A method for planarizing a photoresist-containing wafer

Abstract

The application discloses a kind of planarization methods of photoresist wafer, it is related to the technical field of semiconductor process, the planarization method includes: obtaining the photoresist wafer to be ground, and obtaining first grinding fluid;First ideal parameter of photoresist wafer is obtained, and first grinding parameter is adjusted according to the first ideal parameter;First grinding fluid is sprayed to the photoresist wafer, and the photoresist wafer is ground according to first grinding parameter.By changing grinding pressure and grinding speed, the thickness of photoresist and copper is uniform, and the surface planarization of copper and photoresist combination wafer is realized.

Description

Technical Field

[0001] This invention relates to the field of semiconductor process technology, and in particular to a planarization method for a wafer containing photoresist. Background Technology

[0002] For grinding copper / photoresist (CU / PR) composite wafers, according to the theory of chemical mechanical polishing (CMP), two different polishing slurries are required to grind the different materials separately.

[0003] Copper and photoresist differ significantly in chemical properties and hardness. Copper is used as a wiring material in integrated circuits, and its chemical planarization process is already very mature, with many manufacturers providing copper polishing slurries. However, for photoresist, there are virtually no suppliers that can provide polishing slurries.

[0004] Chemical mechanical polishing (CMP) involves selecting different polishing slurries based on the type of material being polished. Currently, no manufacturers supply polishing slurries for wafers containing photoresist have been found. Photoresist, being a polymer, has a significantly different hardness compared to metallic copper, making it difficult to achieve compatibility between wafers composed of these two substances during CMP. Summary of the Invention

[0005] The purpose of this invention is to provide a planarization method for a photoresist-containing wafer, which achieves surface planarization of the copper-photoresist composite wafer by changing the grinding pressure and grinding speed to obtain a uniform thickness of photoresist and copper.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] One aspect of the present invention provides a planarization method for a photoresist-containing wafer, the planarization method comprising: obtaining a photoresist-containing wafer to be polished, and obtaining a first polishing slurry; obtaining a first ideal parameter of the photoresist-containing wafer, adjusting a first polishing parameter according to the first ideal parameter; controlling the first polishing slurry to be sprayed onto the photoresist-containing wafer, and polishing the photoresist-containing wafer according to the first polishing parameter.

[0008] In some embodiments, after controlling the first polishing slurry to spray onto the photoresist-containing wafer and polishing the photoresist-containing wafer according to the first polishing parameters, the method further includes: obtaining a second polishing slurry; obtaining a second ideal parameter of the photoresist-containing wafer and readjusting the second polishing parameter according to the second ideal parameter; controlling the second polishing slurry to spray onto the photoresist-containing wafer and polishing the photoresist-containing wafer according to the second polishing parameter.

[0009] In some embodiments, in the process of controlling the first polishing slurry to spray onto the photoresist-containing wafer and polishing the photoresist-containing wafer according to the first polishing parameters, the method includes: polishing the photoresist in the photoresist-containing wafer; and stopping when the thickness of the photoresist in the photoresist-containing wafer is polished to be less than the thickness of the metal in the photoresist-containing wafer.

[0010] In some embodiments, in the process of controlling the second polishing slurry to spray onto the photoresist-containing wafer and polishing the photoresist-containing wafer according to the second polishing parameters, the method includes: polishing the metal in the photoresist-containing wafer; and stopping when the thickness of the metal in the photoresist-containing wafer is polished to be consistent with the thickness of the photoresist in the photoresist-containing wafer.

[0011] In some embodiments, the first ideal parameter is the photoresist thickness parameter in the photoresist-containing wafer, and the first polishing parameter includes a set polishing pressure, a first set polishing speed, and a set polishing fluid flow rate.

[0012] In some embodiments, the set grinding pressure is 150-175 hPa, the first set grinding speed is 77 rpm, and the set grinding fluid flow rate is 300 ml / min.

[0013] In some embodiments, the second ideal parameter is the metal thickness parameter in the photoresist-containing wafer, wherein the metal is copper, and the second polishing parameter includes a set polishing pressure, a second set polishing speed, and a set polishing fluid flow rate.

[0014] In some embodiments, the set grinding pressure is 150-175 hPa, the second set grinding speed is 99 rpm, and the set grinding fluid flow rate is 300 ml / min.

[0015] In some embodiments, the pH value of the first polishing slurry is 10, and the first polishing slurry includes polishing particles SiO2 and H2O2 with a content of 1%.

[0016] In some embodiments, the pH value of the second polishing slurry is 7, and the first polishing slurry includes polishing particles SiO2 and 1% H2O2.

[0017] A planarization method for a photoresist-containing wafer according to an embodiment of the present invention has at least the following beneficial effects: it enables the grinding of a wafer containing photoresist; the planarization method of this application is applicable to wafers with other structures containing photoresist, thereby achieving surface planarization of micro-coaxial devices. By changing the grinding pressure and grinding speed, a uniform thickness of photoresist and copper is obtained, thereby achieving surface planarization of the copper-photoresist composite wafer.

[0018] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this disclosure. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart according to an embodiment;

[0021] Figure 2 This is a schematic diagram of the structural flow according to an embodiment. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0024] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the description of this disclosure will be more complete and fully convey the concept of the exemplary embodiments to those skilled in the art. The drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0025] The technical solutions of the embodiments of this application are briefly described below:

[0026] According to some embodiments, such as Figure 1 As shown, this application provides a planarization method for a photoresist-containing wafer, the planarization method comprising:

[0027] Step 101: Obtain the photoresist-containing wafer to be polished, and obtain the first polishing slurry;

[0028] Step 102: Obtain the first ideal parameters of the photoresist-containing wafer, and adjust the first grinding parameters according to the first ideal parameters;

[0029] Step 103: Control the first polishing slurry to spray onto the photoresist-containing wafer, and polish the photoresist-containing wafer according to the first polishing parameters.

[0030] Based on the above embodiments, the photoresist 1 plays a role in defining the structure of the metal 2 in the device and isolating the wiring of the metal 2 in the entire process. In order to achieve good isolation and prevent the metal 2 from overflowing, the thickness of the photoresist 1 is generally relatively thick.

[0031] In some embodiments, the thickness of the multiple metal protrusions 2 on the photoresist-containing wafer is uniform. In this case, it is only necessary to grind the photoresist 1 in the photoresist-containing wafer until it is the same thickness as the metal 2. The first polishing slurry is only used to polish the photoresist 1, and the first polishing slurry has no removal effect on the metal 2.

[0032] The photoresist is positive photoresist AZ40, the resin in the photoresist is linear phenolic resin, and the photosensitizer is diazonaphthoquinone (DNQ).

[0033] The following is in conjunction with the appendix to this instruction manual. Figures 1 to 2 The preferred embodiments of this disclosure will be further described in detail below.

[0034] According to some embodiments, in step 103, after controlling the first polishing slurry to spray onto the photoresist-containing wafer and polishing the photoresist-containing wafer according to the first polishing parameters, the method further includes:

[0035] Step 104: Obtain the second grinding fluid;

[0036] Step 105: Obtain the second ideal parameters of the photoresist-containing wafer, and readjust the second polishing parameters according to the second ideal parameters;

[0037] Step 106: Control the second polishing slurry to spray onto the photoresist-containing wafer, and polish the photoresist-containing wafer according to the second polishing parameters.

[0038] In some embodiments, such as Figure 2 As shown, the thickness of the multiple metal protrusions 2 on the photoresist-containing wafer is inconsistent. Therefore, it is necessary to grind not only the photoresist 1 on the photoresist-containing wafer but also the metal 2 on the photoresist-containing wafer. The first polishing slurry is only used to polish the photoresist 1 and has no removal effect on the metal 2. In step 104, a second polishing slurry is obtained, and the metal 2 is polished using the second polishing slurry.

[0039] Based on the above embodiments, in step 103, the first polishing slurry is sprayed onto the photoresist-containing wafer, and the wafer is polished according to the first polishing parameters. The method includes:

[0040] Step 1031: Grind the photoresist in the photoresist-containing wafer;

[0041] Step 1032: Grind the photoresist thickness in the photoresist-containing wafer until it is all less than the thickness of metal 2 in the photoresist-containing wafer, and then stop.

[0042] Furthermore, in step 106, the second polishing slurry is sprayed onto the photoresist-containing wafer, and the wafer is polished according to the second polishing parameters. The method includes:

[0043] In step 1061, the metal 2 in the photoresist-containing wafer is ground;

[0044] In step 1062, the grinding of the metal 2 in the photoresist-containing wafer is stopped when the thickness is consistent with the thickness of the photoresist in the photoresist-containing wafer.

[0045] Among them, such as Figure 2 As shown, the thickness of photoresist 1 in the photoresist-containing wafer is greater than that of metal 2. The thicknesses of the multiple protruding metal 2 are inconsistent. First, the thickness of all protruding photoresist 1 is ground until it is less than the thickness of the thinnest metal 2, and after grinding, the thickness of each photoresist 1 is uniform. After the photoresist 1 is ground, the thickness of the metal 2 is ground until it matches the thickness of the photoresist 1, and the grinding process is complete.

[0046] In other embodiments, the thickness of all protruding photoresist 1 is first ground until it is equal to the thickness of the thinnest metal 2, and after grinding, the thickness of each photoresist 1 and the thinnest metal 2 is the same. After the photoresist 1 is ground, the thickness of the other metals 2 is ground until it is the same as the thickness of the photoresist 1 and the thinnest metal 2, and then the grinding is stopped, thus completing the grinding process.

[0047] According to some embodiments, the first ideal parameter is the photoresist thickness parameter in the photoresist-containing wafer, and the first polishing parameter includes a set polishing pressure, a first set polishing speed, and a set polishing fluid flow rate.

[0048] Based on the above embodiments, the setting of grinding pressure, the first setting of grinding speed and the setting of grinding fluid flow rate can be set according to actual needs. In some embodiments, the setting of grinding pressure is 150-175 hPa, the first setting of grinding speed is 77 rpm and the setting of grinding fluid flow rate is 300 ml / min.

[0049] Furthermore, the photoresist thickness parameter can be set according to actual needs. The difference between the initial photoresist thickness parameter and the photoresist thickness parameter is the first grinding thickness parameter, which is determined by the grinding time.

[0050] According to some embodiments, the second ideal parameter is the metal thickness parameter in the photoresist wafer, wherein the metal 2 is copper, and the second polishing parameter includes setting polishing pressure, setting polishing speed, and setting polishing fluid flow rate.

[0051] Based on the above embodiments, the setting of grinding pressure, the first setting of grinding speed and the setting of grinding fluid flow rate can be set according to actual needs. In some embodiments, the setting of grinding pressure is 150-175 hPa, the second setting of grinding speed is 99 rpm and the setting of grinding fluid flow rate is 300 ml / min.

[0052] Furthermore, the metal thickness parameter can be set according to actual needs. The difference between the initial metal thickness parameter and the final metal thickness parameter is the second grinding thickness parameter, which is determined based on the grinding time. For example, in some embodiments of this application, metal 2 is copper. The thickness of copper before grinding is 57 micrometers, i.e., the initial metal thickness parameter is 57 micrometers. Finally, the required thickness of copper is 50 micrometers, i.e., the metal thickness parameter is 50 micrometers, and the second grinding thickness parameter is 7 micrometers. In this case, the grinding time for copper is 10 minutes.

[0053] According to some embodiments, the pH value of the first polishing slurry is 10, and the first polishing slurry includes polishing particles SiO2 and H2O2 with a content of 1%.

[0054] Furthermore, the second polishing slurry has a pH value of 7, and the first polishing slurry includes polishing particles SiO2 and 1% H2O2.

[0055] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0056] Although this disclosure has been described with reference to several typical embodiments, it should be understood that the terminology used is descriptive and exemplary, and not restrictive. Because this disclosure can be embodied in many forms without departing from the spirit or substance of this application, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A method for planarizing a photoresist-containing wafer, characterized in that, The flattening method includes: Obtain the photoresist-containing wafer to be polished, and obtain the first polishing slurry; Obtain the first ideal parameters of the photoresist-containing wafer, and adjust the first grinding parameters according to the first ideal parameters; The first polishing slurry is sprayed onto the photoresist-containing wafer, and the photoresist-containing wafer is polished according to the first polishing parameters; Obtain the second grinding fluid; Obtain the second ideal parameters of the photoresist-containing wafer, and readjust the second polishing parameters based on the second ideal parameters; The second polishing slurry is sprayed onto the photoresist-containing wafer, and the photoresist-containing wafer is polished according to the second polishing parameters; In the process of controlling the spraying of the first polishing slurry onto the photoresist-containing wafer and polishing the photoresist-containing wafer according to the first polishing parameters, the method includes: The photoresist in the photoresist-containing wafer is ground; The grinding process is stopped when the thickness of the photoresist in the photoresist-containing wafer is reduced to less than the thickness of the metal in the photoresist-containing wafer.

2. The planarization method according to claim 1, characterized in that, In the process of controlling the spraying of the second polishing slurry onto the photoresist-containing wafer and polishing the photoresist-containing wafer according to the second polishing parameters, the method includes: The metal in the photoresist-containing wafer is ground; The grinding process is stopped when the metal thickness in the photoresist-containing wafer is ground to match the photoresist thickness in the photoresist-containing wafer.

3. The planarization method according to claim 1, characterized in that, The first ideal parameter is the photoresist thickness parameter in the photoresist-containing wafer, and the first polishing parameter includes setting polishing pressure, setting first polishing speed, and setting polishing fluid flow rate.

4. The planarization method according to claim 3, characterized in that, The set grinding pressure is 150~175 hPa, the first set grinding speed is 77 rpm, and the set grinding fluid flow rate is 300 ml / min.

5. The planarization method according to claim 1, characterized in that, The second ideal parameter is the metal thickness parameter in the photoresist-containing wafer, wherein the metal is copper, and the second polishing parameter includes setting polishing pressure, setting polishing speed, and setting polishing fluid flow rate.

6. The planarization method according to claim 5, characterized in that, The set grinding pressure is 150~175 hPa, the second set grinding speed is 99 rpm, and the set grinding fluid flow rate is 300 ml / min.

7. The planarization method according to claim 1, characterized in that, The first polishing slurry has a pH value of 10 and includes polishing particles SiO2 and 1% H2O2.

8. The planarization method according to claim 1, characterized in that, The second polishing slurry has a pH value of 7, and the first polishing slurry includes polishing particles SiO2 and 1% H2O2.

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