A method for reusing defective wafers after packaging

Abstract

The present invention relates to a method for reusing defective wafers after packaging, the method comprising sequentially stripping copper-nickel-tin-silver metal layers, titanium seed layers, PI insulating layers and RDL metal layers; wherein the PI insulating layer stripping comprises sequentially performing first dry degumming, second dry degumming, third dry degumming and fourth dry degumming; the time of the first dry degumming and the time of the fourth dry degumming are both shorter than the time of the second dry degumming or the time of the third dry degumming. The wafer scrapping due to low yield is avoided, and the utilization rate of the wafer is improved.

Description

Technical Field

[0001] The invention relates to the field of wafer applications, and in particular to a method for reusing defective wafers after packaging. Background Art

[0002] At present, with the rapid development of the information age, the application of high-end chips is closely related to our lives. Wafer-level packaging, as a key link in chip manufacturing, directly determines the cost and quality of chip manufacturing.

[0003] For example, CN106876333A discloses a method for preparing a wafer-level packaging structure and a wafer-level packaging structure, wherein the method for preparing a wafer-level packaging structure includes: providing a first wafer with multiple chips integrated therein, wherein the first wafer includes a front side with multiple bumps and a back side relative to the front side, wherein the bumps are electrically connected to the corresponding chips; temporarily bonding the first wafer; etching the first wafer at a set position along the cutting path on the back side of the first wafer, and etching at least to the bonding interface; and debonding the first wafer to form a single chip. This solution can reduce the requirements for the cutting path size and increase the number of effective chips on the wafer.

[0004] CN112382629A discloses a stacked wafer structure and a packaging method thereof, belonging to the field of semiconductor chip packaging technology. It includes a wafer stack, a carrier wafer, and an electrical connection layer. The wafer stack is arranged above the carrier wafer and connected through the electrical connection layer. The wafer stack includes several layers of functional wafers. From bottom to top, the wafer size gradually decreases, and a stepped sidewall is formed around it. Above the carrier wafer, the front of the wafer stack and its stepped sidewall are coated with a dielectric layer III and a dielectric layer III opening is formed. A metal seed layer and a metal bump are arranged inside the dielectric layer III opening, and the metal bump is connected to the metal interconnection layer of the adjacent wafer through the metal seed layer. During the manufacturing process, the edge and thickness of the stacked wafer are constrained to form a specific morphology to ensure that the edge morphology during the bump manufacturing process will not affect the bump manufacturing process.

[0005] As mentioned above, the birth of a chip goes through thousands of processes such as EDA design, wafer manufacturing, wafer packaging, and wafer testing, and wafer packaging has reached the back-end. The front-end has invested a lot of cost in the wafer, and the back-end packaging is approaching the end of chip manufacturing. At this time, the yield loss and wafer scrapping will cause serious economic losses. The current yield rate is mainly guaranteed by controlling the accuracy of the processing process, but there is still a problem that the wafer cannot be reused after being scrapped. Summary of the invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for reusing defective wafers after packaging, thereby avoiding the scrapping of wafers due to too low a yield and improving the utilization rate of wafers.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for reusing defective wafers after packaging, the method comprising sequentially performing copper-nickel-tin-silver metal layer stripping, titanium seed layer stripping, PI insulation layer stripping and RDL metal layer stripping;

[0009] The PI insulating layer stripping includes a first dry debonding, a second dry debonding, a third dry debonding and a fourth dry debonding performed sequentially;

[0010] The first dry degumming time and the fourth dry degumming time are both shorter than the second dry degumming time or the third dry degumming time.

[0011] The reuse method provided by the present invention can restore the packaged defective wafer to the state before packaging by stripping the metal layer and the insulating layer, thereby improving the fault tolerance of the wafer in the packaging process and avoiding the wafer being scrapped due to too low a yield. The wafer can be reused and repackaged to avoid the economic losses caused by too low a wafer yield and the wafer being scrapped.

[0012] In the present invention, the RDL metal layer refers to a rewiring metal layer.

[0013] As a preferred technical solution of the present invention, the power of the microwave in the first dry degumming method is 800-900 W, for example, it can be 800 W, 805 W, 810 W, 815 W, 820 W, 825 W, 830 W, 835 W, 840 W, 845 W, 850 W, 855 W, 860 W, 865 W, 870 W, 875 W, 880 W, 885 W, 890 W, 895 W or 900 W, but is not limited to the listed values, and other values ​​not listed within the range are equally applicable.

[0014] Preferably, the flow rate of oxygen in the first dry degumming process is 800-900sccm, for example, it can be 800sccm, 805sccm, 810sccm, 815sccm, 820sccm, 825sccm, 830sccm, 835sccm, 840sccm, 845sccm, 850sccm, 855sccm, 860sccm, 865sccm, 870sccm, 875sccm, 880sccm, 885sccm, 890sccm, 895sccm or 900sccm, etc., but is not limited to the listed values, and other unlisted values ​​within the range are equally applicable.

[0015] Preferably, the CF in the first dry degumming process 4 The flow rate is 120-130sccm, for example, it can be 120sccm, 120.5sccm, 121sccm, 121.5sccm, 122sccm, 122.5sccm, 123sccm, 123.5sccm, 124sccm, 124.5sccm, 125sccm, 125.5sccm, 126sccm, 126.5sccm, 127sccm, 127.5sccm, 128sccm, 128.5sccm, 129sccm, 129.5sccm or 130sccm, but it is not limited to the listed values, and other values ​​not listed in the range are also applicable.

[0016] Preferably, the time for the first dry degumming process is 10-20s, for example, it can be 10s, 10.5s, 11s, 11.5s, 12s, 12.5s, 13s, 13.5s, 14s, 14.5s, 15s, 15.5s, 16s, 16.5s, 17s, 17.5s, 18s, 18.5s, 19s, 19.5s or 20s, etc., but is not limited to the listed values, and other values ​​not listed in the range are also applicable.

[0017] As a preferred technical solution of the present invention, the power of the microwave in the second dry degumming method is 1200-1300 W, for example, it can be 1200 W, 1205 W, 1210 W, 1215 W, 1220 W, 1225 W, 1230 W, 1235 W, 1240 W, 1245 W, 1250 W, 1255 W, 1260 W, 1265 W, 1270 W, 1275 W, 1280 W, 1285 W, 1290 W, 1295 W or 1300 W, but is not limited to the listed values, and other unlisted values ​​within the range are equally applicable.

[0018] Preferably, the power of the radio frequency in the second dry degumming method is 600-700W, for example, it can be 600W, 610W, 620W, 630W, 640W, 650W, 660W, 670W, 680W, 690W or 700W, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0019] Preferably, the flow rate of oxygen in the second dry degumming process is 800-900sccm, for example, it can be 800sccm, 805sccm, 810sccm, 815sccm, 820sccm, 825sccm, 830sccm, 835sccm, 840sccm, 845sccm, 850sccm, 855sccm, 860sccm, 865sccm, 870sccm, 875sccm, 880sccm, 885sccm, 890sccm, 895sccm or 900sccm, etc., but is not limited to the listed values, and other unlisted values ​​within the range are equally applicable.

[0020] Preferably, the CF in the second dry degumming process 4 The flow rate is 120-130sccm, for example, it can be 120sccm, 120.5sccm, 121sccm, 121.5sccm, 122sccm, 122.5sccm, 123sccm, 123.5sccm, 124sccm, 124.5sccm, 125sccm, 125.5sccm, 126sccm, 126.5sccm, 127sccm, 127.5sccm, 128sccm, 128.5sccm, 129sccm, 129.5sccm or 130sccm, but it is not limited to the listed values, and other values ​​not listed in the range are also applicable.

[0021] Preferably, the time for the second dry method for degumming is 80-160s, for example, it can be 80s, 82s, 84s, 86s, 88s, 90s, 92s, 94s, 96s, 98s, 100s, 102s, 104s, 106s, 108s, 110s, 112s, 114s, 116s, 118s, 120s, 122s, 124s, 126s, 128s, 130s, 132s, 134s, 136s, 138s, 140s, 142s, 144s, 146s, 148s, 150s, 152s, 154s, 156s, 158s or 160s, etc., but is not limited to the listed values, and other values ​​not listed in the range are equally applicable.

[0022] As a preferred technical solution of the present invention, the power of the microwave in the third dry method for degumming is 700-800 W, for example, it can be 700 W, 710 W, 720 W, 730 W, 740 W, 750 W, 760 W, 770 W, 780 W, 790 W or 800 W, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0023] Preferably, the power of the radio frequency in the third dry method for degumming is 300-400 W, for example, it can be 300 W, 310 W, 320 W, 330 W, 340 W, 350 W, 360 W, 370 W, 380 W, 390 W or 400 W, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0024] Preferably, the flow rate of oxygen in the third dry degumming process is 700-800sccm, for example, it can be 700sccm, 710sccm, 720sccm, 730sccm, 740sccm, 750sccm, 760sccm, 770sccm, 780sccm, 790sccm or 800sccm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0025] Preferably, the CF 4 The flow rate is 120-130sccm, for example, it can be 120sccm, 121sccm, 122sccm, 123sccm, 124sccm, 125sccm, 126sccm, 127sccm, 128sccm, 129sccm or 130sccm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0026] Preferably, the time for the third dry method for degumming is 60-120s, for example, it can be 60s, 62s, 64s, 66s, 68s, 70s, 72s, 74s, 76s, 78s, 80s, 82s, 84s, 86s, 88s, 90s, 92s, 94s, 96s, 98s, 100s, 102s, 104s, 106s, 108s, 110s, 112s, 114s, 116s, 118s or 120s, etc., but is not limited to the listed values, and other values ​​not listed in the range are also applicable.

[0027] As a preferred technical solution of the present invention, the power of the microwave in the fourth dry method for degumming is 800-900W800-900W, for example, it can be 800W, 805W, 810W, 815W, 820W, 825W, 830W, 835W, 840W, 845W, 850W, 855W, 860W, 865W, 870W, 875W, 880W, 885W, 890W, 895W or 900W, but is not limited to the listed values, and other unlisted values ​​within the range are equally applicable.

[0028] Preferably, the power of the radio frequency in the fourth dry method for degumming is 290-310W, for example, it can be 290W, 291W, 292W, 293W, 294W, 295W, 296W, 297W, 298W, 299W, 300W, 301W, 302W, 303W, 304W, 305W, 306W, 307W, 308W, 309W or 310W, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0029] Preferably, the gas used in the fourth dry degumming method is a mixture of hydrogen and nitrogen, and hydrogen accounts for 3-4% of the volume of the mixed gas, for example, it can be 3%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9% or 4%, etc., but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0030] Preferably, the flow rate of the mixed gas is 1200-1300sccm, for example, it can be 1200sccm, 1205sccm, 1210sccm, 1215sccm, 1220sccm, 1225sccm, 1230sccm, 1235sccm, 1240sccm, 1245sccm, 1250sccm, 1255sccm, 1260sccm, 1265sccm, 1270sccm, 1275sccm, 1280sccm, 1285sccm, 1290sccm, 1295sccm or 1300sccm, but is not limited to the listed values, and other values ​​not listed in the range are also applicable.

[0031] Preferably, the fourth dry method for degumming is performed for 20-40 seconds, for example, it may be 20 seconds, 21 seconds, 22 seconds, 23 seconds, 24 seconds, 25 seconds, 26 seconds, 27 seconds, 28 seconds, 29 seconds, 30 seconds, 31 seconds, 32 seconds, 33 seconds, 34 seconds, 35 seconds, 36 seconds, 37 seconds, 38 seconds, 39 seconds or 40 seconds, but is not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0032] As a preferred technical solution of the present invention, the copper-nickel-tin-silver metal layer stripping includes immersion treatment with etching solution A.

[0033] Preferably, the immersion treatment time is 5-10 min, for example, it can be 5 min, 5.2 min, 5.4 min, 5.6 min, 5.8 min, 6 min, 6.2 min, 6.4 min, 6.6 min, 6.8 min, 7 min, 7.2 min, 7.4 min, 7.6 min, 7.8 min, 8 min, 8.2 min, 8.4 min, 8.6 min, 8.8 min, 9 min, 9.2 min, 9.4 min, 9.6 min, 9.8 min or 10 min, etc., but is not limited to the listed values, and other values ​​not listed in the range are also applicable.

[0034] Preferably, the etching solution A includes NI636E copper-nickel etching solution or REC-901 copper-nickel etching solution.

[0035] As a preferred technical solution of the present invention, the titanium seed layer stripping includes stripping using a wet etcher.

[0036] Preferably, the flow rate of the etching solution in the stripping of the titanium seed layer is 1.5-2L / min, for example, it can be 1.5L / min, 1.52L / min, 1.54L / min, 1.56L / min, 1.58L / min, 1.6L / min, 1.62L / min, 1.64L / min, 1.66L / min, 1.68L / min, 1.7L / min, 1.72L / min, 1.74L / min, 1.76L / min, 1.78L / min, 1.8L / min, 1.82L / min, 1.84L / min, 1.86L / min, 1.88L / min, 1.9L / min, 1.92L / min, 1.94L / min, 1.96L / min, 1.98L / min or 2L / min, but is not limited to the listed values, and other values ​​not listed in the range are also applicable.

[0037] Preferably, the number of etching swing arms in the titanium seed layer stripping is 36-72 times, for example, it can be 36 times, 37 times, 38 times, 39 times, 40 times, 41 times, 42 times, 43 times, 44 times, 45 times, 46 times, 47 times, 48 ​​times, 49 times, 50 times, 51 times, 52 times, 53 times, 54 times, 55 times, 56 times, 57 times, 58 times, 59 times, 60 times, 61 times, 62 times, 63 times, 64 times, 65 times, 66 times, 67 times, 68 times, 69 times, 70 times, 71 times or 72 times, etc., but is not limited to the listed values, and other values ​​not listed in this range are also applicable.

[0038] Preferably, the etching solution used in stripping the titanium seed layer includes one of GCT ETI 300 titanium etching solution, CZ703 titanium etching solution or KS6506 titanium etching solution.

[0039] Preferably, the rotation speed of the wafer during the titanium seed layer stripping is 400-600r / min, for example, it can be 400r / min, 410r / min, 420r / min, 430r / min, 440r / min, 450r / min, 460r / min, 470r / min, 480r / min, 490r / min, 500r / min, 510r / min, 520r / min, 530r / min, 540r / min, 550r / min, 560r / min, 570r / min, 580r / min, 590r / min or 600r / min, but is not limited to the listed values, and other values ​​not listed in the range are also applicable.

[0040] As a preferred technical solution of the present invention, the RDL metal layer stripping includes RDL copper layer stripping and / or RDL titanium layer stripping.

[0041] In the present invention, the stripping of the titanium layer in the RDL metal layer is additionally provided for some wafers using through silicon vias. If the targeted wafer does not have a through silicon via structure, the RDL titanium layer stripping is not required at this time.

[0042] In the present invention, when the RDL metal layer stripping includes RDL copper layer stripping and RDL titanium layer stripping, the RDL copper layer stripping is performed first, and then the RDL titanium layer stripping is performed.

[0043] As a preferred technical solution of the present invention, the RDL copper layer stripping includes immersion stripping using etching solution B for 5-10 minutes, for example, it can be 5 minutes, 5.2 minutes, 5.4 minutes, 5.6 minutes, 5.8 minutes, 6 minutes, 6.2 minutes, 6.4 minutes, 6.6 minutes, 6.8 minutes, 7 minutes, 7.2 minutes, 7.4 minutes, 7.6 minutes, 7.8 minutes, 8 minutes, 8.2 minutes, 8.4 minutes, 8.6 minutes, 8.8 minutes, 9 minutes, 9.2 minutes, 9.4 minutes, 9.6 minutes, 9.8 minutes or 10 minutes, etc., but are not limited to the listed values, and other values ​​not listed within the range are also applicable.

[0044] Preferably, the etching solution B includes one of GCT ECU 314 copper etching solution, CU-129 copper etching solution or KS6205 copper etching solution.

[0045] Preferably, the RDL titanium layer stripping includes stripping using a wet etcher.

[0046] Preferably, the flow rate of the etching solution in the RDL titanium layer stripping is 1.5-1.8 L / min, for example, it can be 1.5 L / min, 1.52 L / min, 1.54 L / min, 1.56 L / min, 1.58 L / min, 1.6 L / min, 1.62 L / min, 1.64 L / min, 1.66 L / min, 1.68 L / min, 1.7 L / min, 1.72 L / min, 1.74 L / min, 1.76 L / min, 1.78 L / min or 1.8 L / min, etc., but is not limited to the listed values, and other values ​​not listed in the range are also applicable.

[0047] Preferably, the number of etching swing arms in the RDL titanium layer stripping is 40-72 times, for example, it can be 40 times, 41 times, 42 times, 43 times, 44 times, 45 times, 46 times, 47 times, 48 ​​times, 49 times, 50 times, 51 times, 52 times, 53 times, 54 times, 55 times, 56 times, 57 times, 58 times, 59 times, 60 times, 61 times, 62 times, 63 times, 64 times, 65 times, 66 times, 67 times, 68 times, 69 times, 70 times, 71 times or 72 times, etc., but is not limited to the listed values, and other values ​​not listed in this range are also applicable.

[0048] Preferably, the etching solution used in stripping the RDL titanium layer includes one of GCT ETI 300 titanium etching solution, CZ703 titanium etching solution or KS6506 titanium etching solution.

[0049] Preferably, the rotation speed of the wafer during the RDL titanium layer stripping is 400-600r / min, for example, it can be 400r / min, 410r / min, 420r / min, 430r / min, 440r / min, 450r / min, 460r / min, 470r / min, 480r / min, 490r / min, 500r / min, 510r / min, 520r / min, 530r / min, 540r / min, 550r / min, 560r / min, 570r / min, 580r / min, 590r / min or 600r / min, etc., but is not limited to the listed values, and other values ​​not listed in this range are also applicable.

[0050] In the present invention, after the stripping is completed, the wafer may be subjected to surface processing, such as polishing, in order to further meet the utilization of the wafer.

[0051] As a preferred technical solution of the present invention, the reuse method includes sequentially performing copper-nickel-tin-silver metal layer stripping, titanium seed layer stripping, PI insulation layer stripping and RDL metal layer stripping;

[0052] Wherein, the copper-nickel-tin-silver metal layer stripping includes immersing in an etching solution A for 5-10 minutes, and the etching solution A includes NI636E copper-nickel etching solution or REC-901 copper-nickel etching solution;

[0053] The titanium seed layer stripping includes stripping by using a wet etching machine, the flow rate of the etching solution is 1.5-2L / min, the number of etching swing arms is 36-72 times, the etching solution used includes one of GCT ETI 300 titanium etching solution, CZ703 titanium etching solution or KS6506 titanium etching solution, and the rotation speed of the wafer is 400-600r / min;

[0054] The PI insulating layer stripping includes a first dry debonding, a second dry debonding, a third dry debonding and a fourth dry debonding performed in sequence; the time of the first dry debonding and the time of the fourth dry debonding are both shorter than the time of the second dry debonding or the time of the third dry debonding;

[0055] The power of the microwave in the first dry degumming process is 800-900W, CF 4 The flow rate is 120-130sccm and the time is 10-20s;

[0056] In the second dry debonding method, the microwave power is 1200-1300W, the radio frequency power is 600-700W, the oxygen flow rate is 800-900sccm, and the CF 4 The flow rate is 120-130sccm and the time is 80-160s;

[0057] In the third dry debonding method, the microwave power is 700-800W, the radio frequency power is 300-400W, the oxygen flow rate is 700-800sccm, and the CF 4 The flow rate is 120-130sccm and the time is 60-120s;

[0058] In the fourth dry debonding method, the microwave power is 800-900W, the radio frequency power is 290-310W, the gas used is a mixed gas of hydrogen and nitrogen, the hydrogen accounts for 3-4% of the volume of the mixed gas, the flow rate of the mixed gas is 1200-1300sccm, and the time is 20-40s;

[0059] The RDL metal layer stripping includes RDL copper layer stripping and / or RDL titanium layer stripping; the RDL copper layer stripping includes immersion stripping for 5-10 minutes using etching solution B, and etching solution B includes one of GCT ECU 314 copper etching solution, CU-129 copper etching solution or KS6205 copper etching solution; the RDL titanium layer stripping includes stripping using a wet etcher, the etching solution flow rate is 1.5-1.8L / min, the etching arm swing times are 40-72 times, the etching solution used includes one of GCT ETI 300 titanium etching solution, CZ703 titanium etching solution or KS6506 titanium etching solution, and the wafer rotation speed is 400-600r / min.

[0060] Compared with the prior art solutions, the present invention has the following beneficial effects:

[0061] The reuse method provided by the present application can return the wafer to the state before packaging by stripping the metal layer and the insulating layer, thereby improving the fault tolerance of the wafer during the packaging process. Since the cost of wafers is relatively high, this method can reuse the wafers and avoid the scrapping of wafers due to low yield. Through the existing equipment capabilities, the packaging pattern on the surface of the wafer can be stripped and removed, and the wafer can be reused and repackaged to avoid the economic losses caused by low wafer yield and wafer scrapping. It also has the advantages of simple process, strong processability, and can return the wafer to the state before packaging, thereby correcting the wafer packaging defects. DETAILED DESCRIPTION

[0062] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0063] Example 1

[0064] This embodiment provides a method for reusing defective wafers after packaging, the method comprising sequentially performing copper-nickel-tin-silver metal layer stripping, titanium seed layer stripping, PI insulation layer stripping and RDL metal layer stripping;

[0065] The copper-nickel-tin-silver metal layer stripping includes immersing in an etching solution A for 7 minutes, and the etching solution A is NI636E copper-nickel etching solution;

[0066] The titanium seed layer stripping includes stripping by using a wet etcher, the flow rate of the etching solution is 1.7 L / min, the number of etching swing arms is 56 times, the etching solution used is GCT ETI 300 titanium etching solution, and the rotation speed of the wafer is 500 r / min;

[0067] The PI insulating layer stripping includes a first dry debonding, a second dry debonding, a third dry debonding and a fourth dry debonding performed in sequence; the time of the first dry debonding and the time of the fourth dry debonding are both shorter than the time of the second dry debonding or the time of the third dry debonding;

[0068] The power of the microwave in the first dry degumming process is 850W, CF 4 The flow rate is 125sccm and the time is 15s;

[0069] In the second dry debonding method, the microwave power is 1250W, the radio frequency power is 650W, the oxygen flow rate is 850sccm, and the CF 4 The flow rate is 126sccm and the time is 120s;

[0070] In the third dry debonding method, the microwave power is 750W, the radio frequency power is 350W, the oxygen flow rate is 750sccm, and the CF 4 The flow rate is 124sccm and the time is 90s;

[0071] In the fourth dry debonding method, the microwave power is 850W, the radio frequency power is 300W, the gas used is a mixed gas of hydrogen and nitrogen, the hydrogen accounts for 3.5% of the volume of the mixed gas, the flow rate of the mixed gas is 1250sccm, and the time is 30s;

[0072] The RDL metal layer stripping is RDL copper layer stripping; the RDL copper layer stripping is immersion stripping for 8 minutes using etching solution B, and etching solution B is GCT ECU 314 copper etching solution.

[0073] After processing, the indicators of the processed wafers are shown in Table 1.

[0074] Example 2

[0075] This embodiment provides a method for reusing defective wafers after packaging, the method comprising sequentially performing copper-nickel-tin-silver metal layer stripping, titanium seed layer stripping, PI insulation layer stripping and RDL metal layer stripping;

[0076] The copper-nickel-tin-silver metal layer stripping includes immersing in an etching solution A for 5 minutes, and the etching solution A is REC-901 copper-nickel etching solution;

[0077] The titanium seed layer stripping includes stripping by using a wet etching machine, the flow rate of the etching solution is 2L / min, the number of etching swing arms is 36 times, the etching solution used is KS6506 titanium etching solution, and the rotation speed of the wafer is 400r / min;

[0078] The PI insulating layer stripping includes a first dry debonding, a second dry debonding, a third dry debonding and a fourth dry debonding performed in sequence; the time of the first dry debonding and the time of the fourth dry debonding are both shorter than the time of the second dry debonding or the time of the third dry debonding;

[0079] The power of the microwave in the first dry degumming process is 800W, CF 4 The flow rate is 120sccm and the time is 20s;

[0080] In the second dry debonding method, the microwave power is 1200W, the radio frequency power is 700W, the oxygen flow rate is 800sccm, and the CF 4 The flow rate is 130sccm and the time is 80s;

[0081] In the third dry debonding method, the microwave power is 700W, the radio frequency power is 400W, the oxygen flow rate is 700sccm, and the CF 4 The flow rate is 120sccm and the time is 120s;

[0082] In the fourth dry debonding method, the microwave power is 900W, the radio frequency power is 310W, the gas used is a mixed gas of hydrogen and nitrogen, the hydrogen accounts for 3% of the volume of the mixed gas, the flow rate of the mixed gas is 1200sccm, and the time is 40s;

[0083] The RDL metal layer stripping includes RDL copper layer stripping and RDL titanium layer stripping performed in sequence; the RDL copper layer stripping includes immersion stripping for 5 minutes using etching solution B, and etching solution B is CU-129 copper etching solution; the RDL titanium layer stripping is stripping using a wet etcher, the etching solution flow rate is 1.5L / min, the etching swing arm number is 40 times, the etching solution used is KS6506 titanium etching solution, and the wafer rotation speed is 600r / min.

[0084] After processing, the indicators of the processed wafers are shown in Table 1.

[0085] Example 3

[0086] This embodiment provides a method for reusing defective wafers after packaging, the method comprising sequentially performing copper-nickel-tin-silver metal layer stripping, titanium seed layer stripping, PI insulation layer stripping and RDL metal layer stripping;

[0087] The copper-nickel-tin-silver metal layer stripping includes immersing in an etching solution A for 10 minutes, and the etching solution A is NI636E copper-nickel etching solution;

[0088] The titanium seed layer stripping includes stripping by using a wet etching machine, the flow rate of the etching solution is 1.5 L / min, the number of etching swing arms is 72 times, the etching solution used is CZ703 titanium etching solution, and the rotation speed of the wafer is 600 r / min;

[0089] The PI insulating layer stripping includes a first dry debonding, a second dry debonding, a third dry debonding and a fourth dry debonding performed in sequence; the time of the first dry debonding and the time of the fourth dry debonding are both shorter than the time of the second dry debonding or the time of the third dry debonding;

[0090] The power of the microwave in the first dry degumming process is 900W, CF 4 The flow rate is 130sccm and the time is 10s;

[0091] In the second dry debonding method, the microwave power is 1300W, the radio frequency power is 600W, the oxygen flow rate is 900sccm, and the CF 4 The flow rate is 120sccm and the time is 160s;

[0092] In the third dry debonding method, the microwave power is 800W, the radio frequency power is 300W, the oxygen flow rate is 800sccm, and the CF 4 The flow rate is 130sccm and the time is 60s;

[0093] In the fourth dry debonding method, the microwave power is 800W, the radio frequency power is 290W, the gas used is a mixed gas of hydrogen and nitrogen, the hydrogen accounts for 4% of the volume of the mixed gas, the flow rate of the mixed gas is 1300sccm, and the time is 20s;

[0094] The RDL metal layer stripping includes RDL copper layer stripping and RDL titanium layer stripping performed in sequence; the RDL copper layer stripping includes immersion stripping for 10 minutes using etching solution B, and etching solution B is CU-129 copper etching solution; the RDL titanium layer stripping includes stripping using a wet etcher, the etching solution flow rate is 1.8L / min, the etching swing arm number is 72 times, the etching solution used is CZ703 titanium etching solution, and the wafer rotation speed is 400r / min.

[0095] After processing, the indicators of the processed wafers are shown in Table 1.

[0096] Example 4

[0097] The only difference from Example 1 is that only the first dry debonding is performed during the PI insulating layer stripping. After the treatment, the indexes of the processed wafers are shown in Table 1.

[0098] Example 5

[0099] The only difference from Example 1 is that only the second dry debonding is performed during the PI insulating layer stripping. After the treatment, the indicators of the processed wafers are shown in Table 1.

[0100] Example 6

[0101] The only difference from Example 1 is that only the third dry debonding is performed during the PI insulating layer stripping. After the treatment, the indexes of the processed wafers are shown in Table 1.

[0102] Example 7

[0103] The only difference from Example 1 is that only the fourth dry debonding is performed during the PI insulation layer stripping. After the treatment, the indexes of the processed wafers are shown in Table 1.

[0104] Example 8

[0105] The only difference from Example 1 is that the third dry debonding is performed first and then the second dry debonding is performed during the PI insulation layer stripping, that is, the positions of the second dry debonding and the third dry debonding are swapped. After the treatment, the indexes of the processed wafers are shown in Table 1.

[0106] Example 9

[0107] The only difference from Example 1 is that the positions of the first dry debonding and the third dry debonding are exchanged in the PI insulating layer stripping, that is, the third dry debonding, the second dry debonding, the first dry debonding, and the fourth dry debonding. After processing, the indicators of the processed wafers are shown in Table 1.

[0108] Example 10

[0109] The only difference from Example 1 is that the processing sequence in the PI insulation layer stripping is the fourth dry debonding, the second dry debonding, the third dry debonding, and the first dry debonding. After the processing, the indicators of the processed wafers are shown in Table 1.

[0110] Embodiment 11

[0111] The only difference from Example 1 is that the processing sequence in the PI insulation layer stripping is the first dry debonding, the fourth dry debonding, the second dry debonding, and the third dry debonding. After the processing, the indicators of the processed wafers are shown in Table 1.

[0112] Table 1

[0113] Copper-nickel-tin-silver metal layer peeling effect Titanium seed layer peeling effect PI insulation layer removal effect Example 1 Completely peeled off Completely peeled off Completely peeled off Example 2 Completely peeled off Completely peeled off Completely peeled off Example 3 Completely peeled off Completely peeled off Completely peeled off Example 4 Completely peeled off Completely peeled off A large amount of PI remains Example 5 Completely peeled off Completely peeled off A large amount of PI remains Example 6 Completely peeled off Completely peeled off A large amount of PI remains Example 7 Completely peeled off Completely peeled off A large amount of PI remains Example 8 Completely peeled off Completely peeled off A small amount of PI residue and imprint Example 9 Completely peeled off Completely peeled off PI residue, imprint Example 10 Completely peeled off Completely peeled off Lots of marks on the surface Embodiment 11 Completely peeled off Completely peeled off Lots of marks on the surface

[0114] It can be seen from the results of the above embodiments that the reuse method provided by the present application, by stripping off the metal layer and the insulating layer, returns the wafer to the state before packaging, thereby improving the fault tolerance of the wafer during the packaging process. Since the cost of wafers is relatively high, this method can make the wafers reused and avoid the scrapping of wafers due to too low yield. Through the capabilities of existing equipment, the packaging patterns on the surface of the wafer can be stripped and removed, and the wafer can be reused and repackaged to avoid economic losses caused by too low wafer yield and scrapped wafers.

[0115] It is stated that the present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the components selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0116] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0117] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0118] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for reusing defective wafers after packaging, characterized in that: The reuse method comprises sequentially performing copper-nickel-tin-silver metal layer stripping, titanium seed layer stripping, PI insulation layer stripping and RDL metal layer stripping; The PI insulating layer stripping includes a first dry debonding, a second dry debonding, a third dry debonding and a fourth dry debonding performed sequentially; The first dry glue removal time and the fourth dry glue removal time are both shorter than the second dry glue removal time or the third dry glue removal time; The power of the microwave in the first dry debonding process is 800-900W; the flow rate of oxygen in the first dry debonding process is 800-900sccm; the flow rate of CF4 in the first dry debonding process is 120-130sccm; the time of the first dry debonding process is 10-20s; The power of microwave in the second dry degumming is 1200-1300W; the power of radio frequency in the second dry degumming is 600-700W; the flow rate of oxygen in the second dry degumming is 800-900sccm; the flow rate of CF4 in the second dry degumming is 120-130sccm; the time of the second dry degumming is 80-160s; The power of microwave in the third dry degumming process is 700-800W; the power of radio frequency in the third dry degumming process is 300-400W; the flow rate of oxygen in the third dry degumming process is 700-800sccm; the flow rate of CF4 in the third dry degumming process is 120-130sccm; the time of the third dry degumming process is 60-120s; The power of microwaves in the fourth dry degumming method is 800-900W; the power of radio frequency in the fourth dry degumming method is 290-310W; the gas used in the fourth dry degumming method is a mixed gas of hydrogen and nitrogen, and hydrogen accounts for 3-4% of the volume of the mixed gas; the flow rate of the mixed gas is 1200-1300sccm; the time of the fourth dry degumming method is 20-40s.

2. The reuse method according to claim 1, characterized in that: The copper-nickel-tin-silver metal layer stripping includes immersion treatment using etching solution A.

3. The reuse method according to claim 2, characterized in that: The soaking time is 5-10 minutes.

4. The reuse method according to claim 2, characterized in that: The etching solution A includes NI636E copper-nickel etching solution or REC-901 copper-nickel etching solution.

5. The reuse method according to claim 1, characterized in that: The titanium seed layer stripping includes stripping by using a wet etching machine.

6. The reuse method according to claim 1, characterized in that: The flow rate of the etching solution during the stripping of the titanium seed layer is 1.5-2 L / min.

7. The reuse method according to claim 1, characterized in that: The number of etching swing arms during stripping of the titanium seed layer is 36-72 times.

8. The reuse method according to claim 1, characterized in that: The etching solution used in stripping the titanium seed layer includes one of GCT ETI 300 titanium etching solution, CZ703 titanium etching solution or KS6506 titanium etching solution.

9. The reuse method according to claim 1, characterized in that: The rotation speed of the wafer during the titanium seed layer stripping is 400-600 r / min.

10. The reuse method according to claim 1, characterized in that: The RDL metal layer stripping includes RDL copper layer stripping and / or RDL titanium layer stripping.

11. The reuse method according to claim 10, characterized in that: The RDL copper layer stripping includes using etching solution B to perform immersion stripping for 5-10 minutes.

12. The reuse method according to claim 11, characterized in that: The etching solution B includes one of GCT ECU 314 copper etching solution, CU-129 copper etching solution or KS6205 copper etching solution.

13. The reuse method according to claim 10, characterized in that: The RDL titanium layer stripping includes stripping by using a wet etching machine.

14. The reuse method according to claim 10, characterized in that: The flow rate of the etching solution during the RDL titanium layer stripping is 1.5-1.8 L / min.

15. The reuse method according to claim 10, characterized in that: The number of etching swing arms during stripping of the RDL titanium layer is 40-72 times.

16. The reuse method according to claim 10, characterized in that: The etching solution used in the RDL titanium layer stripping includes one of GCT ETI 300 titanium etching solution, CZ703 titanium etching solution or KS6506 titanium etching solution.

17. The recycling method according to claim 10, characterized in that: The rotation speed of the wafer during the RDL titanium layer stripping is 400-600 r / min.

18. The recycling method according to claim 1, characterized in that: The reuse method comprises sequentially performing copper-nickel-tin-silver metal layer stripping, titanium seed layer stripping, PI insulation layer stripping and RDL metal layer stripping; Wherein, the copper-nickel-tin-silver metal layer stripping includes immersing in an etching solution A for 5-10 minutes, and the etching solution A includes NI636E copper-nickel etching solution or REC-901 copper-nickel etching solution; The titanium seed layer stripping includes stripping by using a wet etching machine, the flow rate of the etching solution is 1.5-2L / min, the number of etching swing arms is 36-72 times, the etching solution used includes one of GCT ETI 300 titanium etching solution, CZ703 titanium etching solution or KS6506 titanium etching solution, and the rotation speed of the wafer is 400-600r / min; The PI insulating layer stripping includes a first dry debonding, a second dry debonding, a third dry debonding and a fourth dry debonding performed in sequence; the time of the first dry debonding and the time of the fourth dry debonding are both shorter than the time of the second dry debonding or the time of the third dry debonding; In the first dry debonding method, the microwave power is 800-900W, the CF4 flow rate is 120-130sccm, and the time is 10-20s; In the second dry debonding process, the microwave power is 1200-1300W, the radio frequency power is 600-700W, the oxygen flow rate is 800-900sccm, the CF4 flow rate is 120-130sccm, and the time is 80-160s; In the third dry debonding method, the microwave power is 700-800W, the radio frequency power is 300-400W, the oxygen flow rate is 700-800sccm, the CF4 flow rate is 120-130sccm, and the time is 60-120s; In the fourth dry debonding method, the microwave power is 800-900W, the radio frequency power is 290-310W, the gas used is a mixed gas of hydrogen and nitrogen, the hydrogen accounts for 3-4% of the volume of the mixed gas, the flow rate of the mixed gas is 1200-1300sccm, and the time is 20-40s; The RDL metal layer stripping includes RDL copper layer stripping and / or RDL titanium layer stripping; the RDL copper layer stripping includes immersion stripping for 5-10 minutes using etching solution B, and etching solution B includes one of GCT ECU 314 copper etching solution, CU-129 copper etching solution or KS6205 copper etching solution; the RDL titanium layer stripping includes stripping using a wet etcher, the etching solution flow rate is 1.5-1.8L / min, the etching arm swing times are 40-72 times, the etching solution used includes one of GCT ETI 300 titanium etching solution, CZ703 titanium etching solution or KS6506 titanium etching solution, and the wafer rotation speed is 400-600r / min.