TW483100B - Method of reinforcing a low dielectric constant material layer against damage caused by a photoresist - Google Patents

Abstract

A low dielectric constant (low k) material layer is positioned on a semiconductor wafer. A first hydrogen-containing plasma treatment is performed to reinforce a surface of the low k material layer against corrosion caused by a photoresist stripper. A photoresist layer, having an opening in the photoresist layer to expose portions of the low k material layer, is then coated on the low k material layer. By dry etching the low k material layer through the opening, a pattern in the photoresist layer is transferred to the low k material layer. An ashing process with an oxygen plasma supply is then performed to ash the photoresist layer. Finally, the semiconductor wafer is dipped in a wet stripper to completely remove the photoresist layer.

Description

483100

The present invention provides a method for strengthening a low dielectric constant material layer to resist light and liquid damage, especially a method of removing hydrogen-containing plasma treatment with a hydrogen-containing plasma treatment step to resist photoresist removal with a strong dielectric constant material layer. Damage method. b. Low dielectric background. As the size of semiconductor components is shrinking and integrated circuits are increasing, the Rc delay effect (RC delay effect) between metal wires has seriously affected the operation of integrated circuits. The performance of the integrated circuit has greatly reduced the working speed of the integrated circuit. Especially when the green width of the process: 1 i n e w i d t h) drops to 0. 25 micron, or even 0. 13 micron or less, the effect of the delay effect will be more obvious. 'The Pc delay is caused by the RC delay effect generated between the metal interconnects, and the degree is the product of the resistance value (R) of the metal wire and the dielectric extension between the metal wires. It is directly proportional, so the lower resistance value can be used as the metal wire, or the parasitic capacitance of the dielectric layer between the metal wires can be reduced to reduce the RC delay effect. In terms of reducing resistance, copper connection wire technology using pure steel as the wire material (C pppp interconnect 760061111〇87) replaces traditional copper alloys (1: 010 (0.5%)) as the main 1. multilevel metallization

483100 V. Description of the invention (2) process) has become an imperative trend. Since copper itself has a lower resistivity (1.67 // Ω -cm) and can carry a higher current density without causing the problem of electro migration of a copper alloy, it can reduce the Parasitic capacitance and the number of connection layers of metal wires. However, the copper connection wire technology alone still cannot significantly reduce the RC delay effect generated between the metal wires, and there are some process problems in the copper connection wire technology that need to be resolved. Therefore, the parasitic capacitance of the dielectric layer between the metal wires is reduced by using The method to reduce the RC delay effect is increasingly important. Since the parasitic capacitance of the dielectric layer is related to the dielectric constant (k) of the dielectric layer, the lower the dielectric constant 0 of the dielectric layer, the more the parasitic capacitance formed in the dielectric layer is relatively. low. The traditional silicon dioxide has a dielectric constant of 3.9, which has gradually failed to meet the current semiconductor process requirements of less than 1.3 microns. It is based on some new low-dielectric constant materials such as polyimide (ρ ο 1 yimide (PI), FLARE TM, FPI, PAE-2, PAE-3, or LOSP and other materials have been proposed in recent years. However, although these low dielectric constant materials have a low dielectric constant value between 2. 6 ~ 3.2, these general dielectric components are hydrocarbon-based low dielectric materials, regardless of their adhesion to other materials. , The effect of the afterburner, or its various properties are significantly different from the traditional silicon dioxide, and most of them have shortcomings such as poor adhesion and insufficient thermal stability, so it is currently not possible to properly Integrate into common IC process. Lu

I Therefore, some are based on silicon dioxide and then doped with a <

Page 6 483100 V. Description of the invention (3) — Inorganic low dielectric constant dielectric layers of some hydrocarbons and other elements, for example & > HSQ (hydrogen silsesquioxane) with 2.8, MSQ with 2.7 # methyl silsesquioxane) and HOSP with a dielectric value of 5 and other materials, because of its properties and traditional dioxide dioxide / case 1 value of 2 · Therefore, it has a high degree of understanding for the current semiconductor manufacturing process < Far, optimistic about the future. D this force, and for. Month > Schematic diagrams of the first and second illustrations and the second printed version of the coincidence method. As shown in FIG. 1, a semiconductor wafer i 0 surface scoop, nine resistance two bottom 12 and a chemical vapor deposition method (chemi (^ ai) containing a silicon J deposition, CVD) or spin-coating method (spin- on) Formed on the surface of Vapor 'Low dielectric constant composed of materials such as HSQ, MSQ, or H0SP with silicon dioxide as the basic foundation 1 ^ (si〇2-based) solid

As shown in FIG. 2, the first layer 16 is in the low-k material of the photoresist layer & the electric constant material layer 1 4 and the Tsai number material layer i 4. A pattern opening 18 and a layer 14 are formed in the low dielectric constant material layer 1 1 6. Then, through the pattern opening, a light is applied on the pattern 4 in the photoresist layer 16 to expose the exposed portion 18 to a low dielectric constant after a dry period. As shown in FIG. 3, a photoresist removal process is performed. 〆a = ashing the photoresist layer 16 to make the oxygen plasma and the photoresist layer inverse, & milk = king reaction to form gaseous dioxide * gnat lice first blocking removal solution for dipping (dipping ) Semiconductor wafer 10,

Page 7 V. Description of the invention (4) The photocathode is completely removed and the layer is based on a transfer dielectric plasma to obtain a barrier liquid bond. The electrical layer has holes, however, and it does not cause damage to the etched layer when it is applied to the inorganic structure. Due to the reaction of the built-in surface on the surface of the electric layer, it depends on the dielectric constant of water and the constant dielectric constant such as Hsq. It is easy to be affected by the electric layer surface value and the high current are all produced under the condition of high current, MSQ or several materials, or with the process of 5 ^ ^ oxygen plasma surface formation up to 78, will greatly t, the removal of photoresistance composed of strict HOSP, etc. is usually a liquid barrier. Interruption, easy to absorb, so it is rising. It affects these dielectric layer processes. At the same time, the removal of light and the absorption of water and gas to absorb water and even the product's silicon dioxide will be patterned, which will use dry oxygen resistance, so After the removal of the Si-0H gas, the reliability is toxic. SUMMARY OF THE INVENTION Therefore, the main object of the present invention is to provide a material layer that resists photoresist and removes liquid damage. It is to provide a low-dielectric constant medium-low dielectric constant layer I method to solve the conventional problems. The problem of a large increase in the S charge and the leakage current In a preferred embodiment of the present invention, a layer of low dielectric constant material. First, the semiconductor wafer contains a Plasma), and a first hydrogen-containing plasma (hydrogen-ca-C. — Physical step dsma treatment) is performed to strengthen the low

* 8 pages of invention description (5) Invention description (5) 1 Dielectric constant I Photoresistance on the surface of the low dielectric constant material layer-pattern opening I via this figure | Ability to remove liquid, coating on several material layers-first resistance ;, etching ability. • Focusing on the port to expose ^! 彳 \ _ ^ S sub-layers of the photoresist layer _ formation of the opening dry ::; :: The low dielectric constant material layer. The case is then transferred to the low dielectric constant material layer to block the photoresist layer. Continue;] 3 Recycling-Oxygen step in the 3 material layer to strengthen the low dielectric constant; Finally, dip the photoresist removal solution on the surface of the material layer to completely remove the photoresist layer. The extremities of the sun and the sun are removed in a photoresist. Because of the production of the present invention, the dielectric constant of the dielectric layer is contained. Before the 14-14 etch process, the first: the surface of the electrical layer is formed-a passivation layer is used to lower the dielectric constant | 'Avoid the low dielectric constant dielectric layer; the two "dielectric constant layer is formed from the low dielectric constant +1 人, and at the same time effectively prevent the resulting low dielectric constant dielectric + & gt In the layer, the problem of the conventional manufacturing process is completely solved. "The dielectric constant and leakage current of the layer are both large and the detailed description of the invention. Please refer to Figures 4 to 8. Figures 4 and 5 show the same material layer resistance. Photoresist removal of liquid loss * = J = = reinforced low dielectric-the semiconductor wafer 40 contains a sand ^ ^ map. Figure 4 shows the bottom 4 2 and the use of chemical gas $ 9 page 483100 V. Description of the invention (6)

Phase vapor deposition (CVD) or spin coating (spi η-ο η) was formed on the surface of Shixi substrate 4 2 with dielectric constants of 2. 8 and 2. Ίλ 2.5- ^ HSQ (hydrogen silsesquioxane ), MSQ (methyl si1sesquioxane), or HOSP (hybrid-organic-si loxane-polymer) and other low-dielectric-constant material layers 44 with silicon dioxide as the basic structure (Si 〇2-based), as shown in Figure 5. As shown in the figure, first, the temperature of the main dbUC and the pressure of νυ to 3 5 0¾ Torr (m Torr) are used, with a flow rate of 2000 to 350 standard cubic denominator minutes. cubic centimeter's per minute (sccm) of hydrogen, and a hydrogen-containing plasma formed by a wireless packet power of 90 to 150 watts (Watts), and a first hydrogen-containing plasma treatment step (hydrogen —Containing plasma = r = atm, nt) 46 for more than 1 minute. Since the low dielectric constant dielectric layer ^ gas-bearing stone will be i, the surface of the low dielectric constant dielectric layer 44 will form a passivation layer 48 corresponding to the Ϊ i 仃 to strengthen the low dielectric constant. The ability of the surface to resist photo-resistance to remove the liquid, effectively prevent water ^ # The dielectric constant of the layer surface can be used to extend the resistance? 〇 t t *, the low-dielectric constant material layer 44 is coated with an optical-number material layer 44. Then, as shown in Figure 7,

483100 V. Description of the invention (7) The pattern opening 52 in the photoresist layer 50 is dry-etched and transferred to the low-dielectric-constant material layer 44 by dry etching. For example, the ashing photoreactive type I slurry treatment 1 photoresist removes I liquid, and uses 500 to absorb the dielectric constant I of 4 4 as shown in FIG. 8, and performs a photoresist to remove the resist layer 50 to make oxygen electricity. Plasma and photoresist chip ^ first use an oxygen plasma to form gaseous carbon dioxide and water steam ^, the complete steps of carbon and hydrogen elements to further strengthen the low dielectric = to carry out a second hydrogen-containing electrolyte removal ability. Finally, the surface resistance of the ACT $ material layer 44 is dipped to remove the semiconductor wafer 5 as a photoresist on the surface of the low-k dielectric layer 44 and the right of the photoresist layer is removed. 44 is not easy to remove F and the process is affected by the low water vapor S i -0H bond, so it is effective $ # / > 成 会 大 ^ ^ Avoid low dielectric constant dielectric constant and leakage A sharp rise in current. The number of packets " Hong layer refers to Figure 9, which is the infrared spectroscopy obtained by HSQ under different hydrogen plasma treatment times. As shown in Figure 9, curves A and B respectively represent the η s Q dielectric layers that have not been treated by the method of the present invention. | Infrared spectra before and after the photoresist removal process. Curves C, d, and E are HSQ dielectric layers. First, the method of the present invention is used to perform the hydrogen-containing elenium treatment steps for 3, 6, and 9 minutes, respectively, and then the infrared-ray spectrum obtained after the photoresist removal process is performed. Among them, the absorption peak 1 and the absorption peak 2 respectively represent the absorption peaks of the si-Η and Si-Ο 'bonds, and the absorption positions thereof are in the wavelength ranges of 22 ° to 230 ° cm and 30000 to 3500cnr, respectively. . 483100 V. Description of the invention (8) After comparing the curves A and B, it can be known that after the photoresist removal process of the HSQ dielectric layer, the absorption peak 1 of the Si-Η bond originally located in the HSQ dielectric layer disappears, and appears. Absorptive peak 2 of the Si-0H bond, which did not exist originally, proves that the hydrogen-containing plasma and the wet type photoresist solution obviously cause damage to the surface structure of the dielectric layer. From the curves C, D, and E, it can be seen that the absorption peak 1 of the HSQ dielectric layer that has undergone the hydrogen-containing plasma treatment step still exists and does not generate an absorption peak 2. The hydrogen-containing plasma treatment step can successfully prevent S i -The Η key is interrupted to avoid the formation of the Si-0 Η key. In addition, the absorptivity of the absorption peak 1 of the Si-Η bond significantly decreases with the increase of the processing time of the hydrogen-containing plasma treatment step. Therefore, it is recommended that the plasma treatment time be controlled within 20 minutes to avoid the excessive processing time. If it grows, the Si-Η functional group on the dielectric layer is damaged. 4 Please refer to Figure 10 and Figure 11. Figure 10 and Figure 11 show the effects of hydrogen-containing plasma processing time on the dielectric constant and leakage current of the HSQ dielectric layer. As shown in Fig. 10, the dielectric constant of the HSQ dielectric layer subjected to the hydrogen-containing plasma treatment step for 3, 6, or 9 minutes is lower than that of the HSQ dielectric layer without the hydrogen-containing plasma treatment step. And after the hydrogen-containing plasma treatment step is performed for more than 3 minutes, the dielectric constant of the HSQ dielectric layer can be maintained at about 3, so increasing the time of the hydrogen-containing plasma treatment does not affect the value of the dielectric constant. As shown in Figure 11, the square, regular triangle ▲, and inverted triangle ▼ represent the electric field and leakage in the HSQ dielectric layer after the photoresist removal process after 3, 6, and 9 minutes of hydrogen-containing plasma treatment. The relationship curve of electric current, and the circular type represents the relationship curve of electric field and leakage current in the HSQ dielectric layer that has undergone the photoresist removal process without hydrogen plasma treatment. As shown in Figure 11, compared with

Page 12 483100 V. Description of the invention (9) The leakage current of the HSQ dielectric layer of the plasma treatment step of the dielectric layer can be greatly reduced by 2 to 3 stages, and the hydrogen-containing electricity can be increased. The time of pulp treatment will not significantly affect the magnitude of leakage current. Therefore, in the preferred embodiment of the present invention, the time for performing the hydrogen-containing plasma treatment step is about 3 minutes. Compared with the conventional technology, the present invention performs a hydrogen-containing plasma treatment step on the low-k dielectric layer 44 before performing the I-etching process to form a passivation on the surface of the low-k dielectric layer 44. Layer 48, so that in the subsequent photoresist removal process, the contact between the oxygen plasma and the photoresist removing solution and the low dielectric constant dielectric layer 44 can be reduced, thereby avoiding damage to the low dielectric constant dielectric layer 44. . In addition, the method of the present invention can more effectively prevent Si-0Η bonds from being formed in the low dielectric constant dielectric layer 44, so it can solve both the dielectric constant and leakage current of the low dielectric constant dielectric layer caused by the conventional manufacturing process. Significantly increased problems. -The above are only the preferred embodiments of the present invention, and any equivalent changes and modifications made in accordance with the scope of the patent application for the present invention shall fall within the scope of the patent of the present invention.

Page 13 483100 Simple illustration of the diagrams Simple illustration of the diagrams Figures 1-3 are schematic diagrams of conventional methods for removing photoresist. FIG. 4 to FIG. 8 are schematic diagrams of the method for strengthening the low-dielectric-constant material layer of the present invention to resist photoresist removal liquid damage. Figure 9 shows the infrared spectrum obtained by HSQ under different hydrogen plasma treatment times. Figure 10 shows the effect of the treatment time of the hydrogen-containing plasma on the dielectric constant of the HSQ dielectric layer. Figure 11 shows the effect of hydrogen plasma treatment time on the leakage current of the HSQ dielectric layer. Explanation of symbols in the figure 10 semiconductor wafer 12 silicon substrate 14 low dielectric constant material layer 16 photoresist layer 18 pattern opening 40 semiconductor wafer 42 silicon substrate 44 low dielectric constant material layer 46 first hydrogen-containing plasma processing step 48 passivation layer 50 photoresist layer 52 pattern opening α

Page 14

Claims (1)

4δΜυιι 1. A method for strengthening damage of a low dielectric constant (stripper), providing a semiconductor wafer, a layer; (low-k) material layer resisting photoresist removal liquid, the method includes the following steps: a low dielectric constant material is included thereon Order a first hydrogen-containing plasma treatment step (hydrogen — ⑶ plssma iv taining 41 .. strengthen the abundance of the low-dielectric constant material layer and resist the resistance of the first-removal removal liquid; 1 'surface on the low-dielectric A photoresist layer is coated on the electric constant material layer; an R ampere q W dielectric constant material layer is formed in the 4 photoresist layer; the pattern is exposed to the low part of the chromium # 阳 ί i the pattern opening is dry-etched The low-dielectric constant material | to transfer the solution in the first-resistance layer to the low-dielectric-constant material layer; the = ashing the photoresist layer with an oxygen plasma; and-into ^ = (( (11 叩 1112) The semiconductor wafer is removed in a photoresist removal solution to remove the photoresist layer in a whole method. In this method, the low dielectric constant (S i 0 2-based) low dielectric constant material 2 · If the first layer of the patent application is a silicon dioxide structure layer 0 3 For example, the method of claim 1 in the patent scope, wherein the low dielectric constant layer is composed of one of the following materials: HSQ (hydrogeri si 1 sesquioxane) " MSQ (methyl si 1 sesquioxane) > ^ HOSP (hybrid-organic-siloxane-polymer) o I I I I 483100 6. Scope of patent application 4. The method of the first scope of patent application, wherein the first hydrogen-containing plasma treatment step uses a hydrogen plasma. 5. The method according to item 4 of the patent application, wherein the radio power for forming the hydrogen plasma is 90 to 150 Watts. 6. The method according to item 4 of the patent application, wherein the hydrogen flow rate for forming the hydrogen plasma is from 2000 to 350 standard cubic centimeters per minute, seem. 7. The method according to item 4 of the patent application, wherein the hydrogen plasma is formed at a temperature of 200 to 3 5 (TC. 8. The method according to item 4 of the patent application, wherein the pressure of the hydrogen plasma is formed. It is from 20 to 350 millitorr (mTorr). Among them, the first hydrogen-containing plasma II 9. If the method of the first scope of the patent application, the processing step of the method needs to be performed for at least 1 minute. The method of item 1, wherein the photoresist removal liquid is ACT-935. 1 1. The method of item 1 in the scope of patent application, wherein the oxygen power is used 1" Page 16 483100 Wide, patent application scope. After ashing the photoresist layer, before the second and fifth layers, the method also includes 3 people to completely remove this with the 5 resist removal solution: to further strengthen the second. Hydrogen-containing plasma treatment to remove liquid erosion ability. The surface of the low dielectric constant material layer resists photoresistance. 12.- layer resists lift-up; the dielectric is often passed through the photoresist layer to immerse the photoresist layer on the surface once. To remove the damaged conductive wafer, the low-resistance photoresistance material is removed from the electric constant material layer in the figure; the case is dried; the insect case is transferred to the semiconductor wafer for ashing with an oxygen plasma; and The semiconducting hydrogen-containing photoresist destructuring (S i 〇2- 2-based) low-dielectric-constant material method includes the following steps: ': It includes a low-dielectric-constant material. A light is coated on the layer A resist layer; a pattern opening to expose a part of the low-body wafer and performing a slurry processing step to remove the liquid and etch away the low dielectric constant material layer and the low dielectric constant material layer; the photoresist layer; a photoresist removal liquid In order to completely remove the photoresist removal solution before immersion, perform at least to strengthen the force of the low dielectric constant material layer. Electrical constant material layer It is composed of one of the following materials: kg = hydrogen silsesquioxane-MSQ (methyl 483100 VI, patent application scope si 1 sesquioxane), or HOSP (hybrid-organic-siloxane-polymer) 〇4. The method according to item 12, wherein the hydrogen-containing plasma treatment step uses a nitrogen plasma. 15. The method according to item 14 of the scope of patent application, wherein the radio power for forming the hydrogen plasma is 90 to 150 Watts. 16. The method according to item 14 of the scope of patent application, wherein the hydrogen flow rate for forming the hydrogen plasma is from 200 to 350 standard cubic centimeters per minute, seem. 17. The method according to item 14 of the scope of patent application, wherein the temperature at which the hydrogen plasma is formed is from 200 to 350 ° C. 18. The method according to item 14 of the scope of patent application, wherein the pressure for forming the hydrogen plasma is 200 to 350 millitorr (mTorr). 19. The method according to item 12 of the patent application range, wherein the photoresist removal liquid is ACT-935. 20. The method according to item 12 of the patent application range, wherein the hydrogen-containing plasma treatment step is performed before coating the photoresist layer. Page 18