Separation device and separation method for ultra-thin wafer debonding

Abstract

The present invention provides a separation device and a separation method for debonding an ultra-thin wafer, wherein the separation device comprises: a separation chamber, wherein the upper and lower ends of the separation chamber are set as openings, wherein a first slot and a second slot are set in the separation chamber, wherein the first slot is located above the second slot; a first carrier plate, wherein the first carrier plate has a plurality of first through holes penetrating the first carrier plate, wherein the first carrier plate is bonded to the ultra-thin wafer through a bonding material, wherein the bonding material is exposed through the through holes, wherein the first carrier plate is fixed in the separation chamber through the first slot, and the ultra-thin wafer is placed downward; a second carrier plate, wherein the carrier plate has a plurality of second through holes penetrating the second carrier plate, wherein the second carrier plate is fixed in the separation chamber through the second slot; wherein the separation device is immersed in a chemical liquid, wherein the chemical liquid dissolves and removes the bonding material through the first through holes, thereby separating the ultra-thin wafer from the first carrier plate and sinking to the second carrier plate. The present invention has the advantages of simple process, easy implementation and high yield.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor design and manufacturing, and in particular relates to a separation device and a separation method for debonding ultra-thin wafers. Background Art

[0002] In the process of manufacturing semiconductor devices, in order to obtain better thermal conductivity, electrical properties, and the needs of subsequent processing technology, it is generally necessary to thin the wafer, generally to less than 200 microns, which is called a thin slice. For some special semiconductor devices, especially some power semiconductor devices, in order to obtain thinner chips or to meet the requirements of better electrical performance, the thickness of the wafer needs to be reduced to less than 100 microns, or even less than 50 microns, that is, processed into so-called ultra-thin slices.

[0003] Usually, ultra-thin wafers need to be temporarily bonded on a carrier to thin the substrate, and then the thinned ultra-thin wafer is debonded from the carrier. The commonly used separation processes include laser debonding, mechanical debonding, thermal push debonding, etc. When the InP wafer with back-side through-holes is thinned to an ultra-thin sheet with a thickness of 25 microns to 75 microns, the ultra-thin wafer is very sensitive to stress during the debonding process. If the wafer is made of brittle material, it is very easy to break due to uneven force. Therefore, these traditional debonding processes are not suitable for the debonding of ultra-thin wafers with brittle materials with back holes. The bonding and separation process of ultra-thin wafers has become a difficult point in the device process, which will greatly affect the device yield. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a separation device and a separation method for debonding of ultra-thin wafers, so as to solve the problem that the debonding and separation of ultra-thin wafers in the prior art easily causes the ultra-thin wafer to break.

[0005] To achieve the above-mentioned purpose and other related purposes, the present invention provides a separation device for debonding ultra-thin wafers, the separation device comprising: a separation chamber, the upper and lower ends of the separation chamber are set as openings, a first slot and a second slot are set in the separation chamber, the first slot is located above the second slot; a first carrier plate, the first carrier plate has a plurality of first through holes penetrating the first carrier plate, the first carrier plate is bonded to the ultra-thin wafer through a bonding material, the bonding material is exposed through the first through holes, the first carrier plate is fixed in the separation chamber through the first slot, and the ultra-thin wafer is placed downward; a second carrier plate, the second carrier plate has a plurality of second through holes penetrating the second carrier plate, and is fixed in the separation chamber through the second slot; the separation device is immersed in a chemical solution, the chemical solution dissolves and removes the bonding material through the first through holes, so that the ultra-thin wafer is separated from the first carrier plate and sinks to the second carrier plate.

[0006] Optionally, the bonding material includes one of bonding glue and bonding wax, and the temperature resistance of the bonding material is greater than 180°C.

[0007] Optionally, the bonding material is dissolved in one of acetone and N-methylpyrrolidone, and the chemical liquid is one of acetone and N-methylpyrrolidone.

[0008] Optionally, radial dimensions of the first carrier plate and the second carrier plate are greater than radial dimensions of the ultra-thin wafer.

[0009] Optionally, the second carrier board has a plurality of second through holes penetrating the second carrier board.

[0010] Optionally, a side surface of the separation chamber has a slot for allowing the first carrier plate to be inserted into the first slot from the side surface and for allowing the second carrier plate to be inserted into the second slot from the side surface.

[0011] Optionally, a distance between the first carrier plate and the second carrier plate is less than 5 cm.

[0012] Optionally, the substrate material of the ultra-thin wafer is one of InP and GaAs, and the thickness of the thin wafer is 25 microns to 75 microns.

[0013] The present invention also provides a separation method for debonding of ultra-thin wafers, which is implemented based on the separation device for debonding of ultra-thin wafers as described above, and includes the following steps: 1) bonding the wafer to the first carrier, and performing a back process on the wafer to obtain an ultra-thin wafer bonded to the first carrier; 2) fixing the first carrier to the separation chamber through the first slot, with the ultra-thin wafer facing downward. Fixing the second carrier to the separation chamber through the second slot; 3) immersing the separation device in a chemical solution, which dissolves and removes the bonding material through the first through hole, so that the ultra-thin wafer is separated from the first carrier and sinks to the second carrier, completing the bonding separation of the ultra-thin wafer; 4) pulling out the second carrier carrying the ultra-thin wafer, and cleaning the ultra-thin wafer after separation.

[0014] Optionally, the back side process of the wafer includes: thinning the wafer to form an ultra-thin wafer; etching through holes on the ultra-thin wafer; metallizing the back side of the ultra-thin wafer; and forming cutting paths on the back side of the ultra-thin wafer.

[0015] Optionally, after step 4), the method further includes cutting the ultra-thin wafer based on the cutting path.

[0016] As described above, the separation device and separation method for ultra-thin wafer debonding of the present invention have the following beneficial effects:

[0017] The present invention is a separation device for debonding ultra-thin wafers. The wafer is bonded to a first carrier plate with a through hole to perform a back process, and then a chemical liquid is used to remove the bonding material through the through hole, so that the ultra-thin wafer is peeled off from the first carrier plate and sinks to a second carrier plate below it. During the sinking process, due to the resistance of the chemical liquid, the sinking speed of the ultra-thin wafer can be very slow, and by controlling the spacing between the first carrier plate and the second carrier plate, it is ensured that the ultra-thin wafer will not cause any damage during the sinking process to the second carrier plate, thereby greatly improving the process stability and yield. The present invention has the advantages of simple process, easy implementation and high yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 to Figure 4 It is a schematic structural diagram of steps 1) to 4) of the separation method for debonding ultra-thin wafers according to an embodiment of the present invention, wherein: Figure 3 Shown is a schematic structural diagram of a separation device for ultra-thin wafer debonding according to an embodiment of the present invention.

[0019] Component number description

[0020] 101 First carrier board

[0021] 102 First through hole

[0022] 103 Bonding materials

[0023] 104 Wafer

[0024] 105 Ultra-thin wafer

[0025] 106 Separation chamber

[0026] 107 First Slot

[0027] 108 Second Slot

[0028] 109 Second carrier board

[0029] 110 Second through hole DETAILED DESCRIPTION

[0030] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0031] For example, when describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional view showing the device structure will not be partially enlarged according to the general scale, and the schematic view is only an example, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional space dimensions of length, width and depth should be included.

[0032] For ease of description, spatially relative terms such as "under", "below", "below", "below", "above", "on", etc. may be used herein to describe the relationship of one element or feature shown in the drawings to other elements or features. It will be understood that these spatially relative terms are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the drawings. In addition, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

[0033] In the context of the present application, a structure in which a first feature is described as being "above" a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0034] It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and therefore the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0035] like Figure 3 As shown, this embodiment provides a separation device for debonding an ultra-thin wafer 105, the separation device comprising: a separation chamber 106, the upper and lower ends of the separation chamber 106 are set as openings, the separation chamber 106 is provided with a first slot 107 and a second slot 108, the first slot 107 is located above the second slot 108; a first carrier 101, the first carrier 101 has a plurality of first through holes 102 penetrating the first carrier 101, the first carrier 101 is bonded to the ultra-thin wafer 105 through a bonding material 103, the bonding material 103 is exposed through the first through holes 102; , the first carrier 101 is fixed on the separation chamber 106 through the first slot 107, and the ultra-thin wafer 105 is placed downward; a second carrier 109, the second carrier 109 has a plurality of second through holes 110 penetrating the second carrier 109, and the second carrier 109 is fixed on the separation chamber 106 through the second slot 108; the separation device is immersed in a chemical solution, and the chemical solution dissolves and removes the bonding material 103 through the first through hole 102, so that the ultra-thin wafer 105 is separated from the first carrier 101 and sinks to the second carrier 109.

[0036] The substrate material of the ultra-thin wafer 105 is one of InP and GaAs, and the thickness of the thin wafer is 25 microns to 75 microns. In this embodiment, the substrate material of the ultra-thin wafer 105 is InP, and the ultra-thin wafer 105 is an ultra-thin wafer 105 that has completed back-side processing, and the back-side processing may include wafer thinning, wafer back-side through-hole etching, wafer back-side metallization, and wafer back-side cutting line formation.

[0037] The material of the separation chamber 106 is selected to be a corrosion-resistant rigid material, such as graphite, stainless steel, etc. The shape of the separation chamber 106 is preferably consistent with the shapes of the first carrier plate 101 and the second carrier plate 109. For example, the top view shape of the separation chamber 106 can be rectangular, circular, etc. In this embodiment, the top view shape of the separation chamber 106 is rectangular.

[0038] The side of the separation chamber 106 has a slot for the first carrier 101 to be inserted into the first slot 107 from the side and for the second carrier 109 to be inserted into the second slot 108 from the side. The slot may be formed by removing one or two side surfaces of the separation chamber 106, or may be an opening formed by removing only the area on the side surface corresponding to the first slot 107 and the second slot 108. The size and shape of the opening are set to be larger than the width of the first carrier 101 and the second carrier 109, so that the first carrier 101 and the second carrier 109 can be placed in and taken out of the first slot 107 and the second slot 108. The first slot 107 and the second slot 108 are set to surround the separation chamber 106, or are set on both sides of the separation chamber 106.

[0039] The bonding material 103 includes one of bonding glue and bonding wax, and the temperature resistance of the bonding material 103 is greater than 180° C. In this embodiment, the bonding material 103 is insoluble in a degumming solution (corrosive solution or developer for removing photoresist), and is soluble in one of acetone and N-methylpyrrolidone, and the chemical liquid is one of acetone and N-methylpyrrolidone.

[0040] The materials of the first carrier 101 and the second carrier 109 are selected to be corrosion-resistant materials, especially materials that do not react with the chemical solution, such as sapphire, quartz, silicon carbide, etc. The radial dimension of the first carrier 101 is larger than the radial dimension of the ultra-thin wafer 105. For example, a 4-inch wafer can be bonded to a 6-inch first carrier 101.

[0041] The first through holes 102 are arranged in such a way that the bonding strength between the first carrier 101 and the ultra-thin wafer 105 is ensured on the one hand, and the bonding material 103 can be removed efficiently by using chemical solution through the first through holes 102 on the other hand. The first through holes 102 are evenly spaced on the first carrier 101 to improve the efficiency of removing the bonding material 103. In this embodiment, the aperture of the first through holes 102 can be 0.5 cm to 2 cm, etc., and the spacing between two adjacent first through holes 102 can be 1 cm to 5 cm, etc.

[0042] In this embodiment, the distance between the first carrier plate 101 and the second carrier plate 109 is less than 5 cm, for example, 2 cm. During the sinking process of the ultra-thin wafer 105, due to the resistance of the chemical solution, the sinking speed of the ultra-thin wafer 105 can be very slow, and by controlling the distance between the first carrier plate 101 and the second carrier plate 109, it is ensured that the ultra-thin wafer 105 will not be damaged during the sinking process to the second carrier plate 109, thereby greatly improving the process stability and yield.

[0043] The second carrier plate 109 has a plurality of second through holes 110 penetrating the second carrier plate 109, which can reduce the resistance of the separation device when immersed in the chemical solution on the one hand, and can make it easier to separate the ultra-thin wafer 105 from the second carrier plate 109 after the ultra-thin wafer 105 sinks to the second carrier plate 109, so as to avoid fragmentation during the separation process.

[0044] like Figure 1 to Figure 4 As shown, this embodiment also provides a separation method for debonding the ultra-thin wafer 105, the separation method is implemented based on the separation device for debonding the ultra-thin wafer 105 as described above, and the separation method includes the steps of:

[0045] like Figure 1-2 As shown, firstly, step 1) is performed to bond the wafer 104 to the first carrier 101 , and perform back surface processing on the wafer 104 to obtain the ultra-thin wafer 105 bonded to the first carrier 101 .

[0046] As an example, the back side process of the wafer 104 includes: thinning the wafer 104 to form an ultra-thin wafer 105 ; performing through-hole etching on the ultra-thin wafer 105 ; performing back side metallization on the ultra-thin wafer 105 ; and forming a cutting path on the back side of the ultra-thin wafer 105 .

[0047] The substrate material of the ultra-thin wafer 105 is one of InP and GaAs, and the thickness of the thin wafer is 25 microns to 75 microns. In this embodiment, the substrate material of the ultra-thin wafer 105 is InP, and the ultra-thin wafer 105 is an ultra-thin wafer 105 that has completed back-side processing, and the back-side processing may include wafer thinning, wafer back-side through-hole etching, wafer back-side metallization, and wafer back-side cutting line formation.

[0048] The bonding material 103 includes one of bonding glue and bonding wax, and the temperature resistance of the bonding material 103 is greater than 180° C. In this embodiment, the bonding material 103 is insoluble in a stripping solution (etching solution or developer for removing photoresist) and soluble in one of acetone and N-methylpyrrolidone.

[0049] The materials of the first carrier 101 and the second carrier 109 are selected to be corrosion-resistant materials, especially materials that do not react with the chemical solution, such as sapphire, quartz, silicon carbide, etc. The radial dimension of the first carrier 101 is larger than the radial dimension of the ultra-thin wafer 105. For example, a 4-inch wafer can be bonded to a 6-inch first carrier 101.

[0050] The first through holes 102 are arranged in such a way that the bonding strength between the first carrier 101 and the ultra-thin wafer 105 is ensured on the one hand, and the bonding material 103 can be removed efficiently by using chemical solution through the first through holes 102 on the other hand. The first through holes 102 are evenly spaced on the first carrier 101 to improve the efficiency of removing the bonding material 103. In this embodiment, the aperture of the first through holes 102 can be 0.5 cm to 2 cm, etc., and the spacing between two adjacent first through holes 102 can be 1 cm to 5 cm, etc.

[0051] like Figure 3 As shown, the first carrier 101 is then fixed to the separation chamber 106 through the first slot 107 , and the ultra-thin wafer 105 is placed downward. The second carrier 109 is fixed to the separation chamber 106 through the second slot 108 .

[0052] like Figure 4 As shown, step 3 is then performed to immerse the separation device in a chemical solution, and the chemical solution dissolves and removes the bonding material 103 through the first through hole 102, so that the ultra-thin wafer 105 is separated from the first carrier 101 and sinks to the second carrier 109.

[0053] Finally, step 4) is performed to extract the second carrier plate 109 carrying the ultra-thin wafer 105 to complete the separation of the ultra-thin wafer 105 .

[0054] In this embodiment, after step 4), a step of cutting the ultra-thin wafer 105 based on the cutting path is also included. For example, the ultra-thin wafer 105 can be mechanically cut or laser cut based on the cutting path to obtain multiple independent units.

[0055] As described above, the separation device and separation method for debonding the ultra-thin wafer 105 of the present invention have the following beneficial effects:

[0056] The separation device for debonding the ultra-thin wafer 105 of the present invention performs a back process by bonding the wafer to a first carrier plate 101 having a through hole, and then uses a chemical liquid to remove the bonding material 103 through the through hole, so that the ultra-thin wafer 105 is peeled off from the first carrier plate 101 and sinks to the second carrier plate 109 below it. During the sinking process, due to the resistance of the chemical liquid, the sinking speed of the ultra-thin wafer 105 can be very slow, and by controlling the spacing between the first carrier plate 101 and the second carrier plate 109, it is ensured that the ultra-thin wafer 105 will not cause any damage during the process of sinking to the second carrier plate 109, thereby greatly improving the process stability and yield. The present invention has the advantages of simple process, easy implementation and high yield.

[0057] Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0058] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A separation device for debonding ultra-thin wafers, characterized in that: The separation device comprises: A separation chamber, wherein the upper and lower ends of the separation chamber are set to be openings, and a first slot and a second slot are set in the separation chamber, and the first slot is located above the second slot; A first carrier plate, wherein the first carrier plate has a plurality of first through holes penetrating the first carrier plate, the first carrier plate is bonded to the ultra-thin wafer via a bonding material, the bonding material is exposed through the first through holes, the first carrier plate is fixed in the separation chamber via the first slot, and the ultra-thin wafer is placed downward; A second carrier plate, the second carrier plate having a plurality of second through holes penetrating the second carrier plate and fixed in the separation chamber through the second slot; The separation device is immersed in a chemical solution, and the chemical solution dissolves and removes the bonding material through the first through hole, so that the ultra-thin wafer is separated from the first carrier and sinks onto the second carrier.

2. The separation device for ultra-thin wafer debonding according to claim 1, characterized in that: The bonding material includes one of bonding glue and bonding wax, and the temperature resistance of the bonding material is greater than 180°C.

3. The separation device for debonding ultra-thin wafers according to claim 2, characterized in that: The bonding material is dissolved in one of acetone and N-methylpyrrolidone, and the chemical liquid is one of acetone and N-methylpyrrolidone.

4. The separation device for debonding ultra-thin wafers according to claim 1, characterized in that: The radial dimensions of the first carrier plate and the second carrier plate are larger than the radial dimension of the ultra-thin wafer.

5. The separation device for ultra-thin wafer debonding according to claim 1, characterized in that: The first through holes are distributed on the first carrier board at equal intervals.

6. The separation device for ultra-thin wafer debonding according to claim 1, characterized in that: The side surface of the separation chamber has a slot for allowing the first carrier plate to be inserted into the first slot from the side surface and for allowing the second carrier plate to be inserted into the second slot from the side surface.

7. The separation device for debonding ultra-thin wafers according to claim 1, characterized in that: The distance between the first carrier plate and the second carrier plate is less than 5 cm.

8. The separation device for ultra-thin wafer debonding according to claim 1, characterized in that: The substrate material of the ultra-thin wafer is one of InP and GaAs, and the thickness of the ultra-thin wafer is 25 microns to 75 microns.

9. A separation method for debonding ultra-thin wafers, characterized in that: The separation method is implemented based on the separation device for ultra-thin wafer debonding according to any one of claims 1 to 8, and the separation method comprises the steps of: 1) bonding a wafer to the first carrier, and performing a backside process on the wafer to obtain an ultra-thin wafer bonded to the first carrier; 2) fixing the first carrier plate to the separation chamber through the first slot, placing the ultra-thin wafer downward, and fixing the second carrier plate to the separation chamber through the second slot; 3) immersing the separation device in a chemical solution, the chemical solution dissolving and removing the bonding material through the first through hole, so that the ultra-thin wafer is separated from the first carrier and sinks to the second carrier; 4) Pulling out the second carrier plate carrying the ultra-thin wafer to complete the separation of the ultra-thin wafer.

10. The separation method for ultra-thin wafer debonding according to claim 9, characterized in that: The back side process of the wafer includes: Thinning the wafer to form an ultra-thin wafer; Performing through-hole etching on the ultra-thin wafer; Performing back metallization on the ultra-thin wafer; A scribe line is formed on the back side of the ultra-thin wafer.

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