafer is in-situ placed for a first preset duration.

[0123] In one embodiment, the first preset duration can be selected from [15s, 30s], for example [18s, 27s], such as 20s or 25s. Figure 8 The step shown can also be referred to as a spin-drying treatment.

[0124] As shown, during the spin-drying treatment, the edge cleaning treatment on the edge position of the wafer and the back cleaning treatment on the back of the wafer can be stopped.

[0125] In specific implementation, in addition to the step of in-situ placing the wafer, the first preset duration for in-situ placing the wafer is also set to be greater than the duration for the spin-drying treatment on the wafer, so that the wafer can recover to a certain extent without relying on sufficient spin-drying duration through relatively long in-situ placement.

[0126] In some embodiments, the first preset duration is greater than or equal to 15s; and / or the duration for the spin-drying treatment on the wafer is selected from [5s, 15s].

[0127] In one embodiment, the first preset duration can be selected from [15s, 30s], for example [18s, 27s], such as 20s or 25s.

[0128] In one embodiment, the duration for the spin-drying treatment on the wafer can be selected from [5s, 15s], for example [8s, 12s], such as 10s.

[0129] In some embodiments, the first preset time period is greater than or equal to 15s; and / or the spin-drying time period is selected from [5s, 15s]. By adopting an appropriate spin-drying time period, the amount of glue filament formation can be effectively reduced, and the impact on the thickness of the formed glue material layer is reduced, thereby maintaining the quality of the device. At the same time, by adopting an appropriate first preset time period for in-situ static placement of the wafer, the technical effect of compensating for the relatively short spin-drying process with a relatively long in-situ static placement time can be achieved, further reducing the amount of glue filament formation and better drying the wafer.

[0130] It should be noted that in-situ static placement can be understood as keeping the wafer on the wafer pedestal of the chamber (such as a glue coating chamber) to which the spin-drying process belongs without moving and rotating after the spin-drying process is performed on the wafer. Figure 2 The glue coating chamber is shown.

[0131] In some embodiments, the step of continuing to rotate the wafer to perform spin-drying on the wafer can include rotating the wafer at a fourth rotation rate R4; wherein R4≥R3.

[0132] Specifically, by adopting a larger rotation rate for spin-drying, the process efficiency can be effectively improved.

[0133] In one specific embodiment, the fourth rotation rate R4 can be selected from [2200rpm, 2800rpm], for example [2400rpm, 2600rpm], such as 2500rpm.

[0134] In this embodiment of the invention, after providing adhesive material to the front side of the wafer, edge washing can be performed on the edge of the wafer and back washing can be performed on the back side of the wafer during part or all of the wafer rotation time. Compared with the prior art of performing a large-volume cleaning of the cavity after the adhesive coating process, a small-area, small-volume cleaning can be performed on the wafer itself in advance. By setting a certain cleaning time for the wafer itself, or even increasing the cleaning time according to the specific situation, the adhesive threads adhering to the wafer and the cavity can be cut off more effectively, and the formation of adhesive threads can be reduced to a greater extent. Furthermore, during the spin-drying process, not only are more adhesive filaments easily formed, but the thickness of the already formed adhesive material layer is also easily affected. For example, the film thickness becomes thinner due to prolonged high-speed spin-drying, affecting the process quality. In this embodiment of the invention, by adding an additional step of in-situ resting the wafer, the wafer can recover dryness to a certain extent without relying on sufficient spin-drying time. Moreover, the first preset time for in-situ resting the wafer is longer than the time for spin-drying the wafer. A certain cleaning time can be set for the wafer itself, or even increased according to specific circumstances. By resting in situ for a relatively long time, the shorter spin-drying time can be compensated, which helps to better reduce the amount of adhesive filaments formed and dry the wafer.

[0135] like Figure 1 As shown in step S15, in some embodiments, the method may further include baking the wafer.

[0136] Specifically, in subsequent processes that include wafer baking, not only are residual adhesive fibers easily left with traces during baking, but the cleaning solutions used for edge washing and back washing are also very likely to leave traces during baking, and these traces are difficult to remove. In severe cases, this can cause He leakage vacuum alarms in subsequent processes (such as etching after photolithography), or even prevent the process from continuing. Therefore, in the above application scenarios, it is especially necessary to adopt the technical solution of the present invention to better reduce the amount of adhesive fibers formed and to pre-dry the wafer.

[0137] Furthermore, the adhesive material can be a photoresist material, a bonding adhesive material, or a polyimide material, etc.

[0138] Specifically, for high-viscosity adhesive materials such as photoresist, bonding adhesive, or polyimide, the technical solutions of the embodiments of the present invention are particularly needed to better reduce the amount of adhesive filaments formed and to perform pre-drying treatment on the wafer.

[0139] It should be understood that the term "and / or" as used herein merely describes association between associated objects, and can exist in three forms: A and / or B, A or B, and A and B. In addition, the character " / " as used herein represents an "or" relationship between the front and rear associated objects. As used herein, the term "or" covers all possible combinations, unless otherwise explicitly stated. For example, if it is stated that a component can include A or B, the component can include A, or B, or A and B, unless otherwise explicitly stated or not feasible. As a second example, if it is stated that a component can include A, B, or C, the component can include A, or B, or C, or A and B, or A and C, or B and C, or A and B and C, unless otherwise explicitly stated or not feasible.

[0140] "Multiple" appearing in the embodiments of the present application means two or more.

[0141] The relationship terms appearing in the embodiments of the present application, such as first, second, etc., are only used to distinguish entities or operations from another entity or operation, and do not require or imply any actual relationship or order between the entities or operations. In addition, the words "include", "have" and "contain" and other similar forms are intended to be equivalent in meaning and open-ended, and one or more items following any of these words do not mean an exhaustive list of the one or more items or mean only the listed one or more items.

[0142] It should be noted that the serial numbers of the steps in the embodiments do not represent a limitation on the execution order of the steps.

[0143] In the foregoing specification, implementations have been described with reference to numerous specific details that can vary from implementation to implementation. Certain modifications and changes can be made thereto, and it is intended to embrace all such modifications and changes as fall within the scope of the application disclosed herein. It is to be understood that the foregoing description and example have been given by way of illustration only, and that the true scope and spirit of the application are indicated by the following claims. The sequence of steps shown in the drawings is also intended to be illustrative only, and is not intended to be limiting to any particular sequence of steps. Accordingly, those skilled in the art will recognize that the steps could be performed in a different order, simultaneously, or in parallel, while still achieving the same method.

[0144] In the drawings and specification, there have been disclosed exemplary embodiments. However, many variations and modifications can be made to these embodiments. Accordingly, while specific terminology has been employed, it is for the purpose of description only, and not for limitations.

[0145] Although the present application has been disclosed with reference to the above embodiments, the application is not limited to the above embodiments. It will be apparent to those skilled in the art that various modifications and changes can be made thereto without departing from the spirit and scope of the application. The scope of the application should be limited only by the appended claims.

Claims

1. A method for applying adhesive, characterized in that, include: Provide wafers to be coated with adhesive; Apply adhesive material to the front side of the wafer; The wafer is rotated so that the adhesive material is applied to the surface of the wafer, wherein, during part or all of the time the wafer is rotated, edge washing is performed on the edge of the wafer, and back washing is performed on the back side of the wafer. The wafer is rotated continuously to spin-dry it, and then left to stand in place for a first preset time, wherein the first preset time is longer than the time for spin-drying the wafer.

2. The method according to claim 1, characterized in that, The viscosity coefficient of the adhesive material is greater than or equal to 800 cp.

3. The method according to claim 1 or 2, characterized in that, The first preset duration is greater than or equal to 15 seconds; And / or, The spin-drying time of the wafer is selected from [5s, 15s].

4. The method according to claim 1, characterized in that, The process includes edge washing of the wafer and back washing of the wafer's back side, comprising: The edge of the wafer is cleaned using a cleaning agent with an evaporation rate greater than a preset evaporation rate, and the back side of the wafer is cleaned.

5. The method according to claim 4, characterized in that, The process includes edge washing of the wafer and back washing of the wafer's back side, comprising: The wafer's edge is washed using one or more of the following methods, and the back side of the wafer is back-washed: Propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate.

6. The method according to claim 5, characterized in that, The adhesive material is a photoresist material; Specifically, the combination of propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate is used to perform edge washing treatment on the edge of the wafer and back washing treatment on the back side of the wafer. The content ratio of propylene glycol monomethyl ether to propylene glycol monomethyl ether acetate is selected from [8:2, 6:4].

7. The method according to claim 1, characterized in that, Rotating the wafer to apply the adhesive material to the surface of the wafer includes: Step A: Rotate the wafer at a first rotation speed R1 to homogenize the adhesive material on the front side of the wafer; Step B: Rotate the wafer at the first rotation speed R1 until the adhesive material on the front side of the wafer reaches a preset thickness, then adjust the rotation speed to rotate the wafer at the second rotation speed R2, wherein R2≥R1; Step C: Rotate the wafer at a third rotation speed R3, while simultaneously performing a backwash on the back side of the wafer, wherein R3 ≥ R2; Specifically, during part or all of the time from step A to step B, while the edge of the wafer is being washed, the back side of the wafer is also being washed.

8. The method according to claim 7, characterized in that, Includes one or more of the following: The first rotational speed R1 is selected from [1600 rpm, 1640 rpm]; The second rotational speed R2 is selected from [1780 rpm, 1820 rpm]; The third rotational speed R3 is selected from [1960 rpm, 2040 rpm].

9. The method according to claim 7, characterized in that, The rotation duration in step A is the first rotation duration T1, the rotation duration in step B using the first rotation rate R1 is the second rotation duration T2, the rotation duration in step B using the second rotation rate R2 is the third rotation duration T3, and the rotation duration in step C is the fourth rotation duration T4. The method includes one or more of the following: T2≥T1≥T3; T2≥T1≥T4.

10. The method according to claim 9, characterized in that, Includes one or more of the following: The first rotation duration T1 is selected from [2s, 4s]; The second rotation duration T2 is selected from [15s, 30s]; The third rotation duration T3 is selected from [0.1s, 2s]; The fourth rotation duration T4 is selected from [0.1s, 2s].

11. The method according to claim 7, characterized in that, Between step B and step C, the method further includes one or more of the following: Step D: Rotate the wafer at the second rotation speed R2, and perform edge washing on the edge of the wafer and back washing on the back side of the wafer at the same time, and the rotation time is the fifth rotation time T5. Step E: Rotate the wafer at the second rotation speed R2, and perform edge washing on the edge of the wafer and back washing on the back side of the wafer at the same time, and the rotation time is the sixth rotation time T6. Where T6 ≥ T5.

12. The method according to claim 11, characterized in that, Between step B and step C, the method further includes steps D and E; The rotation is continuous between steps D and E, or there is a non-zero duration of pause between steps D and E.

13. The method according to claim 11, characterized in that, Includes one or more of the following: The fifth rotation duration T5 is selected from [1s, 3s]; The sixth rotation duration T6 is selected from [3s, 5s].

14. The method according to claim 7, characterized in that, The adhesive material is a photoresist material; The preset thickness is greater than or equal to 18 μm.

15. The method according to claim 1, characterized in that, The step of continuing to rotate the wafer to perform a spin-drying process includes: The wafer is rotated at a fourth rotation speed R4; Where R4 ≥ R3.

16. The method according to claim 15, characterized in that, The fourth rotational speed R4 is selected from [2200 rpm, 2800 rpm].

17. The method according to claim 1, characterized in that, The method further includes: The wafer is then baked.

18. The method according to claim 1, characterized in that, The adhesive material is a photoresist material, a bonding adhesive material, or a polyimide material.

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