CN102947246B

CN102947246B - The manufacture method of substrate, substrate and luminous element

Info

Publication number: CN102947246B
Application number: CN201180030057.0A
Authority: CN
Inventors: 中山茂; 辻裕
Original assignee: Sumitomo Electric Industries Ltd
Current assignee: Sumitomo Electric Industries Ltd
Priority date: 2010-06-22
Filing date: 2011-06-21
Publication date: 2015-11-25
Anticipated expiration: 2031-06-21
Also published as: TWI510449B; TW201221500A; JPWO2011162236A1; CN102947246A; WO2011162236A1; JP5838965B2

Abstract

The invention provides a kind of substrate, this substrate manufacture method and employ the luminous element of this substrate, described substrate can form luminous element more cheap compared with the luminous element made with sapphire substrate.Substrate of the present invention (10) is made up of spinel, and is luminous element (30) substrate (10).The sintered compact of the spinel of preferred formation substrate (10) consist of MgOnAl ₂o ₃(1.05≤n≤1.30), and the content of Si element is below 20ppm.

Description

The manufacture method of substrate, substrate and luminous element

Technical field

The present invention relates to substrate, the manufacture method of substrate and luminous element, relate more specifically to Substrate for luminous element and manufacture method thereof and use the luminous element of this substrate.

Background technology

The luminous elements such as photodiode (LED:LightEmittingDiode) have such structure usually: on the major surfaces of substrate side, by (such as) epitaxy, define the stepped construction of the semiconductor layer containing light-emitting zone.As aforesaid substrate, sometimes adopt the substrate be made up of (such as) sapphire.

Compared with adopting the luminous element of sapphire substrate and adopting the luminous element of the substrate be made up of (such as) silicon carbide, the characteristic such as brightness and contrast, electric conductivity of the light sent is all very excellent.Therefore the luminous element of sapphire substrate is adopted usually to be widely known by the people.Adopt disclosed in the luminous element of sapphire substrate has in (such as) Japanese Unexamined Patent Publication 2005-79171 publication (patent documentation 1).

Prior art document

Patent documentation

Patent documentation 1: Japanese Unexamined Patent Publication 2005-79171 publication

Summary of the invention

The problem that invention will solve

But sapphire is quite expensive as mechanicals.Therefore, the luminous element be made up of sapphire substrate has the problem that cost uprises and so on.In the process that luminous element is universal, consider to make luminous element can be applicable to purposes widely, the cost reducing luminous element is necessary.

Carry out the present invention in view of the above problems.The object of this invention is to provide a kind of substrate and manufacture method thereof, described substrate can form luminous element more cheap compared with the luminous element made by sapphire substrate.In addition, the luminous element adopting this substrate is provided.

The method of dealing with problems

The substrate that the present invention relates to is the Substrate for luminous element be made up of spinel.Inventor of the present invention, through concentrating on studies, found that: (such as), as the substrate being used for the luminous elements such as above-mentioned photodiode, can utilize the spinel of main use in optical element field to replace sapphire.The physical propertiess such as physical properties and sapphire intensity such as the intensity of spinel are close.Also find: the Substrate for luminous element using spinel to be formed is also equally durable with the Substrate for luminous element be made up of sapphire.Such as, although Spinel Substrate for luminous element is different from sapphire Substrate for luminous element, show the intensity (Young's modulus) of level no problem in practical.In addition, spinel dispels the heat to the heat that the light-emitting zone in luminous element produces, and therefore has the thermal conductivity of level no problem in practical.

But traditionally, as the substrate of luminous element, use the single crystal such as sapphire to be technology general knowledge, in those skilled in the art, self do not consider to be the candidate material that multicrystal spinel is used as baseplate material originally.Not retrain by the general knowledge of those skilled in the art, the present inventor is through research, and result obtains spinel can be used as the such knowledge of Substrate for luminous element.If utilize spinel to replace sapphire to form Substrate for luminous element, then can reduce the production cost of this substrate.

Above-mentioned Spinel substrate is preferably such sintered compact, and this sintered compact is composite oxides, and the content of Si element is below 20ppm, and these composite oxides have and consist of MgOnAl ₂o ₃the spinel type crystal structure of (1.05≤n≤1.30).For above-mentioned sintered compact, preferably when thickness is 1mm, wavelength is more than 350nm and the straight line transmittance of the light of below 450nm is more than 80%.Thus, for the substrate be made up of polycrystal spinel, obtain good light transmission.

Above-mentioned Spinel substrate has major surfaces, for this major surfaces, when setting the square region of multiple long 5mm × wide 5mm, in described multiple region, for multiple evaluation object region, represent LTV(LocalThicknessVariation) be the PLTV(PercentLTV of the ratio in the evaluation object region of less than 1.0 μm) being preferably more than 90%, wherein said multiple evaluation object region is eliminate to fall into the part after apart from the region within the scope of the 3mm of major surfaces periphery.If above-mentioned PLTV is at least 90%, even then polycrystal Spinel substrate, also can not use grafting material and the semiconductor layer forming luminous element directly be joined to the major surfaces of this substrate.Therefore, by using this substrate, the luminous element of excellent can be obtained.

The manufacture method of substrate involved in the present invention is the manufacture method of the Substrate for luminous element be made up of spinel, described spinel consist of MgOnAl ₂o ₃(1.05≤n≤1.30), and the content of Si element is below 20ppm.The manufacture method of this substrate has: the operation being formed into body, and described molding is below 50ppm by Si constituent content and the spinel powder that purity is more than 99.5 quality % is formed; 1st sintering circuit, wherein, in a vacuum in more than 1500 DEG C and less than 1800 DEG C molding is sintered, thus formed density be the sintered compact of more than 95%; And the 2nd sintering circuit, wherein, more than 1600 DEG C and less than 1900 DEG C pressure sintering is carried out to sintered compact.

By aforesaid method, the substrate as spinel sintered body can be formed, this spinel sintered body consist of MgOnAl ₂o ₃(1.05≤n≤1.30), and the content of Si element is below 20ppm.This substrate has necessary intensity as Substrate for luminous element and light transmission.Therefore, even if adopt this substrate to replace sapphire substrate, as above no problem in practical luminous element can also be provided.

Above-mentioned 1st sintering circuit is carried out under the pressure of below 50Pa, when the shortest thickness outside the centre portions of sintered compact to sintered compact is defined as D(mm), and by from 1000 DEG C until arrive heating-up time of top temperature be defined as t minute time, preferably there is following relation:

D＝a×t ^1/2

0.1≤a≤3。

If carry out the intensification of the 1st sintering circuit with above-mentioned condition, then after this sintering circuit terminates, the content of Si element can be made to be reduced to below 20ppm, and result can obtain the spinel sintered body of high transmission rate.Therefore, in the Substrate for luminous element of Spinel, high transmission rate can be obtained.

The manufacture method of aforesaid substrate also after the 2nd sintering circuit, can have the operation of cutting into slices to sintered compact further, and adopts chemical mechanical polishing method the surface of the substrate obtained by slicing process to be carried out to the operation of polishing.In polishing process, carry out polishing to substrate under the state that can be clipped between polishing pad and rubbing head at substrate, wherein said polishing pad is arranged on platform, and described rubbing head is set to relative with described polishing pad.In addition, preferably between rubbing head and substrate, arrange soft layer, the hardness of the hardness ratio rubbing head of this soft layer is low.Now, the flatness of substrate can be improved.Result can obtain the substrate that semiconductor layer can be engaged to major surfaces.

Luminous element involved in the present invention has: above-mentioned Spinel substrate, and be arranged on this substrate side major surfaces on and containing the semiconductor layer of luminescent layer.As mentioned above, according to Spinel substrate, then can provide at an easy rate and the luminous element adopting the luminous element of sapphire substrate to have said function.In addition, aforesaid substrate can be engaged with semiconductor layer.As method of joining, the grafting material with perviousness can be adopted to be engaged with semiconductor layer by substrate, also can adopt surface activation process etc. that substrate and semiconductor layer are directly engaged.Thus, by the semiconductor layer with good crystallinity is engaged to substrate, the luminous element of excellent can be obtained.

The effect of invention

According to the present invention, can provide at an easy rate and the luminous element adopting the luminous element of sapphire substrate to have said function.Can guarantee in addition substrate through characteristic.

Brief Description Of Drawings

[Fig. 1] is for illustrating the sketch chart of the form of the substrate involved by the present embodiment.

[Fig. 2] is for illustrating the cross section sketch chart of the form of the LED of the substrate that have employed in Fig. 1.

[Fig. 3] schema for being described the manufacture method of the substrate involved by the present embodiment.

The schema that [Fig. 4] is described for the operation had the operation (S30) in Fig. 3.

[Fig. 5] schema for being described the manufacturing procedure in the manufacture method of the embodiment 2 of substrate according to the present invention.

[Fig. 6] mode chart for being described the CMP operation shown in Fig. 5.

[Fig. 7] is for illustrating the cross section sketch chart of the embodiment 3 according to luminous element of the present invention.

[Fig. 8] schema for being described the manufacture method of the luminous element shown in Fig. 7.

[Fig. 9] mode chart for being described the bonding process shown in Fig. 8.

[Figure 10] mode chart for being described the bonding process shown in Fig. 8.

[Figure 11] is for illustrating the cross section sketch chart of the embodiment 4 according to luminous element of the present invention.

[Figure 12] mode chart for being described the bonding process shown in Fig. 8.

[Figure 13] mode chart for being described the bonding process shown in Fig. 8.

[Figure 14] is for illustrating the mode chart of the concavo-convex state in the major surfaces of the substrate of No. 1 sample in three dimensions.

[Figure 15] mode chart for being described the PLTV in the major surfaces of the substrate of No. 1 sample.

[Figure 16] is for illustrating the photo of the outward appearance of the bonded substrate of the substrate that have employed No. 1 sample.

[Figure 17] is for illustrating the mode chart of the concavo-convex state in the major surfaces of the substrate of No. 2 samples in three dimensions.

[Figure 18] mode chart for being described the PLTV in the major surfaces of the substrate of No. 2 samples.

[Figure 19] is for illustrating the photo of the outward appearance of the bonded substrate of the substrate that have employed No. 2 samples.

[Figure 20] is for illustrating the mode chart of the concavo-convex state in the major surfaces of the substrate of No. 3 samples in three dimensions.

[Figure 21] mode chart for being described the PLTV in the major surfaces of the substrate of No. 3 samples.

[Figure 22] is for illustrating the photo of the outward appearance of the bonded substrate of the substrate that have employed No. 3 samples.

[Figure 23] is for illustrating the mode chart of the concavo-convex state in the major surfaces of the substrate of No. 4 samples in three dimensions.

[Figure 24] mode chart for being described the PLTV in the major surfaces of the substrate of No. 4 samples.

[Figure 25] is for illustrating the photo of the outward appearance of the bonded substrate of the substrate that have employed No. 4 samples.

Embodiment

With reference to the accompanying drawings embodiment of the present invention are described.It should be noted that, in following figure, for identical or suitable part with identical reference numbering, do not repeat to be described.

(embodiment 1)

As shown in Figure 1, the substrate 10 of the present embodiment is the wafer that (such as) spinel is made, and the diameter of its major surfaces 10a is 4 inches.As the composition of the spinel of formation substrate 10, (such as) MgOnAl can be enumerated ₂o ₃.

Substrate 10 has the luminous elements 30 such as the LED of structure shown in Fig. 2 for (such as).The luminous element 30 of Fig. 2 has (such as) and stacks gradually on the major surfaces 10a of substrate 10 by buffer layer 1, N-shaped GaN(gan) layer 2, N-shaped AlGaN(aluminium gallium nitride alloy) structure of semiconductor layer that forms of layer 3, Multiple Quantum Well 4, p-type AlGaN layer 5, p-type GaN layer 6.

Buffer layer 1 is the film in order to suppress lattice mismatch to arrange, preferably by (such as) InGaN(InGaN compound) form, described lattice mismatch is both lattice mismatches in the difference of the compound semiconductor lattice parameter of the lattice parameter of the spinel forming substrate 10 and the compound semiconductor film of formation n-type GaN layer 2 grade.

Multiple Quantum Well 4 is the light-emitting zone (luminescent layer) of this LED, preferably has (such as) by multiple In _0.2ga _0.8the very thin rete of N and Al _0.2ga _0.8the structure that the very thin rete of N is alternately laminated.

The semiconductor layer be made up of buffer layer 1, n-type GaN layer 2, N-shaped AlGaN layer 3, Multiple Quantum Well 4, p-type AlGaN layer 5, p-type GaN layer 6 is preferably formed by (such as) epitaxy in this order.

After the lit-par-lit structure of above-mentioned semiconductor layer is all formed, by its part of etching removing, be specially a part and N-shaped AlGaN layer 3, Multiple Quantum Well 4, p-type AlGaN layer 5, the p-type GaN layer 6 of n-type GaN layer 2.The major surfaces of a part for the major surfaces of n-type GaN layer 2 and p-type GaN layer 6 is made to become the state exposed thus.

Thereafter, use the major surfaces of said n type the GaN layer 2 and p-type GaN layer 6 exposed with part respectively to form the metallic substance of ohmic contact, these major surfacess are formed n-type electrode 7 and p-type electrode 8.

According to above step, define the luminous element 30 shown in Fig. 2.About this luminous element 30, by by conducting between n-type electrode 7 and p-type electrode 8, there is being combined again of hole and electronics in as the Multiple Quantum Well 4 of luminescent layer, thus produce luminescence phenomenon.

This light can penetrate from the bottom surface of substrate 10 (major surfaces below the substrate 10 Fig. 2) (through).This is the light that the spinel owing to forming substrate 10 can send through above-mentioned luminous element 30.

Due to light transmission substrate 10, the luminous element 30 comprising substrate 10 generates heat.Therefore suitable stress is applied to substrate 10 and other semiconductor layer.Namely when luminous element 30 works, substrate 10 generates heat, and this heat is also passed to substrate 10.In a word, now thermal stresses is created for substrate 10.Therefore, substrate 10 preferably has corresponding intensity.

For structure, usually, Young's modulus is higher, then intensity is higher; Young's modulus is lower, then intensity is lower.Therefore in order to possess intensity durable in above-mentioned condition, the Young's modulus of substrate 10 is preferably more than 150GPa and below 350GPa.If the Young's modulus of substrate 10 is more than 150GPa, then possesses intensity durable in above-mentioned condition.In addition, for structure, usually, Young's modulus is higher, then hardness is higher; Young's modulus is lower, then hardness is lower.Therefore, such as, when the Young's modulus of substrate 10 is more than 350GPa, then the much higher hard of substrate 10, thus improve and cause cracked possibility.In addition, due to the much higher hard of substrate 10, processing is made to become difficulty.Therefore from having suitable intensity and suppressing the cracked angle of undesirable condition that waits to be considered, the Young's modulus of preferable substrate 10, in above-mentioned scope, wherein thinks that more than 180GPa and below 300GPa are for most preferred scope.

Although the intensity of the substrate 10 of above-mentioned luminous element 30 is different from the LED substrate that sapphire is made, even if replace sapphire to be used as luminous element 30 substrate, its intensity is also level no problem in practical.Therefore, as luminous element 30 substrate, even if adopt Spinel substrate 10 to replace sapphire substrate, also can guarantee to have the function that the LED substrate that forms with by sapphire substrate is same.Therefore, by adopting Spinel substrate 10, compared with adopting the situation of sapphire substrate, the luminous elements such as LED 30 can be formed at an easy rate.

Next, for the spinel sintered body forming substrate 10, it consists of MgOnAl ₂o ₃(1.05≤n≤1.30), and the content of Si element is below 20ppm.This spinel sintered body is when thickness is 1mm, and wavelength is more than 350nm and the straight line transmittance of the visible rays of below 450nm is preferably more than 80%, is more preferably more than 82%, is particularly preferably more than 84%, and straight-line pass rate is very high.In addition, obtain stable high transmission rate, and deviation is little.In addition, even have the starting material of thickness, stable high transmission rate be also obtain for visible rays.

Spinel sintered body is MgOnAl for having composition ₂o ₃the composite oxides of the spinel type crystal structure of (1.05≤n≤1.30), it contains MgO and Al ₂o ₃as composition.Because the crystal formation of spinel sintered body is cubic crystal, be difficult to, in grain boundaries generation scattering of light, therefore when sintering with high-density, obtain good light transmission.By making 1.05≤n≤1.30, the component amount of MgO tails off, and the deviation of the lattice of microcosmic and distortion can be made to diminish, thus improve light transmission.Angle is considered thus, preferably 1.06≤n≤1.125.

Usually, the major cause that the light transmission as spinel sintered body reduces, has: being mixed into of metallic impurity, as metallic impurity, can enumerate: Si, Ti, Na, K, Ca, Fe, C etc.These metallic impurity come from raw material powder and are mixed in sintered compact.By making the content of Si in these metallic impurity be below 20ppm, stable high light transmittance can be obtained.Angle is considered thus, and the content of Si element is more preferably below 10ppm, is particularly preferably below 5ppm.By controlling the content of Si element like this, even be in the spinel sintered body of more than 10mm at thickness, also homogeneous light transmission can be obtained.Si element reacts with spinel powder when sintering, generation liquid phase.This liquid phase has the effect of coking property promoting spinel powder, if but this any residual aqueous phase on crystal boundary, then become out-phase, transmittance reduced.

Because the metallic impurity beyond Si element such as comprise being mixed into of the impurity of Na, K, Ca or Fe etc., the light transmission of spinel sintered body, the deviation of light transmission and the stability manufactured can be adversely affected.Therefore, the MgOnAl in spinel powder ₂o ₃purity be set as more than 99.5 quality %, preferably more than 99.9 quality %, more preferably more than 99.99 quality %.

Next the manufacture method of substrate 10 of the present invention is described.

With reference to Fig. 3, the manufacture method of spinel sintered body of the present invention and substrate 10 has high purity spinel powder preparatory process (S10), forming process (S20), sintering circuit (S30) and manufacturing procedure (S40).

In high purity spinel powder preparatory process (S10), the content preparing (such as) Si element is below 50ppm, median size is more than 0.1 μm less than 0.3 μm, purity is more than 99.5 quality % and consists of MgOnAl ₂o ₃the spinel powder of (1.05≤n≤1.30).

It should be noted that, the particle diameter of powder particle herein refers to: when adopting particle size distribution method to measure by laser diffraction and scattering method, be the value of the diameter of the powder section of 50% cumulative volume when Large stone side is carried out accumulative to the volume of this powder from small particle size side direction.The measuring method of above-mentioned size-grade distribution is specially such method: by resolving the scatter intensity distribution of scattered light of the laser being irradiated to powder particle, thus measure the diameter of powder particle.The mean particle size of the multiple powder particles comprised in the spinel powder prepared is above-mentioned median size.

In forming process (S20), be formed into body by spinel powder prepared in operation (S10).It is especially by stamping or CIP(CoolIsostaticPressing, and isostatic cool pressing is processed) and be shaped.More particularly, preferably (such as) first by the stamping MgOnAl to preparing in operation (S10) ₂o ₃after powder carries out preliminary shaping, then carry out CIP, thus obtain molding.But herein, only can carry out any one in stamping and CIP, also can both carry out, such as carry out stamping after, then carry out CIP etc.

Herein, in stamping, preferably adopt the pressure of (such as) more than 10MPa below 300MPa, particularly 20MPa, in CIP, preferably adopt the pressure of (such as) more than 160MPa below 250MPa, particularly more than 180MPa below 230MPa.

Sintering circuit (S30) shown in following enforcement Fig. 3.About sintering circuit (S30), specifically, with reference to Fig. 4, it preferably has the operation in the 1st sintering circuit (S31) and the 2nd sintering circuit (S32) this 2 stage.

In the first sintering circuit (S31), in a vacuum and in more than 1500 DEG C and less than 1800 DEG C molding is sintered, to form the sintered compact that density is more than 95%.By sintering in vacuum atmosphere, the liquid phase that the Si element as impurity can be made to generate is evaporated in a vacuum and removes.Consider from this angle, preferred below the 50Pa of vacuum tightness, more preferably below 20Pa.

The condition of the 1st sintering circuit is different according to the amount of Si element and the thickness of sintered compact, when the shortest thickness outside the centre portions of sintered compact to sintered compact is defined as D(mm), and by from 1000 DEG C until arrive heating-up time of top temperature be defined as t minute time, preferably there is following relation:

D＝a×t ^1/2

0.1≤a≤3

By heating up in such scope, when the content of the Si element in spinel powder is below 50ppm, after the 1st sintering circuit terminates, the content of Si element can be reduced to below 20ppm, thus obtain the spinel sintered body of high transmission rate.From the Si constituent content reduced further sintered compact thus the angle improving the transmittance of spinel sintered body consider, the Si constituent content in spinel powder is preferably below 30ppm.When the content of the Si element in spinel powder is more than 50ppm, by extending the heating-up time in the 1st sintering circuit in vacuum atmosphere further, the Si constituent content in sintered compact can be reduced.

In addition, from obtaining the angle consideration that density is the high-density sintered body of more than 95%, the temperature in the 1st sintering circuit preferably more than 1500 DEG C.Consider from the angle of the transmittance improving sintered compact, the density of sintered compact more preferably more than 95%.In this manual, density refers to the relative density calculated according to Archimedes method.On the other hand, from the evaporation of the MgO suppressed vacuum, prevent cooling time Al ₂o ₃consider as Second Phase Precipitation, the angle that maintains high light transmittance, sintering temperature preferably less than 1800 DEG C, more preferably less than 1700 DEG C, preferably less than 1650 DEG C further.

After 1st sintering circuit terminates, in the 2nd sintering circuit (S32), by HIP(HotIsostaticPressing, hot isostatic pressing) etc. more than 1600 DEG C less than 1900 DEG C pressure sintering is carried out to sintered compact.When carrying out HIP at temperature more than 1600 DEG C less than 1900 DEG C, pressure under being about the condition of 100MPa, owing to being facilitated the removal in hole by viscous deformation (Group becomes distortion) and flooding mechanism, therefore, it is possible to densification more, and improve transmittance further.The preferred Ar gas of the gas used in HIP, N ₂the rare gas elementes such as gas, O ₂the mixed gas of gas or these gases, if mixing O ₂during gas, then can prevent the reduction of the light transmission caused by deoxidation.

For the sintered compact carrying out in the above described manner sintering, carry out manufacturing procedure (S40) as shown in Figure 3.Specifically, first by MWS(MultiWireSaw) by (substrate 10) thickness (operation to sintered compact is cut into slices) of above-mentioned sintered compact cutting (machining) one-tenth expectation.Complete the matrix with the substrate 10 expecting thickness thus.It should be noted that, desired thickness is preferably considering that final institute expects the thickness of the substrate 10 of formation and decides on the basis of the polishing that the major surfaces 10a of substrate 10 carries out etc. in subsequent handling.

Next polishing is carried out to the major surfaces of the matrix of aforesaid substrate 10.Specifically, this carries out polishing with the operation making average roughness Ra become the value of expectation to the major surfaces 10a of the substrate 10 of final formation as mentioned above.Particularly described above, preferably polishing is carried out to the major surfaces 10a of the substrate 10 as Substrate for luminous element, to obtain the Ra expected as above.

When in order to realize excellent Flatness polishing is carried out to the major surfaces 10a of substrate 10, preferably carry out the polishing in rough polishing, common polishing and this 3 stage of polishing of utilizing diamond abrasive grain to carry out in order.Specifically, in the rough polishing of first stage and the common polishing of subordinate phase, polishing machine is utilized to carry out mirror finish to major surfaces 10a.Herein, in rough polishing and common polishing, the label for the abrasive particle of polishing is different.Specifically, in rough polishing, preferably use the GC grinding stone that the label of abrasive particle is #800 to #2000, in common polishing, preferably the particle diameter of use abrasive particle is the ciamond grinder of 3 μm to 5 μm.

Next, as the finishing step in the 3rd stage, preferably use above-mentioned diamond abrasive grain to carry out polishing.The hardness of diamond abrasive grain is very high, and the median size of abrasive particle very little (about 0.5 μm to 1.0 μm), therefore, diamond abrasive grain is suitable as high precision minute surface precision work abrasive particle.This abrasive particle is used to carry out (such as) 10 minutes polishings.Can realize the major surfaces 10a that above-mentioned flatness is high thus, namely the average roughness Ra of major surfaces 10a is more than 0.01nm below 3.0nm.

(embodiment 2)

With reference to Fig. 5, the manufacture method of the embodiment 2 of substrate 10 according to the present invention is described.Identical with the high purity spinel preparatory process (S10) shown in Fig. 3 ~ manufacturing procedure (S40) on the manufacture method substrate of this substrate 10, but the content of polishing process in manufacturing procedure (S40) some is different.Specifically, the matrix of the substrate 10 obtained for cutting sintered compact, implements polishing operation as shown in Figure 5.Here the polishing in 4 stages is carried out.Specifically, rough polishing operation (s41), half finishing polish operation (S42), finishing polish operation (S43) and CMP operation (S44) is preferably carried out in order.

With reference to Fig. 5, in the rough polishing operation (S41) in the 1st stage, the major surfaces (surface and bottom surface) of polishing machine (such as double-sided polisher) to substrate is adopted to carry out polishing.As rumbling compound, adopt the GC grinding stone that label (such as) is #800 to #2000.It should be noted that, polished amount is (such as) more than 50 μm less than 200 μm.

Next, half finishing polish operation (S42) is implemented.In this operation (S42), (such as) single-sided polishing device is adopted to carry out polishing to the major surfaces (surface and bottom surface) of substrate respectively.As rumbling compound, the particle diameter of (such as) abrasive particle can be adopted to be the diamond abrasive grain of more than 3 μm less than 5 μm.Polished amount can be (such as) more than 10 μm less than 30 μm.

Following enforcement finishing polish operation (S43).In this operation (S43), (such as) single-sided polishing device is used to carry out polishing to the major surfaces (surface and bottom surface) of substrate respectively.As rumbling compound, the particle diameter of (such as) abrasive particle can be adopted to be the diamond abrasive grain of more than 0.5 μm less than 1 μm.Polished amount can be (such as) more than 3 μm less than 10 μm.Here, the hardness of diamond abrasive grain is very high, and the median size of abrasive particle is very little as mentioned above, is therefore suitable as high precision mirror finish abrasive particle.

Next, CMP operation (S44) is implemented.In this operation (S44), the major surfaces side of (such as) CMP device to substrate is adopted to carry out polishing.As the polishing fluid for polishing, adopt the polishing fluid (inhibit the polishing fluid of chemical rightenning effect) that mechanical polishing effect is enhanced compared with common sapphire polishing fluid.Polishing time can be (such as) more than 10 minutes less than 45 minutes, is more preferably less than 15 minutes less than 40 minutes.

It should be noted that, in above-mentioned CMP operation (S44), have employed the CMP device shown in Fig. 6.With reference to Fig. 6, in CMP device, substrate 10 be clipped in planeform be circular platform 42, be arranged on the polishing pad 43 on platform 42 and be set to the state between the rubbing head 45 relative with polishing pad 43 under, polishing is carried out to this substrate 10.The soft layer 44 that hardness is low compared with the hardness of rubbing head 45 is provided with between rubbing head 45 and substrate 10.Substrate 10 presses to polishing pad 43 across soft layer 44 by rubbing head 45.Platform 42 support by the pillar 41 that is connected with its middle body.In addition, rubbing head 45 also support by the swinging strut 46 that is connected with the middle body of this rubbing head 45.In addition, polishing fluid 48 is supplied from polishing fluid supply unit 47 to polishing pad 43.By adopting the CMP device so formed, the flatness of substrate 10 can be improved.Specifically, such substrate 10 can be obtained: for the major surfaces 10a of substrate 10, when setting the square region of multiple long 5mm × wide 5mm, in described multiple region, for multiple evaluation object region, represent that LTV be the PLTV of the ratio in the evaluation object region of less than 1.0 μm is more than 90%, wherein multiple evaluation object region be eliminate to fall into the part after apart from the region within the scope of major surfaces 10a periphery 3mm.On the major surfaces 10a of this substrate 10, semiconductor layer can easily engage.

(embodiment 3)

With reference to Fig. 7, the embodiment 3 of luminous element according to the present invention is described.

With reference to Fig. 7, luminous element is photodiode, and it has substrate 10, the p-type ohmic contact epitaxial film 16 be bonded on the major surfaces 10a of substrate 10, the p-type coating layer 18 that p-type ohmic contact epitaxial film 16 is formed, the active coating 20 that p-type coating layer 18 is formed, the N-shaped coating layer 22 that active coating 20 is formed, n-type electrode 7 and p-type electrode 8.N-type electrode 7 is formed on N-shaped coating layer 22.As p-type coating layer 18, (such as) p-type (Al can be formed _xga _1-x) _0.5in _0.5p.In addition, as active coating 20, (such as) (Al can be formed _xga _1-x) _0.5in _0.5p.In addition, as N-shaped coating layer 22, (such as) N-shaped (Al can be formed _xga _1-x) _0.5in0.5P.Now, the suitable thickness of N-shaped coating layer 22, active coating 20, p-type coating layer 18 is respectively more than about 0.5 μm less than 3.0 μm, more than 0.5 μm less than 2.0 μm, more than 0.5 μm less than 3.0 μm.

By a part for removing N-shaped coating layer 22, active coating 20 and p-type coating layer 18, form opening portion.In the bottom of this opening portion, expose the upper surface of p-type ohmic contact epitaxial film 16.In the bottom of this opening portion, form the p-type electrode 8 contacted with p-type ohmic contact epitaxial film 16.In addition, the n-type electrode 7 with the surface contact of N-shaped coating layer 22 is formed.

The material of p-type ohmic contact epitaxial film 16 can adopt AlGaAs, AlGaInP or AlAsP, the energy gap of material is large compared with the energy gap of active coating 20, as long as the material (or for the very low material of the specific absorption of this light) of the not light that sends of assimilating activity layer 20.

In addition, the A1 composition of active coating 20 is about 0≤x≤0.45, the A1 composition of N-shaped coating layer 22 is about 0.5≤x≤1, the A1 composition of p-type coating layer 18 is about 0.5≤x≤1.It should be noted that, if x=0, then active coating 20 consist of Ga _0.5in _0.5p, the wavelength X of the light that luminous element sends is 635nm.

It should be noted that, above-mentioned (Al _xga _1-x) _0.5in _0.5the proportion of composing of the compounds such as P is suitable example, and any material and the ratio of III-V race's semiconductor material also go for the present invention.In addition, active coating 20 of the present invention can adopt SH structure, DH structure, Multiple Quantum Well (MQW) structure or quantum well heterojunction structure (QWH) etc. to form arbitrarily.

Next, with reference to Fig. 8 to Figure 10, the manufacture method of the luminous element shown in Fig. 7 is described.

First, as shown in Figure 8, constituent material preparatory process (S100) is implemented.In this constituent material preparatory process (S100), adopt the manufacture method shown in above-mentioned embodiment 2 to prepare Spinel substrate 10 of the present invention.In addition, N-shaped GaAs substrate forms semiconductor layer, thus prepare epitaxial structure, described semiconductor layer contains the active coating 20 of the semiconductor layer that become luminous element.As shown in Figure 9, this epitaxial structure is made up of N-shaped GaAs substrate 26, the etching stopping layer 24 that this N-shaped GaAs substrate 26 is formed, the N-shaped coating layer 22 that etching stopping layer 24 is formed, the active coating 20 that N-shaped coating layer 22 is formed, the p-type coating layer 18 that active coating 20 is formed and the p-type ohmic contact epitaxial film 16 that formed on p-type coating layer 18.Above-mentioned each layer uses epitaxial growth method to be formed respectively.

It should be noted that, as the material of above-mentioned etching stopping layer 24, can adopt any group Ⅲ-Ⅴ compound semiconductor material, GaAs substrate 26 can meet lattice parameter and also can not meet.The etching speed of the material of preferred formation etching stopping layer 24 is very little compared with the etching speed of GaAs substrate 26.Such as, InGaP and AlGaAs is preferably as the material of etching stopping layer 24.

Next, bonding process (S110) is implemented.Specifically, as shown in Figure 9, in epitaxial structure, by the surface irradiation ionic fluid 50 to the face engaged with substrate 10 and p-type ohmic contact epitaxial film 16, this surface active is made.It should be noted that, also can make the substitution ion bundles such as plasma body 50 and this surface contact.

Thereafter, as shown in Figure 10, the surface contact of the major surfaces 10a of substrate 10 and the p-type ohmic contact epitaxial film 16 of epitaxial structure is made.It should be noted that, now the major surfaces 10a of substrate 10 also can bearing strength test, with the surface making the major surfaces 10a of substrate 10 press to p-type ohmic contact epitaxial film 16.Here, substrate 10 of the present invention demonstrates excellent flatness with regard to major surfaces 10a, therefore, it is possible to positively engage as above (normal temperature joint).

It should be noted that, as mentioned above, the surface of p-type ohmic contact epitaxial film 16 is directly engaged to the major surfaces 10a of substrate 10, but also can (such as) by perviousness knitting layer by the faced joint of p-type ohmic contact epitaxial film 16 to the major surfaces 10a of substrate 10.The material of perviousness knitting layer can adopt the arbitrary grafting material such as spin-on glasses (SOG), polyimide or silicone resin.

Next, postprocessing working procedures (S120) is implemented.Specifically, 5H is passed through ₃pO ₄: 3H ₂o ₂: 3H ₂o or 1NH ₄oH:35H ₂o ₂deng etching solution, the N-shaped GaAs substrate of non-permeable is removed.Here, the etching stopping layer 24 formed by (such as) InGaP or AlGaAs etc. still can absorb the light sent from active coating sometimes.Therefore, be necessary to remove etching stopping layer 24 further, and only retain the part of the N-shaped coating layer 22 contacted with n-type electrode 7.Can by any means removing etching stopping layers 24 such as dry-etchings.

In addition, adopt the dry etching methods such as (such as) RIE, part removing N-shaped coating layer 22, active coating 20 and p-type coating layer 18, expose a part for the upper surface of p-type ohmic contact epitaxial film 16.Thereafter, p-type ohmic contact epitaxial film 16 forms p-type electrode 8.In addition, N-shaped coating layer 22 forms n-type electrode 7.Thereby, it is possible to form luminous element as shown in Figure 7, this luminous element is the LED structure that p-type and N-shaped ohmic contact metal layer (p-type electrode 8 and n-type electrode 7) are formed at homonymy.

(embodiment 4)

With reference to Figure 11, the embodiment 4 of luminous element of the present invention is described.

With reference to Figure 11, luminous element is AlGaAs red LED (emission wavelength: 650nm), and it has substrate 10, the p-type coating layer 54 be bonded on the major surfaces 10a of substrate 10, the active coating 53 that p-type coating layer 54 is formed, the N-shaped coating layer 52 that active coating 53 is formed, n-type electrode 7 and p-type electrode 8.N-type electrode 7 is formed on N-shaped coating layer 52.As p-type coating layer 54, (such as) Al can be adopted to consist of about 70 ~ 80% and thickness is the p-type AlGaAs layer of more than 0.5 μm less than 2 μm.In addition, as N-shaped coating layer 52, (such as) Al can be adopted to consist of about 70 ~ 80% and thickness is more than 0.5 μm less than 2 μm N-shaped AlGaAs layers.

By removing a part for N-shaped coating layer 52 and active coating 53, form opening portion.In the bottom of this opening portion, expose the upper surface having p-type coating layer 54.In the bottom of this opening portion, form the p-type electrode 8 contacted with p-type coating layer 54.

Next, be described with reference to the manufacture method of Figure 12 and Figure 13 to the luminous element shown in Figure 11.

The manufacture method of the luminous element shown in Figure 11 is substantially identical with the manufacture method of luminous element shown in Fig. 8.That is, first constituent material preparatory process (S100) is implemented.In this constituent material preparatory process (S100), adopt the manufacture method shown in above-mentioned embodiment 2 to prepare Spinel substrate 10 of the present invention.In addition, N-shaped GaAs substrate forms semiconductor layer, thus prepare epitaxial structure, described semiconductor layer contains the active coating 53 of the semiconductor layer that become luminous element.As shown in figure 12, this epitaxial structure is made up of N-shaped GaAs substrate 26, the N-shaped coating layer 52 that this N-shaped GaAs substrate 26 is formed, the active coating 53 that N-shaped coating layer 52 is formed and the p-type coating layer 54 that formed on active coating 53.Above-mentioned each layer uses epitaxial growth method to be formed respectively.

Next, bonding process (S110) is implemented.Specifically, as shown in figure 12, in epitaxial structure, by the surface irradiation ionic fluid 50 to the face engaged with substrate 10 and p-type coating layer 54, this surface active is made.It should be noted that, also can make the substitution ion bundles such as plasma body 50 and this surface contact.

Thereafter, as shown in figure 13, the surface contact of the major surfaces 10a of substrate 10 and the p-type coating layer 54 of epitaxial structure is made.It should be noted that, now the major surfaces 10a of substrate 10 also can bearing strength test, with the surface making the major surfaces 10a of substrate 10 press to p-type coating layer 54.Here, the major surfaces 10a of substrate 10 of the present invention demonstrates excellent flatness, therefore, it is possible to positively engage as above.

It should be noted that, as mentioned above, the surface of p-type coating layer 54 is directly engaged to the major surfaces 10a of substrate 10, but also can (such as) by perviousness knitting layer by the faced joint of p-type coating layer 54 to the major surfaces 10a of substrate 10.The material of perviousness bonding coat can adopt arbitrary grafting material such as spin-on glasses (SOG), polyimide or silicone resin etc. as illustrated in embodiment 3.

Next, postprocessing working procedures (S120) is implemented.Specifically, NH is passed through ₄oH:H ₂o ₂the N-shaped GaAs substrate of non-permeable removes by the etching solution of=1.7:1 etc.In addition, the dry etching methods such as application (such as) RIE, part removing N-shaped coating layer 52 and active coating 53, expose a part for the upper surface of p-type coating layer 54.Thereafter, p-type coating layer 54 forms p-type electrode 8.In addition, N-shaped coating layer 52 forms n-type electrode 7.Thereby, it is possible to form luminous element as shown in figure 11, this luminous element is the LED structure that p-type and N-shaped ohmic contact metal layer (p-type electrode 8 and n-type electrode 7) are formed at homonymy.

(experimental example 1)

In order to confirm effect of the present invention, carry out following experiment.

(sample)

Prepare the Spinel substrate that 4 diameters are 4 inches, thickness is 0.25mm.

In addition, for polishing process, 4 phase polish be described in the embodiment 2 of the invention described above are carried out.It should be noted that, for rough polishing operation (S41), half finishing polish operation (S42), finishing polish operation (S43), 4 substrates are common processing conditions.

In 4 substrates, for No. 1 sample and No. 2 samples, in CMP operation (S44), to add the state of soft layer in the platform side of CMP device to implement CMP operation.In addition, in the sample of 4 substrates, for No. 3 samples and No. 4 samples, in CMP operation, add soft layer in the polishing pad side of CMP device.

(experiment content)

For as mentioned above and the substrate (maintenance substrate) prepared carries out the evaluation of surface accuracy.In addition, the wafer normal temperature be made up of the material being in fact different from spinel is engaged to the major surfaces of the maintenance substrate be made up of spinel, by visual, engagement state is evaluated.For ease of evaluating engagement state, described wafer (joint wafer) employs light transmissive material.Specifically, as the translucent material forming joint wafer, LiTaO is employed herein ₃.

The evaluation of surface accuracy:

For the major surfaces keeping substrate, adopt planeness to measure resolver and measure PLTV.It should be noted that, as PLTV, have employed following numerical value.Namely, for the major surfaces keeping substrate, set the square region of multiple long 5mm × wide 5mm, in the plurality of region, assuming that multiple evaluation object region (site), the plurality of evaluation object region is eliminate to fall into the part after apart from the region within the scope of the 3mm of major surfaces periphery.For described evaluation object region, by LTV(LocalThicknessVariation) be the ratio set in the evaluation object region of less than 1.0 μm be PLTV.Site can be arranged in the mode parallel with planar orientation.LTV can be expressed as the difference of maximum value in a site and minimum value, and this site has the height keeping the bottom surface of substrate as benchmark.

In data parsing, when the central point in the square region (site) of set long 5mm × wide 5mm is comprised in the scope of the periphery 3mm of distance major surfaces, it is got rid of from evaluation object, if this central point is in inner side compared with the scope of the periphery 3mm of distance major surfaces, then adopt it as evaluation object.

In addition, substrate is kept for each, adopt planeness to measure resolver and measure its sinuousness.Wherein, to only fixing maintenance measures apart from the height of reference plane during the central point of substrate bottom surface, the maximum value of this height is set to bending angle value.

The evaluation of engagement state:

After carrying out the evaluation of surface accuracy, be 4 inches by diameter, thickness is the major surfaces that the light transmission joint wafer normal temperature of 0.5mm is engaged to each substrate.Specifically, by the surface irradiation argon ion to joint wafer, by the surface active of this joint wafer, afterwards, by the major surfaces of the maintenance of being made up of spinel substrate being pressed to the described surface of joint wafer to carry out normal temperature joint.Then, for the maintenance substrate after joint, by visual, confirm the part of the part that engagement state is good and the bad joint of generation.Specifically, engaging bad part for occurring, owing to forming space between the described surface at joint wafer and the maintenance substrate be made up of spinel, turning white compared with therefore good with engagement state part, thus confirming this color change portion by visual.

(result)

Measurement result is as shown in Figure 14 to Figure 26.Figure 14 to Figure 16 is the result of No. 1 sample, and Figure 17 to Figure 19 is the result of No. 2 samples, and Figure 20 to Figure 22 is the result of No. 3 samples, and Figure 23 to Figure 25 is the result of No. 4 samples.Figure 14, Figure 17, Figure 20, Figure 23 are the mode chart illustrating that each keeps the concavo-convex state in board main in three dimensions.In addition, at Figure 15, Figure 18, Figure 21, Tu24Zhong, keep the foursquare region of multiple 5mm set in board main for each, white represents that LTV is the region of less than 1.0 μm, and black represents the region of LTV more than 1.0 μm.In addition, Figure 16, Figure 19, Figure 22, Figure 25 show the outward appearance of the substrate (bonded substrate) after joint.

About No. 1 sample, with reference to Figure 14 to Figure 16, eliminate distance and keep the PLTV of the scope of the periphery 3mm of substrate to be 72%, sinuousness is 78 μm.In addition, as seen by the Figure 16 of the engagement state showing joint wafer, in the major surfaces keeping substrate, the ratio demonstrating the good part of engagement state is 80%.

About No. 2 samples, with reference to Figure 17 to Figure 19, eliminate distance and keep the PLTV of the scope of the periphery 3mm of substrate to be 66%, sinuousness is 66 μm.In addition, as seen by the Figure 19 of the engagement state showing joint wafer, in the major surfaces keeping substrate, the ratio demonstrating the good part of engagement state is 70%.

About No. 3 samples, with reference to Figure 20 to Figure 22, eliminate distance and keep the PLTV of the scope of the periphery 3mm of substrate to be 92%, sinuousness is 91 μm.In addition, as seen by the Figure 22 of the engagement state showing joint wafer, in the major surfaces keeping substrate, the ratio demonstrating the good part of engagement state is 98%.

About No. 4 samples, with reference to Figure 23 to Figure 25, eliminate distance and keep the PLTV of the scope of the periphery 3mm of substrate to be 95%, sinuousness is 96 μm.In addition, as seen by the Figure 25 of the engagement state showing joint wafer, in the major surfaces keeping substrate, the ratio demonstrating the good part of engagement state is 98%.

(experimental example 2)

About above-mentioned 1 to No. 4 sample, after joint is engaged with wafer, this bonded substrate is cut into slices, for the sample obtained of cutting into slices, studies the engaging force between maintenance substrate and joint wafer be made up of spinel.

(sample)

Prepare the bonded substrate of the maintenance substrate that have employed 1 to No. 4 sample formed in above-mentioned experimental example 1.

(experiment content)

4 bonded substrates prepared are cut into slices, is cut into the square sample of multiple 10mm × 10mm.Then, from often opening the square sample taking out 10 10mm × 10mm bonded substrate respectively, by two faced joint to stationary installation, the maintenance substrate made by spinel with tension test machine and joint wafer are peeled off along the direction of 180 °, thus measure tensile strength.

(result)

For the sample of the maintenance substrate of employing No. 1 sample and No. 2 samples, its average tensile strength is 5MPa.On the other hand, for the sample of the maintenance substrate of employing No. 3 samples and No. 4 samples, its average tensile strength is 12MPa.Learn thus, particularly when PLTV is more than 90%, the engaging force (tensile strength) between the substrate engaged becomes very large.

Should be understood that, the embodiment disclosed in this is all illustrative, and not restrictive in all fields.Scope of the present invention is not by above-mentioned embodiment, but is illustrated by claimed scope, is intended to comprise all changes be in claimed scope in same meaning and scope.

Industrial applicibility

The present invention is as manufacturing the alternative technology with the luminous element of the luminous element of sapphire substrate in practical more at an easy rate, excellent especially.

Nomenclature

1 buffer layer; 2n type GaN layer; 3n type AlGaN layer; 4 Multiple Quantum Well; 5p type AlGaN layer; 6p type GaN layer; 7n type electrode; 8p type electrode; 10 substrates; 10a major surfaces; 16p type ohmic contact epitaxial film; 18,54p type coating layer; 20,53 active coatings; 22,52n type coating layer; 24 etching stopping layers; 26n type GaAs substrate; 30 luminous elements; 40CMP device; 41 pillars; 42 platforms; 43 polishing pads; 44 soft layers; 45 rubbing heads; 46 swinging struts; 47 polishing fluid supply units; 48 polishing fluids; 50 ionic fluids.

Claims

1. a manufacture method for luminous element, has:

Prepare Spinel substrate (10), on N-shaped GaAs substrate, form semiconductor layer in addition thus the constituent material preparatory process (S100) of preparation epitaxial structure;

In epitaxial structure, make the surface active in the face engaged with substrate (10), and make the major surfaces of substrate (10) (10a) with this surface contact thus the bonding process directly engaged (S110); And

By the postprocessing working procedures (S120) that the N-shaped GaAs substrate of non-permeable removes,

Described luminous element has substrate (10) and semiconductor layer (1 ~ 6), and described substrate (10) is made up of spinel, have major surfaces (10a),

Described semiconductor layer (1 ~ 6) does not use grafting material and directly to join the major surfaces (10a) of the side of this substrate (10) to upper and comprise luminescent layer (4),

For described major surfaces (10a), when setting the square region of multiple long 5mm × wide 5mm, in described multiple region, for multiple evaluation object region, expression LTV is the PLTV of the ratio in the described evaluation object region of less than 1.0 μm is more than 90%, wherein said multiple evaluation object region falls into the part after apart from the described region within the scope of described major surfaces (10a) periphery 3mm for eliminating, wherein LTV refers to local thickness's deviation, and PTLV refers to local thickness's deviation ratio.

2. the manufacture method of luminous element according to claim 1, wherein, the sintered compact of described spinel consist of MgOnAl ₂o ₃, wherein 1.05≤n≤1.30, and the content of Si element is below 20ppm.

3. the manufacture method of luminous element according to claim 2, wherein, described sintered compact is when thickness is 1mm, and wavelength is more than 350nm and the straight line transmittance of the light of below 450nm is more than 80%.

4. the manufacture method of luminous element according to claim 1, wherein, described substrate (10) is the luminous element (30) be made up of spinel substrate (10), described spinel consist of MgOnAl ₂o ₃, wherein 1.05≤n≤the 1.30 and content of Si element is below 20ppm, this substrate is manufactured by following manufacture method,

The manufacture method of described substrate has:

Be formed into the operation (S20) of body, described molding is below 50ppm by Si constituent content and the spinel powder that purity is more than 99.5 quality % is formed;

1st sintering circuit (S31), wherein, in a vacuum in more than 1500 DEG C and less than 1800 DEG C described molding is sintered, thus formed density be the sintered compact of more than 95%; And

2nd sintering circuit (S32), wherein, more than 1600 DEG C and less than 1900 DEG C pressure sintering is carried out to described sintered compact.

5. the manufacture method of luminous element according to claim 4, wherein, the Si constituent content of the described sintered compact formed by described 1st sintering circuit (S31) is below 20ppm.

6. the manufacture method of luminous element according to claim 4, wherein, described 1st sintering circuit (S31) is carried out under the pressure of below 50Pa,

When the shortest thickness outside the centre portions of described sintered compact to described sintered compact is defined as D, the unit of this shortest thickness D is mm, and by from 1000 DEG C until arrive heating-up time of top temperature be defined as t minute time, there is following relation:

D＝a×t ^1/2，

0.1≤a≤3。

7. the manufacture method of luminous element according to claim 4, the manufacture method of described substrate (10) also has:

After described 2nd sintering circuit (S32), to the operation that described sintered compact is cut into slices, and

Chemical mechanical polishing method is adopted the surface of the substrate obtained by above-mentioned slicing process to be carried out to the operation (S44) of polishing,

In described polishing process (S44), under the state that described substrate (10) is clipped between polishing pad (43) and rubbing head (45), polishing is carried out to described substrate (10), wherein said polishing pad (43) is arranged on platform (42), and described rubbing head (45) is set to relative with described polishing pad (43), in addition

Between described rubbing head (45) and described substrate (10), arrange soft layer (44), described in the hardness ratio of this soft layer (44), the hardness of rubbing head (45) is low.