Method for protecting front structure of chip in wet etching process

Abstract

The invention relates to a method for protecting a front surface structure of a chip in a wet etching process, which is used for protecting a metal material layer structure and other sensitive structures on the front surface of the chip by using ProTEK glue, and comprises the following steps of: checking a wafer material sheet, spin-coating Primer adhesive / primer, curing, cooling, spin-coating ProTEK glue, curing, and then conveying to a cold plate for cooling. And completing the chip front surface structure protection process method. Compared with a traditional photoresist coating front surface protection technology and a thermal oxide layer or silicon nitride layer and other dielectric layer front surface protection technology, the protection method has the advantages of being simple in process, high in chemical corrosion resistance, high in adhesive force, excellent in process compatibility, easy to coat and remove, free of residues, low in stress, remarkable in protection effect and the like.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor production, in particular to a method for protecting a front structure of a chip during a wet etching process. Background Art

[0002] MEMS (micro-electromechanical system) gauge pressure sensors have been widely used in industrial automation, automotive electronics, biomedicine and other fields due to their small size, high precision and high sensitivity. The core structure of the sensor is formed on a silicon wafer through micromachining technology, in which the deep groove structure of the back cavity plays a vital role. However, when manufacturing the back cavity structure, the commonly used wet etching process will inevitably damage the metal material layer structure and other sensitive structures on the front side of the wafer material sheet, resulting in sensor performance degradation or failure.

[0003] Traditional front protection technologies include photoresist coating front protection technology, thermal oxide layer or silicon nitride layer and other dielectric layer front protection technology, but these technologies have some shortcomings and certain limitations in practical applications. In the photoresist coating front protection technology, the photoresist is prone to expansion, cracking or falling off after long-term immersion in the corrosive solution, resulting in protection failure. This deficiency is more obvious in deep groove corrosion and long-term corrosion processes. In addition, the corrosion resistance of photoresist is limited and it is difficult to provide long-term and stable protection in harsh corrosion environments; in the thermal oxide layer or silicon nitride layer and other dielectric layer front protection technology, the thermal oxide layer or silicon nitride layer is a thin film protective layer generated on the surface of the wafer material sheet under a high temperature environment. Due to its high manufacturing temperature and time cost, it increases the complexity and cost of the manufacturing process. In addition, the thickness of dielectric layers such as thermal oxide layers or silicon nitride layers is also difficult to control, which may affect subsequent processes. Summary of the invention

[0004] To this end, the technical problem to be solved by the present invention is that in the prior art, in the manufacturing process of MEMS (micro-electromechanical system) gauge pressure sensor, the wet etching process of the back cavity deep groove structure is a key step. However, the wet etching solution (such as TMAH, KOH) used in the etching process is extremely corrosive to the metal material layer structure and other sensitive structures on the front side of the wafer, causing serious damage to the chip front structure and affecting the performance of the sensor. Traditional front protection technologies include photoresist coating front protection technology, thermal oxide layer or silicon nitride layer and other dielectric layer front protection technology, but these technologies have some shortcomings and certain limitations in practical applications, so as to provide a technology for protecting the metal material layer structure and other sensitive structures on the front side of the chip by using ProTEK glue, ensuring the integrity of the front structure during the wet etching process, and improving the reliability of the manufacturing process and the performance of the sensor.

[0005] In order to solve the above technical problems, the present invention provides a method for protecting the front structure of a chip during wet etching, wherein the protection method uses ProTEK glue to treat the metal material layer structure and other sensitive structures on the front of the chip, and comprises the following steps:

[0006] Step S1: Ensure that the front side of the wafer material sheet to be processed is clean and free of dust and impurities; slowly and evenly pour 5 mL to 30 mL of Primer adhesive / primer on the central area of ​​the front side of the wafer material sheet;

[0007] Step S2: Spin-coating the Primer adhesive / primer onto the cleaned front area of ​​the wafer material sheet by spin coating, with a spin coating speed of 1000 to 3000 rpm and a spin coating time of 10 s to 5 min;

[0008] Step S3: After the Primer adhesive / primer coating is completed, the Primer adhesive / primer is transferred to a hot plate for curing, the hot plate temperature is 100°C to 250°C, and the baking time is 30s to 30min; after the curing is completed, the Primer adhesive / primer coating process is completed by transferring the Primer adhesive / primer to a cold plate for cooling.

[0009] Step S4: slowly and evenly pour 5 mL to 30 mL of etching protection generation liquid / corrosion-resistant colloid ProTEK glue on the front center area of ​​the wafer material sheet coated with the Primer adhesive / primer, and when the ProTEK glue is spread out, it covers the entire surface of the wafer material sheet;

[0010] Step S5: Spin-coat the ProTEK glue onto the front area of ​​the wafer material sheet coated with the Primer adhesive / primer by a spin coating process, with a spin coating speed of 1000 to 3000 rpm and a spin coating time of 10 s to 5 min. The thickness of the ProTEK glue can be flexibly adjusted by the spin coating speed and the spin coating time.

[0011] Step S6: After the glue coating is completed, the wafer is transferred to the hot plate for ProTEK glue curing. The hot plate temperature is 100℃~250℃, and the baking time is 30s~60min. After the curing is completed, it is transferred to the cold plate for cooling treatment to complete the process of coating and protecting the metal material layer structure and other sensitive structures on the front side of the chip with ProTEK glue.

[0012] In one embodiment of the present invention, the wafer material sheet is a common single crystal silicon substrate material sheet or a SOI substrate material sheet, and the outermost layer on the front side of the wafer material sheet is an irregular metal layer, which is arranged on the passivation protection layer; therefore, the Primer adhesive / primer is spread on the metal layer to cover the entire surface of the wafer material sheet, and the Primer adhesive / primer is 1-methoxy-2-propanol with a concentration of 10% to 100%.

[0013] In one embodiment of the present invention, the other side of the Primer adhesive / primer is provided with ProTEK glue, and the components of ProTEK glue are 5-methyl-2-ethanone with a concentration of 10% to 80%, 3-ethoxyethyl propionate with a concentration of 10% to 80%, styrene with a concentration of ≤20%, and polymer solids with a concentration of 5% to 60%.

[0014] In one embodiment of the present invention, the thickness of the prepared ProTEK glue is 500 nm to 20 μm.

[0015] The above technical solution of the present invention has the following advantages over the prior art: The protection method of the chip front structure of the present invention uses ProTEK glue (etching protection generating liquid / corrosion-resistant colloid, ingredients: 5-methyl-2-ethanone, ethyl 3-ethoxypropionate, styrene, polymer solid) to protect the metal material layer structure and other sensitive structures on the front of the chip. This front protection technology overcomes the shortcomings of the prior art. The corrosion resistance of ProTEK glue is significantly better than that of photoresist, and it can provide longer stable protection in harsh wet corrosion environments; compared with dielectric layers such as thermal oxide layers or silicon nitride layers, the production cost and complexity of ProTEK glue front protection technology are lower, and it is easier and more flexible to control. The coating and curing process of the ProTEK glue front protection technology adopted in the present invention is simple, and it can be seamlessly integrated into the existing MEMS manufacturing process, and it has strong adaptability. The present invention proposes to spin-coat the Primer adhesive / primer (ingredients: 1-methoxy-2-propanol) and the curing process before spin-coating the ProTEK glue. By adding this step, the high adhesion of the ProTEK glue is significantly improved, and the ProTEK glue is prevented from swelling, cracking or falling off easily after being soaked in the corrosive liquid for a long time, resulting in protection failure. Although the photoresist front protection technology is also simple in process, the photoresist is prone to failure during wet etching; the front protection technology of dielectric layers such as thermal oxide layers or silicon nitride layers requires high-temperature treatment, which increases the complexity and cost of the process. ProTEK glue is easy to remove and has no residue, ensuring the smooth progress of subsequent processes without introducing additional pollution and damage. Although the removal of photoresist is also relatively convenient, it is easy to leave organic residues during the removal process, which may affect the subsequent process; the removal of dielectric layers such as thermal oxide layers or silicon nitride layers requires the use of strong acids, which is complicated to operate and has safety risks.

[0016] The present invention proposes a technology for protecting the metal material layer structure and other sensitive structures on the front side of the chip by using ProTEK glue, which has the advantages of simple process, high chemical corrosion resistance, high adhesion, excellent process compatibility, easy coating, easy removal without residue, low stress, and significant protection effect. It helps to improve the manufacturing yield and product performance of MEMS sensors, is suitable for large-scale production and use, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0018] Figure 1 This is a schematic diagram of pouring the Primer adhesive / primer slowly and evenly on the center area of ​​a clean wafer material sheet.

[0019] Figure 2 This is a schematic diagram of the Primer adhesive / undercoat after curing.

[0020] Figure 3 This is a schematic diagram of ProTEK glue being slowly and evenly poured onto the front center area of ​​a wafer material sheet that has been coated with a Primer adhesive / primer.

[0021] Figure 4 This is a schematic diagram of ProTEK glue after curing.

[0022] As shown in the figure, 1. Wafer material sheet; 2. Primer adhesive / primer; 3. ProTEK glue. DETAILED DESCRIPTION

[0023] Embodiment 1

[0024] This embodiment provides a method for protecting the front structure of a chip during a wet etching process. The specific process flow of the process is as follows:

[0025] Step 1: Make sure the front of the wafer to be processed is clean and free of dust and impurities. Slowly and evenly pour 5mL to 30mL of Primer adhesive / primer on the center area of ​​the wafer. The Primer adhesive / primer can cover the entire surface of the wafer when it is spread. The Primer adhesive / primer is 10% to 100% 1-methoxy-2-propanol. Figure 1 .

[0026] Step 2: Use spin coating process to spin coat the Primer adhesive / primer onto the front area of ​​the cleaned wafer material sheet, with a spin coating speed of 1000 to 3000 rpm and a spin coating time of 10s to 5min.

[0027] Step 3: After the Primer adhesive / primer coating is completed, it is transferred to the hot plate for Primer adhesive / primer curing. The hot plate temperature is 100℃~250℃(±1℃) and the baking time is 30s~30min. After the curing is completed, it is transferred to the cold plate for cooling treatment to complete the Primer adhesive / primer coating process. Figure 2 .

[0028] Step 4: Slowly and evenly pour 5mL to 30mL of etching protection liquid / corrosion-resistant colloid ProTEK glue on the front center area of ​​the wafer material sheet coated with Primer adhesive / primer. When the ProTEK glue is unfolded, it can cover the entire surface of the wafer material sheet. The ingredients of ProTEK glue are 10% to 80% 5-methyl-2-ethanone, 10% to 80% 3-ethoxypropionate, ≤20% styrene, and 5% to 60% polymer solids. Figure 3 .

[0029] Step 5: Use spin coating to spin coat the ProTEK glue onto the front area of ​​the wafer material sheet coated with the Primer adhesive / primer, with a spin coating speed of 1000 to 3000 rpm and a spin coating time of 10s to 5min. The thickness of the ProTEK glue can be flexibly adjusted by the spin coating speed and spin coating time.

[0030] Step 6: After the coating is completed, the wafer is transferred to the hot plate for ProTEK glue curing. The hot plate temperature is 100℃~250℃(±1℃) and the baking time is 30s~60min. After curing, it is transferred to the cold plate for cooling treatment to complete the process of coating the metal material layer structure and other sensitive structures on the front of the chip with ProTEK glue. The thickness of the prepared ProTEK glue is 500nm~20μm. Figure 4 .

[0031] Embodiment 2

[0032] This embodiment provides a method for protecting the front structure of a chip during a wet etching process. The specific process flow of the process is as follows:

[0033] Step 1: Make sure the front of the wafer to be processed is clean and free of dust and impurities. Slowly and evenly pour 1-4mL or more than 30mL of Primer adhesive / primer on the center area of ​​the wafer. The Primer adhesive / primer can cover the entire surface of the wafer when it is spread. The Primer adhesive / primer is 1-methoxy-2-propanol with a concentration of 10% to 100%.

[0034] Step 2: Use spin coating process to spin coat the Primer adhesive / primer onto the front area of ​​the cleaned wafer material sheet, with a spin coating speed of 1000 to 3000 rpm and a spin coating time of 10s to 5min.

[0035] Step 3: After applying the Primer adhesive / primer, the hot plate temperature is 100℃~250℃(±1℃), and the baking time is 30s~30min; after curing, it is transferred to the cold plate for cooling. After the cooling process is completed, it will be observed that the Primer adhesive / primer coating has regional missing or defects or uneven thickness or insufficient curing and other abnormalities, which makes it impossible to continue the next ProTEK glue coating process. If the ProTEK glue coating process is continued, it will be difficult for the ProTEK glue to form a uniform and effective protective film.

[0036] Embodiment 3

[0037] This embodiment provides a method for protecting the front structure of a chip during a wet etching process. The specific process flow of the process is as follows:

[0038] Step 1: Make sure the front of the wafer to be processed is clean and free of dust and impurities. Slowly and evenly pour 5mL to 30mL of Primer adhesive / primer on the center area of ​​the wafer. The Primer adhesive / primer can cover the entire surface of the wafer when it is spread. The Primer adhesive / primer is 1-methoxy-2-propanol with a concentration of 10% to 100%.

[0039] Step 2: Use spin coating process to spin coat the Primer adhesive / primer onto the front area of ​​the cleaned wafer material sheet. The spin coating speed is less than 1000 rpm or greater than 3000 rpm, and the spin coating time is 10s to 5min.

[0040] Step 3: After applying the Primer adhesive / primer, transfer it to the hot plate for Primer adhesive / primer curing. The hot plate temperature is 100℃~250℃(±1℃) and the baking time is 30s~30min. After curing, transfer it to the cold plate for cooling. After cooling, it will be observed that the Primer adhesive / primer coating has uneven thickness, insufficient curing, regional missing, defective or other abnormal conditions, which will make it impossible to continue the next ProTEK glue coating process. If the ProTEK glue coating process is continued, it will be difficult for the ProTEK glue to form a uniform and effective protective film.

[0041] Embodiment 4

[0042] This embodiment provides a method for protecting the front structure of a chip during a wet etching process. The specific process flow of the process is as follows:

[0043] Step 1: Make sure the front of the wafer to be processed is clean and free of dust and impurities. Slowly and evenly pour 5mL to 30mL of Primer adhesive / primer on the center area of ​​the wafer. The Primer adhesive / primer can cover the entire surface of the wafer when it is spread. The Primer adhesive / primer is 1-methoxy-2-propanol with a concentration of 10% to 100%.

[0044] Step 2: Use spin coating process to spin coat the Primer adhesive / primer onto the front area of ​​the cleaned wafer material sheet, with a spin coating speed of 1000 to 3000 rpm and a spin coating time of less than 10 s or greater than 5 min.

[0045] Step 3: After applying the Primer adhesive / primer, transfer it to the hot plate for Primer adhesive / primer curing. The hot plate temperature is 100℃~250℃(±1℃) and the baking time is 30s~30min. After curing, transfer it to the cold plate for cooling. After cooling, it will be observed that the Primer adhesive / primer coating has uneven thickness or insufficient curing or defects or regional missing, which makes it impossible to continue the next ProTEK glue coating process. If the ProTEK glue coating process is continued, it will be difficult for the ProTEK glue to form a uniform and effective protective film.

[0046] Embodiment 5

[0047] This embodiment provides a method for protecting the front structure of a chip during a wet etching process. The specific process flow of the process is as follows:

[0048] Step 1: Make sure the front of the wafer to be processed is clean and free of dust and impurities. Slowly and evenly pour 5mL to 30mL of Primer adhesive / primer on the center area of ​​the wafer. The Primer adhesive / primer can cover the entire surface of the wafer when it is spread. The Primer adhesive / primer is 1-methoxy-2-propanol with a concentration of 10% to 100%.

[0049] Step 2: Use spin coating process to spin coat the Primer adhesive / primer onto the front area of ​​the cleaned wafer material sheet, with a spin coating speed of 1000 to 3000 rpm and a spin coating time of 10s to 5min.

[0050] Step 3: After applying the Primer adhesive / primer, transfer it to the hot plate for Primer adhesive / primer curing. The hot plate temperature is less than 97℃ (±1℃) or greater than 253℃ (±1℃), and the baking time is 30s to 30min. After curing, transfer it to the cold plate for cooling. After the cooling process is completed, it will be observed that the Primer adhesive / primer coating has uneven thickness or insufficient curing or defects, which makes it impossible to continue the next ProTEK glue coating process. If the ProTEK glue coating process is continued, it will be difficult for the ProTEK glue to form a uniform and effective protective film.

[0051] Embodiment 6

[0052] This embodiment provides a method for protecting the front structure of a chip during a wet etching process. The specific process flow of the process is as follows:

[0053] Step 1: Make sure the front of the wafer to be processed is clean and free of dust and impurities. Slowly and evenly pour 5mL to 30mL of Primer adhesive / primer on the center area of ​​the wafer. The Primer adhesive / primer can cover the entire surface of the wafer when it is spread. The Primer adhesive / primer is 1-methoxy-2-propanol with a concentration of 10% to 100%.

[0054] Step 2: Use spin coating process to spin coat the Primer adhesive / primer onto the front area of ​​the cleaned wafer material sheet, with a spin coating speed of 1000 to 3000 rpm and a spin coating time of 10s to 5min.

[0055] Step 3: After applying the Primer adhesive / primer, transfer it to the hot plate for Primer adhesive / primer curing. The hot plate temperature is 100℃~250℃(±1℃), and the baking time is less than 30s or more than 30min. After curing, transfer it to the cold plate for cooling. After the cooling process is completed, it will be observed that the Primer adhesive / primer coating has uneven thickness or insufficient curing or defects, which makes it impossible to continue the next ProTEK glue coating process. If the ProTEK glue coating process is continued, it will be difficult for the ProTEK glue to form a uniform and effective protective film.

[0056] Embodiment 7

[0057] This embodiment provides a method for protecting the front structure of a chip during a wet etching process. The specific process flow of the process is as follows:

[0058] Step 1: Make sure the front of the wafer to be processed is clean and free of dust and impurities. Slowly and evenly pour 5mL to 30mL of Primer adhesive / primer on the center area of ​​the wafer. The Primer adhesive / primer can cover the entire surface of the wafer when it is spread. The Primer adhesive / primer is 1-methoxy-2-propanol with a concentration of 10% to 100%.

[0059] Step 2: Use spin coating process to spin coat the Primer adhesive / primer onto the front area of ​​the cleaned wafer material sheet, with a spin coating speed of 1000 to 3000 rpm and a spin coating time of 10s to 5min.

[0060] Step 3: After the Primer adhesive / primer coating is completed, it is transferred to the hot plate for Primer adhesive / primer curing. The hot plate temperature is 100℃~250℃(±1℃), and the baking time is 30s~30min. After the curing is completed, it is transferred to the cold plate for cooling treatment to complete the Primer adhesive / primer coating process.

[0061] Step 4: Slowly and evenly pour less than 5mL or more than 30mL of etching protection generating liquid / corrosion-resistant colloid ProTEK glue on the front center area of ​​the wafer material sheet coated with Primer adhesive / primer. When ProTEK glue is unfolded, it can cover the entire surface of the wafer material sheet. The composition of ProTEK glue is 5-methyl-2-ethanone with a concentration of 10% to 80%, 3-ethoxypropionic acid ethyl ester with a concentration of 10% to 80%, styrene with a concentration of ≤20%, and polymer solids with a concentration of 5% to 60%.

[0062] Step 5: Use spin coating to spin coat the ProTEK glue onto the front area of ​​the wafer material sheet coated with the Primer adhesive / primer, with a spin coating speed of 1000 to 3000 rpm and a spin coating time of 10s to 5min. The thickness of the ProTEK glue can be flexibly adjusted by the spin coating speed and spin coating time.

[0063] Step 6: After the glue coating is completed, the wafer is transferred to the hot plate for ProTEK glue curing. The hot plate temperature is 100℃~250℃ (±1℃), and the baking time is 30s~60min. After the curing is completed, it is transferred to the cold plate for cooling. After the cooling treatment is completed, it will be observed that the ProTEK glue coating will have regional glue shortage or defects or uneven thickness or insufficient curing and other abnormal conditions. The metal material layer on the front of the chip and other sensitive structures will be exposed to the wet corrosion environment, resulting in corrosion damage, which will affect the performance and reliability of the chip.

[0064] Embodiment 8

[0065] This embodiment provides a method for protecting the front structure of a chip during a wet etching process. The specific process flow of the process is as follows:

[0066] Step 1: Make sure the front of the wafer to be processed is clean and free of dust and impurities. Slowly and evenly pour 5mL to 30mL of Primer adhesive / primer on the center area of ​​the wafer. The Primer adhesive / primer can cover the entire surface of the wafer when it is spread. The Primer adhesive / primer is 1-methoxy-2-propanol with a concentration of 10% to 100%.

[0067] Step 2: Use spin coating process to spin coat the Primer adhesive / primer onto the front area of ​​the cleaned wafer material sheet, with a spin coating speed of 1000 to 3000 rpm and a spin coating time of 10s to 5min.

[0068] Step 3: After the Primer adhesive / primer coating is completed, it is transferred to the hot plate for Primer adhesive / primer curing. The hot plate temperature is 100℃~250℃(±1℃), and the baking time is 30s~30min. After the curing is completed, it is transferred to the cold plate for cooling treatment to complete the Primer adhesive / primer coating process.

[0069] Step 4: Slowly and evenly pour 5mL to 30mL of etching protection generating liquid / corrosion-resistant colloid ProTEK glue on the front center area of ​​the wafer material sheet coated with Primer adhesive / primer. When ProTEK glue is unfolded, it can cover the entire surface of the wafer material sheet. The composition of ProTEK glue is 5-methyl-2-ethanone with a concentration of 10% to 80%, 3-ethoxypropionic acid ethyl ester with a concentration of 10% to 80%, styrene with a concentration of ≤20%, and polymer solids with a concentration of 5% to 60%.

[0070] Step 5: Use spin coating to spin coat the ProTEK glue onto the front area of ​​the wafer material sheet coated with the Primer adhesive / primer. The spin coating speed is less than 1000 rpm or 3000 rpm, and the spin coating time is 10s to 5min. The thickness of the ProTEK glue can be flexibly adjusted by the spin coating speed and spin coating time.

[0071] Step 6: After the glue coating is completed, the wafer is transferred to the hot plate for ProTEK glue curing. The hot plate temperature is 100℃~250℃ (±1℃), and the baking time is 30s~60min. After the curing is completed, it is transferred to the cold plate for cooling. After the cooling treatment is completed, it will be observed that the ProTEK glue coating will have abnormal conditions such as uneven thickness or insufficient curing or regional glue shortage or defects. The metal material layer on the front of the chip and other sensitive structures will be exposed to the wet corrosion environment, resulting in corrosion damage, which will affect the performance and reliability of the chip.

[0072] Embodiment 9

[0073] This embodiment provides a method for protecting the front structure of a chip during a wet etching process. The specific process flow of the process is as follows:

[0074] Step 1: Make sure the front of the wafer to be processed is clean and free of dust and impurities. Slowly and evenly pour 5mL to 30mL of Primer adhesive / primer on the center area of ​​the wafer. The Primer adhesive / primer can cover the entire surface of the wafer when it is spread. The Primer adhesive / primer is 1-methoxy-2-propanol with a concentration of 10% to 100%.

[0075] Step 2: Use spin coating process to spin coat the Primer adhesive / primer onto the front area of ​​the cleaned wafer material sheet, with a spin coating speed of 1000 to 3000 rpm and a spin coating time of 10s to 5min.

[0076] Step 3: After the Primer adhesive / primer coating is completed, it is transferred to the hot plate for Primer adhesive / primer curing. The hot plate temperature is 100℃~250℃(±1℃), and the baking time is 30s~30min. After the curing is completed, it is transferred to the cold plate for cooling treatment to complete the Primer adhesive / primer coating process.

[0077] Step 4: Slowly and evenly pour 5mL to 30mL of etching protection generating liquid / corrosion-resistant colloid ProTEK glue on the front center area of ​​the wafer material sheet coated with Primer adhesive / primer. When ProTEK glue is unfolded, it can cover the entire surface of the wafer material sheet. The composition of ProTEK glue is 5-methyl-2-ethanone with a concentration of 10% to 80%, 3-ethoxypropionic acid ethyl ester with a concentration of 10% to 80%, styrene with a concentration of ≤20%, and polymer solids with a concentration of 5% to 60%.

[0078] Step 5: Use spin coating to spin-coat the ProTEK glue onto the front area of ​​the wafer material sheet coated with the Primer adhesive / primer, with a spin coating speed of 1000-3000 rpm and a spin coating time of less than 10s or greater than 5min. The thickness of the ProTEK glue can be flexibly adjusted by the spin coating speed and spin coating time.

[0079] Step 6: After the glue coating is completed, the wafer is transferred to the hot plate for ProTEK glue curing. The hot plate temperature is 100℃~250℃ (±1℃), and the baking time is 30s~60min. After the curing is completed, it is transferred to the cold plate for cooling. After the cooling treatment is completed, it will be observed that the ProTEK glue coating will have abnormal conditions such as uneven thickness or insufficient curing or regional glue shortage or defects. The metal material layer on the front of the chip and other sensitive structures will be exposed to the wet corrosion environment, resulting in corrosion damage, which will affect the performance and reliability of the chip.

[0080] Embodiment 10

[0081] This embodiment provides a method for protecting the front structure of a chip during a wet etching process. The specific process flow of the process is as follows:

[0082] Step 1: Make sure the front of the wafer to be processed is clean and free of dust and impurities. Slowly and evenly pour 5mL to 30mL of Primer adhesive / primer on the center area of ​​the wafer. The Primer adhesive / primer can cover the entire surface of the wafer when it is spread. The Primer adhesive / primer is 1-methoxy-2-propanol with a concentration of 10% to 100%.

[0083] Step 2: Use spin coating process to spin coat the Primer adhesive / primer onto the front area of ​​the cleaned wafer material sheet, with a spin coating speed of 1000 to 3000 rpm and a spin coating time of 10s to 5min.

[0084] Step 3: After the Primer adhesive / primer coating is completed, it is transferred to the hot plate for Primer adhesive / primer curing. The hot plate temperature is 100℃~250℃(±1℃), and the baking time is 30s~30min. After the curing is completed, it is transferred to the cold plate for cooling treatment to complete the Primer adhesive / primer coating process.

[0085] Step 4: Slowly and evenly pour 5mL to 30mL of etching protection generating liquid / corrosion-resistant colloid ProTEK glue on the front center area of ​​the wafer material sheet coated with Primer adhesive / primer. When ProTEK glue is unfolded, it can cover the entire surface of the wafer material sheet. The composition of ProTEK glue is 5-methyl-2-ethanone with a concentration of 10% to 80%, 3-ethoxypropionic acid ethyl ester with a concentration of 10% to 80%, styrene with a concentration of ≤20%, and polymer solids with a concentration of 5% to 60%.

[0086] Step 5: Use spin coating to spin coat the ProTEK glue onto the front area of ​​the wafer material sheet coated with the Primer adhesive / primer, with a spin coating speed of 1000 to 3000 rpm and a spin coating time of 10s to 5min. The thickness of the ProTEK glue can be flexibly adjusted by the spin coating speed and spin coating time.

[0087] Step 6: After the glue coating is completed, the wafer is transferred to the hot plate for ProTEK glue curing. The hot plate temperature is less than 97℃ (±1℃) or greater than 253℃ (±1℃), and the baking time is 30s to 60min. After the curing is completed, it is transferred to the cold plate for cooling. After the cooling treatment is completed, it will be observed that the ProTEK glue coating will have abnormal conditions such as uneven thickness or insufficient curing or defects. The metal material layer on the front of the chip and other sensitive structures will be exposed to the wet corrosion environment, resulting in corrosion damage, which will affect the performance and reliability of the chip.

[0088] Embodiment 11

[0089] This embodiment provides a method for protecting the front structure of a chip during a wet etching process. The specific process flow of the process is as follows:

[0090] Step 1: Make sure the front of the wafer to be processed is clean and free of dust and impurities. Slowly and evenly pour 5mL to 30mL of Primer adhesive / primer on the center area of ​​the wafer. The Primer adhesive / primer can cover the entire surface of the wafer when it is spread. The Primer adhesive / primer is 1-methoxy-2-propanol with a concentration of 10% to 100%.

[0091] Step 2: Use spin coating process to spin coat the Primer adhesive / primer onto the front area of ​​the cleaned wafer material sheet, with a spin coating speed of 1000 to 3000 rpm and a spin coating time of 10s to 5min.

[0092] Step 3: After the Primer adhesive / primer coating is completed, it is transferred to the hot plate for Primer adhesive / primer curing. The hot plate temperature is 100℃~250℃(±1℃), and the baking time is 30s~30min. After the curing is completed, it is transferred to the cold plate for cooling treatment to complete the Primer adhesive / primer coating process.

[0093] Step 4: Slowly and evenly pour 5mL to 30mL of etching protection generating liquid / corrosion-resistant colloid ProTEK glue on the front center area of ​​the wafer material sheet coated with Primer adhesive / primer. When ProTEK glue is unfolded, it can cover the entire surface of the wafer material sheet. The composition of ProTEK glue is 5-methyl-2-ethanone with a concentration of 10% to 80%, 3-ethoxypropionic acid ethyl ester with a concentration of 10% to 80%, styrene with a concentration of ≤20%, and polymer solids with a concentration of 5% to 60%.

[0094] Step 5: Use spin coating to spin coat the ProTEK glue onto the front area of ​​the wafer material sheet coated with the Primer adhesive / primer, with a spin coating speed of 1000 to 3000 rpm and a spin coating time of 10s to 5min. The thickness of the ProTEK glue can be flexibly adjusted by the spin coating speed and spin coating time.

[0095] Step 6: After the glue coating is completed, the wafer is transferred to the hot plate for ProTEK glue curing. The hot plate temperature is 100℃~250℃ (±1℃), and the baking time is less than 30s or greater than 60min; after the curing is completed, it is transferred to the cold plate for cooling. After the cooling treatment is completed, it will be observed that the ProTEK glue coating will have abnormal conditions such as uneven thickness or insufficient curing or defects. The metal material layer on the front of the chip and other sensitive structures will be exposed to the wet corrosion environment, resulting in corrosion damage, which will affect the performance and reliability of the chip.

[0096] In summary, the protection methods described in Examples 2 to 11 are different from the process parameters of Example 1 for the coating and curing process of Primer adhesive / primer and ProTEK glue, which will make it difficult to achieve effective coating protection of the chip front metal material layer structure and other sensitive structures with ProTEK glue.

[0097] First of all, the coating of Primer adhesive / primer is a crucial step, which ensures that ProTEK glue can be evenly attached to the surface of the wafer. If the dosage, spin coating speed, spin coating time, baking temperature and baking time of Primer adhesive / primer are different from those of the present invention, the Primer adhesive / primer coating will have regional missing or defects or uneven thickness or insufficient curing and other abnormal conditions, resulting in the inability to continue the subsequent ProTEK glue coating process. If the ProTEK glue coating process is continued, it will make it difficult for ProTEK glue to form a uniform and effective protective film. In addition, the component concentration of ProTEK glue and the amount of glue, spin coating speed, spin coating time, baking temperature and baking time during the spin coating process determine the thickness and uniformity of the colloid, which directly affects its corrosion resistance and the protection of the chip surface structure. If these parameters are different from those of the present invention, the thickness of the ProTEK glue coating will be uneven or insufficiently cured or regionally lacking glue or defective. The metal material layer on the front of the chip and other sensitive structures will be exposed to the wet corrosion environment, resulting in corrosion damage, thereby affecting the performance and reliability of the chip. Therefore, only by operating according to the process method and process parameters provided by the present invention can the ProTEK glue be used to effectively coat and protect the metal material layer structure on the front side of the chip and other sensitive structures.

[0098] The coating process of the ProTEK glue in the present invention is simple, and uniform coating can be achieved by spin coating. After coating, it can be cured by low-temperature baking without complicated high-temperature process treatment. The technology of the front protection of the ProTEK glue chip of the present invention is more flexible and easy to integrate into the existing MEMS manufacturing process. The technology of the ProTEK glue proposed in the present invention to protect the metal material layer structure and other sensitive structures on the front of the chip is to first perform Primer adhesive / primer spin coating and curing process before spin coating the ProTEK glue. By adding this step of process, the high adhesion of the ProTEK glue is significantly improved, and the ProTEK glue is prevented from swelling, cracking or falling off easily after being soaked in corrosive liquid for a long time, resulting in protection failure. The technology of the ProTEK glue proposed in the present invention to protect the metal material layer structure and other sensitive structures on the front of the chip has the advantages of simple process, high chemical corrosion resistance, high adhesion, excellent process compatibility, easy coating, easy removal without residue, low stress, and significant protection effect compared to the traditional photoresist coating front protection technology, thermal oxide layer or silicon nitride layer and other dielectric layer front protection technology.

[0099] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A method for protecting the front structure of a chip during wet etching, wherein the method comprises using ProTEK glue (3) to protect the metal material layer structure and other sensitive structures on the front of the chip, characterized in that: The steps include: Step S1: Ensure that the front side of the wafer material sheet (1) to be processed is clean and free of dust and impurities; slowly and evenly pour 5 mL to 30 mL of Primer adhesive / undercoat (2) on the central area of ​​the front side of the wafer material sheet (1); Step S2: Spin-coating the Primer adhesive / primer (2) onto the front area of ​​the cleaned wafer material sheet (1) using a spin-coating process, with a spin-coating speed of 1000 to 3000 rpm and a spin-coating time of 10 s to 5 min; Step S3: After the Primer adhesive / primer (2) is applied, the Primer adhesive / primer (2) is transferred to a hot plate for curing, the hot plate temperature is 100° C. to 250° C., and the baking time is 30 seconds to 30 minutes; after the curing is completed, the Primer adhesive / primer (2) is transferred to a cold plate for cooling, and the Primer adhesive / primer (2) coating process is completed; Step S4: slowly and evenly pour 5 mL to 30 mL of etching protection generating liquid / corrosion-resistant colloid ProTEK glue (3) onto the front center area of ​​the wafer material sheet (1) coated with the Primer adhesive / primer (2), and when the ProTEK glue (3) is spread out, it covers the entire surface of the wafer material sheet (1); Step S5: Spin-coating the ProTEK glue (3) onto the front area of ​​the wafer material sheet (1) coated with the Primer adhesive / primer (2) by a spin-coating process, with a spin-coating speed of 1000 to 3000 rpm and a spin-coating time of 10 s to 5 min; Step S6: After the glue coating is completed, the wafer is transferred to a hot plate to cure the ProTEK glue (3), the hot plate temperature is 100°C to 250°C, and the baking time is 30s to 60min; after the curing is completed, it is transferred to a cold plate for cooling treatment, completing the process of coating the chip front metal material layer structure and other sensitive structures with ProTEK glue (3) for protection.

2. The chip front structure protection method according to claim 1, characterized in that: The wafer material sheet (1) is made of an ordinary single crystal silicon substrate material sheet or an SOI substrate material sheet, and the outermost layer of the front side of the wafer material sheet (1) is an irregular metal layer arranged on the passivation protection layer; therefore, when the Primer adhesive / primer (2) is spread on the metal layer, it covers the entire surface of the wafer material sheet (1), and the Primer adhesive / primer (2) is 1-methoxy-2-propanol with a concentration of 10% to 100%.

3. The chip front structure protection method according to claim 1, characterized in that: The other side of the Primer adhesive / primer (2) is provided with ProTEK glue (3), and the components of ProTEK glue (3) are 5-methyl-2-ethanone with a concentration of 10% to 80%, 3-ethoxyethyl propionate with a concentration of 10% to 80%, styrene with a concentration of ≤20%, and polymer solids with a concentration of 5% to 60%.

4. The chip front structure protection method according to claim 3, characterized in that: The thickness of the prepared ProTEK glue (3) is 500nm to 20μm.

Images